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333 Cards in this Set

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What are the four components of the cell theory?
1. All living things are composed of cells
2. The cell is the basic functional unit of life
3. Cells arise only from pre-existing cells
4. Cells carry genetic information in the form of DNA
What is autoradiography used for?
Used to study protein synthesis; labeling amino acids with radioactive isotopes allows the pathways of protein synthesis to be examined
After centrifugation, where are the sediments of a eukaryotic cell?
High-density ribosomes are at the bottom; low-density mitochondria and lysosomes remain at the top
Describe plasmids in prokaryotes.
Replicate independently of the main chromosome; often contain genes that allow prokaryote to survive adverse conditions
What do cholesterol molecules do in the cell membrane?
Often embedded in the hydrophobic interior to contribute to cell membrane's fluidity
What are cell adhesion molecules (CAMs)?
Proteins that contribute to cell recognition and adhesion; particularly important during development
Through what process do receptors carry specific molecules into the cell?
What occurs in the nucleolus?
Ribosomal RNA (rRNA) synthesis
What occurs on smooth ER and rough ER?
Smooth ER is involved in lipid synthesis, detoxification of drugs and poisons, and transmission of proteins into cytoplasmic vesicles; rough ER is involved in protein synthesis; proteins synthesized on the ribosoms of the rough ER cross into the cisternae, where they undergo chemical modification; the proteins then cross into the smooth ER, where they are secreted in to cytoplasmic vesicles and transported to the Glolgi apparatus
Where are vacuoles more likely to be found?
Plant cells
What is autolysis?
Digestion of cellular contents as a result of a ruptured lysosome membrane
What are two types of microbodies?
Peroxisomes: contain oxidative enzymes that catalyze a class of reactions in which hydrogen peroxide is produced by the transfer of hydrogen frm a substrate to oxygen; break fats down into smaller molecules that can be used for food and detoxify compounds in the liver harmful to the body

Glyoxysomes: found in fat tissue of germinating seedlings; used to convert fats into sugars until seedling is mature enough for photosynthesis
What organelles are inherited from the oocyte (mother)?
Ribosomes and mitochondria
Why are mitochondria semi-autonomous?
Contain their own circular DNA and ribosomes; self-replicate by binary fission
What are microtubules and microfilaments made of?
Microtubules are made of tubulins; microfilaments are made of actin
What are pinocytosis and phagocytosis?
Pinocytosis is the ingestion of fluids or small particles; phagocytosis is the engulfing of large particles
What type of genetic material can viruses have?
Single- or double-stranded RNA or DNA
Because virus s express their genes and reproduce only within a living host cell, what are they called?
Obligate intracellular parasites
What theory of enzyme-substrate interaction is more widely accepted: the induced fit hypothesis or the lock and key theory?
Induced fit
Does activation energy alter the equilibrium constant?
What are enzymes sensitive to?
pH and temperature
Does activation energy affect the overall ∆G of the reaction?
What are enzymes called that are devoid of their necessary cofactors?
What are enzymes called that contain the necessary cofactor?
What are tightly-bound cofactors called?
Prosthetic groups
Describe thiamin's importance in enzymology.
Thiamin is an important cofactor for several enzymes involved inc ellular metabolisma nd nerve conduction; thiamin deficiency often results in a Wernicke-Korsokoff syndrome, in which patients suffer from a variety of neurological deficits
What are two important types of enzyme cofactors?
Metal cations (such as Zn2+, Fe2+_ and small organic groups called coenzymes (such as biotin)
What is Michaelis constant?
Km = (K2 + K3) / K1

K1: E+S --- ES
K2: ES --- E+S
K3: ES --- E+P
What does a low km reflect?
K1 is greater than K2 + K3, so there is a high affinity of the enzyme for the substrate (a lot of ES)
What does 1/2 Vmax represent in terms of Km?
Half of the enzyme's active sites are filled
In terms of temperature, what causes the rate of enzyme-catalized reactiosn to double?
A 10°C increase in temperature
At what pH does the maximal activity of many human enzymes occur?
What is an allosteric enzyme?
Has at least one active site and at least one separate regulatory site; oscillates between an active state and an inactive state, depending on the regulator it binds to (either an allosteric inhibitor or an allosteric activator)
What is an allosteric effect not unique to allosteric enzymes? Give an example.
Increased affinity of an enzyme for its substrate; in hemoglobin, binding of oxygen at one subunit increases teh affinity fr oxygen at remaining three active sites
What are 3 types of enzyme inhibition?
1. Feedback inhibition: end product becomes an allosteric modulator
2. Competitive inhibition: reversible
3. Noncompetitive inhibition: substance forms strong covalent bonds with an enzyme and consequently may not be displaced by the addition of excess substrates; example of allosteric inhibition
How can competitive inhibition and non-competitive be reversed?
Competitive inhibition: increase the number of substrates to decrease the number of enzyme-competitive inhibitor complexes

Non-competitive inhibition: Increase the concentration of the enzyme
What is a zymogen?
An enzyme secreted in an inactive form
What are heterotrophic organisms?
Obtain their energy catabolically via the breakdown of organic nutrients that must be ingested
What is the formula for photosynthesis?
6 CO2 + 6 H2O + Energy --- C6H12O6 + 6O2
What is ATP composed of?
The nitrogenous base adenosine, the sugar ribose, and 3 weakly-linked phosphate groups
What is Pi?
Inorganic phosphate; ATP with only one phosphate group
How many kcal of energy are released per mole of ATP?
Approximately 7 kcal
Does ATP provide energy for endergonic or exothermic reactions?
Are NAD+, NADP+, and FAD reduced or oxidized during catabolic processes?
Reduced to NADH, NADPH, and FADH2 respectively
Aside from the phosphate bonds of ATP, what is a second mechanism by which the cell stores chemical energy?
In the form of high potential electrons, transferred as hydride ions (H:- )
What do NAD+, NADP+, and FAD do?
Transport high-energy electrons (released during the oxidation of glucose) to the electron transport chain (a series of carrier molecules on inner mitochondrial membrane)
Are NAD+, NADP+, and FAD called oxidizing or reducing agents?
Oxidizing agents, because they cause other molecules to lose electrons and undergo oxidation
Is getting a H oxidation or reduction?
What is glycolysis?
Breakdown of glucose into two molecules of pyruvate
How many ATP are generated and produced during glycolysis?
2 are used and 4 are generated, resulting in a net production of 2 ATP
What is the overall reaction for glycolysis, including coupled ATP.
Glucose + 2 ADP + 2 Pi + 2 NAD+ --- 2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
How does pyruvate degradation proceed?
In one of two directions:
- Under anaerobic conditions, pyruvate is reduced through fermentation
- Under aerobic conditions, pyruvate is further oxidized in cell respiration in the mitochondria
What does fermentation refer to?
Glycolysis and the subsequent formation of ethanol or lactic acid.
How many ATP are produced during fermentation?
2 ATP per glucose molecule (from glycolysis)
What is the point of ethanol or lactic acid formation in fermentation?
Regeneration of NAD+
What are the two types of fermentation and where do they occur?
Alcohol fermentation: yeast and some bacteria

Lactic acid fermentation: human muscle cells during strenuous activity; certain fungi and bacteria
Describe what oxygen debt is in lactic acid fermentation.
The amount of oxygen needed to oxidize lactic acid back into pyruvate, so that it can enter cellular respiration (this always happens when enough oxygen is restored)
What are the 3 stages of cellular respiration?
Pyruvate decarboxylation, citric acid cycle, electron transport chain
Where does glycolysis occur?
Where does pyruvate decarboxylation occur?
Mitochondria matrix
What are 2 other names for the citiric acid cycle?
Krebs cycle or tricarboxylic acid cycle (TCA cycle)
What is the net reaction of the citric acid cycle per glucose molecule?
2 Acetyl CoA + 6 NAD+ 2 FAD + 2 ATP + 2 Pi + 4 H2O --- 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP + 4 H+ + 2 CoA
Where does the electron transport chain (ETC) occur?
Inside of the inner mitochondrial matrix
What are most of the molecules of the ETC?
Cytochromes, which resemble hemoglobin in the structure of their active site; functional unit contains a central iron atom, which is capable of undergoing a reversible redox reaction; each carrier is reduced as it accepts an electron and is then oxidized when it passes it on to the next carrier
What is the role of flavin mononcleotide (FMN) in ETC?
First reduced when it accepts electrons from NADH
Why can't the ETC function without oxygen?
At the end of each turn, it combines 1/2 O2 with 2 H+ to form H2O; without the O2, it becomes backlogged with electrons and it cannot regenerate NAD+ for glycolysis (which is when fermentation takes over the formation of NAD+)
What do cyanide and dinitrophenol do to cell respiration?
Cyanide: in ETC, blocks transfer of electrons from final cytochrome a3 to O2

Dinitrophenol: uncouples ETC from protein gradient established across inner mitochondrial membrane
How does the ETC generate ATP?
Because it breaks down NADH into NAD+, a H+ is released; these H+ accumulate in the inner membrane and establish a proton gradient; to pass back into the matrix, have to flow through ATP synthetase complexes, which generate ATP as the H+ flows through
Describe where the 36 ATP come in the aerobic break-down of a glucose molecule.
In Glycolysis:
-2 ATP
(not usual 3 ATP/NADH because cannot cross inner mitochondrial membrane)

Pyruvate decarboxylation:

Citric Acid Cycle:
6 NADH × 3 ATP/NADH = 18 ATP
2 FADH2 × 2 ATP/FADH2 = 4 ATP
2 GTP × 1 ATP/GTP = 2 ATP


Total: 36
Why do prokaryotes produce 38 ATP?
2 NADH of glycolysis don't have any mitochondrial membranes to cross, so still 3 ATP/NADH
Why are fats extremely efficient energy storage molecules?
During β-oxidation (convertion of fatty acids to acetyl CoA), 1 NADH and 1 FADH2 are generated, resulting in 5 extra ATP
What happens when diabetics fail to take their insulin?
Diabetic ketoacidosis (DKA); blood glucose levels accumulate but cannot be used, so bodies resort to breakdown of fats, which produces β-ketoacids eventually resulting in a coma
Where can proteins feed into cellular respiration?
Amino acids can be deaminated (lose NH2), forming α-keto acids, which can become either pyruvate or acetyl CoA
Amino acids can also be transaminated to keto acids, where they feed into the Citric Acid Cycle
Where can fats feed into cellular respiration?
They can be hydrolyzed to glycerol, which can form PGAL, which forms pyruvate
They can also be hydrolyzed to fatty acids, which undergo β-oxidation (releasing 1 NADH and 1 FADH2) to form acetyl CoA
What happens during the G1 stage of mitosis?
Cell doubles in size and new organelles are produced; pass through restriction point, after which it is committed to continue through rest of cell cycle; if do not pass restriction point, enter non-dividing G0 phase
What happens during the S stage of mitosis?
Each chromosome is replicated, after which they consist of two identical sister chromatids held together at centromere
What happens during the G2 stage of mitosis?
Cell continues to grow
When is the DNA called chromatin?
During the mitotic phase, when it appears granular
What are asters?
Outward radiations of spindle fibers from centrioles
What happens during prophase?
Spindle apparatus forms; nuclear membrane dissolves; kinetochores with attached kinetochore fibers appear at the chromosome centromere
What happens during telophase?
Nucleoli reappear; chromosomes uncoil, resuming their interphase form
How many types does the typical somatic cell divide?
20 to 50 times
What is budding?
The replication of the nucleus followed by unequal cytokinesis; occurs in hydra and yeast
What is parthenogenesis?
The development of an unfertilized egg into an adult organism; in most species of bees and ants, the males develop from unfertilized eggs
What happens during prophase I of meiosis I?
Homologous chromosomes come together and intertwine in a process called synapsis; this is when crossing over can occur at points called chiasmata
What separate in anaphase I and II of meiosis?
During anaphase I, homologous chromosomes (doubled versions of chromosomes from each parent) separate (doubled version of a single chromosome)
During anaphase II, sister chromatids separate
What are the two functional components of the testes?
Seminiferous tubules: produce sperm, which are nourished by sertoli cells

Interstitial cells: secrete testosterone and other androgens
What is the pathway of sperm?

Seminiferous tubulus
Vas deferens
Ejaculatory duct
What is seminal fluid and where is it produced?
Mixed with sperm; Seminal vesicles secrete a fructose-rich fluid as an energy source; prostate gland releases alkaline milky fluid that protects sperm from acidic environment; bulbourethral gland secretes viscous fluid with unknown function prior to ejaculation
Describe the terminology of spermatogeneis.
Begin as spermatogonia, which differentiate into diaploid primary spermatocytes; after first meiotic division called secondary spermatocytes; after second meiotic division called spermatids (haploid); mature sperm are called spermatozoa
Describe the organelles of the sperm.
Head is almost entirely nucleus; mitochondria in the neck; caplike structure is called the acrosome, which contains enzymes needed to penetrate the touch outer covering of the ovum
What is a follicle?
Multilayerd sac of cells that contains, nourishes, and protects an immature ovum; produce estrogen
What is the external female genitalia referred to as?
The vulva
Describe oogenesis.
At birth, all in the form of primary oocytes; during menarche, one oocye per month undergoes meiosis I to produce a secondary oocyte and a polar body; the secondary oocyte is expelled from follicle during ovulation; meiosis II does not occur until the zona pellucida and corona radiata are penetrated by a sperm cell, yielding a mature ovum and anther polar body
What are the layers of the oocyte called?
The inner is called the zona pellucida; the outer is called the corona radiata
When and where does fertilization occur?
12-24 hours after ovulation; occurs in the lateral, widest portion of the fallopian tube
Describe what happens when the sperm comes in contact with the membrane.
Sperm forms a tubelike structure called the acrosomal process, which pentrates the egg membrane alowing the sperm nucleus to enter the voum's cytoplasm; this accrosomal reactiontirggers a cortical reactioni n voum, causing calcium ions to be released into the cytoplasm, which initiates a series of reactions that result in the formation of the fertilization membrane, which is a hard membrane prevents multiple fertilizations
For monozygotic twins, what happens if the zygote splits into two embryos at the two-cell stage of development vs. the blastula stage?
Embryos will have separate chorions and separate placentas; during blastula stage, having only one chorionic sac and therefore the same placenta and possible the same amnion
What ratios change during cleavage in early embryonic development.
Increase ratio of nuclear-to-cytoplasmic material; increased ratio of surface-to-volume ratio, improving gas and nutrient exchange
What is the difference between indeterminate and determinatecleavage?
Indeterminate cleavage reuslts in cells that maintain ability to develop into a complete organism (as with monozygotic twins); determinate cleavage results in cells whose future differentiation pathways are determined
What is the difference between a blastula and a blastocyst?
A blastocyst is a mammalian blastula
What are the two parts of the blastocyst?
Inner cell mass, which protrudes into the blastocoel and the trophoblast, which surrounds the blasotcoel
When does the first cell cleavage usually occur in the early embryo?
32 hours after fertilization
Describe the formation of the three-layered gastrula.
Endoderm continues to push into the blastocoel, forming an archenteron (with the opening called the blastopore); proliferation and migration of cells into the space between the ectoderm and the endoderm gives rise to a third cell layer, called the mesoderm
What is the difference between deuterostomes and protostomes?
In deuterostomes, such as humans, blastopore is site of the future anus; in protostomes, blastopore is the site of the future mouth
What cell layer is the thyroid a part of?
What cell layer are the digestive and respiratory tracts a part of?
What cell layer is the bladder a part of?
What cell layer is the excretory system a part of?
Mesoderm (except for the bladder)
What cell layer are the gonads a part of?
Describe the induction of the eye.
Lateral outpocketings from the brain, called optic vesicles, touch overlying ectoderm and induce it to thicken and form the lens placode; the lens placode then induces the optic vesicle to flatten and invaginate inward, forming optic cups, the optic cups then induce the lens placode to invaginate and form the cornea and lens
Describe the inductive effect of the notocord.
Notocord causes overlying ectoderm to bend inward forming neural group ; neural folds group up on the sides and eventually fuse, forming a closed neural tube
Where do neural crest cells come from?
Tips of neural folds; migrate laterally and given rise to many components of the peripheral nervous system
Describe the layers surrounding the fetus
Chorion, chorionic cavity, amnion, amniotic fluid; placenta is the highly vascularized tissue that connects the fetal tissue to the uterine wall
What is the function of the amniotic fluid?
Acts as a shock absorber of external and localized pressure
What is the allantois?
Outpocketing of the gut; blood vessels enlarge and become the umbilical vessel
Does fetal hemoglobin (Hb-F) have a higher or lower affinity for oxygen than adult hemoglobin (Hb-A)?
Do maternal and fetal blood mix?
What is another function of the placenta aside from nourishment?
Produces progesterone, estrogen, and human chorionic gonadotropin (HCG)
What is used to test for pregnancy?
The presence of HCG
What are the three shunts in the fetal circulatory route?
Blood bypasses fetal liver by way of ductus venosus before converging with inferior vena cava; from the right atria, most directly enters left atrium via foramen ovale; blood that does enter the right ventricle is pumped into the pulmonary artery, where it is shunteddirectly fromt eh pulmonary artery to the aorta via the ductus arteriosis; the blood that does reach the lungs is further deoxygenated as blood unloads is oxygen to developing lungs
When does the partially oxygenated blood nourish systemic circulation?
After it goes into the aorta, some returns to the placenta and some nourishes systemic circulation
How does the foramen ovale close?
Decrease blood flow to right atrium; increase blood flow to left atrium from lungs; difference in pressure causes right atrium to close
What happens during the three trimesters?
First trimester: major organs begin to develop; cartilaginous skeleton begins to turn into bone by the seventh week

Second trimester: face apperas

Third trimester: anti-bodies are transported by highly selective active transport from the mother to the fetus for protection against foreign matter
What are the difference between axial and appendicular bones?
Axial is basic framework, including skull, vertebral column, and rib cage; appendicular bones consist of limb bones and pelvic/pectoral girdles
What is cartilage made of?
Firm but elastic matrix called chondrin, secreted by chondrocytes
What is cartilage devoid of?
Vessels and nerves; receives nourishment from nearby capillaries
Describe spongy bone.
Also called cancellous bone; consists of interconnecting lattice of bony spicules, in between which are red and yellow marrow
What is yellow marrow?
Inactive; often infiltrated by adipose tissue
What are diaphysis and epiphysis?
Diaphysis is compact bone surrounding a cavity of bone marrow; epiphysis is spongy bone surrounded by a thin layer of compact bon
What is the epiphysieal plate?
Cartilaginous cells separating diaphysis from epiphysis; site of longitudinal growth
What is the periosteum?
Fibrous sheath surrounding long bone; site of attachment of muscle tissue
What is osteomyelitis?
Infection of a bone's blood supply after injury
What are the components of compact bone?
Collagen fibers, glycoproteins, hydroxyapatite crystals (consisting of calcium, phosphate, and hydroxide)
Define the following:
- Osteons
- Lamellae
- Lacunae
- Canaliculi
- Osteons: structural units of bone; also called Haversian systems (contains lamellae around Haversian canal, which contains nerve and blood supply)
- Lamellae: concentric circles of bony matrix
- Lacunae: house mature bone cells, called osteocytes
- Canaliculi: radiate from each lacuna; connect with each other; allow for exchange of nutrients and wastes
What is the relationship between osteoblasts and osteoclasts (not osteoCYTES)?
Osteoblasts synthesize and secrete organic constituents of bone matrix; once they have become surrounded by their matrix, the mature into osteocytes
What is the difference between endochondral and intramembranous ossification?
In endochondral ossification, existing cartilage is replaced by bone (mostly for long bone formation)
In intramembranous ossification, mesenchymal (embryonic, undifferentiated) connective tissue is transformed into and replaced by bone
What do movable joints consist of?
Synovial capsule, which encloses join cavity/articular cavity; movement facilitated by synovial fluid and articular cartilage on bone surfaces
Define the following:
- myofibrils
- sarcomeres
- sarcoplasmic reticulum
- sarcoplasm
- sarcolemma
- transverse tubulus (T system)
- Myofibrils: fibers divided into sarcomeres
- Sarcomeres: contractile units of myofibrils
- Sarcoplasmic reticulum: modified ER that stores calcium ions; surrounds mofibrils
- Sarcoplasm: cytoplasm of muscle fiber
- Sarcolemma: membrane of muscle fiber; capable of propagating action potentials
- Transverse tubules: channels for ions to flow throughout muscle fibers; propagates action potential
What is the difference between red and white muscle fibers?
Red gibers have a high myoglobin content and many mitochondria for aerobic respiration

White fibers are anaerobic and therefore contain less myoglobin and fewer mitochondria
What are the thin and thick filaments of the sarcomere made of?
Thin filaments are made of actin; thick filaments are made of myosin
What are the H-, I-, and A-bands?
H-band: myosin only
I-band: actin only
A-band: entire myosin fiber
Describe the steps for muscle contraction (on a molecular level).
- At rest, myosin is not attached to actin; hydrolyzed ADP and Pi attached to myosin; troponin and tropomyosin are always attached to actin
- Ca2+ binds to troponin and myosin binds to tropomyosin on actin
- Contraction caused by ATPase activity in myosin head
- ADP and Pi dissociate from myosin and a new ATP binds to myosin, causing detachment of myosin from actin
What is tonus?
Continual low-grade contractions of muscle, even at rest
What happens during the latent period of muscle contraction?
Action potential spreads along the sarcolemma and Ca2+ ions are released
What is tetanus?
Continuous contraction when stimuli are so frequent that the muscle cannot relax
Do smooth muscles have actin and myosin?
Yes, but lack organization of skeletal sarcomeres ~ lack striations
What is myogenic activity?
Reflexive contracting of smooth and cardiac muscle without nervous stimulation
Is cardiac muscle striated?
Yes, because actin and myosin are arranged into sarcomeres
Describe what creatine phosphate is used for?
During rest high-energy phosphate group is transferred to creatine to form creating phosphate and ADP; during exercise, reverse reaction can be used to replenish ATP supply
Does myoglobin have a higher or lower affinity for O2?
What are three types of fibers in loose connective tissue?
Collagenous fibers, elastic fibers, and reticular fibers (join connective tissue to adjoining tissue)

There are also fibroblasts, which make components of these extracellular fibers and macrophages
What is dense connective tissue?
Very high proportion of collagenous fibers in parallel bundles; makes tendons and ligaments
What is the origin and insertion of muscle?
Origin is where muscle attaches to stationary bone (corresponds to proximal end in limb muscles); insertion is the part of the muscle that moves during contraction (corresponds to distal end in limb muscles)
What does an abductor do?
Moves a part of the body away from the midline
Are the contractions of the esophagus voluntary or involuntary?
Initially voluntary; once initiated, involuntary peristalsis proceeds
Describe the two types of glands in the stomach.
Gastric gland responds to nervous impulses from the brain (in response to sense); consists of 3 cell types: 1. Mucous cells, which secrete mucus that protects the lining from acidic juices; 2. Chief cells, which secrete pepsinogen (the zymogen of pepsin); also secrete intrinsic factor which plays a role in absorption of vitamin B12; 3. parietal cells secrete hydrochloric acid, which kills backteria, dissolves intercellualr "glue' in food, and helps convert pepsinogen to pepsin

The pyloric gland secretes gastrin in response to the presence of certain substances; stimulates gastric glands to secrete more HCl and stimulates muscular contractions
What is gastric juice?
Secretions of chief cells and parietal cells
Where are the cardiac sphincter and the pyloric sphincter?
Cardiac spinchter is between esophagus and stomach; pyloric spinchter is between stomach and small intestines
What is the hallmark symptom of pyloric stenosis?
Projectile vomiting
What does the intestinal mucosa secrete to hydrolyze carbohydrates into monosaccharides?
Maltase, lactase, and sucrase
What does the intestinal mucosa secrete to hydrolyze dipeptides and oligo peptides?
What is secretin?
Released by duodenum in response to acidity of chyme, stimulating pancreas to secrete pancreatic juice
What is in pancreatic juice?
Alkaline fluid (high concentration of bicarbonate); trypsinogen (zymogen of trypsin, cleaved by enterokinase), chymotrypsinogen (zymogen of chymotrypsin converted by trypsin); carboxypeptidase; these break down proteins into dipeptides and oligopeptides
What is CCK?
Secreted by duodenum in response to presence of chyme; stimulates secretion of pancreatic enzymes and release of bile
What does bile do?
Walter-soluble region on one end and fat-soluble region on the other; acts as a detergent, exposing more of the lipids' surface area to actions of lipases
What is enterogastrone?
Released by the duodenum if the chyme is particularly fatty; inhibits stomach peristalsis
How are monosaccharides, amino acids, and small fatty acids absorbed?
Diffuse directly into the intestinal capillaries and enter portal circulation via hepatic portal vein
How are larger fatty acids, glyerol, and cholesterol absorbed?
Diffuse into mucosal cells; fatty acids and glycerol recombine to form triglycerides, which, along with phosphoglycerides and cholesterol, are packaged into protein-coated droplets called chylomicrons which are secreted into tiny lymph vessels, called lacteals, in villi; lymphatic system converges with venous blood at the thoracic duct in the neck; processed in blood stream and delivered to the liver, where they are repackaged and released as LDLs, VLDLs, and HDLs
What are 7 functions of the liver?
- Storage of glycogen
- Glyconeogenesis
- Conversin of ammonio to urea
- Lipid metabolism
- Synthesis of proteins in the human blood stream
- Detoxification of drugs and their metabolites in the blood stream
- Production and secretion of bile into the gastrointestinal tract to emulsify fats
What is surfactant?
Lowers tension of alveoli and facilitates gas exchange across membranes
What are the two membranes surrounding the lungs?
Parietal pleura and the visceral pleura; intrapleural space is in between
What muscles contract during inhalation?
External intercostal muscles, causing the diaphragm to contract; (internal intercostal muscles contract during exhalation)
What part of the brain that regulates ventilation?
Medulla oblongata
What type of signals can modify ventilation via the medulla oblongata?
Chemoreceptors (such as those in the aorta), which respond to changes in the pH and pressure of CO2
What does a spirometer measure?
Amount of air normally present in respiratory system and rate at which ventilation occurs
- Vital capacity
- Tidal volume
- Expiratory reserve volume
- Total lung capacity
- Vital capacity: maximum amount of air that can be forcibly inhaled and exhaled from the lungs
- Tidal volume: amount of air normally inhaled and exhaled with each breath
- Expiratory reserve volume: volume of air that can still be forcibly exhaled following a normal exhalation
- Total lung capacity: vital capacity plus the residual volume
How can the body compensate for lower partial pressure of O2 at high altitudes?
Increase rate of ventilation, increase production of red blood cells, increase vascularization in peripheral tissues, decrease hemoglobin's affinity for oxygen to facilitate unloading of oxygen in tissues
What are the first branches off of the aorta?
Coronary veins and coronary sinus, which return deoxygenated blood to the right side of the heart
What are portal system?
Blood travels through two capillary beds before returning to the heart
What is the name of the portal system in the brain?
Hypophyseal portal system
Where are the tricuspid, mitral, and semilunar valves?
Tricuspid valve is between right atrium and ventricle; mitral valve is between left atrium and ventricle; semilunar valves are between right ventricle and pulmonary artery as well as between the left ventricle and the aorta
What is the first heart sound (S1)?
Closing of the two atrioventricular valves
What is the second heart sound (S2)?
Closing of the two semilunar valves
What is the formula for cardiac output?
Cardiac output = heart rate × stroke volume
Describe the neural regulation of heart beat.
SA node (pacemaker) in wall of right atrium spreads impulse to both atria; reaches AV node, which transmits signal to bundle of HIS, which branches into the right and left bundle branches of Purkinje fibers

Parasympathetic system decreases heart rate via vagus nerve; sympathetic system increases heart rate via cervical and upper thoracic ganglia (and epinephrine)
What do P QRS and T represent?
P is the point just before the atria contract; QRS is point right before ventricles contract; T is right before repolarization
What do pulmonary vein transmit blood between?
Carry oxygenated blood from lungs to left atrium
What instrument is blood pressure measured by?
What type of chains does hemoglobin consist of?
2α and 2β chains
What is thallasemia?
Condition where either the β-chain or α-chain of hemoglobin is misconfigured; results in anemia only when one β-chain is affected
How do erythrocytes obtain their ATP?
Glycolysis (they lack mitochondria)
What are the three types of leukocytes?
Granular leukocytes, lymphocytes, and monocytes
What are the 3 types of granular leukocytes and what is their function?
Neutrophils, eosinophils, and basophils; non-specific and attack general invading pathogens; neutrophils predominantly fight bacterial infections, eosinophils are associated with parasitic infection, basophils are associated with allergies and allergic reactions through the release of histamine
What are the 2 types of lymphocytes?
B lymphocytes and T lymphocytes
What are monocytes?
Involved in nonspecific immune response by phagocytizing foreign matter; some migrate from blood to tissue, where they mature into stationary cells called macrophages
Do platlets have a nuclei?
What type of antigens does blood type A have and what type of antibodies does it produce?
A antigens; produces anti-B antibodies
What type of mother-fetus Rh combination is a problem? How is this treated?
When the mother is Rh- and the baby is Rh+; mother is given RhoGAM immediately after delivery, which suppresses the development of active immunity on the mother's part, otherwise erythroblastosis fetalis will occur in which anti-Rh antibodies from mother destroy fetus's blood cells
Describe the chemical reaction when CO2 binds to hemoglobin.
CO2 diffuses into erythrocyte, where it combines with H2O to form H2CO3 via carbonic anhydrase (also causes dissociation), which beaks down into H+ and HCO3-; HCO3- diffuses into plasma;
What happens to hemoglobin's affinity for O2 when H+ increases?
It decreases

(Bohr Effect)
What is the Bohr affect?
Varied affinity in hemoglobin for O2 based on H+, CO2, and O2
What pressures cause fluid to move out of the arteries and into the veins?
Hydrostatic pressure causes fluid to leave the arteries; osmotic pressure (mostly due to proteins such as albumin) causes fluid to enter the veins
What do platlets release when they come in contact with damaged tissue and what does it do?
Thromboplastin, which cleaves the inactive plasma protein prothrombin to thrombin; thrombin converts the plasma protein fibrinogen into fibrin, which coat the damaged area
What is another name for antibodies?
Describe the structure of an antibody.
Two identical heavy chains and two identical light chains, held together by disulfide linkages and noncovalent bonds; antigen binding sites are variable; five different types of constant regions (IgM, IgA, IgD, IgG, and IgE)
What are active immunity and passive immunity?
Active immunity is the production of antibodies during an immune response; passive immunity is the transfer of antibodies produced by another individual (short-lived)
What are the three types of T cells and what do they do?
Cytotoxic T cells, which destroy antigens directly; helper T cells, which activate other B cells, T cells, and other nonlymphocyte cells, such as macrophages; suppressor T cells and , which decrease activity against antigens; some T cells also differentiate into memory cells
What do B cells differentiate into?
Memory cells and plasma cells (which produce antibodies)
Describe the capillary portal system in the kidney.
Afferent arteriole branches into cnvoluted network of capillaries called glomerulus, hich converge into an efferet arterior, which again divides into a capillary network called the vasa recta, which enmeshes the nephron tubule, and then converges in the renal vein
What part of the kidney is the nephron in?:
Loop of Henle runs through the medulla; convoluted tubules and Bowman's capsule are in cortex
Where is there a problem if blood cells or protein are found in the urine?
Glomerulus, because blood pressure forces 20 percent of the blood plasma entering the glomerulus into the surrounding Bowman's capsule
How do diuretics work on the nephron?
Inhibit reabsorption of sodium, increase sodium excretion and in turn water excretion
How is the osmolarity gradient mostly established in the nephron?
Urea diffuses out of collecting duct and into ascending limb; Na+ and Cl- diffuse out of the lower half of the ascending limb and the upper half actively pumps out Na+
Is urine hypotonic or hypertonic to blood?
What are the two hormones that regulate the reabsorption of water?
Aldosterone and ADH
Describe aldosterone.
Produced by the adrenal cortex; stimulates reabsorption of Na+ from the collecting duct and secretion of K+, which increases reabsorption of water, and hence a rise in blood pressure
What is Addison's disease?
Aldosterone is produced insufficiently, causing overexcretion and a drop in blood pressure
What is ADH?
Also known as vasopressin; formed in hypothalamus and stored in posterior pituitary; acts on collecting duct to increase its permeability to water, increasing blood pressure; dependent on plasma osmolarity
Why do alcohol an caffeine cause excess excretion of dilute urine?
Inhibit ADH
What happens to glucose and other monosaccharides after they are absorbed during digestion?
Delivered to liver via hepatic portal vein; glucose-rich blood is processed by the liver, which converts glucose to glycogen for storage; if low glucose concentration , liver converts glycogen into glucose
What is gluconeogenesis?
Synthesis of glucose from noncarbohydrate precursors in the liver
Where are iron and vitamin B12 stored?
What is the lowest layer of the epidermis called that continuously proliferates?
Stratum basilis
What two layers can the dermis be divided into?
Papillary layer, which consists of loose connective tissue; reticular layer, which consists of dense connective tissue
What melanocytes?
Synthesize pigment melanin to protect the body from ultraviolet light
Describe the different in the way the anterior pituitary and posterior pituitary get signals from the hypothalamus.
Anterior pituitary gets signals from hormones produced in hypothalamus; posterior pituitary gets hormones produced by neurosecretory cells from hypothalamus
What are 6 hormones secreted by the anterior pituitary? Give their functions and the hormone from the hypothalamus that stimulates their production.
- Growth hormone; inhibits uptake of glucose by certain cells and stimulates breakdown of fatty acid to conserve glucose; (GHRH)
- Prolactin: stimulates milk production
- ACTH: stimulates adrenal cortex to secrete glucocorticoids (cortisol;cortisone); (CRF)
- TSH: stimulates thyroid to absorb iodine and then release thyroid hormone; (TRH)
- LH: stimulates ovulation and formation of corpus luteum; in males, stimulates interstitial cells to synthesize testosterone (GnRH; also regulated by estrogen and progesterone)
- FSH: causes maturation of ovarian follicles ; in males, stimulates maturation of seminiferous tubules and sperm production (GnRH, also stimulated by estrogen)
What are two hormones secreted by the posterior pituitary? What are their functions?
- Oxytocin: increases strength fand frequency of uterine muscle contractions; stimulates milk secretion (induced by suckling)
- ADH: increase permeability of nephron's collecting duct to water
Are hormones produced by the posterior pituitary?
No, they are only stored from the neurosecretory cells of the hypothalamus.
What are three hormones produced by the thyroid gland what are their functions?
- Thyroxine (T3)
- Triiodothyronine (T4): both T3 and T4 increase rate of cellular respiration and rate of protein and fatty acid synthesis and degradation
- Calcitonin: decreases plasma Ca2+ concentration by inhibiting release of Ca2+ from bone
What are thyroxine and triiodothyronine derived from?
Iodination of tyrosine
What is cretinism?
Hypothyroidism in newborn infants; characterized by mental retardation and short stature
What are 4 hormones produced by the adrenal cortex?
- Cortisol
- Cortisone: both cortisol and cortisone increase blood glucose levels by promoting gluconeogenesis and decrease protein synthesis; reduce body's immunological and inflammatory responses
- Aldosterone
- Androgens
What is aldosterone secretion regulated by?
Renin-angiotensis: when blood volume falls, juxtaglomerular cells of kidney produce renin, which converts angiotensinogen to angiotensis I which is converted to angiotensis II, which stimulates secretion of aldosterone
What produces epinephrine and norepinephrine?
Adrenal medulla
What are catecholamines?
Amino acid-derived compounds, such as epinephrine and norepinephrine, which both increase the rate and strength of the heartbeat, etc.

"Fight-or-flight" hormones
What are the 3 hormones produced by the pancreas and what do they do?
- Glucagon: produced by alpha cells; increases blood glucose levels
- Insulin: lower blood glucose levels; produced by beta cells
- Somatostatin: decreases insulina nd glucagon secretion; regulated by CCK and GH levels
What is hypoglycemia?
Overproduction of insulin, resulting in low blood glucose
What disorder results from the underproduction of insulin?
Diabetes mellitus, characterized by hyperglycemia (high blood glucose levels)
What is ketoacidosis?
Dangerous lowering of blood pH due to excess keto acids and fatty acids in the plasma; usually associated with diabetes mellitus
Describe the menstrual cycle from a hormonal perspective.
FSH and LH promote development of several ovarian follicles, which begin to grow and produce estrogen, which builds up the endometrium; rising estrogen increases GnRH, which stimulates further LH secretion; the surge in LH causes ovulation; LH induces ruptured follicle to develop into corpus luteum, which secretes estrogen and progesterone, which develop and maintain the endometrial lining respectively; if ovum is not fertilized, corpus luteum atrophies, causing estrogen and progesterone levels to drop and the endometrium to slough off
What is the corpus luteum preserved by during the first and second trimester of pregnancy?
Human chorionic gonadotropin (HCG) during the first trimester; during second trimester, HCG levels decline, but progesterone and estrogen produced by placenta itself
Why doesn't a new menstrual cycle start during pregnancy?
High levels of progesterone and estrogen inhibit GnRH secretion, thus preventing FSH and LH from starting a new cycle
What does the pineal gland secrete?
Melatonin, which is believed to play a role in the regulation of circadian rhythms
What is erythropoietin?
Secreted by kidney in response to decreased renal oxygen levels; stimulates bone marrow to produce red blood cells
What hormone does the thymus produce?
Thymosin during childhood, which stimulates T lymphocyte development and differentiation.
What happens to the thymus during adulthood?
It atrophies after the immune system has fully developedI
Where do peptide hormones bind and how do they act on their target?
Bind to surface receptors; generally act as first messengers, causing membrane-bound adenylate cyclase to convert ATP to cAMP, which acts as a second messenger, which causes a cascade effect activated by phosphodiesterase
Where do steroid hormones bind and how do they act on their target?
Bind to intracellular receptors; bind to DNA to promote transcription of specific genes
Give examples of peptide and amino-acid derived hormones.
Peptides: ADH, insulin
Amino-acid derived: epinephrine, thyroxine
How do amino-acid derived hormones act on their targets?
Some like peptide hormones, such as epinephrine, others like steroid hormones, such as thyroxine
What is the axon hillock?
Connects cell body to axon
Are K+ and Na+ higher inside or outside of the neuron?
K+ is higher inside, making it more negative; Na+ is higher outside
What is the usual threshold membrane potential?
Around -50 mV
What happens after a threshold is reached in a neuron?
Voltage-gated Na+ open and Na+ flow inside; in turn, voltage-gated K+ open and K+ flow out, often resulting in hyperpolarization; Na+-K+ pump re-establishes resting potential
What is it called when action potentials "jump" from node to node?
Saltatory conduction
What are afferent and efferent neurons?
Afferent neurons are sensory neurons; efferent neurons are motor neurons
What are the parts of the forebrain?
Telencephalon (cerebral cortex) and diencephalon (thalamus and hypothalamus)
Describe the midbrain
Relay center for visual and auditory impulses; plays an important role in motor control
What are the 3 parts of the hindbrain?
- Cerebellum: modulates motor impulses initiated by motor cortex; important for balance
- Pons: relay center allowing cortex to communicate with cerebellum
- Medulla: vital functions such as breathing, heart rate, and gastrointestinal activity
What is another name for the hindbrain?
What is myasthenia gravis?
Body mounts an immune response against the acetylcholine receptors on skeletal muscle
What part of the spinal cord do sympathetic nerves emerge from?
Thoracic and lumbar regions
What do the preganglionic and postganglionic neurons release in the sympathetic nervous system?
Preganglionic release acetylcholine; postganglionic release norepinephrine
What do the preganglionc and postganglionic neurons release in the parasympathetic nervous system?
Both release acetylcholine
Define the following:
- Sclera
- Choroid layer
- Retina
- Cornea
- Pupil
- Sclera: thick, opaque layer covering eyeball
- Choroid layer: beneath sclera; supplies retina with blood
- Retina: innermost layer
- Cornea: transparent at front f eye; bends and focuses light rays
- Pupil: opening controlled by iris
Is the lens of the eye a convex or a concave curve?
Is a lens with a larger radius of curvature (flatter) better for near or far vision?
Longer focal length, so better for far vision
What colors do cones absorb?
Red, blue, and green
What is the rod pigment called?
Describe the connection pathway in the retina.
Photoreceptors synapse onto bipolar cells, which synapse onto ganglion cells, which bundle to form optic nerves
What is the point at which the optic nerve exist the eye called?
Blind spot
What is the fovea?
Area of retina densely packed with cones for high acuity vision
What is the auricle?
Pinna; outer ear
Describe the transmission of sound in the ear.
At the end of the auditory canal is the tympanic membrane (ear drum) which vibrates at the frequency of the incoming sound, causing malleus, incus, and stapes to amplify stimulus and transmit it through oval window, which leads to cochlea, which contains orga of Corti that has specialized sensory hair cells; vibration of fluid in cochlea stimulates hair cells to transduce pressure into action potentials via auditory nerve
Describe the semicircular canals?
three perpendicular canals in the inner ear; filled with endolymph; rotation of head displace endolymorph which puts pressure on hair cells, which changes nature of impulses sent by vestibular nerve to the brain
Describe taste buds
Composed of approximately 40 epithelial cells with a taste pore, from which taste hairs protrude; transmit information to brainstem via three cranial nerves
Do taste buds respond preferentially?
Though most respond to all four stimuli, they also respond preferentially
Describe the neural sensation of smell.
Odorous substance binds to receptors in cilia, depolarizing olfactory receptors; axons from olfactory receptors join to form olfactory nerves, which project to olfactory bulbs in base of brain
What were Mendel's 4 principles of inheritance?
1. Genes exist in alternate forms (alleles)
2. An organism has two alleles for each inherited trait
3. Two alleles segregate during meiosis
4. If two alleles in an organism are different, only one will be fully expressed
Describe 9:3:3:1
Mixing of two hybrid genes (AaBb and AaBb)

9 are both dominant
3 are dominant for first, recessive for second
3 are dominant for second, recessive for first
1 is recessive for both
Does the number of chromosomes decrease from 2N to N during meiosis I or II?
Meiosis I
What is codominance?
Multiple alleles exist for a given gene and more than one is dominant, such as ABO blood groups
In terms of genetics, what is penetrance?
Percentage of individuals in population carrying allele who express the phenotype associated with it
What is expressivity in genetics?
Degree to which the phenotype associated with genotype is expressed in individuals who carry the allele; degree to which it is expressed
What are non-sex chromosomes called?
How can a girl get a recessive sex-linked gene?
If father expresses and mother is a carrier
What is nondisjunction?
Trisonomy (2N + 1) of chromosome 21
What is Klinefelter's syndrome?
XXY; sterile males with abnormally small testes
What is Turner's syndrome?
XO females; fail to develop secondary sexual characteristics
Describe XXX and XYY individuals.
XXX are females; referred to metafemales; mentally retarded and sometimes infertile
XYY are normal males; tend to be taller than average and more violent
Are purines and pyrmidines single-ringed or double-ringed?
Purines are double-ringed; pyrmidines are single-ringed
What are the purines and pyrmidines in DNA?
Purines are adenine and guanine; pyrmidines are cytosine and thymine
How many hydrogen bonds are formed between A and T and G and C, respectively?
Two between A and T; three between G and Cs
What is at the 5' end of a strand of DNA?
Phosphate group/OH group
What enzymes are involved in the unwinding and initiation of DNA replication?
Helicase unwinds helix; DNA gyrase enhances action of helicase by introducing negative supercoilds into DNA; single-strand binding protein (SSB) binds to single strands and stabilizes them; RNA polyermase (primase) synthesizes primar, which binds to segment of DNA it is complementary to
In what direction does DNA synthesis proceed?
Add proteins from 5' to 3'; follow strand from 3' to 5' (which is automatically in that direction in the leading fragment)
What are the series of short segments called that DNA polymerase synthesizes on the lagging strand?
Okazaki fragments
What does DNA ligase do?
Covalently links DNA fragments
Describe the different types of RNA.
- mRNA: carries complement of a DNA sequence from nucleus to ribosomes, where protein syntehsis occurs; one mRNA codes for one polypeptide
- tRNA: aids in translation of mRNAs nucleotide code into a sequence of amino acids; brings amino acids to ribosome during protein synthesis; at least one tRNA for each amino acid; one end contains anticodon that is complementary to an mRNA codon; other end is site of amino acid attachment
- rRNA:structural component of ribosomes
- hnRNA: precursors of mRNA
What is mRNA synthesized by?
RNA polymerase, which must bind to sites on RNA called promoters and occurs until polymerase encounters termination sequence
What codons signal starting and termination?
Start: AUG
Stop: UAA and UGA
What are the 3 binding sites of the ribosome?
One for mRNA and two for tRNA (P site binds to tRNA attached to growing polypeptide chain that already released its amino acid); A site binds to incoming aminoacyl-tRNA complex
What is always the initiator aminoacyl-tRNA complex?
methionine-tRNA (binds to AUG)
What catalyzes the formation of a peptide bond between the amino acid attached to the tRNA in the A site and that in the P site?
Peptidyl transferase
What is translocation?
Unchanged tRNA from P site is expelled and peptidyl-tRNA from A site moves to P site
What binds to the termination codons on mRNA?
Release factor (rather than an aminoacyl-tRNA), causing a water molecule to be added to the polypeptide chain and causes the release of the polypeptide chain from the tRNA and ribosome
What is a polyribosome?
Several ribosomes translating the same mRNA
What is sickle-cell anemia the result of?
A valing (GUG) where there should be a glutamic acid (GAG) in hemoglobin
What are transposons?
Mobile pieces of DNA that can insert themselves in genes and cause mutation
What is RNA replicase used for in viruses?
Transcribes new RNA from an RNA template; if viruses don't bring RNA replicase,bring mRNA that is translated into RNA replicase
What do retroviruses do?
Use their RNA as a template for DNA syntehsis by reverse transcriptase; retroviral DNA becomes integrated into the host DNA
What is it called when viral DNA becomes integrated into host DNA?
Provirus (animal viruses) or prophage (bacteriophages)
What are virulents?
Baceriophages that replicate by the lytic cycle, killing their host cell
Does prokaryotic DNA code for a single peptide or multiple peptides?
It can be polycystronic, coding for multiple peptides
What is an episome?
Plasmids capable of integrating into the bacterial genome
What are the three mechanisms that bacteria can use to increase genetic variance of a population?
- Transformation: incorporation of a foreign plasmid via recombination
- Conjugation: transfer of genetic material between two bacteria that are temporarily joined; conjugation bridge formed from appendages called sex pili on the donor male; conjugation bridge usually breaks before entire chromosome is transferred, but they are Hfr cell s(have high frequency of recombination)
- : fragments of bacterial chromosome accidentally become packaged into viral progeny; these virions may infect other bacteria and introduce new genetic arrangements through recombination
What type of bacteria are capable of conjugation?
Those containing plasmids called sex factors, such as the F factor in E. coli
What are inducible and repressible systems of transcription?
Inducible require an inducer to bind to the repressor to take it off so transcription can occur; repressible require a corepressor to bind to and activate repressor to inhibit transcription
Give an example of inducible and repressible systems.
Inducible: lac operon
Repressible: trp operon
What are homologous and analagous structures?
Homologous: similar structure and functional origin, as in mammalian forelimbs

Analagous: functional similarity, but different evolutionary origin
What is the Hardy-Weinberg equation?
Frequency of alleles remains the same in a non-evolving population

p2 + 2pq + q2 = 1

p2 = frequency of TT
2pq = frequency of Tt
q2 = frequency of tt
What is genetic drift?
Changes in the composition of gene pool due to chance; tends to be more pronounced in small populations, (founder effect)
What is gene flow?
Migration of individuals between populations
What are directional and disruptive selection?
Direction: occurs when organisms must adapt to a changing environment, as with the emergency of DDT-resistance mosquitos; disruptive selection: favoring of both phenotypic extremes, leading to polymorphism (existence of two or more phenotypic forms)
What is inclusive fitness?
Fitness as the number of an individuals' alleles that are inherited by the next generation
- Microspheres
- Coacervates
- Protobionts
- Microspheres: proteinaceous droplets from abiotically produced polymers
- Coacervates: colloid droplets capable of enzymatic activity within their membrane
- Protobionts: primitive ancestors of living cells
Is pupil dilation a sympathetic or a parasympathetic response?
What are the 3 types of viruses?
1. DNA Viruses: Viral DNA is inserted into host cell DNA
2. Simpe RNA Viruses: Viral RNA is translated directly into mRNA via RNA replicase (host cell DNA is not involved
3. Retroviruses: Viral RNA is translated into DNA via reverse transcriptase and inserted into the host DNA
What do reverse transcriptase and RNA replicase do?
Reverse transcriptase translates viral RNA into DNA, which is then inserted into host cell DNA; RNA replicase translates viral RNA directly into mRNA (which is then translated into proteins) without the host cell's DNA becoming involved
What does increased osmolarity mean?
Increased solute content
Describe the inheritance of the ABO blood system?
A and B are codominant to O, so a person with AO and AA will have type A; if a person with AB has a child with someone with type O, the children can have either AO (A) or BO (B)