MCAT Practice Questions

While cleaning your house, you notice a large spider on the wall by your head and feel your heart rate jump up and your skin temperature grow warm. Which stage of stress response are you experiencing? A. Alarm B. Resistance C. Exhaustion D. Homeostasis

A. Alarm

Which of the following characteristics is NOT attributed to antibodies? A. Antibodies bind to more than one distinct antigen. B. Antibodies label antigens for targeting by other immune cells. C. Antibodies can cause agglutination by interaction with antigen. D. Antibodies have two heavy chains and two light chains.

A. Antibodies bind to more than one distinct antigen.

A stroke patient comprehends speech but cannot move her mouth to form words. Which of the following brain areas is likely affected? A. Broca's area B. Wernicke's area C. arcuate fasciculus D. superior temporal gyrus

A. Broca's area

Which of the following terms refers to the burden or degree of disease associated with a given illness? A. Morbidity B. Mortality C. Second sickness D. Chronicity

A. Morbidity

Matt and Cati discuss the reasons why they avoid driving above the speed limit. Matt says that he wants to avoid a traffic fine, while Cati says that speeding is dangerous and, if everyone did it, there would be more accidents and people would get hurt. According to Kohlberg, which of the following describes the phases of moral reasoning demonstrated by Matt and Cati, respectively? A. Preconventional; conventional B. Preconventional; postconventional C. Conventional; preconventional D. Postconventional; conventional

A. Preconventional; conventional

Some cellular membranes sequester hydrogen ions on one side in order to create an acidic or basic environment. For example, the membrane of lysosomes contains proton pumps that move hydrogen ions into the lysosome. For a cell with the following half-reactions: Anode: SO2 + 2H2O --> SO4-2 + 4H+ + 2e- Cathode: Pd2+ + 2e- --> Pd How would decreasing the pH of the solution inside the cell affect the electromotive force (emf)? A. The emf would decrease. B. The emf would remain the same. C. The emf would increase. D. The emf would become zero.

A. The emf would decrease.

A researcher uses a partial-report procedure after presenting participants with an array of nine numbers for a fraction of a second. Which of the following is the most likely result of this procedure? A. The participant will be able to recall any of the rows or columns in great detail but only immediately after presentation. B. The participant will only be able to recall the first few numbers in the array due to the serial position effect. C. The participant will be able to recall approximately seven of the numbers for a few seconds following presentation of the stimulus. D. The participant will not be able to recall any of the numbers verbally, but will be able to draw the full array under hypnosis.

A. The participant will be able to recall any of the rows or columns in great detail but only immediately after presentation.

Photons and other energy sources can exite electrons into higher energy levels, though these excitations are typically short-lived. X-ray imaging succeeds because different tissue types are differently able to absorb the energy of a photon in order to excite an electron. Suppose an electron falls from n = 4 to its ground state, n = 1. Which of the following effects is most likely? A. A photon is absorbed. B. A photon is emitted. C. The electron moves into a p-orbital. D. The electron moves into a d-orbital.

B. A photon is emitted.

While on the phone, a friend says: "A good friend would let me borrow the bike." This friend is using which impression management strategy? A. Managing appearances B. Alter-casting C. Ingratiation D. Self-disclosure

B. Alter-casting

Which of the following is true about cholesterol? A. Cholesterol always increases membrane fluidity in cells. B. Cholesterol is a steroid precursor. C. Cholesterol is a precursor for vitamin A, which is produced in the skin. D. Cholesterol interacts only with the hydrophobic tails of phospholipids.

B. Cholesterol is a steroid precursor.

Which of the following is/are function(s) of NADPH in the cell? I. Antimicrobial resistance via bacterial destruction by bleach within lysosomes. II. Involvement in the production of the precursors to steroid hormones. III. Functional carriage of energy across organelle membranes for use within the mitochondria A. I only B. I and II only C. II and III only D. I, II, and III

B. I and II only

Which of the following is true regarding bipolar disorders? I. They have little, if any, genetic heritability. II. They are associated with increased levels of serotonin in the brain. III. They all require at least one depressive episode for diagnosis. A. I only B. II only C. I and III only D. II and III only

B. II only

Ingested acetic acid is a common source of biochemical acetyl groups, including those that form acetyl-CoA. Acetic acid dissociates in solution according to the following equation: CH3COOH --> CH3COO- + H+ If sodium acetate is added to a solution of acetic acid in excess water, which of the following effects would be observed in the solution? A. Decreased pH B. Increased pH C. Decreased pKeq (pKa) D. Increased pKeq (pKa)

B. Increased pH

Where does β-oxidation of fatty acids occur within the cell? A. Cytosol B. Mitochondria C. Smooth endoplasmic reticulum D. Plasma membrane

B. Mitochondria

An EMT sees himself as a bit of a rebel, but is highly sociable and is able to keep calm in an emergency. This person would likely score in the lower range of which of the following traits? A. Psychoticism B. Neuroticism C. Extraversion D. Conscientiousness

B. Neuroticism

Elephant seal males mate with multiple females each mating season, while females only have one mate each. What type of mating system is this? A. Polyandry B. Polygyny C. Monogamy D. Promiscuity

B. Polygyny

How does the inner mitochondrial membrane differ from the outer mitochondrial membrane? A. The inner mitochondrial membrane is more permeable and lacks cholesterol. B. The inner mitochondrial membrane is less permeable and lacks cholesterol. C. The inner mitochondrial membrane is more permeable and has cholesterol. D. The inner mitochondrial membrane is less permeable and has cholesterol.

B. The inner mitochondrial membrane is less permeable and lacks cholesterol.

Why is the α-anomer of d-glucose less likely to form than the β-anomer? A. The β-anomer is preferred for metabolism. B. The β-anomer undergoes less electron repulsion. C. The α-anomer is the more stable anomer. D. The α-anomer forms more in L-glucose.

B. The β-anomer undergoes less electron repulsion.

Becoming a college graduate requires hard work and diligence in academics. As such, being a college graduate could be considered a(n): A. ascribed status B. achieved status C. master status D. pigeonholed status

B. achieved status

A 28-year-old male comes to a clinic concerned that he has pancreatic cancer. Review of his medical records shows that this is the fourth time in the past year that the patient has appeared for medical attention. No identifiable medical problem is found. When confronted with this history, he confesses that he feels relieved after being told that all of the tests are negative, but soon becomes worried again that he has cancer. Based on the information, the most likely diagnosis for this patient would be: A. major depressive disorder. B. illness anxiety disorder. C. conversion disorder. D. narcissistic personality disorder.

B. illness anxiety disorder.

Prolonged vitamin B12 deficiency can be associated with subacute combined degeneration of the spinal cord. Patients with this disease have difficulty walking because they lose the ability to feel where their feet are in space. This represents a loss of: A. vestibular sense. B. kinesthetic sense. C. parallel processing. D. feature detection.

B. kinesthetic sense

A young adult male claims to have had sexual relationships mostly with other men, although he has been attracted to women at times. What would be his most likely score on the Kinsey scale? A. 0 B. 1 C. 5 D. 6

C. 5

A woman notices that her father has started to move his fingers in such a way that it looks like he is rolling something, despite nothing actually being there. She also notes slowed movement and a shuffling gait. Which neurotransmitter is likely to be present in decreased levels in her father's brain? A. Epinephrine B. Histamine C. Dopamine D. Serotonin

C. Dopamine

A student is trying to determine the type of membrane transport occurring in a cell. She finds that the molecule to be transported is very large and polar, and when transported across the membrane, no energy is required. Which of the following is the most likely mechanism of transport? A. Active transport B. Simple diffusion C. Facilitated diffusion D. Exocytosis

C. Facilitated diffusion

Your neighbor asks you to check his mail while he is out of town, and you agree. Later that day, he asks you to water his plants as well. What technique for compliance is he using in this scenario? A. Lowball technique B. That's-not-all technique C. Foot-in-the-door technique D. Door-in-the-face technique

C. Foot-in-the-door technique

Glen brings cookies to work. Although you have not yet tasted them, you say to another coworker, "Glen is such a great guy; I'm sure these cookies are fantastic!" What type of bias is this? A. Reliance on central traits B. Direct benefits C. Halo effect D. Similarity

C. Halo effect

A child has experienced nervous system damage and can no longer coordinate the movements to dribble a basketball, although she can walk. Which region of the central nervous system was most likely affected? A. Forebrain B. Midbrain C. Hindbrain D. Spinal Cord

C. Hindbrain

Which of the following is least likely to cause denaturation of proteins? A. Heating the protein to 100 °C B. Adding 8 M urea C. Moving it to a more hypotonic environment D. Adding a detergent such as sodium dodecyl sulfate

C. Moving it to a more hypotonic environment

A rat is trained to press a lever to obtain food under a fixed-interval schedule. Which of the following behaviors would the rat most likely exhibit? A. Pressing the lever continuously whenever it is hungry. B. Pressing the lever exactly once and waiting for the food pellet before pressing it again. C. Pressing the lever slowly at first, but with increasing frequency as the end of the interval approaches. D. None of the above; the association formed by fixed-interval schedules is too weak to increase behavior.

C. Pressing the lever slowly at first, but with increasing frequency as the end of the interval approaches.

Why are triacylglycerols used in the human body for energy storage? A. They are highly hydrated, and therefore can store lots of energy. B. They always have short fatty acid chains, for easy access by metabolic enzymes. C. The carbon atoms of the fatty acid chains are highly reduced, and therefore yield more energy upon oxidation. D. Polysaccharides, which would actually be a better energy storage form, would dissolve in the body.

C. The carbon atoms of the fatty acid chains are highly reduced, and therefore yield more energy upon oxidation.

A student is volunteering in a hospital with a stroke center. When asked what he believes is the prevalence of stroke among those greater than 65 years old, the student states that it is probably about 40% even though data analysis indicates that it is significantly lower. What accounts for this error? A. Deductive reasoning B. Representativeness heuristic C. Base rate fallacy D. Confirmation bias

C. base rate fallacy

Many pets will run toward the kitchen when they hear the sound of a can opener opening a can of pet food. The sound of the can opener is a: A. conditioned response. B. unconditioned response. C. conditioned stimulus. D. unconditioned stimulus.

C. conditioned stimulus.

Which of the following neurotransmitters is associated with both schizophrenia and Parkinson's disease? A. GABA B. serotonin C. dopamine D. enkephalins

C. dopamine

An α-helix is most likely to be held together by: A. disulfide bonds. B. hydrophobic effects. C. hydrogen bonds. D. ion attractions between side chains.

C. hydrogen bonds.

Each individual in a group of teenagers is asked to estimate the height of a tree. One individual estimates the height to be 25 feet, but after discussing with the group is convinced that the height is likely closer to 40 feet. Which type of conformity is seen here? A. obedience B. identification C. internalization D. compliance

C. internalization

Increases in which of the following hormones causes sleepiness? A. Cortisol B. Growth hormone C. Melatonin D. Oxytocin

C. melatonin

Primary groups differ from secondary groups in that: A. primary groups are shorter-lived than secondary groups. B. primary groups are larger than secondary groups. C. primary groups are formed of stronger bonds than secondary groups. D. primary groups are assigned while secondary groups are chosen.

C. primary groups are formed of stronger bonds than secondary groups.

Glucocorticoids have been implicated in stress-related weight gain because: A. they increase appetite and decrease satiety signals. B. they increase the activity of catabolic hormones. C. they increase glucose levels, which causes insulin secretion. D. they interfere with activity of the leptin receptor.

C. they increase glucose levels, which causes insulin secretion.

Which of the following is NOT a method by which enzymes decrease the activation energy for biological reactions? A. Modifying the local charge environment B. Forming transient covalent bonds C. Acting as electron donors or acceptors D. Breaking bonds in the enzyme to provide energy

D. Breaking bonds in the enzyme to provide energy

A medical student is feeling a high level of stress due to upcoming exams and pressure from his family to engage in activities at home. He chooses to go the gym for a workout to help himself relax. This workout is which type of stress? A. Hassle B. Frustration C. Distress D. Eustress

D. Eustress

Which of the following concepts are LEAST likely to coincide? A. Hazardous waste facilities and low-income neighborhoods B. Tuberculosis and poor living conditions C. Environmental pollution and high minority population D. Globalization and global equality

D. Globalization and global equality

How does prokaryotic DNA differ from eukaryotic DNA? I. Prokaryotic DNA lacks nucleosomes. II. Eukaryotic DNA has telomeres. III. Prokaryotic DNA is replicated by a different DNA polymerase. IV. Eukaryotic DNA is circular when unbound by centromeres. A. I only B. IV only C. II and III only D. I, II, and III only

D. I, II, and III only

What role does peptidyl transferase play in protein synthesis? A. It transports the initiator aminoacyl-tRNA complex. B. It helps the ribosome to advance three nucleotides along the mRNA in the 5′ to 3′ direction. C. It holds the proteins in its tertiary structure. D. It catalyzes the formation of a peptide bond.

D. It catalyzes the formation of a peptide bond.

Many double-displacement reactions are enzyme-catalyzed via the "ping pong" mechanism, so called because the reactants appear to bounce off the enzyme like a ping pong ball. These reactions typically have two reactants and two products. In a third-order reaction involving two reactants and two products, doubling the concentration of the first reactant causes the rate to increase by a factor of 2. What will happen to the rate of this reaction if the concentration of the second reactant is cut in half? A. It will increase by a factor of 2. B. It will increase by a factor of 4. C. It will decrease by a factor of 2. D. It will decrease by a factor of 4.

D. It will decrease by a factor of 4.

Which of the following INCORRECTLY pairs a digestive hormone with its function? A. Trypsin—hydrolyzes specific peptide bonds B. Lactase—hydrolyzes lactose to glucose and galactose C. Pancreatic amylase—hydrolyzes starch to maltose D. Lipase—emulsifies fats

D. Lipase—emulsifies fats

A patient comes in with a tumor of the pituitary gland, which grows upwards into the optic chiasm and causes a visual field defect. The most likely defect from compression of the optic chiasm is: A. complete blindness in one eye. B. loss of the upper visual fields in both eyes. C. loss of the nasal visual fields in both eyes. D. loss of the temporal visual fields in both eyes.

D. loss of the temporal visual fields in both eyes.