AAMC FL 4
A peptide consisting of nine amino acids was partially hydrolysed. Three different tripeptides were isolated. None of the tripeptides share a common amino acid. Based on the data, what is the total number of possible structures possible for the full-length peptide? A. 3 B. 4 C. 6 D. 27
not rearrange within tripeptides, just rearrange the tripeptides into total peptide. so 3 things can form 6 diff combos.
eukaryotic phosphorylation residues
serine, threonine, tyrosine
prokaryotic phohsphorylation residues
serine, threonine, tyrosine, histidine, arginine, lysine, aspartate
Passage context implies that Spencer's strong following in the United States during the nineteenth century was attributable, in part, to the country's: 1. relatively substantial number of affluent residents. 2. relatively strong sense of social responsibility. 3. relatively strong grounding in Darwinist theories. A. I only B. III only C. I and II only D. II and III only
1 Spencer long before Darwin and no soc resp. He was popular among rich so pop bc lots of rich ppl end of story. DON'T OVERTHINK
eukaryotic ribosome
40S + 60S = 80S
Prokaryotic ribosomes are
70S (30S and 50S)
What is the equilibrium constant expression for Reaction 1? A. [Acetylphosphate][CO2][H2O2]/[Pyruvate][Pi][O2] C. [Acetylphosphate][CO2][H2O2]/[Pyruvate][Pi][O2][H2O]
A NEVER INCLUDE WATER
Based on the passage, which subunit of PTx is LEAST suitable for generation of vaccine against B. pertussis? (S1 is inserted into cell and interferes) A. S1 B. S2 C. S4 D. S5
A bc while any of the subunits could be used to develop vaccines by injecting and raising antibodies specific to the bacteria S1 is toxic and therefore injection would make the host sick. For vaccines you normally inject an inert version of the virus so that B cells can make antibodies against it so when the active version comes the antibodies recognize these as antigens and can attack. but if you use the toxic part to make the vaccine the person will get sick. better to use the other components that just do binding so you get the antibodies to the overall pathogen without getting sick.
graded potential
A local voltage change in cell body/dendrites from stimulus that can build up into action potential but doesn't have to be all or nothing
Which of the following statements best applies to the inactive X chromosome in mammalian females? A. It does not replicate. B. Its chromatin structure is less condensed than that of an active X chromosome. C. It is one of the last chromosomes to replicate. D. It is highly transcribed.
A- all chromosomes replicate no matter what, and then split. whichever X is inactive is totally random. we always replicate both chromosomes in every cell in mitosis!!! C- while it seems strange all ik is that it does replicate bc all DNA replicates so that we can maintain our DNA ratios
The presence of which type of intercellular connections between endothelial cells of brain capillaries results in the blood-brain barrier? A. Desmosomes B. Gap junctions C. Intercalated discs D. Tight junctions
A- anchors to form strong sheets of cells B- channels btwn cells C- in heart to allow electric coupling D- restrict movement of harmful substances into brain
Which of the following of the archaeologists' assumptions described in paragraph 3 is NOT supported by evidence or reasoning in the passage? A. The mound builders had a large labor force. B. The mound builders had ample leisure time. C. The mound builders grew maize, beans, and squash. D. The mound builders included specialized craftspeople.
A- bc big mounds B- bc big mounds C- yes had to be farmers but no reason they had to grow those crops SPECIFICALLY D- bc artifacts
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.
A- dec w inc temp B- yes but would have less O2 C- yes bc as exercise make acidic lactate D- inc w less CO2
The electric field inside each of the conductors that forms the capacitor in the defibrillator is zero. Which of the following reasons best explains why this is true? A. All of the electrons in the conductor are bound to atoms, and thus there is no way for an external electric field to penetrate atoms with no net charge. B. Free electrons in the conductor arrange themselves on the surface so that the electric field they produce inside the conductor exactly cancels any external electric field. C. Free electrons in the conductor arrange themselves on the surface and throughout the interior so that the electric field they produce inside the conductor exactly cancels any external electric field. D. All electrons in the conductor, both free and bound, arrange themselves on the surface so that the electric field they produce inside the conductor exactly cancels any external electric field.
A- no bc conductors have free electrons to carry current B- yes bc electric fields all cancel out on interior C- if arranged thru interior would have electric field in conductor moving electrons D- no bound electrons can't move
On the day of the experiment, the subjects drank about 1 L of water on average and excreted about 400 mL of urine. The most likely explanation for the difference between water intake and urine excretion is that: A. the extra water was stored as blood. B. water was consumed with the food that was eaten. C. the extra water was excreted by the intestine. D. water was excreted via the skin and the lungs.
A- no bc graph show no change in volume and also lots of water to go to blood, too much B- no bc then would be reabsorbed into blood and no change in volume was seen if not in urine C- possible but would lead to diarrhea (intestine goes to the anus while kidney filtrate to bladder) not supported D- yes bc most likely if no diarrhea, same blood volume and not in urine
The osmolarity of urine in these subjects was 958 milliosmoles/L, compared with an average blood osmolarity of 284 milliosmoles/L. The higher osmolarity of urine suggests that: A. the kidneys are secreting very little Na+. B. the kidneys are acting to conserve water. C. the subjects are on a low-protein diet. D. the subjects are dehydrated.
A- no bc obv are B- yes bc obv reabsorbing more water which is the natural state C- high protein high osmolarity D- no bc low blood osmolarity so plenty of fluid in blood. kidneys just conserve water bc its their job
What is the main point of the first paragraph? (One page or six hundred, a fiction is more than a well-carpentered entertainment. It is also more than the mirror in the roadway that Stendhal said it was. Because a good writer is not really a mirror; a good writer is a lens. One mirror is like another, a mechanical reflector, but a lens may be anything. Ultimately there is no escaping the fact that fiction is only as good as its maker. It sees only with the clarity that the writer is capable of, and it perpetuates the writer's astigmatisms.) A. A writer must be faithful to real life to be successful. B. A work of fiction reveals its creator's strengths and weaknesses. C. A writer is like a camera that perfectly reproduces real life. D. A writer's astigmatisms are what make a work of fiction fascinating.
A- nope B- yes bc clarity and astigmatisms clearly refer to strengths and weaknesses of the author by talking about capability and perpetuating. C- no D- astigmatisms never described as fascinating or positive
Whenever a two-year-old sees a moth, the butterfly-like pattern on her dress shoes, or hair bows that resemble the shape of a butterfly, she proudly exclaims, "Butterfly!" This process is referred to as: A. the naming explosion. B. overextension. C. categorical perception. D. bootstrapping.
A- the opp bc not know many words B- yes bc overextend the term butterfly C- no, perception of distinct categories when there is change along a continuum D- initial stages of grammatical dev, children can acquire the syntax of a language by first learning and recognizing semantic elements and building upon, or bootstrapping from, that knowledge.
Which compound is predicted to mimic the effect of exercise in undifferentiated muscle cells in vivo? (Researchers simulated an in vitro biomechanical stimulus environment with cyclic tension strain cell culture chamber and investigated the effect of cyclic tensile strain (CTS) on myogenic differentiation by measuring the levels of MYOD1 in the presence and absence of TNF-α. TNF-α is a proinflammatory cytokine that induces the expression of nitric oxide synthase (NOS) and NO production.) (CTS inc MYOD1 while TNF-a dec) A. An MYOD1-specific microRNA B. An activator of NOS expression C. A repressor of Cdkn1a expression D. An antagonist of TNF-α signaling
A- this would block MYOD1 which is the opposite of what CTS, which mimics exercise, does B- this is NOT ROS!!! not correlated w metab!!! just used as a proxy for TNF-a! This would mean more TNF-a which is opp of exercise! C- this would block MYOD1 opp of exercise! D- YES! bc CTS opp of TNF-a Don't overthink things! it's not that hard! everything i need is in the passage and the figure! MYOD1 acts on undifferentiated cells so looking at undifferentiated cells not mean we ignore MYOD1??
Which procedure would be the best negative control for endogenous GABA-receptor function in frog oocytes? A. Addition of GABA to mock-transfected frog oocytes B. Transfection of wild-type GABA receptor into insect oocytes C. Addition of excess GABA to Rdl-transfected oocytes D. Transfection of wild-type GABA receptor into Rdl-expressing oocytes
A- want to see if transfection affects GABA reactions or just binding to receptors bc are doing all experiments based on diff receptors and inhibitors of receptors. if do this and GABA reacts then experiment not valid bc GABA rxn based on transfection mech and not receptors. NO TREATMENT NO RESPONSE B- no bc extra receptors just inc GABA response and not rep normal neg control C- not normal, treated receptor and extra GABA D- all you do is replace Rdl receptors w wildtype to get normal functioning of GABA receptors in those cells which isn't a neg control where you expect to see no response
A team of researchers at a pharmaceutical company tests a new cancer drug. The researchers have concluded that the drug is effective, but other scientists CANNOT replicate the findings. Which is the most likely explanation for the lack of replicability of the original results? A. Base rate fallacy B. Hindsight bias C. Observer bias D. Public verifiability
A- when ppl ignore base rates (prior probabilities) when evaluating prob of event B- overestimate how well can predict likelihood of smtg that already happened C- bias on the part of the observers recording the data, like not blinding D- what the new researchers want
The ranking of attributes and the bogus group consensus are best described as making participants feel as though their group is: A. a reference group, so that participants will evaluate themselves against the group. B. a primary group, so that participants will want others in the group to be respected. C. an in-group, so that participants will consider themselves to be similar to the group. D. a status group, so that participants will want others in the group to view them favorably.
A- yes bc want participants to compare their responses to the group and change to conform to the group. a group you are evaluating urself against and that can influence ur behavior is a reference gp. B- not super tight fam/friends C- since give different bogus ratings feel like out-group D- not abt social institutions and prestige EVAL THEMSELVES AND CHANGE ANSWER BASED ON COMPARING TO BIG GROUP. REFERENCE
Efforts to raise public awareness about dementia in LMICs are most likely to take the form of which community-based program? A. Inform people that dementia is an abnormal condition rather than a normal part of aging. B. Educate people about all the disorders that can lead to dementia if they are left untreated. C. Help people to distinguish between fluid intelligence and crystallized intelligence. D. Explain to people that memory interference occurs more often than memory decay.
A- yes so know to look out for it B- see ALL as red flag, not realistic or productive bc Alzheimer's already major cause of dementia so B prob not even necessary as long as it major causes C- while dementia interferes w fluid intelligence merely differentiating the two wouldn't help esp bc lose fluid w age naturally anyway D- not relevant
Most cytochrome P450 enzymes alter the activity of drugs by: (drug-metabolizing) A. phosphorylating them. B. dephosphorylating them. C. oxidizing them. D. reducing them.
A/B no reason to think works by phosphorylation and this is typically to activate/inactivate substances not to metabolize them. C yes bc catabolism involves oxidation mostly (also monooxygenase) D no bc reduction usually in anabolism
NH3 acts as a weak base in water with Kb = 1.76 × 10-5 at 25°C. The corresponding equilibrium is shown below. NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq) At 25°C, the equilibrium concentration of the NH4+ ion in a 10 M aqueous solution of NH3 would be closest to which of the following? A. 0.001 M B. 0.01 M C. 0.1 M D. 1 M
B
Which technique separates proteins independently of their charge? A. Native PAGE B. Gel filtration chromatography C. Ion exchange chromatography D. Isoelectric focusing
B
Which of the following events does the release of CCK likely trigger? A. Relaxation of muscle in wall of gallbladder and relaxation of hepatopancreatic sphincter B. Contraction of muscle in wall of gallbladder and relaxation of hepatopancreatic sphincter C. Relaxation of muscle in wall of gallbladder and contraction of hepatopancreatic sphincter D. Contraction of muscle in wall of gallbladder and contraction of hepatopancreatic sphincter
B LOGICAL- obv muscle contracts to squeeze out bile and sphincter relaxes to let thru. generally organs contract sphincter relaxes.
The nuclear localization sequence of MYOD1 contains how many potential phosphorylation sites? (NDAFEITKRC) A. None B. One C. Two D. Three
B- in euk just S, T, Y
The beginning of the passage indicates that early studies found which relationship between an individual's attraction to the group and the group's influence on an individual's opinion? A. A positive correlation B. A negative correlation C. An inverse effect D. A reverse effect
Bc observational eliminate C and D bc can't est cause and effect
A researcher measures the concentration of CO2(aq) in a solution at equilibrium. Which additional quantity must be measured in order to calculate the Henry's Law constant kH for the gas? A. Atmospheric pressure B. Volume of the solvent C. Partial pressure of the gas D. Vapor pressure of water
C, Henry's law compares concentration in solution (solubility) to constant times partial pressure of gas above solution
Binding of erythromycin to the large subunit of the bacterial ribosome most likely blocks the transfer of the tRNA bound at: (The binding interferes with aminoacyl transferase function, preventing tRNA transfer between the tRNA sites of the ribosome.) A. the E site to the P site of the ribosome. B. the P site to the A site of the ribosome. C. the E site to the A site of the ribosome. D. the A site to the P site of the ribosome
D
Based on the information in the passage, which immune cells would mount the initial immune response to N. meningitidis that results in meningitis? (Although colonization of the nasopharynx is usually asymptomatic, in some cases the bacteria enter the blood, migrate to the brain, and cross the blood-brain barrier. The subsequent immune response causes meningitis, or inflammation of the meninges, which is a life-threatening condition.) A. B cells B. Cytotoxic T cells C. Helper T cells D. Microglia
D bc only immune cell in the brain. all the others need to be activated by microglia to act in the brain DON'T OVERTHINK
Based on the first paragraph, which of the following statements best summarizes Stendhal's view of fiction? (It is also more than the mirror in the roadway that Stendhal said it was. Because a good writer is not really a mirror; a good writer is a lens. One mirror is like another, a mechanical reflector, but a lens may be anything from what is in your Instamatic to what makes you handle your Hasselblad with reverence.) A. Fiction should reveal the author's inner feelings. B. Fiction should reorder life's events in a pleasing manner. C. Fiction should illustrate life's important ideas. D. Fiction should strive to duplicate life's events.
If all mirrors are the same and just reflectors then probably just reflecting reality rather than inner feelings. Also since mirror in roadway appears to capture everything rather than selectively choosing life's "important" ideas D
Suppose that some influential American critics have always expressed strong opinions about the characteristics of good art and of bad art. This supposition implies that the passage author has probably: A. correctly assessed the gullibility of the American public. B. misunderstood the comments made in the Times reviews. C. overestimated the influence of criticism on artists. D. underestimated the merits of recent American art.
Just because critics have strong opinions doesn't mean there is no art recession, it just means the critics who specifically wrote the Times reviews might be unusually soft or just really believe the art is good. But even if critics think the art is good all that matters is that the author doesn't which means from his perspective there is a recession. if there is a recession despite strong critics then that means criticism isn't that vital to good art bc it couldn't save it C
ping pong mechanism (double displacement)
an enzyme mechanism where a substrate binds to the enzyme and releases a product before the second substrate binds to the enzyme
carbamate
an ester connected to a nitrogen
