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If you’re preparing for the Medical College Admission Test (MCAT), you are going to want to consult the experts. These selections from Kaplan’s MCAT Question of the Day series can 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 sections—biological 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 school’s prerequisites and navigating the application process can be a challenge unto itself. For students preparing for the medical school, the AMA premed glossary guide has the answers to frequently asked questions,
For those already in medical school, the AMA and Kaplan have teamed up to support you in reaching your goal of passing the USMLE® or COMLEX-USA®. If you're looking for additional resources, Kaplan provides free access to tools for pre-clinical studies, including Kaplan’s Lecture Notes series, Integrated Vignettes, Shelf Prep and more.
Section: Biological and biochemical foundations of living systems
Question: 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.
The correct answer is A.
Kaplan explains why: Antibodies are specific to a single antigen. Each B-cell produces a single type of antibody with a constant region that is specific to the host and a variable region that is specific to an antigen.
Section: Chemical and physical foundations of biological systems
Question: Photons and other energy sources can excite 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.
The correct answer is B.
Kaplan explains why: Because the electron is moving into the n = 1 shell, the only subshell available is the 1s subshell, which eliminates choices (C) and (D). There will be some energy change, however, as the electron must lose energy to return to the minimum-energy ground state. That will require emitting radiation in the form of a photon.
Section: Psychological, social, and biological foundations of behavior
Question: 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
The correct answer is A.
Kaplan explains why: Broca’s area governs the motor function of language. A stroke that affects Broca’s area will leave receptive language intact, but word formation will be affected. A stroke affecting Wernicke’s area, choice (B), will make it so the individual is unable to comprehend speech. A stroke affecting the arcuate fasciculus, choice (C), will result in an inability to repeat words heard but spontaneous language production is intact. The superior temporal gyrus, choice (D), is where Wernicke’s area is located.
