Blueprint FL #7
30. Which statement about depression is most likely to come from a person with an external locus of control?
"It doesn't matter what I do; everyone in my family has depression and it's just a matter of time before I do too."
34. Addition of aluminium hydride to sphingosine would most likely result in which of the following products?
(2S,3R)-2-aminooctadecan-1,3-diol - aluminium hydride is a powerful hydrogen donor (common reducing agent)
33. Which of the following is the correct IUPAC name for DMS?
(E,2S,3R)-2-(Dimethylamino)-octadec-4-ene-1,3-diol * see passage for image of compound * - the amino group is on C2, not C3 (eliminate choices A and D) - the double bond is trans, not cis (eliminate C) - therefore, just by process of elimination, choice B must be correct
14. Porosity is an important property for cell proliferation. A researcher performed the following set of measurements on the scaffold: Step 1: The dry weight of the scaffold was measured (W1). Step 2: The scaffold was immersed in dry ethanol for hours, and the entirety was weighed (W2). Step 3: After 48 hours, the scaffold was removed from the ethanol and the ethanol was weighed (W3). Which of the following calculations using the measured weights would allow for an estimation of scaffold porosity?
(W2-W3)/W1 - we need a ratio that describes how much ethanol the scaffold absorbs - W2-W3 gives us the weight of the scaffold plus the ethanol that it absorbed - dividing by W1 gives us an estimate of how much the weight of the scaffold increased after being immersed in ethanol
46. A strong wind lifts a 2-g leaf and propels it 3 m along a spiral path to reach a height of 2 m above the ground. What is the work done by gravity throughout this process?
0.04J - U=mgh = (0.002kg)(10m/s^2)(2m) = 0.04J
15. A researcher proposed investigating the relationship between female employment and fertility rates using a new constant Q, defined as the ratio of the female labor force participation rate to the fertility rate. Based on Figure 1, what was the value of Q in 1980?
10 - in 1980, the female labor force participation rate was slightly over 40% and the fertility rate was 4% - 40 divided by 4 is 10
22. The actual size of a sample object appearing 5 mm long when viewed under a compound microscope where the objective focal length is 3 mm, the eyepiece focal length is 25 mm, and the tube distance is 150 mm, is most nearly:
10 micrometers * see hand written notes on this problem* equation used: MA = (d/fo)(25/fe)
50. p-Nitrophenol has a pKa of 7.16. Which of the following most accurately approximates the ratio of the conjugate base to p-nitrophenol in the pH 11 stop solution?
10,000:1 pH = pka+log([conjugate base]/[acid]) - plugging in values gives: 11 = 7+log([conjugate base]/[acid]) - according to the HH equation, log ([conjugate base]/[acid]) = 4 which gives us a ratio of 10^4 or 10,000 to 1
2. What is the approximate pI value for the unknown amino acid?
10.8 *see graph - pI of any amino acid can be calculated as the average of the two most relevant pKa values - in this example the amino acid was triprotic and had two basic pka values indicating that the amino acid is basic - therefore we average the two higher pka values and leave out the lowest pka value - (12.5+9.0)/2 = approx. 10.8
chem/phys
127
psych/soc
127
bio/biochem
128
12. For what reason was 14CO2 production chosen to measure the rate of oxidation of labeled [1-14C] palmitate and TCA cycle flux?
14-C contained in acetyl-CoA entering the TCA cycle may be incorporated into 14-CO2. - given: fatty acid may be transported into the mitochondrial matrix in the form of acyl-carnitine for breakdown to acetyl-CoA and oxidation in the TCA cycle - carbon that enters the cycle as acetyl-CoA is lost as CO2 - because of this, the rate of 14-CO2 production is a sensible value to use to measure the rate of oxidation of labeled acid palmitate and TCA cycle flux
36. In a follow-up experiment, researchers prepared a new system (including all chambers) with the same initial volume as in the experiment and a pressure of 2 atm. If the system was then allowed to expand to a volume of 7 L with the pressure kept constant, by what factor would the temperature inside the new chamber change?
2 - volume increased by 2 but the pressure is held constant - according to Charles' Law (V1/V2=T1/T2), temperature should be doubled as well
53. Which of the following represents the net reaction for the electrolysis of water?
2 H2O (l) → O2 (g) + 2 H2 (g) - this is the only properly balanced option
44. How long must a patient experience symptoms of depression before he or she can be diagnosed with major depressive disorder?
2 weeks - major depressive disorder can be diagnosed once a person has at least one major depressive episode - major depressive episodes last a minimum of 2 weeks
38. A student sought to remove the H2O and CO2 gas emitted by the animals in separate chambers instead of using silica gel and soda lime. 224 mL of each gas was collected at a pressure of 1 atm. What will be the expected ratio of the mass of CO2 to that of H2O if a valve between the two chambers was opened, allowing the gasses to freely mingle with one another? (Note: the temperatures of all chambers were held constant.)
2.5:1 For CO2: PiVi = PfVf (1atm)(224mL)=Pf(448mL) = 0.5 atm For water: PiVi=PfVf (1 atm)(224mL)=Pf(448mL) = 0.5 atm Next use the partial pressure formula to find moles of each gas: Ptotal=(mol CO2)/(total mol)xPtotal Ptotal=(mol water)/(total mol)xPtotal - both gases have the same partial pressures and since the total number of moles and total pressure are equal for both, both gases must have the same number of moles therefore the ratio of the gases is actually the ratio of their molar masses (molar mass of CO2)/(molar mass of water) = 44g/18g = 2
18. A compound microscope contains an objective lens with a focal length of 4 mm. If the objective produces an image located 5 mm behind the lens, then what is the sample's distance from the objective?
20 mm focal length = 4mm image distance = 5mm object distance = ? 1/o=1/f-1/i = (1/4)-(1/5) = (5/20)-(4/20) = 1/20 o = 20 mm
39. The primary component of the soda lime used in the experimental chamber (calcium hydroxide) reacts to produce a white precipitate. If two moles of soda lime reacts this way, how much of the precipitate will be produced?
200 g balanced equation: CO2+Ca(OH)2 --> CaCO3 + H2O - 2 moles of calcium hydroxide produces 2 moles of CaCO3 (the precipitate) - one mole of CaCO3 consists of 100g - therefore the amount of precipitate formed is 200 g
37. In the argon group, what is the PO2?
230 mmHg - need to use the mole fraction equation PO2 = mole fraction of O2 x Ptotal PO2=[(mol O2)/(total mol)]xPtotal - given: each mixture is a 7:3 ratio of noble gas to oxygen - given: the pressure is 760 mmHg - thus, PO2=(30/100)(760) = 228 mmHg
23. The compound 2,3-dihydroxybutanedioic acid (tartaric acid) has how many stereoisomers?
3 * see passage for image of compound * - compound has two chiral carbons - based on the 2^n rule, it should have 2^2 = 4 possible stereoisomers - however two of those will be meso compounds (i.e. two of the stereoisomers are actually just one) - therefore there are 3 stereoisomers
7. While playing, a 40-kg child is accidentally pushed directly forward off a ledge, causing him to fall and hit the ground at a 60° angle. If the child has 720 J of kinetic energy at the instant before impact, at what velocity was he pushed? Assume negligible air resistance.
3.0 m/s KE=mv^2 720J=.5(40kg)(v^2) 720J=20kg(v^2) 36=v^2 v=6 6.0 m/s is the total final velocity which includes both the horizontal and vertical angles v(horizontal) = v(total)cos(60) =0.5v(total) =0.5(6) = 3.0 m/s
3. What was the pH of the unknown amino acid solution?
3.4 - for all aqueous solutions are 25 degrees C, pH+pOH = 14 - pH=-log[H+] and pOH = -log[OH-] - given: [OH-] = 3.6x10^-11 - therefore pOH = -log(3.6x10^-11) = 10.64 - 14-10.64 = pH=3.4
30. In an in vitro test of the pentose phosphate pathway, 30 moles of glucose 6-phosphate were used. In theory, how many moles of ribulose could you create using the 30 moles of glucose 6-phosphate?
30 - G6P has 6 carbons - during the oxidative phase, each mole of glucose-6-phosphate is converted to one mole of ribose-5-phosphate - molar ratio of glucose-6-phosphate consumed to ribulose-5-phosphate produced is 1:1
49. Based on the data provided, which would best approximate uninhibited enzyme activity at a pNP-gal substrate concentration of 1.5 mM?
32 µmol/min - at substrate concentration of 1.5 mM the enzyme activity would have reached its Vmax, which can best be approximated to 32 µmol/min
52. The cytochrome oxidase complex, encoded in part by COI, requires the transfer of electrons from how many molecules of cytochrome C in order to catalyze the formation of two molecules of water from molecular oxygen?
4 - cytochrome c oxidase complex (complex IV) is the last enzyme of the electron transport chain - it receives on electron from each of four soluble cytochrome c molecules, transferring them to a single oxygen molecule and thus converting one O2 molecules into two molecules of water
5. In a follow-up experiment, HUVEC cells are exposed to 125 μM of DMXAA for 4 hours. At the end of this interval, what percent of total drug-exposed cells would be expected to exist in the M phase of the cell cycle?
4% - Figure 2 shows that 4-5% of cells exposed to 125 micro molar DMXAA exist in mitosis after 12 hours
45. A student performs an experiment and determines that the aqueous decomposition of chloromethyl methyl ether at 650°C is first order with a half-life of 118 seconds. If the student began the experiment with 5 moles of chloromethyl methyl ether, how much remained after 354 seconds?
5 x 10^4 mg - this is just a basic half life problems that I panicked and rushed through and got wrong because of it
6. Suppose that a moderately hard surface such as the hard-packed earth described in the passage is found to decelerate a person making a feet-first landing to a stop in an average of 0.09 seconds. What is the person's deceleration in terms of g (where 1 g = 9.81 m/s2) when falling from a height of two meters?
7g First step: determine final velocity v^2=u^2+2as v^2=0^2+2(10m/s^2)(2m) v^2 = 40 v= 6.4 Second step: determine acceleration a=(final vel. - initial vel.)/time a=(0-6.4)/0.09s round: 0-6.4/0.1s a=64 Third step: convert our answer to terms of g 64/10 = 6.4 7 is the closest answer
9. In a healthy individual, when would you expect ACTH levels to be at their lowest?
8:30 am - this is based on the graph of cortisol levels throughout the day - cortisol levels are very high at 8:30 am therefore negative feedback would cause ACTH levels to be very low
29. Which of the following is NOT a difference between a cDNA library and a genomic library?
A cDNA sequence is difficult to express in a prokaryotic system, whereas a genomic sequence can be conveniently expressed in a prokaryotic system. - a cDNA library includes only the coding regions - easily expressed in prokaryotes via their transcriptional machinery - expression of the entire genome is difficult because they have no splicing mechanism
24. Which of the following most likely pushes a cardiac myocyte above the threshold membrane potential level?
A neighboring cell's depolarization allowing some positive ions to enter through gap junctions - electrical signals are propagated through the heart and cardiac myocytes will not be able to achieve an AP on its own
6. In order to diagnose Cushing's syndrome, urine cortisol levels are measured over a period of 24 hours. Which of the following best explains why this procedure is used?
A single cortisol sample does not provide enough information. - cortisol fluctuates over the course of the day so one single sample would not provide a comprehensive analysis of cortisol
12. Alpha waves are characteristic of which state of consciousness?
Awake, but fatigued and less than fully alert - alpha waves are detected when an individual is awake but fatigued and less than fully alert
6. Which of the following is NOT a reason that positive punishment alone for pushing an incorrect button would likely not be an effective strategy in teaching the cats to push the correct button?
Because the buttons are secondary reinforcers, punishment would technically not occur. - the buttons themselves ae not reinforcers, so this would answer the "NOT" question
8. According to Figure 2, at 6:30 PM in an individual with a pituitary ACTH-releasing tumor, which of the following is most likely true?
CRH levels are low and cortisol levels are high - this type of tumor would cause high levels of ACTH at all times - this would cause an overproduction of cortisol release - cortisol inhibits CRH so CRH levels would be low
58. Which of the following has the smallest atomic/ionic radius?
Ca2+ - as a general rule, cations have the smallest radii - calcium has the highest atomic number (of our answer choices) so its electrons will be pulled closest to the nucleus
20. Which of the following represents the greatest challenge to the validity of the study?
Circumstances other than psychotic relapse can contribute to the outcome variable. - many factors other than an outbreak of psychotic symptoms can result in a hospitalization - as the dependent variable does not capture exactly what the researchers are trying to measure - MAJOR issue in validity
9. How is the law of effect different from classical conditioning?
Classical conditioning involves involuntary responses, while the law of effect involves voluntary actions. - classical conditioning involves a response in the presence of a stimulus - the law of effect involves increasingly shaped actions
46. Which of the following is LEAST likely to contribute to the bystander effect?
Correct interpretation of the seriousness of the situation - the tendency to misinterpret the seriousness of a situation is a factor that contributes to the bystander effect
49. Which of the following is NOT likely to cause MDD?
Decreased levels of THI, the main inhibitor of tryptophan hydroxylase - tryptophan hydroxylase is the enzyme responsible for creating serotonin - if we decrease levels of its inhibitor, that will mean more activity from tryptophan hydroxylase, and thus more serotonin, the desired treatment for MDD
31. How should a parent positively reinforce a behavior that a child is already intrinsically motivated to do?
Do not provide any reinforcement to the behavior. - intrinsic motivation to complete a certain take is undermined when the activity begins to be rewarded (both the desire to do the task and the performance on the task suffer as a result)
46. Which of the following translation errors in the pyruvate decarboxylase gene is most likely to yield the same active site configuration on the enzyme?
GAG is misread as GAA. - this is most likely because the third spot in the codon is known as the "wobble" position and is most likely to change
57. Which psychologist would most likely subscribe to the theory that believing in the supernatural is a non-cardinal personality trait?
Gordon Allport - he established trait theories describing cardinal, central, and secondary traits that contribute to an individual's personality - belief in the supernatural is likely an example of a secondary trait
56. Electrolysis can be performed on a molten salt, in a process analogous to the electrolysis of water described in the passage. The products in the case of the electrolysis of molten sodium chloride are sodium metal and chlorine gas. Which species described in the passage performs the same role as the sodium metal in the electrolysis of molten sodium chloride?
H2 - relevant equation: 2NaCl --> 2 Na + Cl2 - Figure 3 shows 2 aqueous H+ ions reducing to H2, thus H2 is analogous to Na
43. In Table 1, the majority of cell cultures incubated with live HHV-1 after 48 hours showed no sign of plaque growth. However, cell cultures which were incubated below 37°C did show plaque formation. Which of the following best describes this result?
HHV-1 lies dormant in the lysogenic cycle until cells become vulnerable to viral infection. - in the lytic cycle, host cell machinery is taken over to create more phage proteins causing cell death by lysis - the lysogenic cycle occurs when the phage genome is incorporated into the host genome, allowing it to be replicated as the host cell replicates - in the lysogenic phase there is no active infection
47. Which of the following best exhibits how diffusion of education could help low-socioeconomic-status (SES) students?
High-SES school systems could expose them to new ways of learning - diffusion refers to a process being transmitted across groups, in this case across SES groups - being exposed to and potentially internalizing new learning methods via the school environment would therefore be an example of diffusion
27. In an isolated system, entropy is maximized when: I. the system is at equilibrium. II. the system is far from equilibrium. III. the system is unable to perform work.
I and III only - at equilibrium deltaG = 0 - with no free energy change, the system is unable to perform work (III is therefore correct) - at equilibrium there are no energy gradients within an isolated system so energy is maximally dispersed resulting in maximum entropy (I is therefore correct)
23. Which of the following variables were directly measured in this study? I. Intergenerational mobility II. Intragenerational mobility III. Overall incidence of psychiatric disorders IV. Hospitalization for psychiatric disorders
I and IV only - this study measured social mobility by comparing subject's social class to that of their parents (intergenerational mobility, I is correct) - the measures in the study do not include all psychiatric disorders or psychiatric disorder for which patient have outpatient treatment
34. Which of the following does the complementary nature of the DNA sense strand and antisense strand encompass? I. Every nucleotide base on the sense strand has a complementary base on the antisense strand. II. Every nucleotide base on the sense strand that is transcribed into RNA has a complementary base on the antisense strand which is also transcribed into RNA. III. Every codon on each strand that can be transcribed onto a parallel RNA strand can also be transcribed onto an antiparallel RNA strand.
I only - the sense and antisense strands of DNA wind around each other, with each nucleotide base having a complementary base on the opposite strand (I)
11. Which of the following constructs can be defined and evaluated within the constructs of culture? I. Health II. Illness III. Patient sick role
I, II, and III - different cultures define health, illness, and the role of sick people in different ways - medicalization: process by which diseases come to be recognized by society as medical issues (leads to changes in how society treats the new "sick" person)
52. Based on the data in Figure 2, what is the most likely mechanism for I- inhibition?
I- binds to an external site on β-galactosidase, altering the enzyme conformation. - the Km of the enzyme doesn't change under I- inhibition but the Vmax drops by approximately half - this is a characteristic of noncompetitive inhibition
38. According to the passage, which social institutions were involved in preventing HIV/AIDS testing and treatment? I. Hospitals in South Africa II. The government of South Africa III. Racism
II only - only the government is mentioned in HIV denialism and racism is not a social institution, this is the only correct choice
41. Which of the following statements are NOT consistent with the experimental results presented in the passage? I. Overexpression of RFC does not provide cells a competitive growth advantage versus FRα-expressing cells when the sole folate source is leucorvin. II. RFC- or FRα-mediated 5MTHF uptake occurred at 2 nM 3H-MTX extracellular concentrations only in Osteo-FRα-expressing cells. III. No measureable cell growth occurred in Osteo-RFC cells below 23 nM folic acid concentrations.
III only - based on Figure 2, 23 nano molar is the approximate EC50 value for Osteo-RFC cells in folic - however this does NOT indicate that no growth occurs at lower folic acid concentrations , it only indicates that less than half-maximal growth occurs
10. Which of the following processes are NOT likely to contribute to hepatic glucose production by mice fed an HFD? I. Gluconeogenesis using TCA cycle intermediate as substrate II. Hepatic glycogen breakdown III. Gluconeogenesis using pyruvate as substrate IV. Gluconeogenesis using acetyl-CoA as substrate
IV only - both the breakdown of stored liver glycogen and hepatic gluconeogenesis could contribute to hepatic glucose production in mice fed HFD - acetyl-CoA does not serve as a substrate for gluconeogenesis
25. According to the passage, which of the following is NOT a reasonable limitation of this study?
Its sample size was too small, limiting its statistical power. - even though we aren't given specific number, we are told that the study drew upon nationwide registries over multiple years so we can assume the sample size is adequately large - this would make this question correct for a "not" question
25. Which of the following most probably accounts for the decrease in membrane potential at point 1 on Figure 2?
K+ voltage-gated channels beginning to open before Ca2+ voltage-gated channels open - question references a decrease in membrane potential, likely attributed to K+ ions LEAVING the cell - during phase 2 of the AP, the membrane potential is held constant by Ca2+ ions entering the cell while K+ ions leave
59. What are the units for k in the following rate law: rate = k[A]2[B]? Note that the concentration unit is mol/L.
L2mol-2s-1
19. What is the most likely physiological cause of the bone loss seen in the mouse model of acute myelogenous leukemia?
Leukemic cells cause osteoblast inhibition. - Figure 1 shows that as the leukemic cells proliferate, osteocalcin levels decrease - Figure 3 shows that levels of CCL-3 are increased, a causative agent of the decreased osteoblast function - the difference between normal and leukemic mice is the presence of the leukemic cells
48. Based on passage information, what is the most likely reason SSRIs replaced MAOIs as the preferred treatment of MDD?
MAOIs can induce schizophrenic symptoms. - MAOIs block the breakdown (oxidation) of monoamines, increasing their relative abundance - one prominent monoamine is dopamine, an excess of which is implicated in the pathophysiology of schizophrenia
50. Combined with the findings shown in Figure 1, the results of what additional test, if performed, would be most helpful in validating the hypothesis that the F genome is evolutionarily more ancient than the M genome?
Measuring the relative mutation rates of the genomes - passage indicates that the results of Figure 1 imply that the F genome may be older than the M genome - this presumes that differences in the rates of the genomes mutations do not confound this conclusion
29. Hydrogen bonds vary in strength depending upon the donor and acceptor atoms. Which of the following hydrogen bonds has the lowest bond dissociation enthalpy? (A dashed line indicates the hydrogen bond in question.)
N-H - - - :O - question reword: which answer choice has the weakest bond? - the greater the electronegativity of the donor atom, the stronger the positive charge that accumulates on the hydrogen - nitrogen is the least electronegative of the options given (periodic table trend) and would therefore provide the weakest bond
44. Compound X strongly is being tested as a potential cancer therapeutic. Compound X inhibits the uptake of glucose by cells from the bloodstream. Is Compound X likely to be an efficient cancer cell treatment?
No, because Compound X would indiscriminately damage normal cells. - if X strongly inhibits the uptake of glucose from the bloodstream all cells affected by the drug would be unable to utilize glucose
24. A second researcher summarizes the findings of this study, stating that downward social mobility causes an increase in psychiatric disorders. Is this summary supported by the findings of the study?
No, because the researchers did not show a causal relationship between downward mobility and the incidence of psychiatric disorders. - the researchers show a correlation between downward mobility and the incidence for psychiatric disorders, but this cannot be labeled as causative.
37. In 1995, a 55-year-old Black man in South Africa presented to his doctor with some concerns about tuberculosis. What was the likelihood that this man had tuberculosis, compared to a white patient in South Africa of the same age and at the same time?
Not enough information is given to draw a conclusion here. - Figure 1 only refers to incidence rates for TB in a very general fashion (cases of TB per 100,000 people) - since it does not break down this data further, we cannot make conclusions regarding an individual black man
42. Methamphetamine is neurotoxic to dopaminergic neurons in humans. Based on this information alone, methamphetamine overuse or overdose could potentially be associated with an elevated risk of which of the following conditions?
Parkinson's disease - given the information provided in the question stem, the correct answer will be a disorder involving dysfunctional or reduced dopamine signaling
51. DNA extracted from the samples of mantle and gonadal tissue was likely amplified using what technique?
Polymerase chain reaction - PCR is routinely and almost exclusively used when amplification of a simple copy or a few copies of a segment of DNA are required
22. Skin cancer of melanocytes (melanoma) does not cause apparent symptoms beyond pigmentation. If left untreated, metastasis of the cancerous cells to other sites in the body is highly likely, and patient mortality significantly increases. Which of the following best explains the high rate of metastasis seen in melanoma?
Proximity of melanocytes to blood vessels - upon induction of oncogenes, melanocytes can migrate into the blood vessels and disseminate to other sites of the body (metastasis)
36. Why does RNA electrophoresis not require SDS?
RNA molecules already have a net negative charge proportional to the number of nucleotides - SDS detergent is used to ensure that all polypeptides being tested have a negative charge proportional to their length - the phosphate backbone on nucleic acids provides a net negative charge on the molecule - allows nucleic acids to migrate towards the positively charged anode
10. Which of the following statements best defines social control?
Social control describes the ways in which society can prevent and sanction behavior that violates social norms. - social control: ways in which society can prevent and sanction behavior that violates social norms
32. Which of the following CANNOT be concluded based upon the results shown in Figure 1?
Superior outcomes are seen with random punishments in comparison to random rewards. - this directly goes against the data presented in Figure 1
15. Which monomer was most likely incorporated at the edges of the CNT-alginate-HAP scaffold?
T - T is threonine - amino acids most likely to be phosphorylated: serine (S), threonine (T), tyrosine (Y), and histidine (H)
28. A student is conducting an experiment in which he collects gaseous CO2 produced during a particular reaction. Under which conditions would the student's CO2 samples behave most ideally?
T = 273°C and P = 50 Pa - gases behave most ideally under high temperature and low pressure conditions - basically just look for the answer choice with the highest temp. and lowest pressure NOT the answer that is closest to standard conditions
47. An enzyme-linked immunosorbent assay (ELISA) can be used to measure the concentration of antigen in a solution. During ELISA, an enzyme is conjugated with an antibody, which results in a color change and end products that correlate to the amount of antigen present in the original solution. If a control has an absorbance of 0.350 and a sample solution has an absorbance of 0.640, which of the following can be concluded?
The antigen of the sample solution was upregulated. - the question indicates that we are measuring antigen, not antibody levels (eliminate A and D) - we are also told that the amount of antigens correlates with the color change - so if the absorbance value increases from control to experiment, then the antigen level must have increased (example of upregulation)
40. In the experiments described in the passage, what was the purpose of using heat-shocked phage cultures?
To act as a negative control to ensure that there is no effect when no effect should be observed - the heat-shocked phage cultures are negative controls because we expect to see a negative result (we expect to see no result)
26. Which of the following describes a reason that the electrical signal would need to travel more slowly through the AV node?
To allow the blood from the atria to enter the ventricles before their contraction - the pause created by the AV node occurs after the atria begin to emptying their blood into the ventricles
1. Which of the statements below gives the most reasonable explanation for the results in Figure 2?
Treatment with CA4 arrests endothelial cells at a mitotic checkpoint. - Figure 2 shows that a high proportion of CA4-treated cells exist in the M phase after 12 hours
50. What is the most likely reason supplemental tryptophan can be used to treat MDD, while artificial serotonin cannot?
Tryptophan, unlike serotonin, is transported across the blood-brain barrier. - anything that is ingested or injected into the body must cross the blood-brain barrier in order to reach cerebral neuron - if tryptophan can be transported across the blood-brain barrier and serotonin cannot, that would explain why tryptophan can be administered directly, while serotonin cannot
33. The dopamine circulating throughout the mesolimbic pathway is largely produced in which brain location?
Ventral tegmental area - passage 1 states in paragraph 1 that the mesolimbic pathway is a dopaminergic pathway that begins in the ventral tegmental area - dopaminergic pathways: pathways in the brain that transmit the neurotransmitter dopamine from one region of the brain to another
1. One reason that individuals do not seek help with hearing until hearing problems are entrenched is related to:
Weber's law - according to the passage, many individuals do not recognize hearing loss due to the gradual nature of its onset - Weber's law implies that gradual changes in a stimulus may elude detection because they fail to recognize the just-noticeable difference threshold
42. It has been observed that tumor cells develop resistance to the growth-suppressive effect of MTX at a higher frequency than do non-cancerous cells of the same origin. Does the mechanism for MTX resistance proposed in the passage provide a possible explanation for this observation?
Yes; increased metabolic demand for folate in the absence of MTX leads to the increased likelihood of cellular modifications that expand the intracellular folate pool.
30. What is the electronic configuration of Fe3+?
[Ar] 3d5 - elemental iron has 8 more electron than argon with an electron configuration of [Ar]4s2 3d6 - however we are asked about Fe3+ which has three fewer electron than Fe - 4s electrons are less tightly held than the 3d electrons so they will go first - the loss of one additional electron is favored because it increases stability
1. The dissociation constant, Ka, of the acidic form of BCG can be expressed as:
[H+][Ind-] / [HInd] - standard dissociation reaction: HA --> H+ + A- - the molecule that accepts and/or loses the proton is the indicator (Ind) - so in this case the dissociation reaction would be: HInd --> H+ + Ind-
17. In its wild-type form, a particular protein has tryptophan as its nineteenth residue. The Trp19 codon is UGG. Which of the following single-nucleotide substitutions would result in the premature truncation of the protein at the position occupied by Trp19?
a nonsense mutation - eukaryotic RNA stop codons: UAG, UAA, and UGA - a point mutation that turns a non-stop codon into a stop codon is a nonsense mutation
55. A conflict theorist would say that medicine is
a part of the superstructure, brought about for reasons of economics, power, or status for one or more groups of people - conflict theory states that society is an arena for constant conflict between different groups of people - conflict theorists call economic conditions "substructure" and everything else "superstructure" - conflict theorists in general do not necessarily limit their analysis to material gain
19. Based on the results of this study, which of the following patients would be LEAST prone to a rapid psychotic relapse?
a patient who presents a low burden to his caregivers - according to Table 1, times to relapse are significantly negatively correlated with burden posed to caretakers - therefore a lower burden would correspond to a longer relapse time
8. According to the passage, which of the following individuals is LEAST likely to experience a fracture, assuming that all have the same mass and fall onto hard-packed earth from a height of 2 m?
a person with a relatively large bone cross-section who hits the earth at an 80 angle to the ground - first paragraph: "larger angles between leg bones and the normal to the landing surface increased break frequency" - BUT we are given angle in relation to the ground not the normal - an 80 degree angle to the ground is a 10 degree angle to the normal - Figure 1 shows that break frequency is directly related to force per area unit - bigger cross section = less force per area unit
29. Physicians earn the right to prescribe medication and call themselves doctors after the completion of medical school and residency. What type of status does this describe?
achieved status - achieved status: a social role that is obtained through voluntary action or achievement (Ex. becoming a doctor)
3. One promising new anti-tumor medication acts in an analogous manner to CA4, but it targets microfilaments rather than microtubules. This new medication most likely binds to:
actin - given: CA4 is a "tubulin-binding VDA" that promotes microtubule depolymerization - microfilaments are made of actin
51. p-nitrophenol has a pKa of 7.16, whereas ethanol has a pKa of 16. What best explains this difference?
anion stability achieved by delocalized pi electrons across the phenolic salt - acidity is determined by the stability of the conjugate base - the more stable the conjugate, the stronger the original acid - in p-nitrophenol the benzene backbone as well as the nitrogen in the NO2 are sp2 hybridized, creating a plan of delocalized p-orbitals capable of stabilizing the excess negative charge
35. Which of the following gases most effectively decreased infarction volume when compared to the control?
argon and xenon - given: the infarction volume is calculated by determining the are under the curves of Figure 2 - area under the curves for argon and xenon are the smallest - this indicates that the two noble gases decreased the infarction volume the most
21. In order for the image produced by the eyepiece to be erect, where must the image focused by the objective lens fall?
at a distance from the eyepiece smaller than the eyepiece's focal length - "point the same direction" implies that the image created by the eyepiece is not inverted with respect to the image formed by the objective - the image is * upright and virtual* - to create a virtual image with a converging lens, the object distance must be smaller than the focal distance of the lens in question - the object must fall within the focal length of the eyepieces lens
8. What is an example of a fixed-ratio reward system using secondary reinforcers?
bonuses paid to employees after every 100 products are completed - bonuses are considered secondary reinforcers - providing reinforcement after a specified number of behaviors represents a fixed-ratio system
21. In the analysis of the internal relationships between different variables in the study, researchers found that patient burden to caregivers and caregiver stress were positively correlated. Which of the following is a confounding demographic variable that would best explain this relationship?
caregiver income - severity of psychotic symptoms is a confounding variable but it is NOT a DEMOGRAPHIC variable - income is a demographic variable that can be expected to affect both the burden the patient poses and the caregiver's stress level - low incomes tend to increase stress in general
26. These findings are most likely to lack external validity for societies that function as a:
caste system - in caste systems a person's social status is determined hereditarily and mobility between castes is very unlikely - since the study is looking at social mobility the external validity would be lacking for a caste system
16. A hiker out in the woods consumes a large amount of L. sativus seeds, which contain neurotoxic β-ODAP acid. 12 hours later, the hiker is having difficulty maintaining balance and opening her water bottle. What region of the brain is likely being attacked by β-ODAP?
cerebellum - cerebellum receives information for sensory systems and then regulates fine motor movements - coordinates posture, balance, fine motor coordination, and speech
42. According to the passage, which metabolic pathway would be directly inhibited due to a HHV-1 infection?
citric acid cycle - paragraph indicates that the viral infection affects the mitochondria - since the citric acid cycle takes place in the mitochondria, it would be directly affected
45. In the enzyme-catalyzed, B12-dependent reaction that converts homocysteine to methionine, what most likely describes the role of vitamin B12?
cofactor - a cofactor is a non-protein compound that is required for the activity of a protein - vitamins are common cofactors
54. Disability activists are likely to react to programs looking to cure a disability with
concern that these programs take attention away from the need to support people who have disabilities now. - passage states that disability activists believe that disability is not a medical issue (paragraph 3) and oppose medical approaches to disability in most areas (paragraph 4)
17. In this study, age acted as a(n):
confounding variable - age is directly effecting both fertility and labor force participation
39. If an American visited South Africa during the height of apartheid and found himself disoriented by the practices he observed, going through periods of negotiation and adjustment as he became used to his surroundings, this would be due to:
culture shock - culture shock is a sense of disorientation as a person experiences an unfamiliar culture - culture shock: honeymoon, negotiation, adjustment, and adaption
27. Many veterans return from combat with serious mental health issues like post-traumatic stress disorder (PTSD). Which of the following is NOT a symptom of PTSD?
cyclic hypomania - cyclic hypomania is typically seen in people with bipolar disorder, not PTSD
16. Tissue engineers have been developing a synthetic mineral apatite to use in prosthetics that is comprised of repeating molybdenum hexacarbonyl [Mo(CO)6] subunits. This bonding is likely to involve which of the following orbitals?
d2sp3 - the central Mo atom is bound to six substituents - leads to an octahedron shape the number of substituents, or bonding regions, around the atom is equal to the number of orbital that hybridize - two 4d, one 5s, and three 5p atomic orbitals = overall hybridization of d2sp3
4. Which of the following is NOT a biological explanation for hearing loss as described in the passage?
damage to the occipital lobe - the occipital lobe is part of the visual system, not the auditory system
3. What is NOT a possible result of ear damage?
decreased feature detection - feature detection is mainly for visual skills
13. In an individualistic society, a person with a disability that decides to remain unemployed and to subside on disability and welfare checks would most likely be labeled:
deviant - deviant behavior violates societal norms - an individualistic society values independence and self-reliance - a disabled person who relies on government support would be violating that norm
32. An organic synthesist seeks to identify an efficient stereoselective reagent with which to produce the enantiomer of the biologically active sphingosine molecule pictured in the passage. Which of the following would be the most logical choice to try?
diethyl tartate - relies on outside knowledge - this is the only stereoselective reagent listed
2. A preventative test for discerning early-onset hearing loss is to test individuals' ability to:
discern the difference between "pat" and "bat." - the passages states that high-frequency hearing (used to distinguish between consonants) is one of the abilities to deteriorate with hearing loss - "pat" vs "bat" is a test to distinguish consonants
5. An employer who refrains from hiring deaf individuals for a copy-editing job for which hearing is unnecessary is demonstrating:
discrimination - discrimination: a behavior that impacts individuals who belong to a certain group or have a trait solely because they belong to that group or have that trait - discrimination involves behavior
41. The researchers found that the subjects who were given methamphetamine exhibited a higher heart rate and blood pressure. Given this information, the subjects would be most likely to exhibit which of the following physiological changes or symptoms?
dry mouth - increased heart rate and blood pressure are signs of sympathetic nervous system activation (this is expected after administration of a stimulant such as methamphetamine) - the correct answer to this question therefore must be a sympathetic nervous system response (i.e. dry mouth) - all other answer choices are side effects of parasympathetic nervous system
20. Studies show that expression of BCR/ABL and C-myc is sufficient to induce acute myelogenous leukemia in mice. All of the following are likely to be oncogenic functions of these proteins EXCEPT:
electron transport carrier inhibition - if BCR/ABL and C-myc are sufficient to cause induction of rapid cell proliferation, it would make sense that the protein could serve as a transcription factor, tyrosine kinase, or signal transducer - all of these functions would be capable of inducing leukemic - electron transport carrier would also be needed for overactive cells
4. A newly-developed VDA is found to target only capillaries, effectively destroying them entirely. Which of the following cell or tissue types will directly be affected by treatment with this drug?
endothelial cells - capillaries are the smallest blood vessel in the body which are compromised of only endothelial cells - therefore this new VDA must only impact endothelial cells
43. Another team of researchers objected to the decision to exclude participants with a history of drug use, questioning whether the findings of this study can meaningfully be applied to individuals with a higher propensity towards addiction. This is a criticism of which aspect of the study design?
external validity - criticism addresses the generalizability of the study's findings to be broader population (external validity)
31. In Experiment 4, the molecules from columns 4 and 5, which are concluded to be the same molecules from columns 2 and 3 in Experiment 2, are later identified as tRNA and pre-tRNA precursor molecules. Intracellular tracking of the paths taken by these molecules would reveal that the primary function of them is to:
facilitate the complementary binding of amino acids to mRNA prior to the formation of peptide bonds. - this option correctly describes the function of tRNA at this stage of the translation process - one end of every tRNA binds with a three-nucleotide sequence of bases in an mRNA strand, while the opposite end of each tRNA binds with an amino acid
2. According to the second paragraph, cells treated with high concentrations of FAA would most likely:
fail to pass the mitotic checkpoint that checks for DNA damage incurred during the S phase - given: promote G2/M arrest at high concentrations - this checkpoint ensures that DNS has been replicated properly before the cell begins to divide
55. As part of a follow-up experiment, researchers were required to separate glutamine from lysine and aspartic acid using isoelectric focusing. If the amino acids begin the procedure at pH = 1.5:
glutamine will move toward the cathode, but will travel a smaller distance than lysine
54. On average, in comparison to the patients with acute fulminant liver failure, the patients with chronic liver failure:
have lower mortality risk, as indicated by MELD score. - third paragraphs states that MELD score is positively correlated with mortality risk - Figure 1 is needed to answer this question
11. Based on the findings presented in the passage, impaired insulin signaling in mice is marked by decreased:
hepatic insulin sensitivity - given: when challenged by insulin injection, mice fed an HFD for 32 weeks showed impaired insulin signaling, increased hepatic gluconeogenesis, and a decreased fraction of hepatic glucose production due to non-gluconeogenic sources - findings also confirmed insulin sensitivity changes - taking these facts together, liver cells of the mice tested likely displayed both an impairment in insulin signaling and decreased insulin sensitivity
7. A patient is given a synthetic glucocorticoid called dexamethasone, which mimics the effects of cortisol, to determine the cause of high cortisol levels. After injection, which of the following would indicate a pituitary tumor?
high ACTH levels - a pituitary tumor would cause ACTH levels to remain high even if cortisol levels are high enough to induce a negative feedback response
48. The enzyme β-galactosidase catalyzes which type of reaction?
hydrolysis - from the diagram we can see that there is an addition water to break the bond (the definition of a hydrolysis reaction)
17. Prior to the collagen protein analysis used in scaffold design, protein samples must undergo proteolysis. What kind of reaction is required to accomplish this task?
hydrolysis - proteolysis is the breakdown of proteins into smaller polypeptides or individual amino acids via hydrolysis reactions
19. An experimenter proposed employing a material with an index of refraction strongly dependent upon the wavelength of transmitted light for use in an objective lens. How would the use of such a material impact the performance of a microscope?
images formed by the eyepiece from transmitted light containing multiple wavelengths will be unfocused - if transmitted light rays refracted differently depending on their wavelengths, then the effective focal length of the lens would differ for wavelength of light - as a result, for any light containing rays of multiple wavelengths, the rays would focus at multiple point, resulting in an unfocused image - this is also known as *chromatic aberration* in which optical instrument fails to converge light rays from a source to a single point
13. The amount of CO2 produced in ADP-stimulated mitochondria that oxidize palmitoylcarnitine/malate in mice fed an HFD for 16 weeks is:
increased equally versus controls than in ADP-depleted mitochondria. - Figure 2: oxidation of labeled palmitate is increased vs controls in mice fed an HFD for 16 weeks - this increased mitochondrial beta-oxidation leads to an increase in TCA cycle inflex and CO2 production - from the figure: mitochondrial utilization of palmitate-derived palmitoylcarnitine in mice fed an HFD for 16 weeks is equally increased vs control mice in the ADP-stimulated and ADP-depleted states
52. All of the following could potentially be ways to treat MDD EXCEPT:
increasing the internalization of serotonin receptors - decreasing the relative amount of serotonin receptors would result in fewer receptor activations, increasing the severity of depressive symptoms
15. All of the following are functions of cholecystokinin EXCEPT:
inhibiting somatostatin - functions of CCK: 1) suppressing hunger, 2) inhibiting gastric emptying, 3) stimulating pancreatic acinar cells - function of somatostatin: inhibits the release of CCK
36. Under apartheid, the unequal medical treatment received by people of different races was a form of:
institutional discrimination, because it was an institution-wide policy with unfair effects for one or more groups of people. - policies of segregation and group-level phenomena are usually not individual - discrimination describes an action - prejudice is just a belief - the descriptor of an action in the form of a policy would be "institutional discrimination"
58. Which cytoskeletal component forms the majority of the outer layer of skin?
intermediate filaments - the outer layer of skin is made of keratin which is an intermediate filament
49. Researchers noted that the M genome was found in the gonads of male P. purpuratus. What explanation best accounts for this observation? In males, transient localization to the gonads:
is necessary for transmission of the M genome. - the first paragraph states that the M genome is normally found in the mantle but does not state that it is not found anywhere else - it is consistent with the passage that mitochondria containing the M genome is found transiently in the male gonad during reproduction
12. What is the function of a ribonuclease in E. coli?
it cleaves RNA - nucleases break down nucleic acids - we know it's RNA and not DNA because of the name "ribo-"
11. How much does the rate of effusion of dichloromethane at 200 K change when the temperature is changed to 800 K? Assume all other conditions are identical.
it increases by 100% - rate of effusion depends on root-mean-square speed which is calculated by v=sqrt(3RT)/M - rate1/rate2 = sqrt(T1/T2) = sqrt(800/200) = 2 - this means the new rate is twice as large or 100% larger than the original
27. At the beginning of an animal study, one of the female mice had ovaries that failed to form and had to be excluded. If the failure of the ovaries to form resulted from a defect early in the differentiation of one of the three germ layers, what other organs could the researchers evaluate for additional defects?
kidneys, bone narrow, spleen - ovaries arise from the mesoderm, as are all of these structures
13. 5 x 105 J of energy is given to each 5-kg sample of the following solid substances at their respective melting points. Which of the following samples will have the highest percentage of melted substance?
lead * see table * - latent heat of fusion is the amount of energy needed for the fusion (melting) of 1 unit of mass - the substance with the lowest latent heat of fusion requires the least amount of energy per unit mass for melting
18. Which of the following is the most likely reason for the change in osteocalcin mRNA expression observed in leukemic mice osteoblasts?
leukemic cells are proliferating - serum osteocalcin is decreased in leukemic mice but that does not CAUSE a decrease in mRNA expression - process of elimination eliminates B and D therefore this must be correct
18. The study described in this passage is best characterized as:
longitudinal - because this study takes place of a defined time period (two years in this case)
26. Which of the following could NOT be used as the base to separate the optically pure amine from the tartrate, in a method similar to that described in the passage?
methyl acetate - given: "... reaction with a stronger base allows the optically pure amine to be extracted into a suitable organic solvent and separated.." - methyl acetate is the only option that is not a base, it is an organic ester, and therefore the correct answer
38. Analysis of the third pellet obtained during centrifugation showed that it possessed significant levels of fumarase, an enzyme which catalyzes the hydration of fumarate to malate. This pellet most likely contained which cellular organelle?
mitochondria - conversion of fumarate to malate is a step in the citric acid cycle - the citric acid cycle occurs in the mitochondrial matrix of the cell - presence of fumarase in the pellet would indicate that there are mitochondria in the pellet
14. The researchers also found that the relationship between female employment and fertility was especially strong in areas where family planning programs had been introduced and popularized from 1980 to the present. This implies that the presence of family planning programs was a(n):
moderating variable in the relationship between female employment and fertility. - moderating variable: one that affects the intensity of the relationship between an independent variable and a dependent variable
40. In this study, methamphetamine administration served as:
neither punishment nor reinforcement - this study involved classical conditioning, not operant conditioning - concepts of punishment and reinforcement are associated with operant conditioning
57. A student places a vial of gas at the bottom of a graduated cylinder. A liquid sample is suspended in a chamber at the top of the cylinder. The vial is broken and the gas is allowed to diffuse throughout the cylinder. When the two compounds mix, a black precipitate is formed. Which gas should the student choose to minimize the time required for the precipitate to form?
neon - rate of effusion is inversely related to the square root of molecular weight - thus the smaller the molecular weight, the higher the rate of effusion
57. Which phases of the pentose phosphate pathway should be activated to produce the greatest amount of nucleotides and NADPH, respectively?
non-oxidative phase, oxidative phase
14. In eukaryotic cells, where is the highest concentration of phosphorus likely to be found?
nucleus - nucleus contains most of the DNA of a eukaryotic cell - DNA is made of nucleic acids which compromised phosphorus - therefore the most phosphorus should be found in the nucleus
21. Excessive levels of parathyroid hormone would stimulate activity of which of the following cells?
osteoclasts - PHT cause bone resorption through the activity of osteoclasts
31. Sphinganine, the immediate biochemical precursor to sphingosine in the human body, is pictured below. Using only the provided diagrams as evidence, which of the following reaction types most likely characterizes the reaction that produces sphingosine from sphinganine? * see question for image of sphinganine *
oxidation - we lose two hydrogen atoms - an alkene bond is created - both of these increase the oxidation state of the involved carbons
5. BCG will convert from yellow to blue-green when the:
pH of the solution is raised above the pka of BCG - pH above the pka indicates a basic environment - the molecule will be deprotonated - from Figure 1 we see that the blue-green form is the deprotonated (basic) form
28. Tay-Sachs disease is an autosomal recessive disorder that progressively destroys neurons in the brain and spinal cord. If q represents the Tay-Sachs allele frequency in a hypothetical population, which of the following variables could be estimated using a population survey?
q^2 - Hardy-Weinberg equation, p and q represent the frequency of the dominant and recessive alleles (p+q=1)
58. Which of the following is NOT used as a measure of socioeconomic status?
race and ethnicity - socioeconomic status is typically measured by occupation, employment, household income, and educational attainment
56. The philosopher Peter Singer has called for the killing of people with disabilities because they cost too much for the state to support. This statement is most likely based on
rational choice theory. - requires classifying "cost to the state" in the four orientations of sociology (functionalism, conflict theory, rational choice theory, and symbolic interactionism) - because the statement in question is about money, it should have a rationalist orientation - because it is about cost to the state and not to different social groups or parties, it cannot be conflict theory
43. The conversion of dihydrofolate to THF occurs via the enzymatic addition of a hydride to dihydrofolate. The enzyme that catalyzes this reaction is an example of a:
reductase - hydride additions are electrochemical reductions - biological reductions are catalyzed by reductases
7. Which of the following strategies would NOT be helpful in increasing the cats' compliance with pushing the correct button?
rewarding the cats for pushing any button - this would decrease compliance, as the cats would not learn to discriminate the target button from other buttons
28. The socialization medical students experience as a result of non-family influences during their adolescence is most likely considered:
secondary socialization - secondary socialization takes place in late childhood and adolescence - it arises out of interactions with non-family members such as teachers at school or peers
34. Researchers have observed that as feelings of euphoria rise in substance abuse patients, their regulation of satiety declines. This leads to these patients craving higher quantities of the drug to obtain the same "high." What neurotransmitter most likely governs this decline in satiety?
serotonin - serotonin signaling within the hypothalamus is the key pathway through which appetite and satiation signaling is conducted
33. The molecular fragment identified in column 1 is later identified as a promoter region, a sequence which has been shown to:
signal at what location on the helical strand to begin transcribing DNA once a transcription factor has activated the RNA polymerase. - this option correctly describes the function of a promoter region
40. The Km for the binding of the FRα receptor to folic acid under physiological conditions is:
smaller than that for 5MTHF binding - Km is an inverse measure of an enzyme's affinity for a substrate - under physiological conditions, the FRa receptor's affinity for folic acid is greater than that for 5MTHF indicating that the Km for its binding to folic acid under those same conditions should be less than for 5MTHF binding
20. Refractive myopia is corrected by the use of a diverging lens of appropriate optical power. When compared to a healthy eye, a myopic, but otherwise normal, eye's near point is most likely:
smaller than that of a healthy eye - diverging lens decrease the optical power of an instrument by increasing its effective focal length - diverging lens are corrective for myopia - increased optical power should lead to a myopic near point small than that found in a healthy eye
59. Which of the following phenomena would provide the most reasonable explanation for the elevated perception of crime observed in economically depressed neighborhoods?
social anomie - social anomie is a feeling of disconnection from moral boundaries in society
22. Additional studies reveal there is a social stigma against mistreating people with mental illness. This poses a validity issue for the study in the passage because it implies that some of the participant responses might be affected by:
social desirability bias - social desirability bias is the tendency for people to answer survey questions in a manner that will be viewed favorably by others - this may cause validity issues due to this phenomenon
35. If the researchers wished to identify which of their pellets contained the DNA sequence required for cTnI production, they would most likely use:
southern blot techniques - southern blot is used to analyze DNA
16. Assuming that mortality rates had been significantly reduced by modern sanitation and medicine before the period described by this study, during which stage of the demographic transition did this study take place?
stage 3 - stage 3 describes a period where the mortality rate is low and the fertility rate declines - results in population whose growth stabilizes
53. Disability activists are similar to feminist theorists of sociology in that they:
state that structures and attitudes of society selectively disadvantage some groups
45. Individuals who first experience a physiological response when asked to speak about being a victim of crime and then perceive a resultant emotion are demonstrating which theory of emotion or perception?
the James-Lange theory - James-Lange theory is a theory of emotion in which individuals first perceive a physiological sensation, then interpret this sensation as a type of emotion Ex. scary stimulus --> physiological response --> emotion
4. Pulmonologists use BCG to measure respiratory rate during exercise by having patients exhale into an aqueous solution containing the indicator. Which of the following would be observed in the final solution?
the formation of carbonic acid and the solution turning yellow - the exhalation will cause CO2 from his breath to be absorbed into the solution - carbon dioxide + water = carbonic acid - when carbonic acid dissociates, it will cause the water to go from neutral to acidic - BCG will end up in the acidic form which we know from the passage turns yellow
24. After reacting 1-phenylethylamine with (R,R)-(+)-tartaric acid, which of the following best explains what causes the two ionic forms to have different physical properties?
the ionic forms are diastereomers - diastereomers have different physical properties, such as solubility
55. In an electrolytic cell set up as described in the passage, electrons flow into the electrolytic solution from:
the negatively-charged cathode, in order to allow reduction. - reduction occurs at the cathode (+ in galvanic cell, - in electrolytic cell) - oxidation occurs at the anode (- in galvanic cell, + in electrolytic cell)
44. An object floats in water with 4/5 of its volume submerged. If the object is then placed in a type of oil with a density half that of water, which of the following is true about the object placed in the oil?
the object will sink to the bottom
32. One way in which a ribosome can be seen to act as a ribozyme is that:
the ribosome can act as a scaffold that assists with the assembly of peptides from amino acids. - in the cell, ribosomes play an assistive role in holding mRNA in a way that allows amino acids to bond to mRNA one at a time during the process of synthesizing these amino acids into a peptide chain
10. A student ran a thin-layer chromatography (TLC) plate and obtained a lengthy streak for one of the samples. Which of the following factors is LEAST likely to have caused the TLC plate to streak?
the sample was highly polar - polarity of sample affects its retention time but has no effect on streaking
35. The most likely reason for stopping tuberculosis treatment for non-white people was:
there was not enough money to buy and distribute the medicine in the Homelands. - paragraph 3 describes the Homeland hospitals as being resource-poor and that medications are not available
9. Given the relationship between force per cross-sectional area and break frequency described in the passage, it is reasonable to expect:
those runners with the briefest interval of ground contact per step to be more liable to breaks - passage states: the greater the force per cross-sectional area (pressure) correlates with higher break frequency, it is logical to assume that either a smaller cross sectional area for the same force or larger forces for the cross sectional area will lead to more fractures - in this example, runners represent a small cross sectional area with a larger force per area
56. Patients entering the ICU with acute liver failure often also display dramatically lowered plasma glucose concentrations. Which of the conditions below could promote the same effect in individuals without liver damage?
under-stimulation of pancreatic alpha cells - alpha cells release glucagon which increase blood glucose levels - if the activity of these cells is lowered, less glucagon will be released, and plasma glucose levels will remain lower than is typical
51. A cognitive theory of MDD would most likely attribute its cause to:
unstable or faulty thought processes. - cognitive theories of behavior focus on how faulty ways of thinking can negatively manifest as behavioral and emotional disorders
59. A biologist wants to determine whether the high levels of a particular transcript result in increased levels of the associated protein. Which of the following tests could be used to measure protein production?
western blot - western blots are used to analyze proteins