MCAT AAMC exam 1 questions and answers with solutions 2025

MCAT AAMC exam 1 questions and answers with solutions 2025 The first peak in a gas chromatograph (gc trace) would be - ANSWER -the one with the lowest molecular weight or weakest intermolecular forces of attraction -it would migrate the fastest making the first peak Thin lens formula - ANSWER -S= 1/o + 1/i S is the strength of the persons eye lens Adding strong acid to weak acid will - ANSWER -decrease the amount of ionization of the weak acid -eg adding HCl to CH3CO2H will decrease the percent ionization of acetic acid The index of refraction of a medium - ANSWER -equals the ratio of the speed of light in vacuum to the speed of light in the medium n= c/v Intensity - ANSWER -is directly proportional to the number of photons emitted Energy of photon emitted - ANSWER -E= hf h is 6.6x10^-34 Js f is frequency of radiation E is energy of photon -THz is 10^12 Hz Standard atmospheric pressure - ANSWER -760 mm Hg Acidic Side chains - ANSWER --are negatively charged at high pH -are neutral at low pH Why is the velocity of blood flow slower in capillaries than in arteries - ANSWER -the total cross-sectional area of capillaries exceeds that of arteries Octahedral compounds - ANSWER -have six sigma bonds and no lone pairs so d^2sp^3 orbitals of the central atom Ideal Gas refers to a gas in which - ANSWER -individual molecular volume and intermolecular forces are considered negligible Opsins - ANSWER -function to enable the detection of different colors -there are a variety of different structurally related opsins to detect a variety of colors Given a molecule that is largely made of C and H - ANSWER -the binding site is most likely hydrophobic like the molecule itself Lipase - ANSWER -hydrolyzes fatty acids Comparing graph with pH 7 to one with pH 4 what is the H ion concentration difference - ANSWER -7-4=3 but because logarithmic it is 10^3= 1000 increase in proton concentration What type of bond is formed by glycogen synthase upon release of UDP - ANSWER - alpha 1,4 glycosidic bond (the main linkages of glycogen) In beta decay - ANSWER -a neutron is converted to a proton, therefore the atom will be changed to the one located just to the right on the periodic table (gain proton) Alpha 1,6 glycosidic bond in glycogen - ANSWER -"Branching enzyme" -if a glycogen molecule lacks branching it is most likely deficient in these bonds An acid with a highly negative charge - ANSWER -will not easily dissociate in water Gamma decay - ANSWER -means the emission of a photon How will the rate of a catalyzed reaction be affected if the solid catalyst is finely ground before it is added to the reaction mixture - ANSWER -the rate will be faster because a greater surface area of catalyst will be exposed If given Al (s) with Zn2+ creates new solid but Zn (s) with Al3+does not - ANSWER - then Al is more susceptible to oxidation than Zn Given that the variant allele transcripts are not present in noncancerous tissue of people with the variant allele - ANSWER -the deletion mutation is somatic not germ line and will therefore not be heritable If the deletions in Intron 8 cause Exon 9 to be omitted then - ANSWER -the splice acceptor site must be located within the deleted region Transmembrane proteins require a - ANSWER -signal sequence in order to dock at the rough ER (enter the endomembrane system) Mature mRNAs are not likely to contain - ANSWER -introns or promotor sequences Nuclear localization signal - ANSWER -permits proteins to enter the nucleus During muscle contraction, myosin binds actin after troponin binds - ANSWER -Ca2+ -when free Ca2+ in cytosol binds troponin it pulls tropomysin away from actins myosinbinding site, allowing actin and myosin to bind Glomerular filtrate of the kidney is most concentrated - ANSWER -in the medullary portion of the collecting duct Transcription factors - ANSWER -bind DNA and subsequently recruit RNA polymerase Molecules that are very hydrophobic, for example have many ring structures - ANSWER -diffuse directly through the memebrane into a cell (simple diffusion) Mitochondrial disruption occurs when - ANSWER -the apoptotic machinery is stimulated Cholesterol rich domains are located - ANSWER -within lipid rafts The initial filtration step in the glomerulus of the mammalian kidney occurs primarily by - ANSWER -passive flow due to a pressure difference (blood pressure forces fluid from glomerulus into lumen of Bowmans capsule) Enzymes do not - ANSWER -alter substrate primary structure Enzymes can - ANSWER -co-localize substrates, alter local pH, alter substrate shape what is the most fundamental reason why ornithine is unlikely to be found in proteins synthesized in vivo - ANSWER -there is no codon for it in the standard genetic code Enzymes are - ANSWER -catalysts Specificity of enzyme means - ANSWER -highly specific both in the reactions that they catalyze and in their choice of substrates -catalyze only a single chemical reaction or occasionally a set of closely related reactions If you have increased concentrations of an enzyme you also have - ANSWER - increased concentrations of mRNA sequences that code for it -protein levels relate most directly to mRNA levels Interphase - ANSWER -the phase of the cell cycle between cell divisions where the cell obtains nutrients, grows, reads its DNA, and conducts other normal cell functions Circulating Erythrocytes - ANSWER -do not contain DNA What type of cell is most important in the exchange of O2 between the blod and the surrounding tissue - ANSWER -Endothelial cells