Mcat- Biology

Front 1

Plasma Hemoglobin as a marker of hemolysis, or cell death

Back 1

Normally, hemoglobin is found on the inside of erythrocytes in the blood and carry oxygen/carbon dioxide. When erythrocytes lyse, or break, they would be expected to release hemoglobin into the blood.

Front 2

How can a bacterium that has certain genes give rise to a daughter cell that lacks these genes?

Back 2

copies of the plasmid containing the genes were not equally distributed to the new daughter cells.

Front 3

Bacterial conjugation is similar to the sexual reproduction of eukaryotic organisms in that it:

Back 3

results in genetic recombination

Front 4

Two Primary factors that determine blood pressure:

Back 4

Cardiac Output & Resistance to blood flow

Front 5

Most fungal spores are:

Back 5

metabolically inactive and haplpoid

Front 6

Inflation of the lungs in mammals is accomplished by:

Back 6

negative pressure pumping action

Front 7

An organism is likely to be a bacterium rather than a virus if it:

Back 7

reproduces via fission

Front 8

Would an increase in the level of plasma aldosterone be expected to follow ingestion of excessive quantities of NaCl?

Back 8

No; aldosterone causes Na+ reabsorption by kidney tubules.

Front 9

The sequence of events in the human menstrual cycle involves close interaction among which organs?

Back 9

Hypothalamus-pituitary-ovary

Front 10

A colony of smooth strain bacteria is grown on a culture containing an experimental drug that cleaves nucleic acid base sequences wherever adenine is paired with uracil. Which of the following processes will be directly affected?

I. Transcription
II. Translation
III. Transformation

Back 10

I and II only. Transcription and translation.

Front 11

Which of the following conditions increases affinity of hemoglobin for oxygen?

I. Increased H+ concentration in the blood
II. Increased CO2 concentration in the blood
III. Increased O2 concentration in the alveolar capillaries

Back 11

III only. Increased O2 concentration in the alveolar capillaries.

Front 12

Glucagon release is stimulated by excess amino acids in the blood. This leads to:

Back 12

increased gluconeogenesis

Front 13

The breakdown of body fat reserves in female athletes would involve which of the following metabolic pathways?

Back 13

Beta Oxidation

Front 14

The role played by tropomyosin in skeletal muscle contraction is most similar to that of:

Back 14

a repressor

Front 15

Oral contraceptives contain a combination of synthetic estrogens and progestins. By which of the following methods do oral contraceptives suppress ovulation?

Back 15

The presence of high levels of estrogen and progesterone inhibit secretion of gonadotopin-releasing hormones, thereby inhibiting leteinizing hormone and follicle stimulating hormone.

Front 16

All of the following are true of RBCs EXCEPT:

A.The cannot synthesize ATP
B. They are incapable of cell division
C. they do not have mitochondria
D.They are derived from the same original type of cells as white blood cells.

Back 16

A. They cannot synthesize ATP.

Front 17

During periods of starvation, the human body can generate glucose from:

Back 17

Glycogen, the glycerol potion of triacylglycerol, and amino acids.

Front 18

Which of the following best explains why, after several weeks of starvation, acetyl CoA is used almost exclusively to produce ketone bodies?

Back 18

Gluconeogenesis depletes the supply of oxaloacetate, which is essential for the entry of acetyl CoA into the Krebs Cycle.

Front 19

Why does the brain use glucose rather than fatty acids as its major metabolic fuel during the early stages of starvation?

Back 19

Glucose can cross the blood-brain barrier via specific carrier molecules, while fatty acids cannot.

Front 20

Parathyroid hormone, which is an antagonist, stimulates activity in:

Back 20

osteoclasts, which dissolve bone.

Front 21

Which of the following symptoms would be present in a patient with Addison's disease, which is the result of adrenocortical deficiency?

Back 21

Low blood pressure and high K+ in the extracellular fluid.

Front 22

The passages of the respiratory tract which do not participate in gas exchange are called anatomical dead space. Compared to air in the alveoli, air in the anatomical dead space will have:

Back 22

lower Pco2 and higher Po2

Front 23

A patent foramen ovale occurs when an infant's foramen ovale does not close completely at birth. Based on the information presented in the passage, this can lead to:

Back 23

hypoxic hypoxia because much of the blood does not reach the lungs to be oxygenated leading to low Po2.

Front 24

During labor, fetal heart rate tracings are monitored for drops in fetal heart rate termed decelerations. A variable deceleration is caused by compression of the umbilical cord. The fetal heart rate initially increases as the flimsy umbilical vein is compressed and then decreases as the umbilical arteries are compressed. How can this be explained?

Back 24

Compression of the umbilical vein decreases fetal blood volume while compression of the umbilical artery increases fetal blood volume.

Front 25

Which of the following regarding somatostatin is true?

Back 25

I. is increased by high blood glucose levels
II. decreases insulin secretion
III. decreases glucagon secretion

Front 26

Which of the following will reduce the amount of filtrate that is entering the Bowman's capsule from the glomerular capillaries?

Back 26

increased plasma protein concentration

Front 27

Which of the following will favor the movement of water, ions, and glucose from the intercellular space of the proximal tubule into the peritubular capillaries?

Back 27

Low capillary hydrostatic and high capillary osmotic pressures

Front 28

DNA with which of the following characteristics would be most easily denatured?

Back 28

Complementary strands which have a higher A-T content than G-C content

Front 29

The main difference between ssDNA and dsDNA is that:

Back 29

dsDNA has strands oriented in an antiparallel fashion, while ssDNA does not.

Front 30

What is the mechanism of action of tropomyosin?

Back 30

Calcium binds to troponin molecules to cause the tropomyosin to shift and expose the myosin-binding sites

Front 31

If an individual voluntarily elevates ventilation rate by increasing the rate and depth of breathing, then which of the following compensatory mechanisms would be helpful for maintaining plasma pH?

Back 31

Decreased absorption of HCO3-

Front 32

What would be the effect of a drug that selectively inhibits carbonic anhydrase in the lumen of the tubule without affecting carbonic anhydrase elsewhere?

Back 32

Both the amount of H+ secreted and the amount of HCO3- reabsorbed will be decreased.

Front 33

Patent ductus arteriosus is a condition that results from a failure of the ductus arteriosus to close completely after birth. Patent ductus arteriosus would result in blood flow from the:

Back 33

aorta to the pulmonary artery