AAMC FL 1 FULL REVIEW- Bio/Biochem Questions and Answers 2023

AAMC FL 1 FULL REVIEW- Bio/Biochem Questions and Answers 2023 Based on the data presented in the passage, which statement best describes the HSP110ΔE9 allele? A.Cancer-promoting and dominant to HSP110WT B.Cancer-promoting and recessive to HSP110WT C.Cancer-suppressing and dominant to HSP110WT D.Cancer-suppressing and recessive to HSP110WT Cross out A and B. LOOK AT THE FIGURE! Tumor volume is DOWN. Table 2 shows that HSP110ΔE9 allele when mixed with HSP110WT there is more apoptotic cells. So it's dominant. SLOW THE HECK DOWN AND READ Based on the passage, in MSI CRC primary tumor cells, the size of the deletion in the HSP110 T17 microsatellite is inversely correlated with: A.the amount of HSP110ΔE9 protein expressed. B.the number of mature HSP110WT transcripts synthesized. C.the frequency of the omission of HSP110 Exon 9 during splicing. D.the extent of premature translation termination in Exon 10. INVERSELY CORRELATED WITH According to Table 1, as the size of the deletion increases, the amount of HSP110ΔE9 and HSP110WT transcripts synthesized increase and decrease, respectively. also: The larger HSP110 T17 deletions cause Exon 9 to be omitted from the final sequence during pre-mRNA processing. This generates a premature stop codon in Exon 10, resulting in the mutant protein HSP110ΔE9. You're going to have MORE PRE-MATURE transcripts, SO LESS mature ones. A man with a CRC mutation that results in the synthesis of HSP110ΔE9 and a woman that does not carry this mutation in any of her tissues have a child. What is the percent chance that the child will inherit the CRC mutation? A.0% B.25% C.50% D.100% passage: People with MSI CRC have HSP110ΔE9 transcripts in cancerous tissue only. YOU AINT GONNA PASS DOWN CANCEROUS TISSUE A! Which nucleotide pairing(s) would be recognized by the MMR system during DNA replication? dTMP and dCMP dGMP and dAMP dAMP and dTMP A.I only B.III only C.I and II only D.I, II, and III Looking for mismatched bases! Roman numeral 2 comes up twice so start there. G and A are not paired correctly (cross out a and b) Now looking at 3. Adenine and Thymine are paired together normally, eliminate D, end with C. The information in the passage best supports the conclusion that Intron 8 of HSP110 most likely contains which of the following? A.Stop codon B.Splice acceptor site C.HSP110 gene promoter D.Partial coding sequence of HSP110 Introns are useless pieces of shit only think it will have is a place for the splice some to come and crunch it. According to the information in the passage, HSP110 is most likely which type of protein? A.Adhesion B.Chaperone C.Clathrin D.Enzyme Passage: HSP110 can bind structurally similar heat shock proteins and functions to facilitate proper protein folding and to reduce levels of nonfunctional protein aggregates. FACILITATING PROTEIN FOLDING = CHAPERONE Which amino acid, in addition to tryptophan, is most likely to be transported by AT1? A.Phenylalanine B.Lysine C.Arginine D.Glutamate A. only one that is neutral and aromatic! Based on the information in the passage, a mature AT1 mRNA is most likely to contain a sequence coding for which genetic factor(s)? A.Signal sequence B.Introns C.Promoter D.Nuclear localization signal Passage: AT1 localization to the luminal plasma membrane of small intestinal epithelial cells. AT1 simultaneously transports tryptophan against its concentration gradient and a sodium ion along its concentration gradient into the cytoplasm of intestinal epithelial cells. Aight. So we know this sucker is a transmembrane protein transporter. They transport ish by a signal sequence (A). A nuclear localization signal permits proteins to enter the nucleus. This is NOT likely for a transmembrane protein (D). Which effect did a protein-free diet have on DSS-treated +/y and -/y mice, respectively? A.Both the +/y and the -/y mice gained weight. B.The +/y mice lost weight, and the -/y mice gained weight. C.The +/y mice gained weight, and the -/y mice lost weight. D.Both +/y and the -/y mice lost weight. You read the table. You rock. D. Pellagra also results from a deficiency of nicotinamide, which is synthesized from tryptophan. Nicotinamide nucleotides are neither oxidized nor reduced during which step of cellular respiration? A.Glycolysis B.Chemiosmosis C.Citric acid cycle D.Electron transport chain OKAY. SLOW. THE. Eff. DOWN. A, C, and D all use NADH. NAD+ is neither reduced to form NADH, nor is NADH oxidized to form NAD+ specifically during chemiosmosis. If a man with a mutant copy of Ace2 has a child with a woman that is heterozygous for the mutant Ace2 allele, what is the probability that the child will be a female and homozygous for the mutant Ace2 allele? A.0 B.0.25 C.0.75 D.1 Do NOT be scared of genetics problems. Use probability or punnet. AIGHT Probability: Okay dude has 1/2 chance of giving his dirty X chromosome to make a daughter. Mom has 1/2 chance to give her dirty X chromosome to daughter. .5x.5= .25 OR Cross if you flip a shit XA Xa Xa XAxa XaXa Y XAY XaY 25 percent chance. DO NOT FREAK OUT. During the initiation of muscle contraction, mysosin binds actin after troponin binds to which ion? A.H+ B.K+ C.Na+ D.Ca2+ D. during the initiation of muscle contraction, free Ca2+ in the cytosol binds to troponin, which pulls tropomyosin away from actin's myosin-binding site. This allows myosin to bind to actin. What is the total number of fused rings present in a steroid? A.1 B.2 C.4 D.6 C. steroids are 4 fused rings! Epilepsy may result in motor seizures due to massive synchronous firing of neurons in a small area of the cerebral cortex (the epileptic focus). Excitation spreads from the focus, involving an increasingly larger area of the cortex. A drug for the treatment of epilepsy would be most effective if it caused which of the following changes in the epileptic focus? A.An increase in the neuron-firing threshold B.An increase in extracellular Na+ concentration C.A decrease in axon-membrane permeability to negative ions D.A decrease in the length of the depolarization stage You need to DECREASE excitation. POE- B. increasing the extracellular concentration of Na+ would make Na+ want to enter the cell all that much more. And when Na+ enters the cell, depolarization happens. AKA action potential starts and excitation happens C: chlorine ions do not have a huge role in action potential D: excitation is still happening A. Increasing the neuronal firing threshold will make it harder to generate the action potential. Thus, reducing the excitatory effect of the neuron because it would decrease the chance of individual neurons firing. A drug that would best treat epilepsy, as described, should reduce the activity of the neurons in the epileptic focus, which are excitatory neurons based on their effect throughout the cortex. The answer to this question is A because increasing the threshold required to generate an action potential would decrease the chance that individual neurons would fire, thus reducing the overall amount of excitation that spreads from the epileptic focus throughout the cortex. When concentrated urine is being produced, in which of the following regions of the kidney will the glomerular filtrate reach its highest concentration? A.Proximal convoluted tubule B.Distal convoluted tubule C.Cortical portion of the collecting duct D.Medullary portion of the collecting duct D. Water is continuously being absorbed wherever it can in the nephron when concentrated urine is being produced. It logically follows that because of this, the most concentrated urine will be found at the location farthest along the tubule pathway. The medullary portion of the collecting duct is the final part before urine is sent for excretion and thus should be most concentrated. What aspect of Experiment 1 does NOT address whether membrane composition has an effect on Na+K+ ATPase activity? The activity of the Na+K+ ATPase: A.showed less temperature dependence in the 14:1 liposome than the 14:0 liposome. B.was highest in the 14:0 liposomes at all temperatures. C.increased with temperature in both the 14:1 liposome and the 14:0 liposome. D.was greater at all temperatures when cholesterol was present. NOT is key word! POE: A- yes this is showing a difference in membrane composition. This is comparing both liposomes that have different compositions. B-Yes, this is comparing a difference in the two liposomes membrane composition. C- NO. Yes the activity increased BUT THIS IS NOT COMPARING MEMBRANE COMPOSITION. D- yes!!! Cholesterol is an element of membrane composition and this is comparing membranes with and without cholesterol. Which approach does NOT measure the activity of the Na+K+ ATPase? A.Measuring the rate of ATP hydrolysis B.Measuring the free energy of the ion transport C.Measuring the rate of ADP production D.Measuring the change in ion concentration within the liposome B- free energy has to do with thermodynamics, not kinetics! Kinetics properties in each answer choice: A- RATE C- RATE D- ion concentration rate would refer to the RATE of ion transport. What is the function of the Na+K+ ATPase during a neuronal action potential? A.Stimulation of the action potential B.Depolarization of the membrane C.Hyperpolarization of the membrane D.Restoration of the resting potential Asking for the FUNCTION of the pump. A- done my voltage gated sodium channels causing depolarization (which is the same as d) C- this is done by VG sodium channels inactivating and potassium VG channels opening B- done by VG Na channels opening D- Na+ K+ ATPase is moving ions AGAINST their gradient. All of the other choices are not having things go against their gradient. In which direction does the Na+K+ ATPase transport ions across the cell membrane upon ATP hydrolysis? A.Na+ is transported out of the cell; K+ is transported into the cell. B.Na+ is transported into the cell; K+ is transported out of the cell. C.Both Na+ and K+ are transported into the cell. D.Both Na+ and K+ are transported out of the cell. 3 NA out, 2 K in!!!!! A Upon activation, p65 and cRel control the level of IL-6 mRNA by: A.binding RNA. B.binding DNA. C.replicating RNA. D.replicating DNA. Passage: p65 and cRel are transcription factors that can be continuously activated when mutations occur to proteins upstream in the signaling pathway Transcription factors BIND DNA and recruit RNA polymerase for TRANSCRIPTION Considering the structure of STN, what is the most likely mechanism for its entry into the cell? A.Active transport B.Receptor mediated endocytosis C.Diffusion directly through the membrane D.Passage through an ion channel Stn structure has a ton of fused rings and hydrophobic regions! C. Hydrophobic molecules will always pass on through! Assuming no mutations to the signaling pathway described in the passage, what event directly activates CARD11? A.Proteolytic cleaveage B.GTP binding C.Membrane association D.Phosphorylation Passage: One such drug is a selective protein kinase C (PKC) inhibitor called Sotrastaurin (STN, Figure 2). So the experiment is testing STN. STN is a kinase inhibitor, so it is inferred that CARD11 will be activated by phosphorylation! According to the passage, what is most likely correct about the genes that are expressed as a result of the constant activation of the NF-κB pathway? A.They cause disruption of the mitochondria. B.They contain a p65/cRel binding site in their promoter region. C.They have accumulated mutations that alter function. D.They bind to STN in the cytoplas Passage: The NF-κB proteins p65 and cRel are transcription factors that can be continuously activated when mutations occur to proteins upstream in the signaling pathway (Figure 1) There HAS to be a biding site for p65/cREl because they are transcription factors! Which mechanism best describes how P-gp facilitates drug resistance? A.P-gp binds to antitumor drugs in the presence of ATP and degrades the drugs. B.P-gp serves as a pump and uses active transport to move antitumor drugs outside the cell. C.P-gp prevents the entry of anti-tumor drugs into the cell. D.P-gp causes increased membrane permeability, which causes antitumor drugs to exit the cell. Passage: "P-glycoprotein (P-gp) is a plasma membrane ABC transporter" "P-gp is responsible for multidrug resistance (MDR) in tumor cells by preventing drugs from accumulating to cytotoxic levels." "P-gp exhibits ATPase activity" POE A- this is NOT transporting anything! B- YES. This is also a perfect example of ATPase activity. C- this is not transporter activity!!!!!! D- This is NOT transporter activity!!!!