Try these MCAT practice questions

[mcat prep]

MCAT practice question #1

In a research study, some students were asked to rate different lecturers’ personality traits. The study results showed that the lecturers who received higher ratings on the attractiveness scale usually also achieved higher ratings for “intelligence” and “fairness” than other lecturers. The ratings for “moodiness” and “intimidation” were not influenced by the attractiveness rating. The phenomenon that most accurately explains those findings is called:

A. confirmation bias.
B. halo effect.
C. belief perseverance bias.
D. branding.

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[Fluidity of Movement]

Spoiler

B

 

[mcat prep]

MCAT practice question #2

A spherical air bubble is rising in a test tube which is illuminated from one side by a flashlight. What happens to a ray of light incident on the air bubble at A?

Image:
https://www.mcat-prep.com/images/content/admin/images/gs5image3.jpg

A. Reflection at both surfaces
B. Reflection at A; no reflection at B
C. Reflection at B; no reflection at A
D. no reflection at either surface

 

[mcat prep]

MCAT practice question #1

In a research study, some students were asked to rate different lecturers’ personality traits. The study results showed that the lecturers who received higher ratings on the attractiveness scale usually also achieved higher ratings for “intelligence” and “fairness” than other lecturers. The ratings for “moodiness” and “intimidation” were not influenced by the attractiveness rating. The phenomenon that most accurately explains those findings is called:

A. confirmation bias.
B. halo effect.
C. belief perseverance bias.
D. branding.

Answer: B

Foundational Concept: 6
Biological, psychological, and sociocultural factors influence the ways that individuals perceive, think about, and react to the world

Content Category: 6B
Making sense of the environment

Scientific Reasoning and Inquiry Skill: 2
Scientific Reasoning and Problem Solving

This is a psychology question that requires knowledge about “making sense of the environment,” more specifically about common heuristics and biases. The correct answer is B.

Cognitive biases are common reasoning mistakes that culminate in incorrect conclusions. The halo effect is a form of confirmation bias. It means that once we have formed positive feelings toward a trait of a person (or object), it might influence how we perceive his other positive or neutral traits; we might perceive them more positively. This explains why higher ratings on the attractiveness scale led to higher ratings for “intelligence” and “fairness,” two positive traits, but not for “moodiness” and “intimidation,” two negative traits.

In general, confirmation bias refers to the tendency to look for information and interpret it in a way that confirms our preconceptions. Disconfirming information is discarded and forgotten. It is not the right answer for this question, as it is just the general description of a bias rather than an explanation for the findings of only positive traits being influenced by “attractiveness.”

Branding is an expression used in the marketing industry to achieve a more positive customer attitude toward a product. It is not the correct explanation for the findings.

Belief perseverance bias is the tendency for original beliefs to persist, even after disconfirming evidence has been shown. In other words, people’s beliefs are often resistant to challenge and change. This is not the case in the scenario, as no disconfirming evidence has been mentioned.

 

[mcat prep]

MCAT practice question #2

A spherical air bubble is rising in a test tube which is illuminated from one side by a flashlight. What happens to a ray of light incident on the air bubble at A?

A. Reflection at both surfaces
B. Reflection at A; no reflection at B
C. Reflection at B; no reflection at A
D. no reflection at either surface

Answer: A

Reflection is the process by which light rays bounce back into a medium from a surface with another medium. Note that there are 2 surfaces, both A and B, which meet the criterion for reflection. Remember: just because some light reflects, does not mean that all of the light reflects. Specifically, some of the light will transmit completely through the bubble while some would have been reflected at A and some at B.

 

[mcat prep]

MCAT practice question #3

Which of the following represents the relative penetrating power of the three types of radioactive emissions in decreasing order?

A. beta > alpha > gamma
B. beta > gamma > alpha
C. gamma > alpha > beta
D. gamma > beta > alpha

 

[mcat prep]

MCAT practice question #3

Which of the following represents the relative penetrating power of the three types of radioactive emissions in decreasing order?

A. beta > alpha > gamma
B. beta > gamma > alpha
C. gamma > alpha > beta
D. gamma > beta > alpha

MCAT practice question #3

Answer: D

Alpha radiation consists of the largest particles (helium nuclei with a mass number of 4 thus the greatest inertia, PHY 4.2) and are the slowest (about 1/3 times the speed of light). Beta radiation consists of smaller (electrons, 1/1370 times lighter than a proton), faster particles (about 4/5 times the speed of light). Gamma radiation consists of the smallest particles (photons, no mass) which travel at the greatest speed (at the speed of light).

See: https://www.mcat-prep.com/images/content/admin/images/question_15_gs6cp.png

 

[mcat prep]

MCAT practice question #4

Source: Sample MCAT Questions by MCAT-prep.com

The human kidney can be damaged from a number of causes resulting in a patient's inability to filter toxins (i.e. urea) from the body which could result in death. Complete kidney failure is usually first treated with dialysis which "cleans" the blood.



Figure 1: Dialysis. The "dialyzer" is a glass container that has 3 main components: (1) blood percolating through to be cleaned; (2) a dividing membrane; and (3) the dialysate. The latter is liquid containing chemicals used to draw fluids and toxins out of the bloodstream and supply electrolytes and other chemicals to the bloodstream. (kidney.niddk.nih.gov)

Considering the information provided, which of the following is NOT consistent with the process of dialysis?

A. The membrane in the dialyzer separating the dialysate and the blood must be semipermeable.
B. The concentration of toxins in the dialysate must increase during dialysis.
C. The concentration of glucose and vital minerals in the dialysate must be similar to that of the patient's blood.
D. Excessive minerals and toxins cross the membrane in the dialyzer by osmosis.

 

[mcat prep]

MCAT practice question #4

Source: Sample MCAT Questions by MCAT-prep.com

The human kidney can be damaged from a number of causes resulting in a patient's inability to filter toxins (i.e. urea) from the body which could result in death. Complete kidney failure is usually first treated with dialysis which "cleans" the blood.

View attachment 373194

Figure 1: Dialysis. The "dialyzer" is a glass container that has 3 main components: (1) blood percolating through to be cleaned; (2) a dividing membrane; and (3) the dialysate. The latter is liquid containing chemicals used to draw fluids and toxins out of the bloodstream and supply electrolytes and other chemicals to the bloodstream. (kidney.niddk.nih.gov)

Considering the information provided, which of the following is NOT consistent with the process of dialysis?

A. The membrane in the dialyzer separating the dialysate and the blood must be semipermeable.
B. The concentration of toxins in the dialysate must increase during dialysis.
C. The concentration of glucose and vital minerals in the dialysate must be similar to that of the patient's blood.
D. Excessive minerals and toxins cross the membrane in the dialyzer by osmosis.

MCAT practice question #4

Answer: D

On the Surface: Dialysis only refers to the transfer of the solute (diffusion), while the transfer of the solvent is called osmosis.

Going Deeper: Diffusion is the movement of a substance down its concentration gradient (from a region of high concentration to one of lower concentration). This is the process that must be occurring in the dialyser to remove toxins from the blood (because the dialysate, logically, would have no toxins so the toxins defuse out of the blood into the dialysate). Note that vital substances in the blood should be kept in the blood: options would include having a dialysate with the same concentration of those substances (so they don’t diffuse out of the blood) or by adjusting the permeability of the membrane.

Osmosis is the movement of a solvent across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration. In Biology and Biochemistry, that solvent is, of course, water. In this context, the easier way to imagine osmosis is that it is simply the diffusion of water across a semi-permeable membrane from a region of high water concentration (i.e. low solute concentration) to a region of low water concentration (i.e. high solute concentration).

So in summary, osmosis deals with how much water passes through the membrane, while dialysis deals with what type of solute (i.e., sodium, protein, glucose) passes through by simple diffusion.

N.B. Notice the link between diffusion and osmosis and the Second Law of Thermodynamics (Physics). All spontaneous change leads to an increase in the entropy (randomness) of the universe. Of course, biological systems exist because processes which increase entropy can be coupled with processes which increase order, as long as the overall (net) entropy of the universe increases.

 

[mcat prep]

MCAT practice question #5

It has been well established that disulfide bonds are formed between cysteine side chains during protein folding. The adding of beta-mercaptoethanol to a solution results in the cleavage of disulfide bonds and protein misfolding because beta-mercaptoethanol:

A. contains ethanol which means hydroxyl groups that can interfere with proper disulfide bond formation.
B. provides reducing power restoring the SH groups on cysteine side chains.
C. binds to the SH groups of cysteine side chains.
D. acts as an oxidizing agent removing the SH groups from cysteine side chains.

 

[mcat prep]

MCAT practice question #5

It has been well established that disulfide bonds are formed between cysteine side chains during protein folding. The adding of beta-mercaptoethanol to a solution results in the cleavage of disulfide bonds and protein misfolding because beta-mercaptoethanol:

A. contains ethanol which means hydroxyl groups that can interfere with proper disulfide bond formation.
B. provides reducing power restoring the SH groups on cysteine side chains.
C. binds to the SH groups of cysteine side chains.
D. acts as an oxidizing agent removing the SH groups from cysteine side chains.

Answer to MCAT practice question #5

Answer: B

Disulfide bonds are covalent bonds that are normally formed through the coupling of two thiol groups, where a thiol is an organosulfur compound that contains a carbon-bonded sulfhydryl (–C–SH or R–SH) group. Disulfide bonds in proteins are formed during oxidation of sulfhydryl (-SH) groups through the following mechanism:

Image: https://www.mcat-prep.com/images/content/admin/images2/d2wpad.png

Thus two cysteine residues participate in the formation of a disulfide bond producing a cystine residue facilitating protein folding. To cleave disulfide bonds, the SH groups on cysteine residues must be restored (i.e. the reverse of the summarized reaction above), which could be done by adding more protons into the solution to reduce the thiol groups. Beta-mercaptoethanol must serve as a reducing agent during the restoration of SH groups on cysteine residues leading to protein denaturation. Note that in the process, beta-mercaptoethanol itself must be oxidized (‘reducing agents are oxidized, oxidizing agents are reduced’).

Note about answer choice A: The question said "Adding beta-mercaptoethanol to a solution results in the cleavage of disulfide bonds" so when answer choice A tries to give a reason that would "interfere with proper disulfide bond formation" that does not address how existing bonds are cleaved.

Going Deeper: One of the reasons for sensitivity of many proteins and enzymes to the pH is the issue of cysteine bridges, which are crucial for a proper protein folding and function. Methionine is another sulfur-containing amino acid, however, it cannot form disulfide bonds.

 

[mcat prep]

Gold Standard MCAT Practice Question #6

Using ultrasound waves targeted at the brain, a team of researchers restored memory to mice with symptoms of Alzheimer’s disease. The ultrasound technique removed amyloid beta plaques from the brains of the mice. Which of the following is the most likely explanation for why ultrasonic waves break apart plaque formations?

A. Mica bonds in plaque formations absorb heat generated by the ultrasonic waves.
B. The plaque formations are moved in the direction in which the ultrasonic waves travel.
C. The plaque formations vibrate at a resonant frequency equal to the frequency of the ultrasonic waves.
D. The medium in which the ultrasonic waves travel forces the plaque formations to break apart.

We'll post the answer soon!

 

[mcat prep]

Gold Standard MCAT Practice Question #6

Using ultrasound waves targeted at the brain, a team of researchers restored memory to mice with symptoms of Alzheimer’s disease. The ultrasound technique removed amyloid beta plaques from the brains of the mice. Which of the following is the most likely explanation for why ultrasonic waves break apart plaque formations?

A. Mica bonds in plaque formations absorb heat generated by the ultrasonic waves.
B. The plaque formations are moved in the direction in which the ultrasonic waves travel.
C. The plaque formations vibrate at a resonant frequency equal to the frequency of the ultrasonic waves.
D. The medium in which the ultrasonic waves travel forces the plaque formations to break apart.

We'll post the answer soon!

Answer: C

Explanation
The frequency of the ultrasonic waves must be equal to or is an integral multiple of the natural frequency of the plaque formations. As a result, the plaque formations resonate when forced to vibrate by the ultrasonic waves; the amplitude of vibrations of the plaques are such that they break apart/shatter like a wine glass does in response to a resonant frequency.

 

[jhmmd]

MCAT practice question #1

In a research study, some students were asked to rate different lecturers’ personality traits. The study results showed that the lecturers who received higher ratings on the attractiveness scale usually also achieved higher ratings for “intelligence” and “fairness” than other lecturers. The ratings for “moodiness” and “intimidation” were not influenced by the attractiveness rating. The phenomenon that most accurately explains those findings is called:

A. confirmation bias.
B. halo effect.
C. belief perseverance bias.
D. branding.

A

 

[jhmmd]

MCAT practice question #2

A spherical air bubble is rising in a test tube which is illuminated from one side by a flashlight. What happens to a ray of light incident on the air bubble at A?

Image:
https://www.mcat-prep.com/images/content/admin/images/gs5image3.jpg

A. Reflection at both surfaces
B. Reflection at A; no reflection at B
C. Reflection at B; no reflection at A
D. no reflection at either surface

A

 

[jhmmd]

MCAT practice question #3

Which of the following represents the relative penetrating power of the three types of radioactive emissions in decreasing order?

A. beta > alpha > gamma
B. beta > gamma > alpha
C. gamma > alpha > beta
D. gamma > beta > alpha

C

 

[jhmmd]

We like these test questons! Thanks!

 

[mcat prep]

Gold Standard MCAT Practice Question #7

A patient with a complete obstruction of the common bile duct would have a decreased ability to digest:

A. lipids.
B. proteins.
C. nucleic acids.
D. carbohydrates.

 

[jhmmd]

Is it A? If not, why?

 

[mcat prep]

Gold Standard MCAT Practice Question #7

A patient with a complete obstruction of the common bile duct would have a decreased ability to digest:

A. lipids.
B. proteins.
C. nucleic acids.
D. carbohydrates.

Answer: A

Obstructing the bile duct will prevent bile from reaching the small intestine. Thus the role of bile in the emulsification of fats (lipids) would be blocked. Therefore, answer choice A is the correct answer.

Note: Emulsification is the process of breaking down fat into smaller globules. Emulsification greatly increases the surface area of the fat on which the lipase (the enzyme which chemically breaks down/digests/hydrolyzes lipids) can actually act on.

Distractors

B. Proteins: The obstruction of the common bile duct primarily affects the digestion of lipids because bile, which is produced by the liver and stored in the gallbladder, is essential for the emulsification of fats. Proteins are primarily digested in the stomach and small intestine with the help of enzymes like pepsin and trypsin, and this process is not directly impacted by a bile duct obstruction.

C. Nucleic acids: Nucleic acids, such as DNA and RNA, are primarily digested and broken down in the small intestine with the help of specific enzymes like nucleases. Bile plays a minimal role, if any, in the digestion of nucleic acids. Therefore, a bile duct obstruction would not significantly affect the digestion of nucleic acids.

D. Carbohydrates: Carbohydrates are primarily digested in the mouth and small intestine with the help of enzymes like amylase. Bile is not directly involved in the digestion of carbohydrates, so a bile duct obstruction would not have a significant impact on carbohydrate digestion.

 

[mcat prep]

Is it A? If not, why?

You got it right! Answer: A

Obstructing the bile duct will prevent bile from reaching the small intestine. Thus the role of bile in the emulsification of fats (lipids) would be blocked. Therefore, answer choice A is the correct answer.

Note: Emulsification is the process of breaking down fat into smaller globules. Emulsification greatly increases the surface area of the fat on which the lipase (the enzyme which chemically breaks down/digests/hydrolyzes lipids) can actually act on.

Distractors

B. Proteins: The obstruction of the common bile duct primarily affects the digestion of lipids because bile, which is produced by the liver and stored in the gallbladder, is essential for the emulsification of fats. Proteins are primarily digested in the stomach and small intestine with the help of enzymes like pepsin and trypsin, and this process is not directly impacted by a bile duct obstruction.

C. Nucleic acids: Nucleic acids, such as DNA and RNA, are primarily digested and broken down in the small intestine with the help of specific enzymes like nucleases. Bile plays a minimal role, if any, in the digestion of nucleic acids. Therefore, a bile duct obstruction would not significantly affect the digestion of nucleic acids.

D. Carbohydrates: Carbohydrates are primarily digested in the mouth and small intestine with the help of enzymes like amylase. Bile is not directly involved in the digestion of carbohydrates, so a bile duct obstruction would not have a significant impact on carbohydrate digestion.

 

[mcat prep]

Gold Standard MCAT Practice Question #8

Suppose that the oxygen supply to continuously contracting red muscles fibers is abruptly cut off. Which of the following processes would occur in the muscles?

A. Increased rate of synthesis of muscle glycogen
B. Increased rate of production of ATP
C. Increased rate of production of carbon dioxide
D. Increased rate of production of lactic acid

 

[mcat prep]

Gold Standard MCAT Practice Question #8

Suppose that the oxygen supply to continuously contracting red muscles fibers is abruptly cut off. Which of the following processes would occur in the muscles?

A. Increased rate of synthesis of muscle glycogen
B. Increased rate of production of ATP
C. Increased rate of production of carbon dioxide
D. Increased rate of production of lactic acid

Answer: D

Conversion to anaerobic (lack of oxygen) respiration means less efficiency, less ATP per molecule of glucose, increased lactic acid (fermentation), more need for glucose which means more breakdown of glycogen and reduced production of the waste products of aerobic respiration: carbon dioxide and water.

Distractors:

A. This option is not correct because when oxygen supply to muscle fibers is abruptly cut off, the muscles switch to anaerobic respiration, which relies on the breakdown of glycogen to produce glucose for energy. The existing muscle glycogen stores are broken down to provide glucose, not synthesized.

B. This option is not correct because when oxygen supply is cut off, the muscles shift to anaerobic respiration, which is much less efficient at producing ATP compared to aerobic respiration. Therefore, there is not an increased rate of ATP production; in fact, ATP production may decrease due to the switch to anaerobic metabolism.

C. This option is not correct because in anaerobic respiration, the production of carbon dioxide is reduced compared to aerobic respiration. Anaerobic respiration primarily produces lactic acid, not carbon dioxide.