AAMC FL 4 BB Questions and Answers 100% correct

AAMC FL 4 BB Questions and Answers 100% correct Most cytochrome P450 enzymes alter the activity of drugs by: A. phosphorylating them. B. dephosphorylating them. C. oxidizing them. D. reducing them. cytochrome is found in ETC, which is known for oxidative phosphorylation! cytochrome is known to accept electrons therefore they are oxidizing agents phosphorylation part is for the ATPase so not that oxidation is the correct answer cytochrome An iron-containing protein, a component of electron transport chains in mitochondria and chloroplasts oxidizing agent During phosphorylation of STAT5b proteins, phosphate groups are exchanged for what atoms on tyrosine residues? A. Hydrogen atoms of hydroxyl groups B. Hydrogen atoms of methyl groups C. Oxygen atoms of hydroxyl groups D. Carbon atoms of methyl groups phosphorylation effects the OH group they want the hydrogen on the hydroxyl group! so A phosphorylation effects OH group of the amino acid where the H is exchanged Given that antibiotics like erythromycin are metabolized by estrogen-sensitive P450 enzymes within the liver, which graph best predicts the expected relative half-life of erythromycin in adult males versus adult females? Passage: "erythromycin are metabolized by estrogen-sensitive P450 enzymes within the liver" Female rats, GH secretion is more frequent -> high GH presence in circulation erythyomycin are metabolized by estrogen sensitive p450 enzymes p450 genes are regulated by continuous GH females have more GH secretion P450 regulated by continuous GH erythyomycin are metabolized by 940 therefore we expect female to have lower erythyomycin half life compared to males because they have continuous GH secretion that is metabolized by P450 A defining characteristic of proteins that act as transcription factors (such as STAT5b) is that they: A. can dimerize. B. can phosphorylate other proteins. C. contain a DNA binding domain. D. are present within the nucleus of the cell. transcription factors influence transcription C! Transcription factors: have DNA binding domain that allows it to bind to regulatory nucleic acid sequences in a gene to alter transcription Based on the passage, ACC2 is most likely compartmentalized to: A. the mitochondria. B. the cell membrane. C. the cytosol. D. the lysosome. ACC2 uses acetyl coa, found in TCA which occurs in mitochondria fatty acid oxidation occurs in mitochondria Based on the passage, as compared to a wild-type mouse, an Acc2–/–/Cpt1–/– double knockout mouse is most likely to exhibit: A. increased insulin secretion. B. decreased fatty acid oxidation. C. decreased triglyceride synthesis. D. increased malonyl-CoA production. Passage: ACC2 regulate fatty acid synthesis and fatty acid oxidation, respectively, through the conversion of acetyl-CoA to malonyl-CoA KO = for fatty oxidation gene = no fatty acid oxidation ACC2 = codes for insulin resistance = yes fatty acid oxidation ACC2 (-) = no insulin resistance = no fatty acid oxidation IF THERE IS NO ACC2 THERE IS NO FATTY ACIS SYNTHESIS/OXIDATION B!!! decreased fatty acid oxidation During the ACC1- or ACC2-catalyzed formation of malonyl-CoA, what is the structure of the functional group added to acetyl-CoA? Passage: "The acetyl-CoA carboxylases ACC1 and ACC2" expecting a carboxyl group on acc1/acc2 so C! The researchers want to generate a mutant mouse strain that expresses a constantly active variant of ACC2 by replacing the amino acid at position 212 with a different residue. Which residue is the best choice as a replacement? A. Tyrosine B. Serine C. Alanine D. Threonine Passage: "AMPK-mediated phosphorylation of mouse ACC1 (at residue 79) and ACC2 (at residue 212) inactivates these enzymes." keyword: mutant therefore you want to change the sequence phosphorylation = OH! (SYTH) so you want a group without OH group so C! alanine Bacteriophages were labeled with radioactive phosphorous (32P) and sulfur (35S). The labeled bacteriophages were then allowed to infect their host cells. At the end of the experiment, the 32P label was found only inside the host cells and the 35S label was found only outside the host cells. This experiment shows that: A. bacteriophages consist only of DNA and protein. B. only DNA, not protein, can enter the host cell. C. only protein, not DNA, can enter the host cell. D. both DNA and protein can enter the host cell. DNA has a phosphate group (32P bind there) outside would be Sulfur then 32P found inside host cell 35S found outside host cell B! only DNA, not protein, can enter the host cell Which statement describes ATP consumption and production during the preparatory and payoff phases of glycolysis, respectively? A. Two ATP molecules consumed, four ATP molecules produced B. Four ATP molecules consumed, eight ATP molecules produced C. Four ATP molecules consumed, two ATP molecules produced D. Eight ATP molecules consumed, four ATP molecules produced Glycolysis requires 2 ATP but creates 4 ATP How much ATP is used and produced in glycolysis? 2 ATP consumed, 4 ATP produced As blood passes through actively contracting skeletal muscle tissue, the affinity of hemoglobin for oxygen in the muscle tissue: A. increases as a result of an increase in plasma temperature. B. increases as a result of an increase in plasma PO2. C. decreases as a result of a decrease in plasma pH. D. decreases as a result of a decrease in plasma PCO2. If blood is passing thru active skeletal muscle = need more O2. therefore need quicker production of O2/lower affinity for hemoglobin for O2 contracting skeletal muscles would produce more lactic acid. This makes the affinity for hemoglobin for O2 would decrease due to the presence of lactic acid. it decreased due to the acidity C! decreases as a result of decrease in plasma pH bicarbonate buffer regulate pH in both intracellular and extracellular fluids affinity would decrease with an increase in plasma temperature affinity would increase when Po2 increases affinity would increase with decrease plasma Pco2 Henry's Law the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid Which of the following hypotheses best accounts for the differences in the level of circulating ghrelin in individuals who are obese with no underlying condition and this level in individuals who are lean? A. The hypothalamus secretes less ghrelin in individuals who are lean because their metabolic needs are greater than those of individuals who are obese. B. Ghrelin secretion is suppressed in individuals who are obese because their bodies have greater energy stores than do the bodies of individuals who are lean. C. The hypothalamus secretes more ghrelin in individuals who are lean because their metabolic needs are less than those of individuals who are obese. D. Ghrelin secretion is suppressed in individuals who are obese because their bodies have fewer energy stores than do the bodies of individuals who are lean. A & D. ghrelin acts on hypothalamus, it is not secreted ghrelin is suppressed in obese individuals B! because obese individuals have more fat, they have greater energy store than those who are lean!! refer to fig 1 Based on the passage, what can be determined about the composition of the mRNA that encodes the protein from which ghrelin is cleaved? It is composed of: A. more than 28 amino acids. B. exactly 84 nucleotides. C. exactly 87 nucleotides. D. more than 87 nucleotides. 28 amino acids x 3 nucleotides per codon = 84 nucleotides total but! we need to take account for the start and stop codons, so it'll be way more than 84. so D is the correct answer