If youre preparing for theMedical College Admission Test(MCAT),you will want to consult the experts. These selections from Kaplans MCATQuestion of the Day seriescan help you sharpen your skills as you prepare to begin your potential journey into medical training.

The questions below come from three of the four MCAT sectionsbiological and biochemical foundations of living systems; chemical and physical foundations of biological systems; and psychological, social, and biological foundations of behavior. A fourth section, critical analysis and reasoning skills (commonly referred to as CARS), is based largely on inference.

Medicine can be a career that is both challenging and highly rewarding but figuring out a medical schools prerequisites and navigating the application process can be a challenge unto itself. For students preparing for the medical school, theAMA premed glossary guidehas the answers to frequently asked questions.

For those already in medical school, the AMA selected Kaplan as apreferred providerto support you in reaching your goal of passing the USMLEor COMLEX-USA.AMA members can save 30% on access to additional study resources, such as KaplansQbankand High-yield courses.

Section: Biological and biochemical foundations of living systems

Question: 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.

The correct answer is D.

Kaplan explains why: Peptidyl transferase is an enzyme that catalyzes the formation of a peptide bond between the incoming amino acid in the A site and the growing polypeptide chain in the P site. Initiation and elongation factors help transport charged tRNA molecules into the ribosome and advance the ribosome down the mRNA transcript, as in choices (A) and (B). Chaperones maintain a proteins three-dimensional shape as it is formed, as in choice (C).

Section: Chemical and physical foundations of biological systems

Question: The bodys pH is tightly regulated because specific enzymes function best within a narrow pH range. What is the approximate pH of a 1.2 105 M aqueous solution of NaOH?

A. 4.92.

B. 7.5.

C. 9.08.

D. 12.45.

The correct answer is C.

Kaplan explains why: NaOH is a strong base; as such, there will be 1.2 105 M OH in solution. Based on this information alone, the pOH must be between 4 and 5, and the pH must be between 9 and 10. Using the shortcut, pOH 5 0.12 = 4.88. pH = 14 pOH = 9.12 (actual = 9.08).

Section: Psychological, social and biological foundations of behavior

Question: 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 fathers brain?

A. Epinephrine.

B. Histamine.

C. Dopamine.

D. Serotonin.

The correct answer is C.

Kaplan explains why: The symptoms indicate that the womans father likely has Parkinsons disease. This disease is caused by decreased dopamine production in the substantia nigra

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February 2021: Kaplan MCAT stumpers put premeds to the test - American Medical Association