MCAT Practice Questions | Strategies Review of Key Quizzes & Correct Answers | Verified |2025 |2026 – Graded A+

MCAT Practice Questions | Strategies Review of Key Quizzes & Correct Answers | Verified |2025 |2026 – Graded A+ Quiz_________________? Action potentials travel down neural axons that resist the flow of current. In considering a theoretical circuit, one normally assumes that the wire has no resistivity. In the real world, however, wire resistivity is an important consideration. Which of the following is a way to increase resistance? A) Lengthen the wire B) Widen the wire C) Lower the temperature D) Change from tungsten to copper wire - Answer A This question tests your knowledge of resistance in wires. An electrical wire's resistance is directly proportional to its length and inversely proportional to its cross-sectional area. Think of it as gravel in a pipe—the wider the pipe and the shorter the pipe, the easier it is for water to go through it. B is incorrect because when a wire's cross-sectional area is increased, its resistivity is decreased. C is incorrect because lowering temperature decreases resistivity. Think superconductors. D is incorrect because tungsten has higher resistivity than copper. Tungsten is used for lightbulb filaments because of its higher resistivity. Quiz_________________? Chemical extraction is a simple, but powerful, means of isolating a desired compound, and this technique is used to isolate many pharmacological agents. A chemist requires that a mixture of two species be separated. In order to do this, the chemist allows the mixture to separate and extracts the top, non-polar layer. Based on this information, what is least likely to be true of the original two species? A) The densities of the species are different. B) The original species rotate plane-polarized light in opposite directions. C) The bottom layer is hydrophobic. D) The two species have the same molecular weight. - Answer B describes the species as enantiomers. If the two species can be separated through ordinary means, without first changing them chemically, they cannot be enantiomers! Enantiomers cannot be separated by physical properties alone. Quiz_________________? Ideal gasses are useful for calculations, but perfectly "ideal" gasses do not exist in the real world. Under what conditions does a real gas differ in behavior from an ideal gas? A) increased pressure only B) increased temperature only C) increased pressure and decreased temperature D) only when the molar volume is very large - Answer C Real gases deviate from the ideal gas law due to elevated pressures and decreased temperatures. This is because as pressure increases, the molecules are forced closer together, so intermolecular interactions become important. When the molecules are far apart, the intermolecular forces are minimal. As temperature decreases, gas particles move more slowly, so as they pass each other, the period of time in which they are in close proximity increases. This allows more opportunities for the molecules to affect one another. Hence, deviations from ideal conditions result. Quiz_________________? Most of the CO2 in the blood travels as HCO3- and H+ ions in the plasma. Which of the following would a physician most likely find upon examining a person who has recently had Acute Mountain Sickness (Altitude Sickness)? A) Increased levels of O2 in the plasma B) A decreased rate of ventilation C) An increased red blood cell count D) An increased white blood cell count - Answer C Altitude sickness occurs when a person climbs faster than his body can adjust. One of the ways that the body compensates for the lack of O2 at high altitude is by releasing erythropoitin, a hormone that increases the RBC mass after a period ranging from a few days to several weeks. Quiz_________________? Osteogenesis imperfecta is an autosomal dominant disease that results in abnormal collagen synthesis and fragile bone structure. What is true regarding the probability that the sister of an affected man will have the disease, if their mother was unaffected? A) The probability equals 50%. B) The probability depends on the genotype of the father, which cannot be determined from the given information. C) The probability depends on the genotype of the mother, which cannot be determined from the given information. D) The probability depends on the genotype of the brother, which cannot be determined from the given information. - Answer B If the disease is autosomal dominant, from the passage, we know the mother had two good alleles. Therefore, the father had at least 1 diseased allele: heterozygous or homozygous dominant (i.e. diseased). If the father were homozygous, the sister would have a 100% chance of getting the disease. If the father were heterozygous, the sister would have a 50% chance. Therefore, choice (B) is correct (A) No, it depends on the father's genotype. (C) We know that the mother is homozygous recessive since she is unaffected. (D) The brother's genotype is not important and can be determined: it is heterozygous.