MCAT Test exam 2022/2023 with 100% correct answe

If a person drank a large quantity of hypersaline ocean water, the person could die because absorption of salt into the blood will cause it to become -Hypertonic compared with the cytosol of the bodies cells, causing osmosis of water out of the cells -If a cell is placed in an environment that contains a higher concentration of solutes than the interior of the cell, we call this environment hypertonic. When a cell is placed in a hypertonic solution, the solution is relatively solute-rich, while the cell is relatively watery. Therefore, water will move from the cell into the surrounding solution to equalize the solute concentration. Water is a rare substance in that the solid is less dense than the liquid at the freezing point, resulting in a solid form that floats on top of the liquid. Which of the following best explains this phenomenon? The bent structure of the water molecule and ratio of covalently-bonded hydrogens to lone pairs of electrons on the oxygen atom maximizes the hydrogen bonding that occurs in the solid phase, producing a hexagonal structure with large empty spaces. In an area that has a high rate of radiated iodine, why would researchers decide to study pediatric, rather than adult, thyroid cancers? -children receive a higher relative dose of I-131 at the same contamination level -the most likely reason for the use of pediatric cancer cases is that these cases are more likely to be caused by I-131 than those in adults. Because children weigh less than adults, the same quantity of external I-131 would result in a higher concentration of the isotope in the body, making DNA damage and cancer more likely. What is an easy way of separating 2-methyludecanal and 2-methylundecanoic acid? an extraction based on their differing solubilities boiling chips and vacuum distillation, respectively are used in distillations to do what? provide nucleation sites that give the liquid a place to start forming bubbles to prevent superheating; lower the boiling points of the substances to be distilled. In a distillation procedure, the liquid remaining at the bottom of a round bottom flask in a distillation to separate 2-methylundecanal and 2-methylundecanoic acid will most likely be what? -2-methylundecanoic acid -In distillation procedures, the component with the lower boiling point boils off first, leaving the remaining components in the original flask. Thus, this question is basically asking which component has the higher boiling point. The hydrogen bonding created by the carboxylic acid functional group in 2-methylundecanoic acid (shown below) would lead to a vastly higher boiling point than the aldehyde (over 300ºC compared to 170ºC). If a 65-kg man undergoes a turning acceleration of 5 m/s2 during a running turn, what is the magnitude of force experienced by the foot due to the ground? -750 N -F=(65 kg)(5 m/s^2)= 325 N -F=(65 Kg)(10 m/s^2)= 650 N =((650)^2+(325)^2)^1/2= 750 If the students perform an enzyme inhibition assay using captopril, a competitive inhibitor, what changes in the kinetic parameters of ACE should be expected? -Vmax unchanged; Km increased What is the protonation state of captorpil, which has a thiol and carboxyl group, required to maximize the inhibition of ACE at pH of 3.8 to 9.5? -protonated thiol and deprotonated carboxyl -the lowest in vivo IC50 for captopril is observed in the pH range of 3.8 to 9.5. Since the lower the IC50 value, the less inhibitor required to achieve a certain effect, the lowest IC50 should correspond to the conditions where inhibitory activity is greatest. For this reason, captopril appears to be most effective as an ACE inhibitor between pH 3.8 and 9.5.