Biochemistry And Physiology

Front 1

What are the predominant linkages in glycogen between glucose units?
- Alpha 1, 4
- Alpha 1, 6
- Beta 1, 3
- Beta 1, 4
- Beta 1, 6

Back 1

Alpha 1, 4

Front 2

Which of the following describes the movement of glycine molecules in an electric field at a pH of 6.06 (the isoelectric pH for glycine)? The glycine molecule will:
- not move
- move to the anode
- move to the cathode
- move to both anode and cathode

Back 2

not move

Front 3

Zine is an essential component of which of the following?
- Pepsin
- Amylase
- Hexokinase
- Adenylate cyclase
- Carbonic anhydrase

Back 3

Carbonic anhydrase

Front 4

Facilitated diffusion differs from active transport in that net transport by facilitated diffusion:
- has a transport maximum
- uses ATP as an energy source
- requires a concentration gradient
- occurs as an endergonic process

Back 4

requires a concentration gradient

Front 5

Each of the following statements regarding aldosterone is correct except one. Which one is this exception?
- Is a mineralocorticoid
- Increases Na+ uptake from the kidneys
- Production is stimulated by angiotensin II
- Is produced in the zona fasciculata of the adrenal cortex

Back 5

Is produced in the zona fasciculata of the adrenal cortex

Front 6

The sensory receptors serving the stretch reflex are classified as:
- nociceptors
- chemoreceptors
- proprioceptors
- exteroceptors

Back 6

proprioceptors

Front 7

Which of the following base pairs promotes helix stabilization in DNA but does not do so in RNA?
- G:C
- A:T
- G:U
- C:T
- A:U

Back 7

A:T

Front 8

If the anticodon of transfer-RNA is 5' ACG 3', then which of the following is its corresponding codon on messenger-RNA?
- 5' CGT 3'
- 5' CGU 3'
- 5' TGC 3'
- 5' UAG 3'
- 5' UGC 3'

Back 8

5' CGU 3'

Front 9

Before swallowing can be initiated, afferent information must be received:
- from muscle spindles, indicating the consistency of a soft bolus of food
- in a lesser amount from nociceptors, indicating a soft bolus of food
- from mucosal mechanoreceptors, indicating the consistency of a soft bolus of food
- from pharyngeal taste receptors, indicating the consistency of a soft bolus of food

Back 9

from mucosal mechanoreceptors, indicating the consistency of a soft bolus of food

Front 10

Coupled respiration requires each of the following except one. Which one is this exception?
- ADP
- Oxygen
- Carbon dioxide
- Electron donor
- Inorganic phosphate

Back 10

Carbon dioxide

Front 11

Which of the following is produced when a mutation occurs in an enzyme controlling a signal pathway involved in cell growth processes?
- Epigene
- Antigene
- Oncogene
- Monogene
- Transgene

Back 11

Oncogene

Front 12

DNA that is complementary to mRNA can be made using which of the following?
- A plasmid
- DNA ligase
- A retrovirus
- RNA polymerase
- Reverse transcriptase

Back 12

Reverse transcriptase

Front 13

Which of the following statements best applies to saliva?
- Phosphate is the main pH buffer
- Supplies sialate for additional mucins
- Main source of enzymes for protein digestion
- Supplies calcium and phosphate for remineralization
- Undersaturated with respect to hydroxyapatite at neutral pH

Back 13

Supplies calcium and phosphate for remineralization

Front 14

Smooth muscle contains each of the following muscle proteins except one. Which one is this exception?
- Actin
- Myosin
- Troponin
- Tropomyosin

Back 14

Troponin

Front 15

As blood flows through the periodontal membrane, tremendous pressures occur in response to forceful occlusion. Blood flow is temporarily reduced, but platelets do not aggregate because of the presence of:
- Ca2+
- ADP
- thrombin
- thromboxane A2
- prostacyclin (PgI2)

Back 15

prostacyclin (PgI2)

Front 16

Which of the following substances is the predominant source of ATP at moderate levels (for greater than 60 minutes) of activity?
- Amino acids
- Fatty acids
- Carbohydrates
- Proteins

Back 16

Fatty acids

Front 17

Which of the following promotes the release of bile from the gallbladder?
- Gastrin
- Secretin
- Galla
- Bombesin
- Cholecystokinin

Back 17

Cholecystokinin

Front 18

Which of the following would produce the greatest decrease in resistance in a single artery 2 mm long and with a radius of 1.2 mm?
- A halving in length
- A doubling in length
- An increase in radius by a factor of 2
- A decrease in blood viscosity by a factor of 2

Back 18

An increase in radius by a factor of 2

Front 19

The cell membrane is least permeable to which of the following substances?
- O2
- CO2
- H2O
- Sodium
- Ethanol

Back 19

Sodium

Front 20

In the contractile cycle, the dissociation of the actomyosin complex results most immediately from:
- ATP hydrolysis
- release of ATP hydrolysis products
- ATP replacing ADP on the myosin heads
- tiltin of the myosin heads (brossbridges)

Back 20

ATP replacing ADP on the myosin heads

Front 21

Which of the following represents the consequence of the fact that DNA strands are complementary?
- Hairpin loop structures can be generated
- They will always have identical sequences
- Separated strands are able to reassociate
- They cannot get back together once separated

Back 21

Separated strands are able to reassociate

Front 22

Which of the following is most likely to promote depolymerization of extracellular matrix?
- Cortisone
- Collagenase
- Chymotrypsin
- Hyaluronidase

Back 22

Hyaluronidase

Front 23

A substance alters the rate of an enzymatic reaction by binding to the enzyme at a site other than the active site. The substance described is a(an):
- uncoupler
- covalent modifier
- allosteric inhibitor
- competitive inhibitor
- post translational modifier

Back 23

allosteric inhibitor

Front 24

During which of the following would blood flow to the coronary arteries be greatest in a resting individual?
- Isovolumetric contraction
- Ventricular ejection
- Atrial contraction
- Ventricular relaxation

Back 24

Ventricular relaxation

Front 25

Atropine prevents the secretion of saliva resulting from stimulation of the chorda tympani because it:
- denatures the salivary gland proteins
- prevents the action of acetylcholine on the secreting cells
- prevents release of acetylcholine by sympathetic postganglionic fibers
- prevents release of acetylcholine in autonomic ganglia

Back 25

prevents the action of acetylcholine on the secreting cells

Front 26

Which of the following best describes the primary ionic movement during the depolarization phase of a nerve action potential?
- Potassium ions moving from inside to outside the membrane
- Potassium ions moving into the fiber from interstitial fluid
- Large organic negative ions moving from inside the fiber to outside the fiber
- Sodium ions moving from inside the membrane to outside the membrane
- Sodium ions moving from outside the membrane to inside the membrane

Back 26

Sodium ions moving from outside the membrane to inside the membrane

Front 27

A mature ovum is expelled from which of the following?
- Corpus luteum
- Corpus albicans
- Graafian follicles
- Corpus hemorrhagicum

Back 27

Graafian follicles

Front 28

Which of the following statements best describes hydroxyapatite in enamel?
- Has a nonpolar surface
- Has 10 ions in each unit cell
- Contains no ion substitutions
- Has a higher solubility than fluorapatite
- Has a solubility that decreases as the pH decreases

Back 28

Has a higher solubility than fluorapatite

Front 29

Prior to surgery, an anxious patient has a higher systolic blood pressure than previously noted. Which of the following represents the most likely reason?
- Cardiac shock
- Anaphylactic shock
- Atrial fibrilation
- Ventricular fibrilation
- Decreased arterial compliance

Back 29

Decreased arterial compliance

Front 30

Glucose can be made from each of the following substances except one. Which one is this exception?
- Lactate
- Acetyl CoA
- Glycerol
- Pyruvate
- Fructose

Back 30

Acetyl CoA

Front 31

Increased pulmonary ventilation observed at high altitudes results directly from the effect of hypoxia of the:
- carotid body
- aortic sinus
- hypothalamus
- carotid sinus
- respiratory center

Back 31

carotid body

Front 32

Juxtamedullar and cortical nephrons differ primarily in:
- filtration fraction
- location of macula densa
- length of proximal tubule
- length of distal convoluted tubule
- length of the thin segment of the loop of Henle

Back 32

length of the thin segment of the loop of Henle

Front 33

Which of the following is an allosteric effector of an enzymatic reaction?
- Competitive inhibitor
- Noncompetitive inhibitor
- Substance that binds to the substrate
- Substance affecting enzymatic activity by binding to the active site
- Substance affecting enzymatic activity by binding to non active sites

Back 33

Substance affecting enzymatic activity by binding to non active sites

Front 34

Hormones tha texert their effects through the activation of second messengers are:
- lipophilic
- usually water soluble peptide/protein hormones
- initially bound to cytoplasmic hormone receptors
- secreted by ovaries, testes, adrenal cortex, and placenta

Back 34

usually water soluble peptide/protein hormones

Front 35

Each of the following coenzymes is a component of the pyruvate dehydrogenase complex except one. Which one is this exception?
- NAD
- Biotin
- Coenzyme A
- Thiamine pyrophosphate

Back 35

Biotin

Front 36

Which of the following enzymes seals nicks in DNA?
- Exonuclease
- Endonuclease
- Ligase
- DNA polymerase
- RNA polymerase

Back 36

Ligase

Front 37

Which of the following is the pathway that results in the formation of glucose in the liver from lactate produced in muscle?
- Cori cycle
- Glycolysis
- Citric acid cyctle
- Pentose phosphate pathway

Back 37

Cori cycle

Front 38

Glucose reabsorption in the nephron is usually completed in which of the following?
- Distal tubule
- Loop of Henle
- Collecting duct
- Proximal tubule

Back 38

Proximal tubule

Front 39

Which of the following directly catalyzes urea formation in a cell?
- Urease
- Uricase
- Arginase
- Glutaminase

Back 39

Arginase

Front 40

A practicioner administers a 90:10 nitrous oxide-oxygen mixture to a patient, causing respiratory depression. Which of the following conditions is likely to result?
- Metabolic acidosis
- Respiratory acidosis
- Metabolic alkalosis
- Respiratory alkalosis

Back 40

Respiratory acidosis

Front 41

Rifampin (Rifadin) is effective in treating active tuberculosis because it targers which of the following pathways?
- Mitosis
- Replication
- Translation
- Transcription
- mRNA splicing

Back 41

Transcription

Front 42

Internal temperature is monitored by central thermoreceptors located in the:
- medulla
- cerebellum
- hypothalamus
- anterior pituitary
- posterior pituitary

Back 42

hypothalamus

Front 43

Tissue swelling associated with inflammation is due to which of the following factors?
- Vasodilating kinins
- Increased blood pressure
- Increased serum osmolarity
- Decreased capillary permeability

Back 43

Vasodilating kinins

Front 44

Each of the following is a common manifestation of an asthmatic attack except one. Which one is this exception?
- Airway edema
- Bronchospasm
- Decreased surfactant
- Increased mucous secretion
- Increased airway resistance

Back 44

Decreased surfactant

Front 45

Treatment of respiratory symptoms from asthma requires activation of which of the following pathways?
- Cholinergic nicotinic
- Cholinergic muscarinic
- Adrenergic Alpha 1
- Adrenergic Beta 1
- Adrenergic Beta 2

Back 45

Adrenergic Beta 2

Front 46

The immediate consequences of an acute asthmatic attack include each of the following except one. Which one is this exception?
- Hypoxia
- Tachycardia
- Hypercapnia
- Acute respiratory acidosis
- Increased renal bicarbonate production

Back 46

Increased renal bicarbonate production

Front 47

For which of the following reasons would glucagon be used?
- Acts as a source of glucose for the hypoglycemic patient
- Promotes glycogen formation in the hyperglycemic patient
- Promotes glycogenolysis in the hypoglycemic patient
- Stimulates secretion of insulin in the hyperglycemic patient

Back 47

Promotes glycogenolysis in the hypoglycemic patient

Front 48

Each of the following is a clinical manifestation of hypoglycemia except one. Which one is this exception?
- Coma
- Dizziness
- Confusion
- Convulsion
- Hyperventilation

Back 48

Hyperventilation

Front 49

Which of the following glucose transporters is responsible for a type I diabetic's "insulin reaction?"
- GLUT 1
- GLUT 2
- GLUT 3
- GLUT 4
- GLUT 5

Back 49

GLUT 4

Front 50

Sudden onset of a seizure in a patient with poorly controlled type 1 diabetes would most likely be due to which of the following?
- Hypoxia
- Ketoacidosis
- Hyponatremia
- Hypoglycemia
- Hyperglycemia

Back 50

Hypoglycemia

Front 51

Vasodepressor syncope might be associated with each of the following circumstances except one. Which one is this exception?
- Pallor
- Diaphoresis
- Decreased heart rate
- Decreased cerebral blood flow
- Increased systemic blood pressure

Back 51

Increased systemic blood pressure

Front 52

Which of the following pairs of amino acids is expected to be found on the interior of a globular protein?
- Lysine and arginine
- Arginine and leucine
- Leucine and valine
- Valine and glutamic acid
- Glutamic acid and lysine

Back 52

Leucine and valine

Front 53

An anemic individual is expected to have which of the following conditions in systemic arterial blood?
- Elevated oxygen tension, Normal oxygen content
- Elevated oxygen tension, Reduced oxygen content
- Reduced oxygen tension, Normal oxygen content
- Normal oxygen tension, Reduced oxygen content
- Reduced oxygen tension, Reduced oxygen content

Back 53

Normal oxygen tension, Reduced oxygen content

Front 54

Protein and RNA synthesis occur in each of the following phases of the cell cycle except one. Which one is this exception?
- G0
- G1
- S
- G2
- M

Back 54

M

Front 55

The main route of calcium excretion from a normal human adult is:
- urine
- sweat
- saliva
- feces
- tears

Back 55

feces

Front 56

Which of the following is a ketone body?
- Glycerol
- Glucagon
- Acetyl CoA
- Acetoacetate
- Phosphatidylcholine

Back 56

Acetoacetate

Front 57

Which of the following coenzymes is required for the synthesis of pyrimidines such as thymine?
- Niacin
- Thiamine
- Folic acid
- Riboflavin
- Pyridoxine

Back 57

Folic acid

Front 58

Vitamin C deficiency primarily affects which of the following tissues?
- Hematopoietic
- Connective
- Epithelial
- Muscular
- Nervous

Back 58

Connective

Front 59

Each of the following is expected to be active during fatty acid biosynthesis except one. Which one is this exception?
- Tricarboxylic acid cycle
- Pyruvate dehydrogenase
- Amino acid catabolism
- Beta oxidation
- Glycolysis

Back 59

Beta oxidation

Front 60

Which of the following best describes the major function of histones?
- Unwind DNA
- Activate genes
- Stabilize DNA in a compact form
- Remove exons during RNA splicing
- Stabilize RNA during transcription

Back 60

Stabilize DNA in a compact form

Front 61

Under physiologic conditions, the lowest partial pressure of oxygen is found in:
- expired air
- alveolar air
- venous blood
- arterial blood
- normal atmospheric air

Back 61

venous blood

Front 62

The first step in the pathway for fatty acid synthesis is catalyzed by an allosteric enzyme which is the principal regulator of the pathway. This enzyme is:
- thiolase
- pyruvate carboxylase
- citrate synthetase
- acetyl CoA carboxylase
- pyruvate dehydrogenase

Back 62

acetyl CoA carboxylase

Front 63

Glucose-6-[hosphatase is found associated with which of the following?
- Kidneys and liver
- Liver and muscles
- Kidneys and brain
- Kidneys and muscles

Back 63

Kidneys and liver

Front 64

The catabolism of which of the following results in no energy production in the form of ATP?
- Lipid
- Protein
- Nucleotide
- Carbohydrate

Back 64

Nucleotide

Front 65

Which of the following best describes restriction enzymes?
- Exonucleases
- Topoisomerases
- Enzymes that degrade RNA
- Non specific endonucleases
- Site specific endonucleases

Back 65

Site specific endonucleases

Front 66

Which of the following types of blotting can be used to identify DNA restriction fragments?
- Eastern
- Southern
- Northern
- Western

Back 66

Southern

Front 67

The unique amino acid composition of collagen is reflected in the high content of:
- valine, threonine, and lysin
- desmosine, glycine, and proline
- cysteine, tyrosine, and phenylalanine
- glycine, proline, and hydroxyproline
- cysteine, hydroxylysine, and proline

Back 67

glycine, proline, and hydroxyproline

Front 68

Which of the following vitamins is essential for the normal elaboration and maintenance of bone matrux, cartilage, and dentin?
- Niacin
- Vitamin E
- Ascorbic acid
- Pantothenic acid

Back 68

Ascorbic acid

Front 69

Calcium stimulates muscle contraction. Its effect is mediated through binding to which of the following?
- Actin
- Tropomyosin
- Troponin I
- Troponin C
- Sarcoplasmic reticulum

Back 69

Troponin C

Front 70

Bile salts are sodium salts of bile acid that are conjugated with:
- cysteine and serine
- taurine and glycine
- methionine and lysin
- hemocysteine and ornithine

Back 70

taurine and glycine

Front 71

Which of the following statements best describes the strength of cardiac muscle contraction? It is:
- decreased when extracellular Ca2+ is increased
- increased when extracellular Ca2+ is increased
- mainly regulated by vagal impulses
- unaffected by extracellular Ca2+
- mainly regulated by heart rate

Back 71

increased when extracellular Ca2+ is increased

Front 72

Which of the following mechanisms operates in liver cells to regulate breakdown of glycogen?
- Zymogen activation
- Phophorylation of phosphorylase b to phosphorylase a
- Induction of phosphorylase b by an inducer
- Inhibition of adenylate cyclase

Back 72

Phosphorylation of phosphorylase b to phosphorylase a

Front 73

Which main product of protein nitrogen metabolism is found in human urine?
- Urea
- Ammonia
- Creatine
- Uric acid
- Creatinine

Back 73

Urea

Front 74

Stimulation of the posterior hypothalamus by a reduction in core temperature will produce which of the following?
- Panting
- Sweating
- Vomiting
- Shovering
- Vasodilation

Back 74

Shivering

Front 75

Which of the following compounds is a precursor of the pigments of the skin, hair, and eyes?
- Tyrosine
- Cysteine
- Lysine
- Creatine
- Galactosamine

Back 75

Tyrosine

Front 76

Which of the following organs secretes insulin-like growth factor 1 (IGF-1), and what stimulates this secretion?
- Anterior pituitary, increasing IGF RH in the blood
- Anterior pituitary, increasing GRH in the blood
- Kidney, increasing growth hormone in the blood
- Liver, increasing growth hormone in the blood
- Liver, increasing TSH in the blood

Back 76

Liver, increasing growth hormone is the blood

Front 77

Which of the following enzymes synthesizes polynucleotide chains from nucleotides and does not require a primer chain?
- Ligase
- Exonuclease
- Endonuclease
- DNA polymerase
- RNA polymerase

Back 77

RNA polymerase

Front 78

Which of the following describes a mjor effect of sickle cell anemia?
- Absence of biphosphoglycerate binding of hemoglobin
- Substitution of 2 proximal histidines
- Decreased solubility of the deoxy form of hemoglobin
- A P50 value for hemoglobin similar to that of myoglobin
- Decreased number of subunits in hemoglobin

Back 78

Decreeased solubility of the deoxy form of hemoglobin

Front 79

Which of the following hormones exerts the least effect on calcium metabolism of bone tissue?
- Androgen
- Estrogen
- Norepinephrine
- Thyroid hormone
- Parathyroid hormone

Back 79

Norepinephrine

Front 80

Tooth erosion in bulimic patients is due to:
- hyposalivation
- hypersalivation
- action of pepsin
- excessive fluoride intake
- solubility of hydroxyapatite in acid

Back 80

solubility of hydroxyapatite in acid

Front 81

Which of the following represents normal glucose clearance?
- 0 mg/min
- 44 mg/min
- 125 mg/min
- 600 mg/min

Back 81

0 mg/min

Front 82

A patient bites down rapidly on an unexpected hard surface while chewing. Cessation of motor unit recruitment in jaw closing muscles is caused by stimulation of:
- muscle spindles
- mucosal mechanoreceptors
- periodontal mechanoreceptors
- nociceptors in the dental pulp

Back 82

periodontal mechanoreceptors

Front 83

Active transport systems generally involve specific binding molecules that are classified as a:
- lipid
- protein
- lipoprotein
- carbohydrate
- phospholipid

Back 83

protein

Front 84

Which of the following provides the immediate energy source for the transport of glucose into intestinal epithelial cells?
- NADH
- NADPH
- Na+ gradient across the luminal membrane
- H+ gradient across the luminal membrane

Back 84

Na+ gradient across the luminal membrane

Front 85

An action potential initiated at the midpoint along the length of an axon will:
- not propagate
- propagate towards the soma
- propagate towards the nerve ending
- propagate towards both the soma and the nerve ending

Back 85

propagate towards both the soma and the nerve ending

Front 86

Which of the following explains why an increased filling of the ventricle during diastole causes a more forceful heart beat? The increased ventricular volume:
- diminishes the refractory period of the ventricle
- increases end diastolic fiber length
- facilitates conduction in the heart
- produces a less than optimal load

Back 86

increases end diastolic fiber length

Front 87

The biologically active conformation of trimeric G-proteins requires:
- the alpha subunit to bind GDP
- the alpha subunit to bind GTP
- the hydrolysis of BetaGamma subunits
- the alpha subunit to phosphorylate downstream targets

Back 87

the alpha subunit to bind GTP

Front 88

The kidney dialysis machine is an example of which of the following mechanical systems?
- Sorting
- Cotransport
- Countercurrent
- Active transport

Back 88

Countercurrent

Front 89

Each of the following statements correctly describes similar characteristics of the chemical senses of taste and smell except one. Which one is this exception?
- Receptor cells are replaced regularly
- There are primary classes of taste and odor
- Receptors are located on cilia or microvilli at the apical ends of cells
- Receptors initiate action potentials directly to respective cranial nerve sensory fibers
- Molecules must be dissolved in saliva or mucus to interact with receptor membrane proteins

Back 89

Receptors initiate action potentials directly to respective cranial nerve sensory fibers

Front 90

Ingestion of which of the following most markedly decreases gastric emptying?
- Fats
- Water
- Minerals
- Proteins
- Carbohydrates

Back 90

Fats

Front 91

A dietary iodine deficiency will increase the secretion of which of the following?
- Thyroxine
- Thyroglobulin
- Triiodothyronine
- Thyroid stimulating hormone

Back 91

Thyroglobulin

Front 92

Which of the following will most likely be increased in a patient with hyperparathyroidism?
- Intestinal calcium absorption
- Intestinal organic phosphate absorption
- Renal calcitriol production
- Renal calcium excretion
- Renal organic phosphate excretion

Back 92

Renal calcium excretion

Front 93

A patient with hyperparathyroidism will most likely be predisposed to which of the following?
- Muscle spasm
- Reduced serum Ca2+ levels
- Increased osteoblastic activity
- Increased likelihood of bone fracture

Back 93

Increased likelihood of bone fracture

Front 94

If a patient's leukemia contributed to increased intraoral bleeding, the the increase is most likely due to which of the following conditions?
- Anomia
- Leukopenia
- Ca2+ deficiency
- Thrombocytopenia
- Factor VIII deficiency

Back 94

Thrombocytopenia

Front 95

A patient's cardiovascular disease has resulted in chronic atrial fibrilation. Her physician has prescribed warfarin (Coumadin) most likely to prevent:
- stroke
- hypertension
- atherosclerosis
- sudden cardiac death
- left ventricular hypertrophy

Back 95

stroke

Front 96

The bone resorption seen in elderly patients with low dietary calcium is enhanced by which of the following hormones?
- Insulin
- Estrogen
- Aldosterone
- Thyroid stimulating hormone
- Parathyroid hormone

Back 96

Parathyroid hormone

Front 97

Administration of a local anesthetic with epinephrine will most likely produce which of the following cardiovascular effects?
- Increased heart rate
- Decreased heart rate
- Increased diastolic blood pressure
- Decreased systolic blood pressure

Back 97

Increased heart rate

Front 98

Infection with hepatitis C results in liver dysfunction which might decrease the liver's ability to store glycogen. In addition to the liver, which of the following is the other major site of glycogen storage?
- Brain
- Kidney
- Smooth muscle
- Cardiac muscle
- Skeletal muscle

Back 98

Skeletal muscle

Front 99

Damage to the liver from hepatitis C infection might impair bilirubin metabolism. Bilirubin is a product of which of the following pathways?
- Albumin synthesis
- Cholesterol synthesis
- Heme degradation
- Copper degradation

Back 99

Heme degradation

Front 100

Death from advanced liver disease caused by hepatitis C infection is primarily due to which of the following?
- Inhibition of replication
- Inhibition of transcription
- Inhibition of urea synthesis
- Increase in serum glucose levels
- Inhibition of immunoglobulin production

Back 100

Inhibition of urea synthesis

Front 101

Which of the following represents the vitamin necessary for coenzyme A synthesis?
- Retinol
- Pyridoxine
- Folic acid
- Cobalamine
- Pantothenic acid

Back 101

Pantothenic acid

Front 102

Which of the following statements best describes vitamin A's function?
- Prevents pellagra
- Stimulates collagen synthesis
- Promotes absorption of calcium
- Promotes differentiation of epithelial cells
- Maintains the integrity of connective tissues

Back 102

Promotes differentiation of epithelial cells

Front 103

An example of primary active transport is the movement of:
- glucose into muscle
- potassium into a nerve cell
- proteins across capillaries
- sodium into an endothelial cell
- oxygen across the alveolar wall

Back 103

potassium into a nerve cell

Front 104

Many hormones are believed to act by way of stimulation of the membrane-bound enzyme:
- glutaminase
- phosphatase
- phosphorylase
- adenylate cyclase
- carbonic anhydrase

Back 104

adenylate cyclase

Front 105

Which of the following are the major target tissues of the calcium regulating hormones?
- Intestine, lung, kidney
- Heart, duodenum, bone
- Bone, heart, kidney
- Bone, intestine, kidney

Back 105

Bone, intestine, kidney

Front 106

A dental patient presents with a bluish discoloration of the mucous membranes indicative of cyanosis. This condition is most likely the result of:
- increased Pco2
- a decreased hemoglobin concentration
- a decreased red blood cell concentration
- increased levels of reduced hemoglobin
- decreased blood flow to the affected area

Back 106

increased levels of reduced hemoglobin

Front 107

Which of the following clinical manifestations is observed in an adult patient with an adenoma of the pituitary gland causing hypersecretion of Growth Hormone?
- Hypotension
- Hyperglycemia
- Short stature
- Decreased urine formation
- Decreased basal metabolic rate

Back 107

Hyperglycemia

Front 108

Which of the following provides the immediate energy source for the transport of glucose into intestinal epithelial cells?
- NADH
- NADPH
- Na+ gradient across the luminal membrane
- H+ gradient across the luminal membrane

Back 108

Na+ gradient across the luminal membrane

Front 109

Which of the following is most often associated with transport of fatty acids and bile acids in blood?
- Albumin
- Globulin
- Cholesterol
- Sphingolipid
- Mucopolysaccharide

Back 109

Albumin

Front 110

The extracellular edema in patients with cirrhosis of the liver is caused by which of the following?
- Decreased capillary permeability
- Decreased plasma proteins
- Decreased capillary pressure
- Increased lymphatic return
- Increased plasma proteins

Back 110

Decreased plasma proteins

Front 111

Which of the following vessels contains the highest viscosity blood in the body?
- Aorta
- Vena cava
- Vasa recta
- Pulmonary vein
- Pulmonary artery

Back 111

Vena cava

Front 112

The hyperglycemic effect of glucagon is mediated primarily through:
- the growth hormone
- muscle glycolysis
- liver glycogenolysis
- inhibition of cortisol action
- enhanced glucose reabsorption by renal tubules

Back 112

liver glycogenolysis

Front 113

Which of the following characterizes the generator potential of a receptor?
- An all or none response
- Propagated in a non decremental manner
- Universally present in all nerve tissues
- Graded according to the strength of the stimulus

Back 113

Graded according to the strength of the stimulus

Front 114

Methyl xanthines such as caffeine and theophylline enhance lipolysis in adipose tissue by:
- inducing adenylate cyclase synthesis
- inducing triglyceride lipase synthesis
- inhibiting cyclic AMP phosphodiesterase activity
- directly activating an intracellular protein kinase
- enhancing the binding of epinephrine to an extracellular membrane receptor

Back 114

inhibiting cyclic AMP phosphodiesterase activity

Front 115

Which of the following can increase the rate of net flux or diffusion of oxygen through the alveolar membrane?
- Decreasing the temperature
- Increasing the cross sectional area
- Decreasing the concentration gradient
- Increasing the path length of diffusion

Back 115

Decreasing the concentration gradient

Front 116

At which stage in the process of gene cloning are restriction nucleases used?
- Isolation of mRNA
- Synthesis of double stranded cDNA
- Insertion of the cDNA into the vector DNA
- Expression of the cloned gene by the bacteria
- Introduction of recombinant DNA into a bacterial cell

Back 116

Expression of the cloned gene by the bacteria

Front 117

Which of the following statements best describes the primary role of calcium in the activation of cardiac muscle?
- Cause depolarization of the muscle
- Couple myosin and actin to form actinomyosin
- Reduce inhibition of tropomyosin upon the myofilaments
- Activate myosin molecules so that they can interact with actin filaments

Back 117

Couple myosin and actin to form actinomyosin

Front 118

Which of the following represents the principle allosteric regulator of pyruvate metabolism in the liver?
- ATP
- NAd
- Citrate
- Cyclic AMP
- Acetyl CoA

Back 118

Acetyl CoA

Front 119

Which of the following compounds is an intermediate in the biosynthesis of cholesterol?
- Squalene
- Hexosamine
- Cholic acid
- Pregnanediol
- Deoxycholic acid

Back 119

Squalene

Front 120

During oxidative phosphorylation, the hydrogen ion gradient is created using energy from which of the followin?
- ADP transport
- ATP synthesis
- ATP hydrolysis
- Reduction of NAD+
- Electron transfers

Back 120

ATP hydrolysis

Front 121

During nuclear processing of hnRNA to mRNA, the portion of the molecule that is removed is the:
- exon
- anticodon
- intron
- codon
- 5' cap

Back 121

intron

Front 122

In the biosynthesis of purines, which of the following is the source of most of the nitrogen?
- Urea
- Ammonia
- Uric acid
- Pyrimidines
- Amino acids

Back 122

Amino acids

Front 123

Which of the following hormones generally increases the rate of anabolic (biosynthetic) reactions?
- Insulin
- Glucagon
- Cortisol
- Epinephrine
- Somatostatin

Back 123

Insulin

Front 124

Which of the following statements best characterizes simple diffusion?
- It requires a carrier
- It is independent of temperature
- It requires hydrophobic interaction
- It requires a semipermeable membrane
- It moves down its concentration gradient

Back 124

It moves down its concentration gradient

Front 125

Which of the following membrane components consists of glycerol, phosphate, fatty acids, and choline?
- Cephalin
- Lecithin
- Ganglioside
- Cerebroside
- Sphingomyelin

Back 125

Lecithin

Front 126

Which of the following amino acids has a hydroxyl group that sometimes participates in enzyme reactions?
- Serine
- Alanine
- Glycine
- Proline
- Arginine

Back 126

Serine

Front 127

The enterogastric reflex prooduces a(an):
- increase in gastric motility
- decrease in gastric motility
- decrease in intestinal motility
- increase in intestinal motility

Back 127

decrease in gastric motility

Front 128

Which of the following statements best describes the activity of DNA ligase?
- Seals single stranded nicks in DNA
- Proofreads the DNA proper base pairing
- Prevents the polymerase from falling off the DNA
- Removes the RNA primer from the lagging strand

Back 128

Seals single-stranded nicks in DNA

Front 129

During the period of isovolumetric contraction, which of the following happens?
- The semilunar valves are open
- The left ventricular pressure is rising
- The aortic pressure is slightly less than the left ventricular pressure
- The right ventricular pressure is greater than the left ventricular pressure

Back 129

The left ventricular pressure is rising rapidly

Front 130

Linolenic and arachidonic acids serve as precursors to which of the following?
- Leithin
- Prostaglandins
- Steroid hormones
- Cholesterol
- Cholecalciferol

Back 130

Prostaglandins

Front 131

Transmission of impulses from the motor nerve to the muscle cell regularly produces:
- an action potential in the muscle cell
- a graded potential in the muscle cell
- hyperpolarization of the muscle cell
- hypopolarization of the muscle cell
- alteration in the treshold potential of the muscle cell

Back 131

a graded potential in the muscle cell

Front 132

Each of the following occurs during swallowing except one. Which one is this exception?
- Larynx is elevated
- Eustacian tubes close
- Respiration is inhibited
- Epiglottus covers the trachea

Back 132

Eustacian tubes close

Front 133

Which of the following statements best describes the action of antidiuretic hormone?
- Decrease renal filtration fraction
- Increase storage capacity of the bladder
- Decrease permeability of distoconvoluted tubules and/or collecting ducts to water
- Increase permeability of distoconvoluted tubules and/or collecting ducts to water

Back 133

Increase permeability of distoconvoluted tubules and/or collecting ducts to water

Front 134

Pernicious anemia is frequently associated with a deficiency of:
- vitamins A and D
- vitamins C and D
- vitamins E and K
- vitamins B12 and folic acid
- thiamine and riboflavin

Back 134

vitamin B12 and folic acid

Front 135

Which of the following usually has an H+ concentration greater than 1 x 10^-3 M?
- Bile
- Urine
- Saliva
- Gastric juice
- Pancreatic juice

Back 135

Gastric juice

Front 136

Which of the following statements explains why hyperventilation often produces muscular spasms?
- There is too much O2 available
- The respiratory muscles are fatigued
- There is not enough phosphate present
- The loss of CO2 has causes alkalosis
- The pH of the blood has dropped sharply

Back 136

The loss of CO2 has caused alkalosis

Front 137

After taking part in fat digestion and absorption, the bulk of the bile salts are:
- excreted in the urine
- excreted in the feces
- reabsorbed into the lymph
- destroyed by bacteria in the colon
- reabsorbed into the portal circulation

Back 137

reabsorbed into the portal circulation

Front 138

A dental patient begins to experience acute pain and becomes anxious, begins to hyperventilate, and becomes dizzy and shows signs of loss of consciousness. These symptoms are the result of:
- elevated arterial Pco2
- decreased Hco3
- decreased arterial Po2
- decreased arterial Pco2
- elevated arterial Hco3

Back 138

decreased arterial Pco2

Front 139

Which of the following compounds is directly involved in the action of hormones on their targer cells?
- ATP
- UTP
- AMP
- UDGP
- Cyclic AMP

Back 139

Cyclic AMP

Front 140

Oxaloacetate plays an important role in the body by:
- participating in transacetylation reactions
- participating in transmethylation reactions
- reacting with acetyl coenzyme A to form citrate
- reacting with coenzyme A to form acetoacetate

Back 140

reacting with acetyl coenzyme A to form citrate

Front 141

The first step in the utilization of amino acid for protein synthesis requires:
- aminoacyl tRNA synthetase
- initiation and elongation factors
- self assembly of 30S and 50S ribosomal subunits
- binding of N formylmethionyl tRNA to the ribosomes

Back 141

aminoacyl tRNA synthetase

Front 142

Each of the following is characteristic of creatinine except one. Which one is this exception?
- Freely filtered
- Slightly secreted
- Slightly reabsorbed
- Produced endogenously at a constant rate

Back 142

Slightly reabsorbed

Front 143

Secondary protein structures, such as beta-pleated sheets, are stabilized by which of the following?
- Hydrogen bonds
- Disulfide bonds
- van der Waals force
- Hydrophobic interactions
- Electrostatic interactions

Back 143

Hydrogen bonds

Front 144

Which of the following statements describes a property or function of salivary lysozymes?
- They have bacteriocidal activity
- They bind selectively to dental enamel
- They promote calcium phosphate precipitation
- They hydrolyze alpha 1,4 linkages in starch

Back 144

They have bacteriocidal activity

Front 145

Reduced serum potassium (hypokalemia) might produce which of the following results?
- Reduced membrane treshold potential
- Elevated membrane treshold potential
- Hyperpolarized cell membrane potential
- Hypopolarized cell membrane potential
- Hyperactive neuromuscular reflexes

Back 145

Hyperpolarized cell membrane potential

Front 146

Which of the following best describes glucose handling by the kidney?
- Transport is blocked by aldosterone
- Transport occurs in exchange for H+
- Reabsorption is largest in the distal tubule
- Transport is primarily by active secretion into the tubular fluid
- Transport from the lumen of the nephron depends upon Na+ transport

Back 146

Transport from the lumen of the nephron depends upon Na+ transport

Front 147

Which of the following represents the sensory organs concerned with maintenance of skeletal muscle tonus?
- Sarcomeres
- Muscle spindles
- Gamma efferents
- Pacinian corpuscles
- Golgi tendon organs

Back 147

Sarcomeres

Front 148

A 0.9% solution of sodium chloride is isotonic with blood because:
- blood contains 0.9% NaCl
- the erythrocyte is not permeable to NaCl
- it has the same surface tension as blood
- it exhibits the same osmolarity as blood
- it has the same salt concentration as blood

Back 148

it exhibits the same osmolarity as blood

Front 149

Which of the following statements best describes infants with phenylketonuria?
- Can synthesize tyrosine
- Cannot synthesize phenylalanine
- Have to eat a diet high in phenylalanine
- Have a deficiency of the enzyme phenylalanine hydroxylase

Back 149

Have a deficiency of the enzyme phenylalanine hydroxylase

Front 150

Dopamine is synthesized in two steps from which of the following compounds?
- Choline
- Tyrosine
- Tryptophan
- Acetyl CoA
- Arachidonic acid

Back 150

Tyrosine

Front 151

Reduced renal blood flow can cause hypertension by which of the following?
- Release of renin
- Reflex vasoconstriction
- Retention of potassium in blood
- Increased output of epinephrine

Back 151

Release of renin

Front 152

The amino acid inserted in a polypeptide chain during protein synthesis is determined by a complementary relationship between mRNA and:
- DNA
- tRNA
- amino acids
- ribosomal RNA

Back 152

tRNA

Front 153

A dehydrated dental patient, as a result of severe vomiting following over use of a narcotic analgesic, might present with which of the following symptoms?
- An increased pulse rate
- An increased blood pressure
- Facial edema
- Distended neck veins
- Desire to constantly urinate

Back 153

An increased pulse rate

Front 154

Spasticity is best characterized by which of the following?
- Failure of recruitment
- Depressed stretch reflexes
- Exaggerated stretch reflexes
- Presence of fibrillary contractions

Back 154

Exaggerated stretch reflexes

Front 155

Which of the following best describes collagen?
- A soluble fiber of ground substance
- The most abundant protein in the body
- A fibrous protein with a high content of tryptophan
- A globular protein with a high content of hydroxyproline

Back 155

The most abundant protein in the body

Front 156

Destruction of the left spinocerebellar tract at T2 would be expected to eliminate positional sense on the:
- right side of the body above T2
- right side of the body below T2
- left side of the body above T2
- left side of the body below T2

Back 156

left side of the body below T2

Front 157

Which of the following substances is responsible for initiating cross-bridge cycling in smooth muscle?
- Myosin ATPase
- Myosin kinase
- Myosin reductase
- Myosin phosphatase

Back 157

Myosin kinase

Front 158

Which of the following functional groups are essential for a substance to act as an amphipathic (amphiphilic) molecule?
- Polar, nonpolar
- Polar, negatively charged
- Nonpolar, positively charged
- Cyclic, hydrophilic
- Branches, hydrophilic

Back 158

Polar, negatively charged

Front 159

Which of the following is the major storage form of carbohydrates in the liver?
- Dextran
- Glucose
- Amylose
- Glycogen
- Fructose

Back 159

Glycogen

Front 160

Which of the following fatty acids has the greatest number of double bonds?
- Oleic
- Stearic
- Palmitic
- Arachidonic

Back 160

Arachidonic

Front 161

Which of the following natural metabolisms is measured clinically as a predictor of glomerular filtration rate?
- Renin
- Inulin
- Fructose
- Creatinine
- Angiotensin

Back 161

Creatinine

Front 162

Which of the following is a component coenzyme required for a transamination process?
- Niacin
- Thiamine
- Folic acid
- Pyridoxine
- Riboflavin

Back 162

Pyridoxine

Front 163

Tapping on the side of the face elicits a contraction of the masseter muscle. This is an example of which of the following kinds of reflex?
- Stretch
- Polysynaptic
- Cross extensor
- Withdrawal
- Inverse stretch

Back 163

Stretch

Front 164

Thyroid secretion is stimulated by which of the following?
- Hypoxia
- Propylthiouracil
- Exogenous thyroid hormone
- High serum iodide concentration
- Prolonged exposure to a cold environment

Back 164

Prolonged exposure to a cold environment

Front 165

A patient is a Type I diabetic and is scheduled for extractions. Which of the following potential clinical complications should most concern the dentist?
- Excessive bleeding
- Frequent desire to urinate
- Increased potential for infection
- Inability to obtain anesthesia
- Probability of seizure

Back 165

Increased potential for infection

Front 166

Sodium permeability (conductance) of an axon membrane is maximal during the:
- negative after potential
- positive after potential
- ascending limb of the action potential
- descending limb of the action potential

Back 166

ascending limb of the action potential

Front 167

The conversion of vitamin D metabolite to its most active form takes place in the:
- bone
- skin
- liver
- kidney
- intestinal mucosa

Back 167

kidney

Front 168

Voluntary overventilation of lungs results in which of the following?
- Decreased hydrogen ion concentration in blood
- Increased hydrogen ion concentration in blood
- Marked increase in pulmonary uptake of oxygen
- Increased oxygen carrying capacity of venous blood
- Decreased oxygen concentration in arterial blood

Back 168

Decreased hydrogen ion concentration in blood

Front 169

Which of the following mediates dissolution of the fibrin clot during vessel repair?
- Plasmin
- Factor II (thrombin)
- Factor III (tissue thromboplastin)
- Factor XIII (fibrin stabilizing factor)

Back 169

Plasmin

Front 170

Which of the following represents the compound that contains an active (labile) methyl group?
- Serine
- Creatine
- Methionine
- S adenosyl methionine
- 5, 10 methylene tetrahydrofolate

Back 170

S adenosyl methionine

Front 171

Production of phosphoenolpyruvate carboxykinase is stimulated by:
- insulin
- cortisol
- aldosterone
- somatotropin

Back 171

insulin

Front 172

Oxytocin is responsible for which of the following actions?
- Regulating blood calcium levels
- Preventing formation of goiters
- Preventing release of insulin
- Causing contractions of uterine smooth muscle during labor

Back 172

Causing contractions of uterine smooth muscle during labor

Front 173

Which of the following represents the pressure change when the diaphragm and external intercostal muscles simultaneously contract?
- Alveolar volume decreases
- Alveolar pressure increases
- Intrapleural pressure decreases
- Intrapleural pressure increases

Back 173

Intrapleural pressure decreases

Front 174

Sucrose will most directly contribute to the addition of which of the following to dental plaque?
- Mucins
- Calcium ions
- Polysaccharides
- Salivary protein
- Glycolytic enzymes

Back 174

Polysaccharides

Front 175

Reverse transcriptase is used in vitro to make:
- tRNA from cDNA
- rRNA from cDNA
- cDNA from rRNA
- mRNA from cDNA
- cDNA from mRNA

Back 175

cDNA from mRNA

Front 176

The primary defect in myopia is related to which of the following?
- Unequal curvature of refracting material of the cornea
- Eyeball length relative to refractive power of the lens
- Deficiency of vitamin A for conversion to rhodopsin
- Loss of elasticity of crystalline lens
- Detachment of the retina

Back 176

Eyeball length relative to refractive power of the lens

Front 177

The basic principles for sequencing DNA by the Sanger procedure derive from which of the following processes?
- Translation
- Transcription
- Replication
- Reverse Transcription

Back 177

Translation

Front 178

Which of the following represents a bleeding disorder due to lack of Factor VIII?
- Thrombosis
- Hemophilia A
- Thrombocytopenia
- Von Willebrand disease

Back 178

Hemophilia A

Front 179

Each of the following conditions alters the rate of product formation by an enzyme except one. Which one is this exception?
- pH
- Temperature
- Ionic strength
- Isoelectric point
- Substrate concentration

Back 179

Isoelectric point

Front 180

Polypeptide hormones generally exert their effect by binding to which of the following?
- Intracellular receptors and stimulating protein synthesis
- Receptors on the cell membrane and stimulating protein synthesis
- Intracellular receptors and altering the specific activity of certain enzymes
- Receptors on the cell membrane and altering the specific activity of certain enzymes

Back 180

Receptors on the cell membrane and altering the specific activity of certain enzymes

Front 181

A dental patient with left heart failure might show signs of dyspnea when placed in the supine position for which of the following reasons?
- Edema caused by excessive pulmonary capillary oncotic pressure
- Edema caused by excessive systemic capillary oncotic pressure
- Edema caused by excessive pulmonary capillary hydrostatic pressure
- Edema caused by excessive systemic capillary hydrostatic pressure
- Ineffective pulmonary lymphatic function

Back 181

Edema caused by excessive pulmonary capillary hydrostatic pressure

Front 182

In evaluating an EKG of a patient, it was observed the PR interval was increased. This observation represents:
- slow conduction of impulses through the SA node
- rapid conduction of impulses through the ventricle
- slow conduction of impulses through the AV node
- rapid conduction of impulses through the atria
- slow repolarization of the atria

Back 182

slow conduction of impulses through the AV node

Front 183

Which of the following substances, under physiologic conditions, is essential to the transformation of G-actin to F-actin?
- ATP
- Chloride
- Manganese
- Pyrophosphate
- Creatine phosphate

Back 183

ATP

Front 184

Chondroitin sulfate and hyaluronic acid are characterized by which of the following?
- Cell walls of caries related streptococci decomposition end products of oral lactobacilli
- Byproducts of carbohydrate metabolism by oral streptococci
- Enzymes which break down gram positive cell walls
- Components of extracellular matrix

Back 184

Components of extracellular matrix

Front 185

Which of the following best explains the primary action of antidiuretic hormone?
- It decreases the activity of the Na K pump in the distal tubule
- It increases the H2O permeability of the collecting ducts and the distal tubules
- In decreases the pore size of the distal tubules and the collecting ducts
- It decreases the glomerular filtration rate
- It inhibits the action of glutaminase

Back 185

It increases the H2O permeability of the collecting ducts and the distal tubules

Front 186

Which of the following takes place as proinsulin is converted to insulin?
- Disulfide bonds are formed
- Disulfide bonds are broken
- The polypeptide chain is lengthened
- A segment of the polypeptide chain is removed

Back 186

A segment of the polypeptide chain is removed

Front 187

GABA increase the premeability of postsynaptic membranes to which of the following ions?
- Sodium
- Calcium
- Chloride
- Magnesium
- Potassium

Back 187

Chloride

Front 188

The polymerase chain reaction is most useful for which of the following?
- Preparing enzymes that synthesize nucleic acids
- Isolating the genome of an organism
- Amplifying a specific DNA sequence
- Separating polyclonal antibodies
- Synthesizing RNA from DNA

Back 188

Amplifying a specific DNA sequence

Front 189

Each of the following segments of the gastrointestinal tract consists of smooth muscle under autonomic nervous control except one. Which one is this exception?
- Rectum
- Internal anal sphincter
- Antrum of the stomach
- Upper esophagus
- Gastro esophageal sphincter

Back 189

Upper esophagus

Front 190

The movement of Ca2+ across a membrane is characterized by which of the following?
- A facilitated diffusion
- An example of a cotransport system
- In many cell membranes involves a Ca2+:Na+ countertransport system
- Maintains Ca2+ concentration very much higher in the cell than in the extracellular fluid

Back 190

In many cell membranes involves a Ca2+:Na+ countertransport system

Front 191

The enzyme catalyzing the rate controlling step in the de novo synthesis of fatty acids is regulated allosterically by the positive modulator:
- ATP
- NADPH
- citrate
- cyclic AMP
- oxaloacetate

Back 191

citrate

Front 192

Which of the following is required for vitamin D3 synthesis?
- Decarboxylation in the liver
- UV activation of precursors in skin
- Metabolism by gut bacteria
- Deamination in the kidney

Back 192

UV activation of precursors in skin

Front 193

The maximal frequency of impulses that can be carried by a nerve fiber is limited by which of the following?
- Intensity of the stimulus
- Diameter of the nerve fiber
- Duration of the absolute refractory period
- Duration of the relative refractory period

Back 193

Duration of the absolute refractory period

Front 194

Which of the following represents the normal substrate of thrombin?
- Fibrin
- Thrombospondin
- Prothrombin
- Thromboplastin
- Fibrinogen

Back 194

Fibrinogen

Front 195

A sustained, severe carbohydrate deficiency in the diet will result in which of the following?
- Ketoacidosis
- Severe metabolic alkalosis
- A deficiency in prostaglandin formation
- An inability to synthesize ascorbic acid

Back 195

Ketoacidosis

Front 196

The anticaries effect of fluoride is least related to which of the following?
- Ion exchange
- Decreased solubility
- Facilitation of remineralization
- Its presence during enamel formation
- Activation of plaque polysaccharide hydrolysis

Back 196

Activation of plaque polysaccharide hydrolysis

Front 197

Which of the following represents a polyunsaturated fatty acid that is commonly found in animal cell membranes?
- Oleic
- Lactic
- Sialic
- Stearic
- Linoleic

Back 197

Linoleic

Front 198

As DNA is denatured, each of the following events takes place except one. Which event is this exception?
- Total GC content of total DNA increasing
- UV light absorption increasing
- Complementary strands becoming random coils
- Base stacking becoming disrupted
- Hydrogen bonds breaking

Back 198

Total GC content of total DNA increasing

Front 199

Each of the following is a mechanism in humans helping to raise body temperature except one. Which one is this exception?
- Shivering
- ATP hydrolysis
- Exothermic reactions
- Peripheral vasodilation
- Increased thyroxine release

Back 199

Peripheral vasodilation

Front 200

Which of the following types of bonds link amino acid residues to form proteins?
- Amide
- Anomeric
- Epimeric
- Hydrogen
- Glycosidic

Back 200

Amide

Front 201

In skeletal muscle, excitation-contraction coupling is mediated by which of the following?
- Binding of calcium and calmodulin
- Efflux of potassium from transverse tubules
- A sudden rise in permeability to chloride ions
- Release of acetylcholinesterase from nerve terminals
- Release of calcium from the sarcoplasmic reticulum

Back 201

Release of calcium from the sarcoplasmic reticulum

Front 202

A mucin is which of the following types of proteins?
- Simple protein
- Phosphoprotein
- Chromoprotein
- Nucleoprotein
- Glycoprotein

Back 202

Glycoprotein

Front 203

The tricarboxylic acid cycle is initiated by the condensation of which of the following two molecules?
- Pyruvate and malate
- NAD+ and oxaloacetate
- NAD+ and oxalosuccinate
- Acetyl coenzyme A and oxaloacetate
- Acetyl coenzyme A and oxalosuccinate

Back 203

Acetyl coenzyme A and oxaloacetate

Front 204

Compared to skeletal muscle contraction, smooth muscle contraction:
- requires more energy for a given tension
- occurs several times more rapidly
- can be maintained for a longer time
- is unaffected by the autonomic nervous system

Back 204

can be maintained for a longer time

Front 205

Androgens are produced in the testis and:
- adrenal cortex
- thyroid
- adrenal medulla
- pituitary
- hypothalamus

Back 205

adrenal cortex

Front 206

What thermodynamic parameter is a measure of randomness or disorder in a system?
- Entropy
- Enthalpy
- Free energy
- Potential energy
- Activation energy

Back 206

Entropy

Front 207

A number of catabolic pathways are allosterically inhibited by an increase in the concentration of which of the following?
- ADP
- AMP
- ATP
- NAD+
- Pyruvate

Back 207

ATP

Front 208

Both systemic and pulmonary circulations have the same:
- pulse pressure
- total capacitance
- diastolic pressure
- resistance
- flow rate

Back 208

flow rate

Front 209

Under strict anaerobic conditions, the catabolism of one glucose molecule would yield a net of:
- 2 ATP and 2 lactic acid molecules
- 4 ATP and 2 lactic acid molecules
- 2 ATP and 2 pyruvic acid molecules
- 4 ATP and 2 pyruvic acid molecules

Back 209

2 ATP and 2 lactic acid molecules

Front 210

Which of the following is least descriptive of lipids?
- Nonpolar
- Carbon containing
- Amphipathic
- Hydrophilic

Back 210

Hydrophilic

Front 211

The ability to concentrate urine varies among animal species. The maximum urine concentration that can be produced by an animal is most closely related to which of the following?
- Renal blood flow
- Total number of nephrons
- Glomerular filtration rate
- Length of the loop of Henle
- Diameter of the distal tubule

Back 211

Length of the loop of Henle

Front 212

Each of the following appears in the glomerular filtrate in concentrations approximately equal to those in plasma except one. Which one is this exception?
- Urea
- Glucose
- Amino acids
- Steroid hormones
- Plasma electrocytes

Back 212

Steroid hormones

Front 213

If an axonal membrane transiently becomes very permeable to Na+ ions, then the membrane potential of the cell will approach:
- - 70 mV
- - 60 mV
- - 50 mV
- 0 mV
- + 60 mV

Back 213

+60 mV

Front 214

The clinical symptoms of dermatitis, diarrhea, and dementia suggest a deficiency in which of the following vitamins?
- Retinol
- Riboflavin
- Tocopherol
- Ascorbic acid
- Niacin

Back 214

Niacin

Front 215

Streptomycin is an antibiotic which inhibits the process of:
- translation in eukaryotes
- translation in prokaryotes
- transcription in eukaryotes
- transcription in prokaryotes
- DNA replication in prokaryotes

Back 215

translation in prokaryotes

Front 216

Insulin increases the activity of which of the following?
- Enolase
- Phosphorylase a
- Phosphofructokinase
- Glucose 6 phosphatase
- Fructose 1, 6 diphosphatase

Back 216

Phosphofructokinase

Front 217

Increased parasympathetic activity results in:
- decreased salivary secretion
- increased cardiac contractility
- decreased gastric motility and tone
- increased bronchiolar smooth muscle contraction

Back 217

increased bronchiolar smooth muscle contraction

Front 218

A patient who has emphysema is most likely to exhibit which of the following changes in functional residual capacity (FRC) and compliance?
- FRC increased, Compliance increased
- FRC decreased, Compliance no change
- FRC increased, Compliance no change
- FRC decreased, Compliance increased
- FRC decreased, Compliance decreased

Back 218

FRC increased, Compliance increased

Front 219

The stimulating effect of low arterial O2 tension on respiration is usually produced through an effect on the:
- carotid bodies
- carotid sinuses
- expiratory center
- inspiratory center
- alveolar nerve endings

Back 219

carotid bodies

Front 220

Most endogenous cholesterol in the liver is usually converted into which of the following?
- Glucose
- Steroids
- Cholic acid
- Oxaloacetate
- Ketone bodies

Back 220

Oxaloacetate

Front 221

Which of the following could be beneficial in reducing edema in the arms of women who have had radical masectomy with removal of axial lymph nodes?
- Hypertensive agents
- Avoidance of all diuretic agents
- Increase interstitial oncotic pressure
- Decrease interstitial hydrostatic pressure
- Administration of a plasma volume expander

Back 221

Administration of a plasma volume expander

Front 222

Which of the following substances is least polar?
- Ethanol
- Cholesterol
- Palmitic acid
- Glycocholic acid

Back 222

Cholesterol

Front 223

Which of the following molecules would likely form a micelle when mixed with water and agitated?
- Serine
- Glycerol
- Phospholipid
- Triglyceride

Back 223

Phospholipid

Front 224

Which of the following is most likely to result from increased vagal activity?
- Increased heart rate
- Increased stroke volume
- Increased cardiac output
- Decreased cardiac oxygen consumption
- Decreased transit time through the AV node

Back 224

Decreased cardiac oxygen consumption

Front 225

Which of the following noncollagenous protein components best characterizes dentin matrix?
- Laminin
- Vimentin
- Phosphophoryn
- Osteonectin
- Fibronectin

Back 225

Phosphophoryn

Front 226

Some carbohydrates convert Cu2+ ions to Cu+ ions. This property is related to their ability to act as:
- a reducing agent
- an oxidizing agent
- both a reducing agent and an oxidizing agent
- neither a reducing agent nor an oxidizing agent

Back 226

a reducing agent

Front 227

Coenzyme A participates in:
- formylation
- protein synthesis
- methionine activation
- activation of carboxyl groups

Back 227

activation of carboxyl groups

Front 228

Which of the following is the first step in the catabolism of many amino acids?
- Formation of a dipeptide with glutamate
- Conjugation of the alpha amino to glucuronate
- Transamination of the alpha amino to a keto acid
- Conjugation of the alpha carboxyl group to glucuronate
- Decarboxylation of the alpha carboxyl group to form a primary amine

Back 228

Transamination of the alpha amino to a keto acid

Front 229

In respiratory acidosis, arterial CO2 content and pH become abnormal. Which of the following best describes their respective changes?
- CO2 increases, pH increases
- CO2 increases, pH decreases
- CO2 decreases, pH increases
- CO2 decreases, pH decreases

Back 229

CO2 increases, pH decreases

Front 230

Which of the following is the major protein component of cementum?
- Elastin
- Keratin
- Collagen
- Amelogenin
- Osteonectin

Back 230

Collagen

Front 231

Which of the following do elastin and collagen have in common?
- Easily stretched
- Absence of proline
- Disulfide crosslinking
- Triple helix structure
- About one third glycine

Back 231

About one third glycine

Front 232

The plasma osmolarity decreases after infusion of:
- aldosteron
- vasopressin (ADH)
- angiotensin II
- parathyroid hormone
- isotonic saline solution

Back 232

vasopressin (ADH)

Front 233

Which of the following features distinguishes active transport from facilitated diffusion?
- Specificity
- Carrier mediated
- Requires metabolic energy
- Presence of a transport maximum (Tm)

Back 233

Requires metabolic energy

Front 234

Each of the following secretes HCO3- into the gastrointestinal tract except one. Which one is this exception?
- Chief cells
- Colon mucosa
- Salivary glands
- Stomach mucosa

Back 234

Chief cells

Front 235

The chemical energy generated by mitochondrial electron transport results from which of the following?
- Excess H+ in the matrix
- An H+ gradient across the inner membrane
- The formation of thioesters in the matrix
- A conformational change in the inner membrane

Back 235

An H+ gradient across the inner membrane

Front 236

Which of the following is necessary for de novo synthesis of cholesterol?
- NA+
- NADH
- NADP+
- NADPH
- FADH2

Back 236

NADPH

Front 237

The function of which of the following types of nucleic acid is to activate and select specific amino acids for protein synthesis?
- rRNA
- mRNA
- cDNA
- tRNA
- hnRNA

Back 237

tRNA

Front 238

Which of the following is a pyrimidine base that is present in RNA but is not present in DNA?
- Uracil
- Guanine
- Thymine
- Adenine
- Cytosine

Back 238

Uracil

Front 239

Which of the following changes in lung compliance and vital capacity would be observed in the absence of pulmonary surfactant?
- Lung compliance increase, Vital capacity increase
- Lung compliance increase, Vital capacity decrease
- Lung compliance increase, Vita capacity no change
- Lung compliance decrease, Vital capacity increase
- Lung compliance decrease, Vital capacity decrease

Back 239

Lung compliance decrease, Vital capacity decrease

Front 240

Which of the following represents a decrease in the frequency of action potentials in an afferent neuron despite a constant stimulus intensity?
- Refracion
- Potentiation
- Perception
- Adaptation
- Accomodation

Back 240

Adaptation

Front 241

Which of the following is a typical finding for a normal 23-year-old man?
- Hematocrit of 45%
- Venous blood with pH of 7.2
- White blood cell count of 10,000/mm^3
- Red blood cell count of 7,000,000/mm^3
- Pulse pressure equivalent to 80 mm Hg

Back 241

Hematocrit of 45%

Front 242

Earaches may develop as a result of blockage of the eustachian tube because:
- of anvil misalignment
- the ossicle can no longer vibrate
- fluid in the middle ear cannot escape
- pressure on the round window distorts the basement membrane
- pressure in the middle ear is not equalized with atmospheric pressure

Back 242

pressure in the middle ear is not equalized with atmospheric pressure

Front 243

Which of the following stimulates vagal nerve endings in the lung parenchyma and inhibits inspiration?
- Decreased arterial pH
- Expansion of the lungs
- Decreased alveolar O2 tension
- Increased alveolar CO2 tension

Back 243

Expansion of the lungs

Front 244

Plasmid vectors suitable for cloning have which of the following characteristics?
- Must be able to replicate synchronously with the host chromosome
- Several unique recognition sequences for one restriction enzyme
- Two genes conferring resistance to different antibiotics
- Large size to facilitate plasmid's entry into cells

Back 244

Two genes conferring resistance to different antibiotics

Front 245

Right-sided lesions of the spinal cord result in loss of which of the following (below the level of the lesion)?
- Motor activity and pain and temperature sensations on the same side
- Motor activity on the same side and pain and temperature sensations on the opposite side
- Motor activity and pain and temperature sensations on the opposite side
- Motor activity on the opposite side and pain and temperature sensations on the same side

Back 245

Motor activity on the same side and pain and temperature sensations on the opposite side

Front 246

If the molar percentage of A (adenine) in a native DNA specimen is 22%, then what is the molar content of G (guanine)?
- 22%
- 28%
- 44%
- 56%
- 78%

Back 246

28%

Front 247

During an isotonic contraction, which of the following bands or structures do not change in width of length?
- A band
- I band
- Muscle sarcomeres
- Two consequtive Z lines
- Series elastic elements

Back 247

A band

Front 248

A diminished oxygen tension in the myocardium causes immediate:
- vasoconstriction of coronary vessels
- vasodilation of coronary vessels
- stimulation of chemoreceptors
- inhibition of chemoreceptors

Back 248

vasodilation of coronary vessels

Front 249

In relative insulin insufficiency, acetyl CoA is usually channeled into:
- ketone body formation
- cholesterol synthesis
- fatty acid synthesis
- gluconeogenesis
- the Krebs cycle

Back 249

ketone body formation

Front 250

After prolonged acidosis, which of the following represents the nitrogenous product that is excreted in high amounts in the urine?
- Urea
- Ammonia
- Uric acid
- Creatinine
- Aspartic acid

Back 250

Ammonia

Front 251

Which of the following are the immediate effects of calcitonin on serum levels of calcium and phosphate?
- Serum calcium increased, Serum phosphate increased
- Serum calcium increased, Serum phosphate decreased
- Serum calcium decreased, Serum phosphate decreased
- Serum calcium no change, Serum phosphate increased
- Serum calcium decreased, Serum phosphate no change

Back 251

Serum calcium decreased, Serum phosphate decreased

Front 252

Atoms are isotopes of each other only if:
- their nuclei contain the same number of neutrons
- their atomic numbers are the same, but their mass numbers differ
- their mass numbers are the same, but their atomic numbers differ
- one is a beta emitter, but the other is an alpha emitter

Back 252

their atomic numbers are the same, but their mass numbers differ

Front 253

Sodium fluorid inhibits glycolysis by affecting which of the following?
- Amylase
- Enolase
- Phosphatase
- Phosphorylase

Back 253

Enolase

Front 254

Hyperventilation alters the acid-base balance of arterial blood by:
- increasing CO2 and increasing pH
- increased CO2 and decreasing pH
- decreasing CO2 and decreasing pH
- decreasing CO2 and increasing pH

Back 254

decreasing CO2 and increasing pH

Front 255

Whch of the following collagen synthesis post-translational events occurs extracellularly?
- Glycosylation
- Hydroxylation
- Intermolecular cross linkage
- Disulfide bond formation

Back 255

Intermolecular cross linkage

Front 256

If the pH becomes lower than the isoelectric point of a protein, then how will the protein respond in an electrophoretic system? It will:
- become denatured
- migrate to the negative pole
- migrate to the positive pole
- remain stationary and unchanged
- separate into its different monomeric forms

Back 256

migrate to the negative pole

Front 257

The level of nonprotein nitrogen in the blood is due principally to the level of which of the following?
- Urea
- Ammonia
- Creatine
- Arginine
- Uric acid

Back 257

Urea

Front 258

The Henderson-Hasselbalch equation shows that:
- dilution of a buffer increases its pH
- pH = pKa when an acid is 0.1 N
- pH = pKa when an acid is half neutralized
- pH is independent of the dissociation constant of the acid

Back 258

pH = pKa when an acid is half neutralized

Front 259

Truglyceride absorbed into the lymphatic system is transported to the liver as which of the following?
- Very low density lipoprotein
- Low density lipoprotein
- Chylomicrons
- Liposomes
- Micelles

Back 259

Chylomicrons

Front 260

BLocking the hypothalamic-hypophyseal venous portal system increases the secretion of which of the following?
- Prolactin
- Oxytocin
- ACTH
- TSH

Back 260

Prolactin

Front 261

Which of the following represents the plasma protein that transports ferrous iron?
- Ferritin
- Myoglobin
- Hemoglobin
- Transferrin
- Cytochrome c

Back 261

Transferrin

Front 262

Which of the following sweeteners is non-nutritive as well as non-cariogenic?
- D fructose
- Saccharin
- Galactose
- Sorbitol
- Maltose

Back 262

Saccharin

Front 263

Epinephrine causes an elevation in cAMP levels in muscle cells which in turn activate:
- ATPase
- adenyl cyclase
- glycogen synthetase
- glycogen phosphorylase
- glycogen phosphorylase phosphatase

Back 263

glycogen pphosphorylase

Front 264

Acromegaly is due to an excessive production of which of the following?
- Thyrotropin
- Gonadotropin
- Somatotropin
- Adrenocorticotropin

Back 264

Somatotropin

Front 265

Intravenous injections of KCl solution would increase the secretion of which of the following?
- Insulin
- Cortisol
- Calcitonin
- Aldosterone
- Parathyroid hormone

Back 265

Aldosterone

Front 266

Frank-Starling's law of the heart states that the:
- initial length of cardiac muscle fibers affects the strength of contraction
- strength of contraction depends on the strength of the ventricular muscle
- heart rate depends directly on thickness of the ventricle
- strength of contraction depends on the strength of stimulus

Back 266

initial length of cardiac muscle fibers affects the strength of contraction

Front 267

When arterial pressure increases, pressoreceptors discharge and:
- increase cardiac rate and strength of contraction
- cause vasoconstriction throughout the peripheral circulatory system
- excite sympathetic nerves and inhibit parasympathetic nerves
- inhibit tonic activity of sympathetic nerves and excite parasympathetic nerves

Back 267

inhibit tonic activity of sympathetic nerves and excite parasympathetic nerves

Front 268

The rate of diffusion across the alveolar wall is inversely proportional to which of the following?
- The surface area for gaseous exchange
- The thickness of the alveolar wall
- The difference in the partial pressure of the gas
- The solubility of the gas

Back 268

The thickness of the alveolar wall

Front 269

Pieces of dog parotid gland and pancreas are transplanted under the skin of the donor animal. After reestablishment of circulation, ingestion of food will result in secretion from which of the following?
- Parotid and pancreatic transplants
- The fragment of the pancreas only
- The fragment of the parotid only
- Neither fragment

Back 269

The fragment of the pancreas only

Front 270

Which of the following conditions is indicated during isovolumetric ventricular contraction of the heart?
- All valves are open
- All valves are closed
- The aortic and pulmonary valves are open and the mitral and tricuspid valves are closed
- The aortic and pulmonary valves are closed and the mitral and tricuspid valves are open

Back 270

All valves are closed

Front 271

Which of the following controls the excitability of the muscle spindle?
- Load on the muscle
- Gamma efferent system
- Alpha efferent discharge
- Length of the extrafusal fibers

Back 271

Gamma efferent system

Front 272

In the denervated heart, adjustments to increased workload are mediated by mechanisms associated with:
- increased end systolic volume
- decreased end systolic volume
- decreased end diastolic volume
- increased end diastolic volume

Back 272

increased end diastolic volume

Front 273

Which of the following is secreted more during the absorptive state than during the postabsorptive state?
- Insulin
- Glucagon
- Cortisol
- Thyroxine
- Epinephrine

Back 273

Insulin

Front 274

Bulging veins in the neck result from which of the following?
- Pulmonary edema
- Hemolytic anemia
- Systemic hypotension
- Congestive heart failure
- Intermittent claudication

Back 274

Congestive heart failure

Front 275

A parathyroidectomized animal will exhibit which levels of calcium and phosphate ion concentration in the plasma?
- Calcium low, Phosphate ion concentration high
- Calcium normal, Phosphate ion concentration low
- Calcium high, Phosphate ion concentration low
- Calcium normal, Phosphate ion concentration normal
- Calcium low, Phosphate ion concentration low

Back 275

Calcium low, Phosphate ion concentration high

Front 276

Which term in the Michaelis-Menten equation, v = (Vmax[S])/(Km + [S]), can be determined from the y intercept of a Lineweaver-Burk plot?
- v
- Vmax
- Km
- [S]

Back 276

Vmax

Front 277

Absence of which of the following blood enzymes drastically reduces blood CO2 carrying capacity?
- Carbonic anhydrase
- Alkaline phosphatase
- Pyruvate carboxykinase
- Histidine decarboxylase
- Serum glutamic oxaloacetate

Back 277

Carbonic anhydrase

Front 278

Glucosuria with hyperglycemia usually occurs in which of the following?
- Pellagra
- Addison's disease
- Diabetes mellitus
- Diabetes insipidus
- Parkinson's disease

Back 278

Diabetes mellitus

Front 279

The largest amount of glomerular filtrate is reabsorbed in the:
- proximal convoluted tubule
- descending loop of Henle
- ascending loop of Henle
- distal convoluted tubules
- collecting ducts

Back 279

proximal convoluted tubule

Front 280

How many anomeric carbons are presnet in a fructose molecule?
- 0
- 1
- 2
- 5
- 6

Back 280

1

Front 281

Which of the following vitamins is the least likely to be involved in tooth development and calcification?
- A
- B1
- C
- D

Back 281

B1

Front 282

The major function of serum LDL is to transport which of the following?
- Bile salts from the intestine
- Triglycerides from the intestine
- Free fatty acids from adipose tissue
- Cholesterol and phospholipids from peripheral tissues
- Cholesterol, cholesterol esters, and phospholipids from the liver

Back 282

Cholesterol, cholesterol esters, and phospholipids from the liver

Front 283

The fluid-mosaic model for membrane structure proposes that:
- the outer and inner faces of the membrane are identical
- peripheral proteins are situated only on the outer face of the plasma membrane
- integral proteins are associated with the hydrophobic phase of the bilayer
- both polar and nonpolar ends of membrane phospholipids are within the hydrophobic phase of the bilayer

Back 283

intergral proteins are assocated with the hydrophobic phase of the bilayer

Front 284

A protein in solution is at its isoelectric point when the:
- pH is the same as that of the blood
- logrithm of the concentration is zero
- pH allows for maximum solubility
- pH is such that no migration occurs during electrophoresis
- pH is produced by a 1:1 mixture of the protein solution with isotonic saline

Back 284

pH is such that no migration occurs during electrophoresis

Front 285

The absolute refractory period of a nerve action potential is determined by the duration of which of the following?
- Sodium activation gate opening
- Sodium inactivation gate closure
- Potassium activation gate opening
- Potassium inactivation gate closure

Back 285

Sodium inactivation gate closure

Front 286

Which of the following represents the chemical substance that is the immediate source of energy for muscle contraction?
- Glycogen
- Acetyl CoA
- Lactic acid
- Creatine phosphate
- Adenosine phosphate

Back 286

Adenosine triphosphate

Front 287

Intracellular and interstitial body fluids have similar:
- total osmotic pressure
- colloid osmotic pressure
- sodium ion concentrations
- chloride ion concentrations
- potassium ion concentrations

Back 287

total osmotic pressure

Front 288

Breathing a gas mixture with 5% CO2 ultimately leads to which of the following?
- Hypoventilation
- A decrease in heart rate
- A stimulation of central chemoreceptors
- An inhibition of peripheral chemoreceptors
- A decrease in cerebrospinal fluid hydrogen ion concentration

Back 288

A stimulation of central chemoreceptors

Front 289

Ovulation is triggered by a marked increase in which of the following?
- Estrogen
- Estradiol
- Progesterone
- Lutenizing hormone
- Follicle stimulating hormone

Back 289

Lutenizing hormone

Front 290

Which of the following must be digested before being in a form that can be absorbed by enterocytes?
- Monoglycerides
- Fatty acids
- Fructose
- Glycine
- Maltose

Back 290

Maltose

Front 291

Alpha-ketoglutarate, oxygen, and ascorbic acid are essential for which of the following processes?
- Incorporation of proline
- Hydroxylation of proline
- Gamma Carboxylation of proline
- Oxidative deamination of lysine
- Activation of procollagen peptidase

Back 291

Hydroxylation of proline

Front 292

Low Density Lipoprotein (LDL) particles get into cells by:
- simple diffusion
- cell cell fusion
- active transport
- facilitated diffusion
- receptor mediated endocytosis

Back 292

rceptor mediated endocytosis

Front 293

Which of the following represents the major pathway for metabolism of excessive inraneuronal free norepinephrine?
- Hydrolysis by cholinesterase
- Deamination by monoamine oxidase
- Hydroxylation by monoamine oxidase
- Hydroxylation by dopamine beta hydroxylase
- Methylation by catechol O methyl transferase

Back 293

Deamination by monoamide oxidase

Front 294

Assuming that P50= 26 torrs, under conditions where pO2 = 30 torrs, the average number of O2 molecules bound per hemoglobin molecule is closest to:
- 0.5
- less than 1
- almost 2
- greater than 2
- greater than 3

Back 294

greater than 2

Front 295

In the DNA molecule, guanine on 1 strand is joined to cytosine on the complementary strand by which of the following bonds?
- Amide
- 1 hydrogen
- 2 hydrogen
- 3 hydrogen
- Phosphodiester

Back 295

3 hydrogen

Front 296

Where in the autonomic nervous system is norepinephrine stored?
- Preganglionic sympathetic nerve endings
- Postganglionic sympathetic nerve endings
- Preganglionic parasympathetic nerve endings
- Postganglionic parasympathetic nerve endings

Back 296

Postganglionic sympathetic nerve endings

Front 297

Which of the following will inactivate human immune deficiency virus (HIV) reverse transcriptase?
- ATP
- AZT
- dATP
- Fluorouracil
- Methotrexate

Back 297

AZT

Front 298

Which of the following hormones conserves body protein, carbohydrate, and fat stores?
- Cortisol
- Glucagon
- Insulin
- Somatotropin

Back 298

Insulin

Front 299

Each of the following is involved in gene cloning except one. Which one is this exception?
- DNA ligase
- RNA polymerase
- DNA polymerase I
- Restriction nucleases
- Reverse transcriptase

Back 299

RNA polymerase

Front 300

Which of the following has a high affinity for binding calcium and collagen in the calcifying matrix?
- Calcitonin
- Osteogenin
- Osteonectin
- Amelogenin
- Fibronectin

Back 300

Osteonectin

Front 301

In the glycolytic sequence, the enzyme that brings about the transition from 6-carbon metabolites to 3-carbone metabolites is:
- phosphoglucoisomerase
- phosphofructokinase
- phosphorylase
- hexokinase
- aldolase

Back 301

aldolase

Front 302

Which of the following represents a striated muscle that contains transverse tubules, a slow rate of calcium sequestration, and is inhibited by acetylcholine?
- Cardiac
- Skeletal
- Multi unit smooth
- Single unit smooth

Back 302

Cardiac

Front 303

Tay-Sachs disease is associated with an inborn error of metabolism involving a specific enzyme which normally degrades a particular molecule in the gray matter. This enzyme acts on which of the following?
- Polysaccharides
- Acylglycerols
- Gangliosides
- Fatty acids
- Proteins

Back 303

Gangliosides

Front 304

Vascular smooth muscle relaxes in response to:
- hyperoxia
- adenosine
- vasopressin
- angiotensin
- norepinephrine

Back 304

adenosine

Front 305

Which of the following is most often associated with free fatty acid transport in human blood?
- Albumin
- Globulin
- Cholesterol
- Sphingolipid
- Mucopolysaccharide

Back 305

Albumin

Front 306

During oxidative phosphorylation, the energetically unfavorable porton gradient is created using energy from which of the following?
- ATP hydrolysis
- ATP synthesis
- ADP transport
- Electron transfers
- The reduction of NAD+

Back 306

Electron transfers

Front 307

Which of the following explains why enamel is harder than bone?
- Enamel crystals are larger and more firmly packed
- Enamel contains amelogenins in its organic matrix
- Enamel contains more magnesium and carbonate
- Enamel crystals have more surface area
- Enamel contains more collagen

Back 307

Enamel crystals are larger and more firmly packed

Front 308

Which of the following represent(s) the matrix proteins of enamel?
- Carboxylglutamic acid containing proteins
- Type I collagen
- Amelogenins
- Proteoglycans
- Elastin

Back 308

Amelogenins

Front 309

ADH receptors in the nephron are locared on the tubular membrane of which of the following?
- Distal tubule
- Proximal tubule
- Ascending loop of Henle
- Descending loop of Henle

Back 309

Distal tubule

Front 310

Which of the following changes promotes the formation of extracellular edema?
- Increase in tissue fluid hydrostatic pressure
- Increase in plasma protein concentration
- Decrease in capillary hydrostatic pressure
- Capillary filtration exceeds capillary absorption
- Capillary absorption exceeds capillary filtration

Back 310

Capillary filtration exceeds capillary absorption

Front 311

In addition to phosphoric acid, which of the following are the products of hydrolysis of lecithin?
- Glycerol, fatty acids, serine
- Glycerol, fatty acids, choline
- Sphingosine, acetic acid, inositol
- Glyceraldehyde, fatty acids, choline
- Glyceraldehyde, fatty acids, ethanolamine

Back 311

Glycerol, fatty acids, choline

Front 312

Ployuridylic acid in a cell-free system capable of protein synthesis results in production of polyphenylalanine. In this system, polyuridylic acid functions as:
- DNA
- transfer RNA
- messenger RNA
- ribosomal RNA
- mitochondrial RNA

Back 312

messenger RNA

Front 313

A derivative of vitamin K is the coenzyme for which of the following?
- Production of menadiol
- Esterification of retinol
- Hydrolysis of peptide bonds
- Cross linking of fibrinogen
- Carboxylation of glutamate side chains

Back 313

Carboxylation of glutamate side chains

Front 314

What single substance is effective in reversing ketosis in a non-diabetic patient?
- Urea
- Glucose
- Insulin
- Leucine
- Palmitic acid

Back 314

Glucose

Front 315

Intensity of sound is dependent mainly on which of the following physical characteristic of sound waves?
- Frequency
- Amplitude
- Wavelength
- Secondary waves
- Sympathetic vibrations

Back 315

Amplitude

Front 316

ATP inhibits phosphofructokinase even though ATP also is a substrate for the enzyme. Which of the following types of inhibitions best explains this phenomenon?
- Allosteric
- Competitive
- Irreversible
- Uncompetitive
- Noncompetitive

Back 316

Allosteric

Front 317

Which of the following best explains why proteins are able to buffer physiologic solutions over a wide range of pH?
- They are macromolecules of high molecular weight
- They contain many functional groups with differing pKs
- They have unique tertiary structures that sequester hydrogen ions
- They have peptide bonds that are resistant to hydrolysis

Back 317

They contain many functional groups with differing pKs

Front 318

The intrinsic factor for vitamin B12 absorption is produced in the:
- liver
- stomach
- panreas
- duodenum
- lacteals

Back 318

stomach

Front 319

Which of the following bonds link the monomeric units of nucleic acids?
- Ionic
- Peptide
- Thioester
- Glycosidic
- Phosphodiester

Back 319

Phosphodiester

Front 320

Emotional feelings are most closely related to which area of the brain?
- Thalamus
- Brain stem
- Cerebellum
- Hypothalamus
- Limbic system

Back 320

Limbic system

Front 321

Each of the following is a glycosaminoglycan except one. Which one is this exception?
- Chondroitin sulfate
- Dermatan sulfate
- Hyaluronic acid
- Heparan sulfate
- Karatine

Back 321

Keratin

Front 322

Each of the following describes hyaluronate except one. Which one is this exception?
- Polyanion
- Highly polar
- Glycosaminoglycan
- Compact, folded structure
- Extracellular matrix component

Back 322

Compact, folded structure

Front 323

Glutamate decarboxylase, an enzyme that catalyzes the formation of gamma-amino butyric acid (GABA), is unique to:
- bone
- skin
- heart muscle
- nervous tissue
- connective tissue

Back 323

nervous tissue

Front 324

The largest amount of body water can be found in which of the following?
- Urine
- Blood plasma
- Intracellular fluid
- Interstitial fluid
- Stomach and intestines

Back 324

Intracellular fluid

Front 325

Most fluid reabsorption by the kidney occurs in which of the following?
- Distal tubule
- Proximal tubule
- Collecting duct
- Ascending loop of Henle
- Descending loop of Henle

Back 325

Proximal tubule

Front 326

Which of the following portions of the cardiovascular system contains the greatest volume of blood?
- Arterioles
- Capillaries
- Systemic veins
- Chambers of the heart
- Pulmonary vasculature

Back 326

Systemic veins

Front 327

Each of the following enzymes functions in association with a membrane except one. Which one is this exception?
- Succinate dehydrogenase
- Na+/K+ ATPase
- Adenylate cyclase
- Phosphofructokinase
- Coenzyme Q reductase

Back 327

Phosphofructokinase

Front 328

Which of the following generates a slowly developing long-term response in targer tissues by binding to an intracellular receptor?
- Glucagon
- Estrogen
- Prolactin
- Growth hormone
- Parathyroid hormone

Back 328

Estrogen

Front 329

Which of the following functions as part of the extracellular matrix?
- Mucin
- Heparin
- Collagenase
- Chondroitin sulfate
- Dolichol phosphate

Back 329

Chondroitin sulfate

Front 330

Which of the following represents the pH of a solution that has a 10^-5 concentration of OH- ions?
- 5
- 7
- 9
- Determinable only if pKa is known
- Determinable only if base composition is known

Back 330

9

Front 331

Compared to slow-twitch (Type I) muscle fibers, each of the following is more characteristic of fast-twitch (Type II) muscle fibers except one. Which one is this exception?
- They contain more mitochondria
- They have higher myosin ATPase activity
- They have fewer capillaries surrounding them
- They have a more extensive sarcoplasmic reticulum
- They contain higher concentrations of glycolytic enzymes

Back 331

They contain more mitochondria

Front 332

Which of the following is most likely to cause respiratory acidosis?
- Moving from high altitude to sea level
- Untreated diabetes mellitus
- Hypoventilation
- Kidney failure
- Vomiting

Back 332

Hypoventilation

Front 333

Hydrolysis of sucrose by the enzyme sucrase yields:
- glucose only
- glucose and maltose
- glucose and fructose
- glucose and galactose
- fructose and maltose

Back 333

glucose and fructose

Front 334

Calcium ions initiate contraction in skeletal muscle when they:
- bind to T tubules
- bind to troponin
- interact with actin
- interact with myosin
- bind to sarcoplasmic reticulum

Back 334

bind to troponin

Front 335

Which of the following enzymes converts trypsinogen to trypsin?
- Enterokinase
- Peptidase
- Secretin
- Pepsin

Back 335

Enterokinase

Front 336

Enzymes that catalyze the anaerobic processes of carbohydrate metabolism are found predominantly in which part of a cell?
- Cytoplasm
- Membrane
- Cell wall
- Nucleus
- Mitochondria

Back 336

Cytoplasm

Front 337

Each of the following characterizes a peptide hormone except one. Which one is this exception?
- Stored in secretory granules
- Synthesized in a precursor form
- Binds to intracellular receptors
- Acts by generating a second messenger
- Usually transported unbound in plasma

Back 337

Binds to intracellular receptors

Front 338

Which of the following substances represents an unsaturated fatty acid?
- Cholesterol
- Palmitate
- Stearate
- Choline
- Oleate

Back 338

Oleate

Front 339

Which of the following acids represents both a product of bacterial glycolysis and is cariogenic?
- Lactic
- Acetic
- Succinic
- Propionic
- Phosphoric

Back 339

Lactic

Front 340

What linkages occur in glycogen at branch points between glucose units?
- Alpha 1, 4
- Alpha 1, 6
- Beta 1, 3
- Beta 1, 4
- Beta 1, 6

Back 340

Alpha 1, 6

Front 341

Protein kinase regulate the activities of key enzymes through which of the following?
- Oxidation
- Hydrolysis
- Acetylation
- Phosphorylation
- Dephosphorylation

Back 341

Phosphorylation

Front 342

Regulation of each of the following mechanisms is associated with the hypothalamus except one. Which one is this exception?
- Sleep
- Water balance
- Body temperature
- Pupillary diameter
- Carbohydrate metabolism

Back 342

Pupillary diameter

Front 343

Each of the following represents an amino acid found in proteins and used directly in the reactions of protein synthesis except one. Which one is this exception?
- Proline
- Arginine
- Tryptophan
- Asparagine
- Hydroxylysine

Back 343

Hydroxylysine

Front 344

For a reaction catalyzed by an enzyme with a Km = 1 mM, which of the following represents the effect on the velocity if [S] is changed from 10 mM to 20 mM? (Assume that the enzyme obeys Michaelis-Menten kinetics)
- Small decrease
- Small increase
- Twofold decrease
- Twofold increase
- Twentyfold increase

Back 344

Small increase

Front 345

Each of the following is an effect of parathyroid hormone except one. Which one is this exception?
- Stimulation of 1 alpha hydroxylase in kidney
- Stimulation of osteoclastic activity in bone
- Stimulation of calcium reabsorption by kidney
- Inhibition of phosphate reabsorption by kidney
- Inhibition of intestinal absorption of calcium

Back 345

Inhibition of intestinal absorption of calcium

Front 346

Which of the following liver enzymes, absent from other tissues, gives the liver an advantage over other cells in taking up glucose after a meal?
- Glucokinase
- Aldolase
- Hexokinase
- Enolase
- Glucose 6 phosphatase

Back 346

Glucokinase

Front 347

In which of the following conditions might the systolic blood pressure be abnormally high?
- Cardiac shock
- Heart failure
- Anaphylactic shock
- Decreased arterial compliance
- Ventricular fibrilation

Back 347

Decreased arterial compliance

Front 348

The concentration of which of the following amino acids can be used as an estimation of the amount of collagen present in a tissue?
- Hydroxyproline
- Aspartic acid
- Proline
- Serine

Back 348

Hydroxyproline

Front 349

If the air temperature is 105ºF and the relative humidity is 10%, then which of the following represents the primary cause for loss of body heat?
- Evaporation
- Conduction
- Convection
- Radiation
- Hyperventilation

Back 349

Evaporation

Front 350

Which of the following hormones is released by the zona fasciculata and exerts permissive actions to allow insulin, glucagon and epinephrine to work more effectively at their targer tissues?
- Androstenedione
- Somatomedin
- Aldosterone
- Thyroxine
- Cortisol

Back 350

Cortisol

Front 351

Which of the following enzymes or processes ensures that the correct amino acid is incorporated for a particular codon during protein synthesis?
- Amino Acyl tRNA synthetase
- Ribosomal protein synthesis
- Post transcription splicing
- RNA synthetase
- Helicase

Back 351

Amino Acyl tRNA synthetase

Front 352

If protein is catabolized for energy, the most of the energy is derived from which of the following?
- Urea production
- Oxidative deamination
- Transamination reactions
- Cleavage of peptide bonds
- Oxidation of alpha keto acids derived from amino acids

Back 352

Oxidation of alpha keto acids derived from amino acids

Front 353

Each of the following lipid classes is incorporated into membranes except one. Which one is this exception?
- Cholesterol
- Ganglioside
- Triglyceride
- Sphingomyelin
- Phosphatidylcholine

Back 353

Triglyceride

Front 354

The amplitude fo an action potential can be increased most easily by increasing which of the following concentrations?
- Intracellular sodium
- Extracellular sodium
- Intracellular chloride
- Intracellular potassium
- Extracellular potassium

Back 354

Extracellular sodium

Front 355

Decreased arterial pressure upon standing is compensated by:
- decreased heart rate
- dilation of mesenteric vessels
- constriction of systemic arterioles
- dilation of venules

Back 355

constriction of systemic arterioles

Front 356

Synaptic vesicles contents are released at the neuromuscular junction when which of the following occurs?
- Hyperpolarization of motor end plate
- Shortening of skeletal muscle
- Release of ATP from neeve terminal
- Entry of calcium at nerve terminal
- Release of acetylcholine from motor end plate

Back 356

Entry of calcium at nerve terminal

Front 357

Which of the following characterizes exergonic reactions?
- Decreased entropy
- Increased enthalpy
- Decreased enthalpy
- Negative free energy change
- Positive free energy change

Back 357

Negative free energy change

Front 358

In an aqeuous solution at pH 7, a peptide containing 1 amino group side chain and 2 carboxyl group side chains would have which of the following net charges?
- 2+
- 1+
- 0
- 1-
- 2-

Back 358

1-

Front 359

A subject consumes 250 ml of oxygen per minute with a tidal volume of 400 ml and a respiratory rate of 18 per minute. Which of the following represents this subject's respiratory minute volume in liters?
- 1.8
- 4.5
- 5.4
- 7.2
- 10.0

Back 359

7.2

Front 360

Each of the following combinations lists the name of the hormone, its chemical type, and its major tissue of origin except one. Which one is this exception?
- ACTH, Steroid, Adrenal cortex
- Vasopressin, Peptide, Posterior pituitary
- Epinephrine, Catecholamine, Adrenal medulla
- Thyrotropin, Glycoprotein, Anteiror pituitary
- Somatostatin, Peptide, Hypothalamus

Back 360

ACTH, Steroid, Adrenal cortex

Front 361

Which of the following causes activation of the pyloric pump, relaxation of the pylorus, and contraction of the lower esophageal sphincter?
- Gastrin
- Secretin
- Pepsinogen
- Acetylcholine
- Cholecystokinin

Back 361

Gastrin

Front 362

An animal is in negative nitrogen balance if its:
- urine is nitrogen free
- nitrogen intake equals output
- nitrogen intake exceeds output
- nitrogen output exceeds intake
- new tissue is being synthesized

Back 362

nitrogen output exceeds intake

Front 363

Each of the following can cause glucosuria except one. Which one is this exception?
- Low insulin level
- High blood sugar level
- Impaired tubular reabsorption
- High glomerular filtration rate
- High renal treshold for glucose

Back 363

High renal treshold for glucose

Front 364

The clearance rate for a substance that is completely removed from the blood during one pass through the kidney is equal to which of the following?
- Renal plasma flow
- Filtration fraction
- Urinary excretion rate
- Glomerular filtration rate
- Tubular transport maximum

Back 364

Renal plasma flow

Front 365

A marked fall from normal in the oxygen tension in arterial blood would stimulate the receptors in the:
- central nervous system chemoreceptors
- aortic arch and the carotid sinus
- aortic and carotid bodies
- walls of the great veins
- respiratory center

Back 365

aortic and carotid bodies

Front 366

Oxygen tension is greatest in which of the following blood vessels?
- Aorta
- Pulmonary vein
- Pulmonary artery
- Coronary artery
- Coronary vein

Back 366

Pulmonary vein

Front 367

Which of the following groups includes only amino acids essential for humans?
- Valine, serine, leucine
- Leucine, lysine, glycine
- Tyrosine, threonine, tryptophan
- Phenylalanine, methionine, proline
- Tryptophan, methionine, isoleucine

Back 367

Tryptophan, methionine, isoleucine

Front 368

Which of the following represents the major force that causes glomerular filtration?
- Tubular hydrostatic pressure
- Tubular colloid osmotic pressure
- Glomerular capillary hydrostatic pressure
- Glomerular capillary colloid osmotic pressure

Back 368

Glomerular capillary hydrostatic pressure

Front 369

If the plasma clearance of a substance which is freely filtered is less than that of inulin, then:
- the substance becomes bound to protein in the tubules
- there is net secretion of the substance in the tubules
- there is a net reabsorption of the substance in the tubules
- the substance is neither secreted nor reabsorbed in the tubules
- the substance is secreted in the proximal tubule to a greater degree than it is in the distal tubule

Back 369

there is net reabsorption of the substance in the tubules

Front 370

Hypoactivity of the posterior pituitary gland leads to:
- dwarfism
- cretinism
- acromegaly
- diabetes insipidus

Back 370

diabetes insipidus

Front 371

The metabolite, 25-hydroxycholecalciferol, is derived most immediately from:
- ergosterol
- cholesterol
- 7 dehydro sitosterol
- 7 dehydro cholesterol
- 22 dihydro ergosterol

Back 371

7 dehydro cholesterol

Front 372

In a complete heart block, the electrocardiograph shows which of the following?
- An increased PQ interval
- An increase in height of the P wave
- One QRS complex for every three P waves
- An increase in amplitude of the QRS complex
- Dissociation of the P wave and the QRS complex

Back 372

Dissociation of the P wave and the QRS complex

Front 373

Cardiac output is expressed as a product of:
- stroke volume and heart rate
- venous pressure and heart rate
- stroke volume and respiratory rate
- stroke volume and diastolic filling
- venous pressure and coronary blood flow

Back 373

stroke volume and heart rate

Front 374

Most of the CO2 in blood is combined as:
- H2CO3
- HCO3-
- CH3COOH
- carbonic acid
- carbaminohemoglobin

Back 374

HCO3-

Front 375

A deficiency of choline in the diet can cause abnormalities in the metabolism of:
- lipids
- proteins
- minerals
- carbohydrates
- nucleoproteins

Back 375

lipids

Front 376

Which of the following is a function of the enterogastric reflex?
- Decreases the opening of the gastroesophageal sphincter
- Increases motility of the esophagus
- Decreases motility of the stomach
- Increases motility of the ileum
- Increased gallbladder emptying

Back 376

Decreases motility of the stomach

Front 377

Which of the following represents a soluble polysaccharide found in dental plaque and is formed from the fructose moiety of sucrose?
- Levan
- Dextran
- Amylopectin
- Hyaluronic acid

Back 377

Levan

Front 378

Preganglionic autonomic nerve fibers are exclusively:
- somatic
- adrenergic
- sympathetic
- cholinergic
- parasympathetic

Back 378

cholinergic

Front 379

Which of the following represents an adequate stimulus for semicircular canals?
- A nystagmus
- A change in the force of gravity
- A linear acceleration and deceleration
- An angular acceleration and deceleration

Back 379

An angular acceleration and deceleration

Front 380

Two-point discrimination requires that two sensory receptors are:
- different in threshold
- of two different morphologic types
- innervated by two different axons
- innervated by branches of the same axon
- separated by a distance of at least 5 mm

Back 380

innervated by two different axons

Front 381

The most important test for hypoventilation is the determination of:
- arterial pH
- arterial CO2 tension
- arterial oxygen tension
- venous CO2 tension
- venous oxygen tension

Back 381

arterial CO2 tension

Front 382

Renal compensation for chronic metabolic alkalosis involves which of the following?
- An increased tubular synthesis of NH3
- A partial reabsorption of the filtered HCO3-
- An elevated production of "new" bicarbonate
- None of these

Back 382

A partial reabsorption of the filtered HCO3-

Front 383

What is the effective filtration pressure under the following conditions?
Capillary blood pressure = 30 mm Hg
Plasma osmotic pressure = 6,000 mm Hg
Tissue fluid osmotic pressure = 5,975 mm Hg
Tissue fluid pressure = 5 mm Hg
- Plus 10 mm Hg
- Plus 5 mm Hg
- 0
- Minus 5 mm Hg
- Minus 10 mm Hg

Back 383

0

Front 384

The length-tension diagram shows that the maximum active tension of a muscle occurs:
- when a muscle is unstretched
- when sarcomere length increases
- when there is maximum overlap of crossbridges
- at the maximum length that a muscle may be stretched

Back 384

when there is maximum overlap of crossbridges

Front 385

Various substances are transported in the blood as complexes associated with plasma proteins. An example of this is the binding of:
- calcium to albumin
- iron to cytochrome c
- cholesterol to globulin
- fatty acids to hemoglobin
- thyroxine to thyroglobulin

Back 385

calcium to albumin

Front 386

Primary recognition of Beta-estradiol by its target cell depends upon the binding of the hormone to a specific:
- nuclear receptor
- cytoplasmic receptor
- cell membrane receptor
- adenylate cyclase

Back 386

cytoplasmic receptor

Front 387

Immediately following the production of Okazaki fragments, the gap between fragments becomes connected through the action of:
- DNA ligase
- exonucleases
- DNA polymerase
- DNA directed RNA polymerase

Back 387

DNA ligase

Front 388

Phosphorylation of some enzymes by ATP converts these enzymes from an active form into a form that is inactive. Which of the following conversion exemplifies this process?
Trypsinogen to trypsin
- Phosphylase b to phosphorylase a
- Phosphodiesterase a to phosphodiesterase b
- Glycogen synthetase I to glycogen synthetase D

Back 388

Glycogen synthetase I to glycogen synthetase D

Front 389

Which of the following amino acids can most easily be converted to tyrosine in the human body?
- Glysine
- Arginine
- Methionine
- Tryptophan
- Phenylalanine

Back 389

Phenylalanine

Front 390

Which of the following classes of steroids contain 18 carbons and an aromatic ring?
- Estrogens
- Androgens
- Progestagens
- Glucocorticoids
- Mineralocorticoids

Back 390

Estrogens

Front 391

A physiologic buffer functions to:
- regulate the partial pressure of venous carbon dioxide
- carry fixed acid from the site of its elimination to the site of its production
- transport carbon dioxide from the site of its production to the site of its elimination
- minimize the increase in hydrogen ion concentration that accompanies cellular acid production
- maximize the decrease in hydrogen ion concentration that accompanies alkali formation

Back 391

minimize the inrease in hydrogen ion concentration that accompanies cellular acid production

Front 392

Platelets play an important role in hemostasis. Which of the following describes this role?
- They convert fibrinogen to fibrin
- They agglutinate and plug small, ruptured vessels
- They initiate fibrinolysis in thrombosis
- They supply fibrin stabilizing factor
- They supply proconvertin for thromboplastin activation

Back 392

They agglutinate and plus small, ruptured vessels

Front 393

The primary force stabilizing the lipid-protein complex in cell membranes is which of the following?
- The covalent linkage
- The ionic interaction
- The hydrophilic bonding
- The hydrophobic interaction

Back 393

The hydrophobic interaction

Front 394

In procaryotic protein synthesis, the elongation factor G serves to:
- form the initiation complex
- facilitate the binding of Fmet tRNA
- translocate the growing peptide chain and to move the ribosome along the mRNA
- prevent the larger ribosomal subunits fro binding with those that are smaller

Back 394

translocate the growing peptide chain and to move the ribosome along the mRNA

Front 395

Gangliosides are glycoproteins found on various cell surfaces. In addition to sphingosine, their unit composition contains another characteristic component. This component is:
- uronic acid
- plasmalogen
- triglyceride
- N acetylmuramic acid
- N acetylneuraminic acid

Back 395

N acetylneuraminic acid

Front 396

Cholesterol is primarily used by mammalian cells as:
- an energy storage material
- a precursor of ketone bodies
- a component of cell membranes
- a precursor of polyunsaturated fatty acids

Back 396

a component of cell membranes

Front 397

Glycosaminoglycans function as important structural components of:
- glycogen
- nucleic acids
- hyaluronidase
- connective tissue

Back 397

connective tissue

Front 398

Which of the following represents the amount of dietary calcium normally absorbed from the gut of an adult man?
- An amount less than 50%
- An amount between 60-70%
- An amount between 80-100%
- An amount dependent upon the mucosal ferritin level

Back 398

An amount less than 50%

Front 399

During which of the following phases of the cardiac cycle are cadiac valves open?
- Rapid filling
- Early ejection
- Isovolumetric relaxation
- Isovolumetric contraction
- None of these

Back 399

None of these

Front 400

What are the end products of glycolysis from glucose produced by L. casei and by other oral acidogenic bacteria?
- 2 CH3CH2OH + 2 ATP
- 2 CH3CHOHCOOH + 2 ATP
- 2 CH3CHO + 2 CO2 + 2 NADH
- 2 CO2 + 2 CH3COCOOH + 2 NADH
- 2 CH3CHOHCOOH + 2 CO2 + 2 NADH + 2 ATP

Back 400

2 CH3CHOHCOOH + 2 ATP

Front 401

For which of the following are the loops of Henle responsible?
- The acidification of urine
- The reabsorption of amino acids
- The reabsorption of most of the glomerular filtrate
- The formation of most of the ammonium ion excreted in the urine
- The establishment of an osmotic gradient within the medulla of the kidney

Back 401

The establishment of an osmotic gradient within the medulla of the kidney

Front 402

Which of the following vitamins functions in coenzyme that are specifically involved in the transfer and utilization of the single carbon moiety?
- Niacin
- Thiamine
- Vitamin A
- Vitamin K
- Folic acid

Back 402

Folic acid

Front 403

Decarboxylation of which of the following amino acids results in formation of a vasodilator?
- Valine
- Histidine
- Arginine
- Aspartic acid
- Glutamic acid

Back 403

Histidine

Front 404

In sickle cell anemia, a variation in an amino acid of hemoglobin is detected. This substitution of valine for glutamic acid:
- results in no change in solubility
- results in no change in isoelectric point
- is a result of a change in DNA coding
- has no noticeable effect on the O2 transport behavior of the erythrocyte

Back 404

is a result of a change in DNA coding

Front 405

Clinical adult onset diabetes mellitus (Type II) results from:
- deficient secretion of insulin
- excess secretion of epinephrine
- failure of the kidneys to retain sugar
- secretion of oxytocin from the posterior pituitary
- loss of the insulin receptor function in the target tissues

Back 405

loss of the insulin receptor function in the target tissues

Front 406

Ammonia helps to reduce the hydrogen ion concentration in body fluids. This mechanism involves the:
- excretion of Na+ into urine
- secretion of ammonia into blood
- reabsorption of sodium into blood
- transfer of ammonia from the tubule lumen to the bloodstream

Back 406

reabsorption of sodium into blood

Front 407

Which of the following represents the basic contractile unit of muscle myofibril?
- The H band
- The Z band
- The sarcomere
- The sarcoplasm
- The sarcolemma

Back 407

The sarcomere

Front 408

In the human female, ovulation is believed to be caused by:
- a shift in anterior pituitary gonadotropin secretion with LH predominating in the mixture
- a sudden diminution of anterior pituitary gonadotropin secretion
- a sudden increase in FSH secretion by the anterior pituitary
- all of these
- none of these

Back 408

a shift in anterior pituitary gonadotropin secretion with LH predominating in the mixture

Front 409

Purine ribonucleoside phosphates are all synthesized de novo from the common intermediate:
- inosine phosphate
- guanosine phosphate
- adenosine phosphate
- guanosine diphosphate
- deoxyadenosine phosphate

Back 409

inosine phosphate

Front 410

Spinal summation in spinal reflexes is dependent upon:
- change in synaptic resistance
- greater frequency of sensory end organ discharge
- increased cholinesterase activity at the synapse
- simultaneous arrival of impulses from a large number of receptors

Back 410

simultaneous arrival of impulses from a large number of receptors

Front 411

If the presence of a specific compound, C, increases the Km for an enzyme-substrate reaction, which of the following would be true about that enzyme?
- C would be a competitive inhibitor of the enzyme
- C would be a noncompetitive inhibitor of the enzyme
- The velocity vs. [S] plot for the enzyme would be the same with or without C
- With C present, the enzyme would convert substrate to product faster
- With C present, it would take less substrate to drive the reaction to half maximum velocity than without C

Back 411

C would be a competitive inhibitor of the enzyme

Front 412

Which of the following enzymes catalyzes the formation of uric acid from purines?
- Urease
- Uricase
- Xanthine oxidase
- Aspartate transcarbamoylase
- Carbamoyl phosphate synthetase

Back 412

Xanthine oxidase

Front 413

The partial pressures of respiratory gases found in arterial blood correspond most closely to those partial pressures found in the:
- alveoli
- atmosphere
- tissue fluid
- venous blood
- cells throughout the body

Back 413

alveoli

Front 414

In the regulation of calcium balance, the greatest elimination of calcium occurs in the:
- kidneys
- sweat glands
- salivary glands
- gastrointestinal tract

Back 414

gastrointestinal tract

Front 415

The lack of which of the following substances during tooth formation most likely induces enamel hypoplasia?
- Vitamins A and D
- Vitamins C and D
- Vitamins C and K
- Phosphorus and iron
- Calcium and fluoride

Back 415

Vitamins A and D

Front 416

Which of the following substances represents the immediate precursor for fatty acid synthesis?
- Glucose
- Citrate
- Acetyl CoA
- Acetoacetate
- B hydroxy B methylglutaryl CoA

Back 416

Acetyl CoA

Front 417

When a substance is filtered by the glomerulus and is neither reabsorbed, nor secreted by the tubules, its clearance is a measure of:
- filtration rate
- renal plasma flow
- filtration fraction
- Tm of the substance
- level of the substance in the blood

Back 417

filtration rate

Front 418

Ingestion of which of the following most markedly affect the rate of gastric emptying?
- Fats
- Minerals
- Proteins
- Carbohydrates
- None of these

Back 418

Fats

Front 419

In both RNA and DNA, the internucleotide linkage is a phosphodiester bond that connects the pentose hydroxyl groups:
- 2' to 3'
- 2' to 5'
- 3' to 1'
- 3' to 5'
- 5' to 1'

Back 419

3' to 5'

Front 420

A low concentration of glucose in the blood and a high concentration of liver glycogen are likely to be caused by:
- insulin
- fasting
- epinephrine
- a high protein diet
- cirrhosis of the liver

Back 420

insulin

Front 421

Which of the following serves as the adrenal medulla's principal function?
- The secretion of steroid hormone
- The biotransformation of carbohydrate
- The secretion of epinephrine and norepinephrine
- The regulation of electrolyte and fluid balance

Back 421

The secretion of epinephrine and norepinephrine

Front 422

Which of the following explains why the biosynthesis of fatty acids requires carbon dioxide or bicarbonate?
- The bicarbonate/carbonic acid buffer system is very efficient at the pH optimum of this sensitive enzyme system
- Bicarbonate is a positive effector for this system and favorably alters the conformation of its enzymes
- Carbon dioxide is incorporated into acetyl coenzyme A forming malonyl coenzyme A (an intermediate in the synthetic process)
- Carbon dioxide is incorporated into carbamoyl phosphate (a reactive intermediate in the synthetic process)
- Carbon dioxide provided an anerobic environment that prevents oxidation of the sulfhydryl groups present in the reactive sites of the enzyme system

Back 422

Carbon dioxide is incorporated into acetyl coenzyme A forming malonyl coenzyme A (an intermediate in the synthetic process)

Front 423

Which of the following is a reflex mediated by the vagus?
- Bile flow from the liver
- Mucus secretion from the Brunner's glands
- Cephalic phase of gastric secretion
- Pancreatic secretion of bicarbonate

Back 423

Cephalic phase of gastric secretion

Front 424

How will a protein respond in an electrophoretic system, should the pH become lower than the isoelectric point of the protein?
- It will become denatured
- It will migrate to the negative pole
- It will migrate to the positive pole
- It will remain stationary and unchanged
- It will separate into its different monomeric forms

Back 424

It will migrate to the negative pole

Front 425

Fluoroapatite can form during hard tissue formation by a(an):
- substitution of OH ions by F ions
- reaction between CaF2 and CaHPO4
- reaction of F ions with hydroxylysine residues
- adsorption of F ions onto hydroxyapatite crystal surfaces

Back 425

substitution of OH ions by F ions

Front 426

Distribution of fluids between intracellular and extracellular compartments is mainly achieved by:
- bulk flow across the capillary wall
- unrestricted movement of sodium to achieve osmotic balance
- unrestricted movement of water to achieve osmotic balance
- unrestricted movement of both sodium and potassium to achieve osmotic balance
- movement of potassium out of the intracellular compartment to achieve osmotic balance

Back 426

unrestricted movement of water to achieve osmotic balance

Front 427

Which of the following characterizes feedback regulation?
- The enterohepatic circulation of bile salts
- The inhibition of gastrin secretion by gastric acid
- The absorption of water from the lumen of the small intestine
- The partitioning of fatty acids by chain length as they are absorbed
- The synthesis of triglyceride from triglyceride digestion products in intestinal epithelial cells

Back 427

The inhibition of gastrin secretion by gastric acid

Front 428

Which of the following amino acids is important in the active site or trypsin and chymotrypsin?
- Serine
- Leucine
- Phenylalanine
- Glutamic acid

Back 428

Serine

Front 429

It is reasonably well-established that the release of which of the following hormones is controlled mainly by nerve impulses?
- Insulin
- Epinephrine
- Testosterone
- Parathyroid hormone
- Deoxycorticosterone

Back 429

Epinephrine

Front 430

Which of the following describes the principal mechanism by which glucocorticoids stimulate their target cells?
- They activate specific genes
- They activate initation factors for protein synthesis
- They increase the intracellular Ca2+ concentration
- They allosterically modify adenylate cyclase activity
- They bind to cell membrane receptors and activate adenylate cyclase

Back 430

They activate specific genes

Front 431

Drinking large quantities of carbonate cola-type beverages could lead to:
- a metabolic alkalosis
- a deposition of pigment in the teeth
- an excessive Ca2+ deposition on enamel
- enamel decalcification due to low pH
- enamel decalcification due to high pH

Back 431

enamel decalcification due to low pH

Front 432

FSH and LH produced by the anterior pituitary act on:
- ovaries but not on testes
- testes byt not on ovaries
- both ovaries and testes
- the adrenal cortex in both sexes

Back 432

both ovaries and testes

Front 433

A component of the coenzyme required for a transamination process is:
- niacin
- thiamine
- folic acid
- pyridoxine
- riboflavin

Back 433

pyridoxine

Front 434

Establishing a tracheostomy results in:
- increased airway resistance
- increased anatomic dead space
- increased physiologic dead space
- decreased respiratory work
- decreased effective alveolar ventilation

Back 434

decreased respiratory work

Front 435

Mobilization of fat stored in adipocytes involves:
- activation of fatty acids by synthesis of acyl CoA
- rearrangement of fatty acids in triglycerides
- phosphorylation of glycerol at the expense of ATP
- activation of triglyceride lipase by ADP
- activation of triglyceride lipase by a cAMP dependent protein kinase

Back 435

activation of triglyceride lipase by a cAMP dependent protein kinase

Front 436

Which of the following is solely determined by the Nernst (equilibrium) potential for sodium between the inside of the axon and the surrounding tissue fluid?
- The membrane potential
- The extent of the after potential
- The sodium permeability of the nerve
- The potassium permeability of the nerve
- The limit of the peak of the action potential

Back 436

The limit of the peak of the action potential

Front 437

Which of the following important nutrients is present in milk in low concentration?
- Iron
- Protein
- Calcium
- Phosphorus
- Carbohydrate

Back 437

Iron

Front 438

Breathing a gas mixture containing 10% O2 and 90% N2 will stimulate respiration. This stimulated respiration will occur because:
- nitrogen has an excitatory effect on the chemoreceptors
- the lack of inspiratory CO2 has an excitatory effect on the chemoreceptors
- low oxygen tension has an excitatory effect on the respiratory center in the brain
- low oxygen tension has an excitatory effect on the peripheral chemoreceptors

Back 438

low oxygen tension has an excitatory effect on the peripheral chemoreceptors

Front 439

In the normal cardiac cycle, the volume of the ventricles is greatest:
- at end systolic volume
- at end diastolic volume
- between aortic valve closure and AV valve opening
- before the "a" wave of the atrial pressure curve
- between the "c" and "v" waves of the atrial pressure curve

Back 439

at end diastolic volume

Front 440

The PR interval in the electrocardiogram is an index of the:
- atrial repolarization
- ventricular depolarization
- ventricular repolarization
- atrial depolarization and conduction through the AV node
- ventricular depolarization plus ventricular repolarization

Back 440

atrial depolarization and conduction through the AV node

Front 441

The affinity of hemoglobin for oxygen diminishes as which of the following is decreased?
- pH
- Pco2
- Temperature
- Hydrogen ion concentration
- 2, 3 diphosphoglyceric acid (DPG)

Back 441

pH

Front 442

Acquired pellicle is primarily composed of:
- aerobic bacteria
- anaerobic bacteria
- salivary glycoproteins
- mineralized calcium phosphate

Back 442

salivary glycoproteins

Front 443

Consider the conversion: alanine --> lactic acid --> glucose. This is an example of:
- glycolysis
- glycogenolysis
- gluconeogenesis
- synthesis of glycerol

Back 443

gluconeogenesis

Front 444

Alanine can be synthesized by transamination directly from which of the following acids?
- Lactic acid
- Pyruvic acid
- Glutaric acid
- alpha ketoglutaric acid
- 3 phosphoglyceric acid

Back 444

Pyruvic acid

Front 445

Which of the following is the best method for determining the three-dimension structure of protein?
- Dialysis
- Electrophoesis
- X ray diffraction
- Ultracentrifugation
- None of these

Back 445

X ray diffraction

Front 446

Mediated (facilitated) diffusion of substances across cell membranes differs from simple diffusion in that mediated diffusion:
- requires ATP
- requires another solute
- is a one directional process
- exhibits saturation kinetics

Back 446

exhibits saturation kinetics

Front 447

Which of the following molecular features contributes to the water-binding properties of proteoglycans?
- The carboxyl groups acting as buffers
- Central hyaluronate (a helix) trapping water within
- The space between the core proteins and the hyaluronate being highly charged
- The large number of alcohol groups on the polysaccharide chaining H bond to water
- The large number of serine and threonine residues in the core protein offering H bonding sites

Back 447

The large number of alcohol groups on the polysaccharide chaining H bond to water

Front 448

Derivatives of riboflavin and niacin function as:
- CO2 receptors
- coenzymes in redox reactions
- factors in transamination reactions
- replacements for each other in biologic reactions

Back 448

coenzymes in redox reactions

Front 449

Negative nitrogen balance (nitrogen excretion > intake) may be caused by:
- growth
- protein synthesis
- dietary lack of essential amino acid
- synthesis and catabolism of equal amounts of body protein

Back 449

dietary lack of essential amino acid

Front 450

Which of the following represents unsound therapeutic protocols?
- Treating hypothyroidic patients with thyroxine
- Treating hyperthyroidic patients by thyroidectomy
- Treating Type I diabetic patients with pig or cow insulin
- Treating acromegalics with biosynthetic human growth hormone
- Treating Type II diabetics with diet and oral medication that stimulate insulin production and/or secretion

Back 450

Treating acromegalics with biosynthetic human growth hormone

Front 451

The cerebellum functions to:
- integrate sensory perception
- initiate nerve impulses responsible for activation of skeletal muscle
- control release of hormones from the posterior pituitary gland
- modify the pattern of muscular response in reflex and voluntary contractions

Back 451

modify the pattern of muscular response in reflex and voluntary contractions

Front 452

In respiration, the removal of hydrogen ions from a substrate is always accompanied by the removal of:
- ATP
- heat
- energy
- oxygen
- electrons

Back 452

electrons

Front 453

How will chronotropy and inotropy be affected when there is sympathetic stimulation to the heart?
- Chronotropy negatively, Inotropy negatively
- Chronotropy negatively, Inotropy positively
- Chronotropy positively, Inotropy negatively
- Chronotropy positively, Inotropy positively

Back 453

Chronotropy positively, Inotropy postively

Front 454

Stimulation of a carotid sinus nerve results in which of the following changes in heart rate, arterial blood pressure and venous return?
- Heart rate increased, Arterial blood pressure decreased, Venous return decreased
- Heart rate increased, Arterial blood pressure increased, Venous return decreased
- Heart rate decreased, Arterial blood pressure decreased, Venous return decreased
- Heart rate decreased, Arterial blood pressure decreased, Venous return no change
- Heart rate no change, Arterial blood pressure decreased, Venous return no change

Back 454

Heart rate decreased, Arterial blood pressure decreased, Venous return decreased

Front 455

Which of the following is not a function of the liver?
- Detoxification
- Gluconeogenesis
- Formation of plasma protein
- Secretion of digestive enzymes
- Regulation of blood sugar level

Back 455

Secretion of digestive enzymes

Front 456

Which of the following is not a reflex mediated by the medulla oblongata?
- Blinking
- Coughing
- Vomiting
- Patellar
- Swallowing

Back 456

Patellar

Front 457

Which of the following is not produced by the hydrolysis of nucleic acids?
- Pentoses
- Phosphates
- Amino acids
- Purine bases
- Pyrimidine bases

Back 457

Amino acids

Front 458

Which of the following are likely to result in highly concentrated urine?
(a) Low sodium diet
(b) Diabetes insipidus
(c) Cellular dehydration
(d) Decreased plasma volume
- a and b only
- a and c only
- a and d only
- b and c only
- b and d only
- c and d only
- a, b, c, and d

Back 458

c and d only

Front 459

Frequency of impulse activity in the afferent nerve from a muscle spindle (Group Ia afferent fibers) is increased by a(an):
(a) relaxation of intrafusal muscle fibers
(b) increased activity in gamma efferent fibers
(c) passive stretch of the muscle
- a only
- a and b
- a and c
- b only
- b and c
- c only

Back 459

b and c

Front 460

Which of the following types of noncovalent bonding are found in proteins?
(a) Ionic
(b) Peptide
(c) Hydrogen
(d) Hydrophobic
- a, c, and d only
- a and d only
- b and c only
- b, c, and d only
- a, b, c, and d

Back 460

a, c, and d only

Front 461

Which of the following can alter the function of the medullary centers for respiration?
(a) The central and peripheral chemoreceptors
(b) The apneustic and pneumotaxic centers in the pons
(c) The central nervous system at the conscious level
- a and b only
- a and c only
- b and c only
- a, b, and c

Back 461

a, b, and c

Front 462

Functions of the hexose monophosphate shunt include the production of:
(a) NADP for lactate oxidation
(b) NADPH for fatty acid synthesis
(c) glucuronic acid for heparin synthesis
(d) D ribose for nucleic acid synthesis
(e) ATP for anaerobic muscle contraction
- a, c, and e
- a and d
- b, c, and e
- b and d
- c only

Back 462

b and d

Front 463

In a system of diffusable ions (Gibbs-Donnan equilibrium), the presence of impermeant ions on one side of a semi-permeable membrane causes which of the following?
(a) An osmotic pressure
(b) A transmembrane potential
(c) An asymmetric distribution of diffusable ions across the membrane
(d) A transient diffusion potential only that will rapidly disappear
- a and b only
- a, b, and c
- b and c only
- b and d only
- c and d only
- d only
- a, b, c, and d

Back 463

a, b, and c

Front 464

Which of the following enzymes require vitamin C for their activity?
(a) Lysyl oxidase
(b) Procollagen proline hydroxylase
(c) Procollagen amino peptidase
(d) Procollagen lysine hydroxylase
(e) Procollagen carboxyl peptidase
- a and c
- a and e
- b and c
- b and d
- c and e
- d and e

Back 464

b and d

Front 465

Temperature-regulating mechanisms that increase heat production include:
(a) shivering
(b) cutaneous vasodilation
(c) increased voluntray activity
(d) cutaneous vasoconstriction
(e) increased secretion of epinephrine from the adrenal medulla
- a, b, and c
- a, b, and e
- a, c, and d
- a, c, and e
- c, d, and e

Back 465

a, c, and e

Front 466

Which of the following changes in the electrical properties of a pacemaker cell can slow down the rate at which the cell initiates impulses?
(a) The treshold potential becoming more positive
(b) The rate of spontaneous depolarization decreasing
(c) The maximum diastolic potential becoming more negative
- a only
- a or b only
- a or c only
- b only
- b or c only
- c only
- a, b, and c

Back 466

a, b and c

Front 467

A person who lacks fruit and vegetables in his diet is likely to develop a dietary deficiency in which of the following vitamins?
(a) Vitamin A
(b) Vitamin B1
(c) Vitamin B12
(d) Vitamin C
(e) Vitamin K
- a, b, and e
- a, c, and d
- a and d only
- a, d, and e
- b, c, and e
- c and d only

Back 467

a and d only

Front 468

Which two of the following characterize smooth muscle?
(a) Spontaneous activity in the absence of nervous stimulation
(b) Sensitivity to the chemical agents either released locally from nerves, or carried in the circulation
(c) Decreased activity in response to stimulation of both divisions of the autonomic nervous system
(d) Decreased tone in response to passive stretch
- a and b
- a and c
- a and d
- b and c
- b and d
- c and d

Back 468

a and b

Front 469

The major driving force for formation of a lipid micelle is:
- protein lipid interaction
- hydrophobic interaction between hydrocarbon tails
- hydrogen bonding between water molecules and the micellar core
- electrostatic interaction between the micellar core and polar heads

Back 469

hydrophobic interaction between hydrocarbon tails

Front 470

Excluding the effect of drugs, apnea occuring after hyperventilation of an anesthetized patient results from:
- decreased demand for oxygen
- increased cerebral blood flow
- decreased carbon dioxide tension
- increased hydrogen ion concentration
- decreased oxygenation of carotid bodies

Back 470

decreased carbon dioxide tension

Front 471

Within physiologic limits, activity of the respiratory center is decreased directly by:
- decreased pH
- increased pH
- increased hemoglobin concentration
- increased plasma carbon dioxide partial pressure

Back 471

increased pH

Front 472

Strong stimulation of spindles in the masseter muscle causes:
- relaxation of the masseter muscle
- contraction of the masseter muscle
- contraction of the digastric muscle
- no change in mandibular position

Back 472

contraction of the masseter muscle

Front 473

Chondroitin sulfate occurs primarily in:
- bile
- blood
- liver
- urine
- cartilage

Back 473

cartilage

Front 474

Combined hydrolysis of one mole of lecithin yields:
- L amino acids
- D monosaccharides
- phosphatidylethanolamines
- 2 fatty acids, 1 glycerol, 1 phosphoric acid and 1 choline residue
- 2 fatty acids, 1 glycerol, 1 phosphoric acid and 1 cholesterol molecule

Back 474

2 fatty acids, 1 glycerol, 1 phosphoric acid and 1 choline residue

Front 475

Which of the following amino acids lessens the need for phenylalanine?
- Lysine
- Leucine
- Glycine
- Tyrosine
- Tryptophan

Back 475

Tyrosine

Front 476

What is the product P in the following reaction?
alpha ketoglutarate + alanine --> pyruvate + P
- Glutamate
- Glutamine
- Aspartate
- Succinate
- Pyridoxine phosphate

Back 476

Glutamate

Front 477

Pantothenic acid is an integral part of:
- NAD
- cobalamin
- folic acid
- coenzyme A
- pyridoxine phosphate

Back 477

coenzyme A

Front 478

Spatial summation results from the:
- convergence of several afferent impulses on the same postsynaptic nerve soma
- repetitive firing of discharges (from the same presynaptic terminal), eventually producing an action potential
- exhaustion of the stores of transmitter substance at the synapse
- elaboration of some inhibitory substance, such as gamma aminobutyric acid, at the synapse

Back 478

convergence of several afferent impulses on the same postsynaptic nerve soma

Front 479

What type of bonds link amino acid residues to form proteins?
- Amide
- Anomeric
- Epimeric
- Hydrogen
- Glycosidic

Back 479

Amide

Front 480

Of the following, the most immediate source of oxaloacetic acid during metabolism is:
- glycine
- aspartic acid
- glutamic acid
- acetoacetic acid
- alpha ketoglutaric acid

Back 480

aspartic acid

Front 481

Proteins rich in basic amino acids, such as lysine and arginine, which bind strongly to DNA are:
- albumin
- keratins
- histones
- gamma globulins
- scleroproteins

Back 481

histones

Front 482

When are nerve fibers hypoexcitable?
- During resting potential
- At the firing level
- During local depolarization
- During negative after potential
- During positive after potential

Back 482

During positive after potential

Front 483

The spinal cord is the only structure in the central nervous system necessary for which of the following body functions?
- Respiration
- Simple reflex
- Temperature regulation
- Coordinated muscle movement

Back 483

Simple reflex

Front 484

Neutral fats contain mixtures of one or more fatty acids esterified with:
- sterol
- glycerol
- lecithin
- sphingosine
- alcohols of high molecular weight

Back 484

glycerol

Front 485

The degenerate nature of the genetic code implies:
- a common tRNA for at least two amino acids
- that a remarkable degree of inaccuracy occurs in transcription
- the existance of multiple codons for each amino acid
- the existance of multiple species of ribosomes for control of messenger translation

Back 485

the existance of multiple codons for each amino acid

Front 486

In which of the following conditions is oxygen partial pressure in arterial blood low?
- Anemia
- Polycythemia
- Pulmonary AV shunt
- Hypovolemia due to hemorrhage

Back 486

Pulmonary AV shunt

Front 487

Which of the following characterizes the links between monomeric units of nucleic acids?
- Ionic bonds
- Gylcosidic bonds
- Phosphodiester bonds
- Phosphotriester bonds

Back 487

Phosphodiester bonds

Front 488

Purine bases taken in the human diet in the form of DNA or RNA are mostly:
- excreted as urea
- excreted in the form of uric acid
- reused and converted to ATP needed as a source of energy
- broken down to give NH3 and either malonic acid or methylmalonic acid

Back 488

excreted in the form of uric acid

Front 489

Ribose phosphate needed for nucleic acid synthesis can be derived from:
- gluconeogenesis
- the pentose phosphate pathway
- the Krebs' tricarboxylic acid cycle
- decarboxylation of aromatic amino acids
- one carbon transfer from tetrahydrofolate derivatives

Back 489

the pentose phosphate pathway

Front 490

A submaximal direct stimulus to skeletal muscle causes:
- contraction of no fibers
- contraction of some fibers
- partial contraction of all fibers int he muscle
- less contraction that with a subminimal stimulus
- more contraction than with a maximal stimulus

Back 490

contraction of some fibers

Front 491

A deficiency of choline in the diet may cause abnormalities in metabolism of:
- lipids
- proteins
- minerals
- carbohydrates
- nucleoproteins

Back 491

lipids

Front 492

Destruction of the cerebellum causes loss of:
- memory
- vision
- hearing
- muscular coordination
- both vision and hearing

Back 492

muscular coordination

Front 493

Which of the following lipids participates in mitochondrial electron transport?
- Ubiquinone
- Beta carotene
- alpha tocopherol
- Sphingomyelin

Back 493

Ubiquinone

Front 494

Corti's organ is responsible for perception of:
- light
- sound
- taste
- temperature
- proprioception

Back 494

sound

Front 495

The annulospiral (primary) ending of the skeletal muscle spindle is stimulated when the:
- muscle is relaxed
- muscle is stretched
- intrafusal fibers are relaxed
- gamma efferent fibers are inhibited

Back 495

muscle is stretched

Front 496

Functionally, visceral smooth muscle and cardiac pacemaker cells are similar in that:
- neither contracts without neural input
- neither has a true "resting" membrane potential
- both require a precontractile stretch to initiate contraction
- the "resting" membrane potential of each is approximately 85 mV

Back 496

neither has a true "resting" membrane potential

Front 497

Failure of the heart to show tetanus when stimulated is explained by:
- fatigue
- automaticity
- a long chronaxie
- a long refractory period

Back 497

a long refractory period

Front 498

The usual plasma concentration of glusoce is 80-100 mg/dl, yet, normally, glucose does not appear in the urine. The best explanation for this fact is:
- glucose is freely filtered, but is removed by the collecting duct
- glucose is freely filtered, but is removed by reabsorption in the proximal convoluted tubule
- the glomerulus prevents glucose from being filtered into the nephron

Back 498

glucose is freely filtered, but is removed by reabsorption in the proximal convoluted tubule

Front 499

Avidin influences which of the following vitamins?
- Niacin
- Biotin
- Thiamine
- Tocopherol
- Phylloquinone

Back 499

Biotin

Front 500

Mobilization of blood sugar from liver glycogen occurs by way of a series of enzymatic reactions. The last step in this sequence is catalyzed by:
- glucokinase
- adenylate cyclase
- glucose 6 phosphatase
- glycogen phosphorylase
- phosphorylase phosphatase

Back 500

glucose 6 phosphatase

Front 501

Acids found in the citric acid (Krebs') cycle are:
- glutamic acid and succinic acid
- glucuronic acid and aspartic acid
- oxaloacetic acid and aspartic acid
- oxaloacetic acid and pyruvic acid
- oxaloacetic acid and alpha ketoglutaric acid

Back 501

oxaloacetic acid and alpha ketoglutaric acid

Front 502

Albinism is a genetic disease that results in incomplete metabolism of:
- alanine
- tyrosine
- cysteine
- histidine
- tryptophan

Back 502

tyrosine

Front 503

Which of the following reactions is the immediate source of energy for muscle contraction?
- Creatine --> creatinine
- ATP --> ADP + inorganic phosphate
- Creatine phosphate + ADP --> ATP + creatine
- Creatine phosphate --> creatine + inorganic phosphate

Back 503

ATP --> ADP + inorganic phosphate

Front 504

Decreased blood colloidal osmotic pressure causes fluid to shift from:
- interstitial space to blood
- blood to interstitial space
- intracellular space to interstitial space
- extracellular space to intracellular space
- None of the above

Back 504

blood to interstitial space

Front 505

The most abundant form of iron in human blood plasma is found:
- as free Fe2+
- as free Fe3+
- as ferritin
- associated with transferrin
- associated with ceruloplasmin

Back 505

associated with transferrin

Front 506

Hydroxylation at the 1 position of 25-hydroxycholecalciferol occurs primarily in the:
- skin
- liver
- kidney
- intestinal mucosa

Back 506

kidney

Front 507

Carbonic anhydrase in erythrocytes increases:
- rate of dissociation of H2CO3
- rate of formation of oxyhemoglobin
- permeability of erythrocytes to HCO3-
- formation of carbamino compounds with hemoglobin

Back 507

rate of dissociation of H2CO3

Front 508

Which of the following is present in plasma but absent in serum?
- Albumin
- Globulin
- Lecithin
- Fibrinogen
- Prothrombin

Back 508

Fibrinogen

Front 509

Which of the following hormones are produced by the neurohypophysis and affect contraction of smooth muscle?
- Vasopressin (ADH) and oxytocin
- Thyrotropin and intermedin
- Adrenotropin and somatotropin
- Aldosterone and lutenizing hormone

Back 509

Vasopressin (ADH) and oxytocin

Front 510

During extended, strenuous exercise, the energy requirement for contracting skeltal muscle is supplied largely from:
- oxidation of fatty acids and acetoacetate
- oxidative decarboxylation of pyruvic acid to acetyl coenzyme A
- oxidation of acetyl coenzyme A in the tricarboxylic acid cycle
- anaerobic transformation of glucose from glycogen to lactic acid

Back 510

anaerobic transformation of glucose from glycogen to lactic acid

Front 511

Dental plaque arised primarily as a result of enzymatic reactions using which of the following?
- Sucrose and lipid
- Sucrose and saliva
- Glucose and saliva
- Glucose and protein

Back 511

Sucrose and saliva

Front 512

Compared with systemic circulation under normal conditions, pulmonary circulation is characterized by low pressure and:
- low flow and low resistance
- equal flow and low resistance
- low flow and equal resistance
- equal flow and equal resistance
- high flow and equal resistance

Back 512

equal flow and low resistance

Front 513

Sounds heard during systole in the antecubital space are produced by:
- closure of AV valves
- closure of the aortic valve
- turbulent blood flow through the artery
- laminar blood flow through the occluded artery

Back 513

turbulent blood flow through the artery

Front 514

The PR interval in an electrocardiogram is an index of the:
- length of auricular filling
- period of isometric relaxation
- length of auricular contraction
- conduction time between atria and ventricle
- period of maximal ejection of ventricular systole

Back 514

conduction time between atria and ventricle

Front 515

The high ration of postganglionic to preganglionic fibers in the sympathetic system has the physiologic result that:
- convergence of stimuli occurs
- synaptic transmission is low, leading to a delay in response
- stimulation of the sympathetic nervous system leads to widespread effects
- stimulation of the sympathetic nervous system leads to very localized, discrete effects
- the presynaptic stimulus must have a greater amplitude than when the number of preganglionic and postganglionic fibers is equal

Back 515

stimulation of the sympathetic nervous system leads to widespread effects

Front 516

Cell bodies of sympathetic preganglionic neurons are located in:
- dorsal root ganglia
- sympathetic chain ganglia
- the brain stem and the spinal cord
- thoracic and lumbar segments of the spinal cord
- none of the above

Back 516

thoracic and lumbar segments of the spinal cord

Front 517

Which of the following causes some degree of temporary alkalosis?
- Hyperventilation
- High fluid intake
- Excessive smoking
- Severe muscular effort
- Ingestion of ammonium chloride

Back 517

Hyperventilation

Front 518

The pathway of extramitochondrial synthesis of even-numbered fatty acids differs from that of the catabolism of fatty acids in that:
- malonyl CoA is an intermediate in synthesis
- acyl carrier protein is needed in catabolism
- no flavoprotein enzymes are required for catabolism
- propionyl CoA may serve as an intermediate in synthesis

Back 518

malonyl CoA is an intermediate in synthesis

Front 519

Tropic hormone releasing factors produced in the hypothalamus are transported into the anterior pituitary through:
- nerve impulses
- the ultrashort feedback mechanism
- the peripheral circulatory system
- the microcirculatory portal system
- long nerve fibers or ducts that also transport neurophysins

Back 519

the microcirculatory portal system

Front 520

Glomerular filtration rate may be determined by clearance of:
- urea
- water
- inulin
- glucose
- para aminohippuric acid (PAH)

Back 520

inulin

Front 521

Secretin functions in digestion of proteins by increasing:
- flow of bile
- secretion of pepsin
- flow of pancreatic juice
- secretion of carboxypeptidase

Back 521

flow of pancratic juice

Front 522

The air remaining in alveoli at the end of a forced maximal expiration is the:
- tidal volume
- vital capacity
- residual volume
- expiratory reserve volime
- inspiratory reserve volume

Back 522

residual volume

Front 523

Normal hemoglobin concentration is about 15 gm/dl blood and normal arterial oxygen content is about 20 ml O2/dl blood. An anemic individual breathing room air with a hemoglobin concentration of 10 gm/dl blood is expected to have:
- normal arterial oxygen tension and normal arterial oxygen content
- reduced arterial oxygen tension and normal arterial oxygen content
- normal arterial oxygen tension and reduced arterial oxygen content
- reduced arterial oxygen tension and reduced arterial oxygen content

Back 523

normal arterial oxygen tension and reduced arterial oxygen content

Front 524

The hemoglobin dissociation curve is shifted to the right by:
- a decrease in temperature
- an increase in arterial Pco2
- an increase in arterial hydrogen ion concentration
- both a decreased in temperature and an increase in arterial hydrogen ion concentration
- both an increase in arterial Pco2 and an increase in arterial hydrogen ion concentration

Back 524

both an increase in arterial Pco2 and an increase in arterial hydrogen ion concentration

Front 525

Prlonged medication with cortisol produces atrophy of the adrenal cortex through:
- inhibition of ACTH production
- inhibition of aldosterone secretion
- direct action on the synthesis of C21 corticoids
- none of the above

Back 525

none of the above

Front 526

Countercurrent multiplier activity of the kidney is dependent upon the:
- presence of ADH
- reabsorption of water from collecting ducts
- intensity of vasoconstriction of efferent arterioles
- active reabsorption of water in the ascending limb of the loop of Henle
- active reabsorption of sodium ions in the ascending limb of the loop of Henle

Back 526

active reabsorption of sodium ions in the ascending limb of the loop of Henle

Front 527

In the absence of compensatory changes, a drop in blood pressure results from:
- vasoconstriction
- increased hematocrit
- increased stroke volume
- increased cardiac output
- decreased venous return

Back 527

decreased venous return

Front 528

The chemical mediator at the neuroeffector junction in sweat glands is:
- atropine
- serotonin
- epinephrine
- acetylcholine
- norepinephrine

Back 528

acetylcholine

Front 529

Hypothyroidism in an adult results in:
- myxedema
- thyrotoxicosis
- osteitis fibrosa cystica
- increased basal metabolic rate

Back 529

myxedema

Front 530

Which of the following hormones facilitates reabsorption of sodium in renal tubules?
- Insulin
- Cortisone
- Vasopressin
- Aldosterone
- Parathyroid hormone

Back 530

Aldosterone

Front 531

Which of the following is the principal action of insulin?
- To mobilize lipid deposits
- To enhance cell permeability to glucose
- To decrease cell permeability to glucose
- To conserve glucose by breaking down amino acids

Back 531

To enhance cell permeability to glucose

Front 532

Which of the following occurs in a normal menstrual cycle?
- Ovulation generally occurs 10 days from the beginning of the cycle
- The ovum generally disintegrates or becomes nonviable if it is not fertilized within four days
- The blood concentration of estradiol increases as the corpus luteum develops
- The blood level of follicle stimulating hormone increases and the level of lutenizing hormone decreases at the time of ovulation

Back 532

The ovum generally disintegrates or becomes nonviable if it is not fertilized within four days

Front 533

The nitrogenous product that is excreted in high amounts after prolonged acidosis is:
- urea
- ammonia
- glutamine
- creatinine
- aspartic acid

Back 533

ammonia

Front 534

Epinephrine is most closely related in structure to:
- niacin
- glucose
- glycerol
- tyrosine
- methionine

Back 534

tyrosine

Front 535

Development of ovarian follicles to the point of ovulation is stimulated primarily by:
- estrone
- progesterone
- luteinizing hormone
- follicle stimulating hormone
- chorionic gonadotropic hormone

Back 535

follicle stimulating hormone

Front 536

Neutralization of acids by saliva results mainly from which of the following salivary contents?
- Mucin
- Ammonia
- Carbonate
- Bicarbonate
- Amino acids

Back 536

Bicarbonate

Front 537

After functioning in the small intestines, the largest portion of bile salts are:
- excreted in the feces
- reabsorbed into the central lacteal
- destroyed by bacteria in the large intestines
- reabsorbed into the portal circulation and reused
- removed from the circulation by the kidneys and excreted in the urine

Back 537

reabsorbed into the portal circulation and reused

Front 538

The function of rhythmic segmentation is chiefly that of:
- macerating food
- mixing food with digestive secretions
- increasing the surface available for absorption
- transporting material down the gastrointestinal tract

Back 538

mixing food with digestive secretions

Front 539

The arrangement of sugars into D- and L- configurations is based upon their resemblance to D- and L-:
- glycine
- glucose
- fructose
- glyceraldehyde
- None of the above

Back 539

glyceraldehyde

Front 540

Which of the following proteins contain trace elements essential for their biologic action?
(a) Trypsin
(b) Myoglobin
(c) Thyroglobulin
(d) Salivary amylase
(e) Carbonic anhydrase
- a, b and c
- a, c and d
- a, d and e
- b, c and e
- b, d and e
- All of the above

Back 540

b, c and e

Front 541

Normal production of sound enamel and dentin requires adequate amounts of which of the following vitamins?
(a) A
(b) B12
(c) C
(d) D
(e) E
- a, b and c
- a, b and d
- a, b and e
- a, c and d
- b, d and e
- c, d and e

Back 541

a, c and d

Front 542

The amino acid composition of mammalian collagen (Type I) is characterized by the presence of:
(a) cysteine
(b) hydroxyproline and hydroxylysine
(c) no sulfer containing amino acids
(d) glycine, as nearly one third the total number of amino acid residues
(e) a high content of aromatic amino acids

Back 542

b, c and d

Front 543

In an experimental animal, the heart rate can be accelerated by:
(a) sectioning vagus nerves
(b) stimulating vagus nerves
(c) sectioning sympathetic nerves
(d) stimulating sympathetic nerves
- a only
- a or b
- a or d
- b or d
- c only

Back 543

a or d

Front 544

Which of the following occur when active transport is involved in the movement of a solute across a biologic membrane?
(a) Expenditure of metabolic energy
(b) A gain in free energy by the system
(c) A unidirectional movement of the solute
(d) Movement of the solute against a concentration gradient
- a and b
- a, c and d
- b, c and d
- b and d only
- All of the above

Back 544

All of the above

Front 545

Which of the following are examples of local (electronic or subtreshold) potentials?
(a) Inhibitory postsynaptic potentials
(b) Excitatory postsynaptic potentials
(c) Generator potentials in pacinian corpuscles
(d) Endplate potentials at the neuromuscular junction
- a, b and c
- a, b and d
- a, c and d
- b, c and d
- All of the above

Back 545

All of the above

Front 546

Which of the following is not a primary (major) electrolyte of saliva?
- Sodium
- Calcium
- Fluoride
- Potassium
- Bicarbonate

Back 546

Fluoride

Front 547

Excessive use of fats by the body as a source of energy during starvation or disturbances in carbohydrate metabolism may lead to any of the following conditions except:
- ketosis
- acidosis
- ketonuria
- alkalosis

Back 547

alkalosis

Front 548

A substance that is actively secreted by the kidney is helpful in measurement of all of the following except:
- renal blood flow
- renal plasma flow
- tubular maximum
- filtration fraction
- glomerular filtration rate

Back 548

glomerular filtration rate

Front 549

Coupled respiration requires all of the following except:
- ADP
- oxygen
- carbon dioxide
- an electron donor
- inorganic phosphate

Back 549

carbon dioxide

Front 550

Each of the following is a function of the liver except:
- bile formation
- urea elimination
- steroid conjugation
- carbohydrate storage
- prothrombin synthesis

Back 550

urea elimination

Front 551

Gastrointestinal hormones act on each of the following organs except the:
- stomach
- pancreas
- duodenum
- gallbladder
- urinary bladder

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urinary bladder

Front 552

The hypothalamus-pituitary complex controls hormonal secretions of all of the following except:
- corpora lutea
- thyroid glands
- ovarian follicles
- parathyroid glands
- interstitial cells of the testes

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parathyroid glands