Next Step 3

Which of the following is a weak acid in aqueous solution? A. HF B. HCl C. HBr D. HI

A is correct. All but one of the hydrohalic acids completely dissociate. The one exception is hydrofluoric acid, which is a weak acid in aqueous solution due to its unusually high degree of covalent bonding between the fluorine and the hydrogen.

According to the information presented in the passage, how would the absorbance at 570 nm change over time for enzyme A if a linear starch was used? A. It would remain relatively constant. B. It would decrease. C. It would increase. D. It would initially increase and then decrease as the starch is consumed.

A is correct. Based on Figure 3, enzyme A increased absorbance with no change in current. Thus, enzyme A likely breaks down 1,6 linkages, producing more linear polysaccharides, thereby increasing absorbance. However, if the initial starch is an entirely linear polysaccharide, then a debranching enzyme like enzyme A would have no effect on absorbance, and it would remain relatively constant over time.

Phosphorous acid, a common ingredient used for potable water treatment, has a molecular formula of: A. H3PO5 B. H3PO4 C. H3PO3 D. H3PO2

C is correct. The anion in phosphorous acid is phosphite, PO33-. When comparing the -ous acids and -ic acids, the -ous acids will have 1 fewer oxygen atoms than their -ic counterparts. A: This is perphosphoric acid. B: This is phosphoric acid. D: This is hypophosphorous acid.

Which of the following locations is expected to have the highest number of glucagon receptors? A. Kidney B. Heart C. Liver D. Skeletal muscle

C is correct. This question is asking you to recall the function of glucagon and where it is likely to induce this function. Glucagon is released by the pancreas as a response to low blood glucose levels. Its main purpose is to increase glycogenolysis to increase blood glucose. The glycogen stored in the liver is broken down to create glucose that is released into the bloodstream; therefore, most of glucagon's action occurs in the liver.

convergence theory

Convergence theory has its roots in the functionalist perspective, which assumes that societies have certain requirements that must be met if they are to survive and operate effectively. This is not a trait among creative individuals.

relative configuration

L or D

Rorschach Test (Inkblot Test)

Used to examine personality and emotional functioning The Rorschach test is a psychological test in which subjects' perceptions of inkblots are recorded and then analyzed using psychological interpretation, complex algorithms, or both. Some psychologists use this test to examine a person's personality characteristics and emotional functioning

second order kinetics

describes a reaction whose rate depends on the product of the concentration of two reactants second-order reaction is one whose rate is proportional to the square of the concentration of one reactant

Declarative memory impairment would occur if there were lesions to the

hippocampus

projective personality assessment

require the participant to respond, and then their response is assessed for meaning

retroactive interference

the disruptive effect of new learning on the recall of old information

self-serving bias

the tendency for people to take personal credit for success but blame failure on external factors

Meyers-Briggs personality assessment

An objective personality assessment measures specific personality characteristics based on a set of discrete options

According to French and Raven's bases of power model, when compared to a high motivation high knowledge individual, someone with low motivation and low knowledge is more likely to be influenced by a person with: A. expert power. B. referent power. C. legitimate power. D. coercive power.

B is correct. According to the bases of power model, an individual with referent power exerts control by appealing to others' desire to belong to a group. This type of control is most likely to appeal to individuals through external factors, such as appearing desirable or feeling included and not knowledge or logic or evidence. Thus, a low-motivation, low-knowledge individual would most likely be motivated by this type of persuasion. A: An expert tends to motivate through using his knowledge of subject matter, which would likely appeal to high-motivation and high-knowledge people. C: Those with legitimate power, such as a president, exert power through the legitimacy of their role. There is no indication that this would lead either group to be more persuaded. D: Those with coercive power exert control through force or its threat. It is likely that both high and low groups would be persuaded by this.

That there might be differences between this experiment and actual prison conditions represents a critique of which aspect of the study design? A. Construct validity B. Ecological validity C. Researcher bias D. Reliability

B is correct. Ecological validity refers to how findings from an experimental setting can be generalized to the environmental considerations in the real world. A: Construct validity refers to whether measures actually do assess the variables that they are intended to assess. For example, issues with how verbal abuse was defined in this study might pertain to construct validity. C: Researcher bias involves the researchers interjecting their own views into the experiment and biasing it. D: Reliability refers to the likelihood that results could be replicated.

According to the reported responses, which of the following changed for Student E? A. Implicit attitudes towards study pills B. Explicit attitudes toward study pills C. Covert drug use behavior D. Attitude polarization

B is correct. Explicit attitudes are conscious attitudes. Student E was aware of his attitudes towards study pills and how they changed over time. He once viewed study pills as a negative habit; now he sees them as a means to an end. A: Implicit attitudes towards study pills are unconscious attitudes. C: Covert behavior is unobservable behavior. Student E made changes in his overt (observable) behavior. D: Attitude polarization describes changes in attitudes among people in groups - tendency to go to the extreme.

A balloon has a volume of 3.0 L at 25°C. What is the approximate volume of the balloon at 50°C? A. 1.5 L B. 2.0 L C. 3.3 L D. 6.0 L

C is correct. Charles' law states that there is a direct relationship between the volume of an ideal gas and its temperature, when pressure is constant. Note that the temperature must be in Kelvin! We can approximate the initial temperature as 300 K and the final temperature as 320 K. (3.0 L)/(300 K) = V2/(320 K) [(3.0)(320)] / (300) = (3.0)(1.1) = 3.3 L

This study illustrates that those who assume abuses in institutions are done by those with dispositional propensities to violence have committed an error of what type? A. Confirmation bias B. Availability heuristic C. Fundamental attribution D. Expectation bias

C is correct. This experiment showed that anyone can act in the way the participants did in the right conditions, not because of certain personality characteristics. To assume otherwise is to commit the fundamental attribution error. A: Confirmation bias is selectively finding evidence to support views. B: The availability heuristic is recalling information that is most readily available. D: Expectation bias is when expectations influence attitudes or behavior.

Which of the following is NOT a strategy to induce compliance in a target group, as described in the passage? A. A dress code at an organization B. Referring to military recruits by their military number C. Hazing rituals in a club involving humiliation D. Pointing out differences between one group of students' performance and another group's performance

D is correct. Compliance is induced in groups that view themselves as similar. The other strategies were specified in the passage as ways to induce compliance. A, B, C: Since all of these groups view themselves as similar, these choices serve as good examples for inducing compliance.

The true weight of the p53 protein, as calculated by summing the weight of the amino acids encoded by its gene, is 43.7 kDa. Which of the following possible mechanisms would best explain this discrepancy from its estimated weight, as mentioned in the passage? A. The protein migrated a greater distance because it contains many positively charged residues. B. The protein migrated a smaller distance because it contains many negatively charged residues. C. The protein migrated a greater distance because it contains many negatively charged residues. D. The protein migrated a smaller distance because it contains many positively charged residues.

D is correct. The final paragraph of the passage mentions that p53 is so named for its estimated molecular weight using SDS-PAGE. This question is asking us to determine a plausible reason for the 9.3-kDa discrepancy. SDS-PAGE is used to grant a uniform negative charge to all proteins in an assay. However, if the protein has enough charged residues on its own, it causes the measurements to be less accurate. If there are enough positive charges, the negative charge of the protein will not be as great as anticipated and the molecule will travel a smaller distance, which, to the individual running the assay, usually means the mass of the protein is greater and would lead to the discrepancy described.

Which pair of enzymes, if used simultaneously, will produce the greatest amount of glucose if the experiment is repeated? A. A and B B. A and C C. B and C D. C and D

D is correct. The greatest glucose production per mass of starch will occur when there is the greatest rate of starch breakdown. For complete breakdown, this requires both enzymes that break the 1,4 linkages in linear sequences and those that break the 1,6 linkages at branch points. The enzymes that are most active at the 1,4 sites will cause the largest amount of current, as they will produce the most glucose 6-phosphate from the available linear portions of the starch. The enzymes most active at the 1,6 linkages will result in the largest absorbance of light at the peak wavelength (570 nm). Based on paragraph 3, iodine binds linear polysaccharides, so as the 1,6 linkages are broken, more linear polysaccharides are formed; this will lead to more iodine-starch interactions and an increased absorbance. Thus, the combination that maximizes total breakdown should have the maximum current and maximum absorbance at 570 nm, which matches to enzymes C and D, respectively.

Based on the concept of the looking-glass self, which reaction is most likely for a male Seattle welfare recipient who has a mental illness? A. He will redirect feelings of bias towards police during potential MHA incidents. B. He will seek out other welfare recipients. C. He will seek out other welfare recipients with mental illness. D. He will internalize perceived police bias.

D is correct. The looking-glass self is a social psychological concept stating that a person's self grows out of society's interpersonal interactions and the perceptions of others. The term refers to people shaping their self-concepts based on their understanding of how others perceive them. If the man feels bias from society and/or police (as mentioned in paragraph 1) the looking-glass self theory states that he will internalize the bias/stigmatization directed towards him. A, B, C: These may happen to the welfare recipient, but they do not relate directly to the looking-glass self theory of self-identity.

An artificial leg designed for use by runners is spring-based, to mimic the compression required of a muscle during hard running. For safety reasons, it was determined that the leg should be able to absorb as much as 125 J of kinetic energy without compressing more than 10 cm, or the runner would be likely to stumble. What should the spring constant be? A. 250 N/m B. 2,500 N/m C. 12,500 N/m D. 25,000 N/m

D is correct. When the leg "absorbs" kinetic energy, it is converted to elastic potential energy. While this process involves the loss of some energy as heat, we can assume that it is a perfectly elastic process here for the sake of simplicity. Thus, the leg needs to hold up to 125 J of elastic PE. The formula for potential energy contained in a spring is PE = (1/2) kx2. Since PE and KE are interconverted as the individual runs, we can write this formula as KE = (1/2) kx2, which can be rearranged to yield k = 2 KE/x2. k = (2)(125 J) / (0.10 m)2 k = (250 J) / (.01 m2) k = 25,000 N/m

molecule chirality

For molecule chirality priority is based on molecular weight Prioritize the four atoms, or groups of atoms, attached to the chiral center based on the atomic number of the atom that is bonded directly to the chiral center. The higher the atomic number, the higher the priority.

Zero order kinetics

Term used to describe a constant rate of drug removal from the body, regardless of drug concentration in the blood. zero order elimination rate is independent of concentration

carnitine

The main function of carnitine is the transfer of long-chain fatty acids to mitochondria for subsequent β-oxidation

First order kinetics

Type of kinetics when a constant percentage of substrate is metabolized per unit time first order kinetics are considered as a « linear process », because the rate of elimination is proportional to the drug concentration. This means that the higher the drug concentration, the higher its elimination rate.

affinity chromatography

beads are coated w/ a receptor that binds the protein of interest (high affinity) - protein is retained in column - can be eluted by washing the column w/ a free receptor that competes w/ the bead bound receptor & frees protein -eluted also by changing pH or salinity levels to disrupt bond b/w ligand & protein

proactive interference

the disruptive effect of prior learning on the recall of new information Proactive interference refers to the fact that currently existing long-term memories can interfere with the process of forming new long-term memories.

fundamental attribution error

the tendency for observers, when analyzing another's behavior, to underestimate the impact of the situation and to overestimate the impact of personal disposition

During strenuous exercise, lactic acid buildup in cells causes the creation of a hydronium complex known as the Eigen cation (H9O4+). If water molecules then experience hydrogen bond attractions to the Eigen cation, this attractive force: A. results in a semi-stable shell of water molecules around the hydronium. B. results in an inability of hydronium to be neutralized by bases the way normal H+ ions would be. C. results in the ability of muscle cells to reverse both the hydronium creation process and the lactic acid creation process once sufficient oxygen is once again made available. D. results in mobility of hydronium within the environment surpassing the mobility of regular water molecules.

A is correct. A process known as "hydration" or "solvation" occurs when the attractive force of an ion molecule causes a thin shell of water molecules to surround it. In the case of hydronium (H3O+), each of the H atoms attracts the O atom in an H2O molecule due to hydrogen bonding. These H2O molecules cause a "shell" of water molecules to surround the hydronium.

Which of the following strategies would likely reduce the occurrence of criminal behavior from a differential association theoretical perspective? A. A child in a high-crime area being adopted by an affluent family B. Repeated messages in school that students are expected to uphold prosocial values C. Deemphasizing the importance of values, such as material wealth, that would lead individuals to commit crimes D. Increasing penalties for crime to a degree that individuals are dissuaded from committing it

A is correct. According to differential association theory, individuals engage in criminal choices because they are exposed to it, while individuals who don't commit crimes have not been exposed to this type of behavior. Thus, a child going from an area in which he is likely to be exposed to crime to an area where he is not likely to be exposed will reduce the likelihood of this individual committing a crime. B: This is an example of reducing crime through labeling theory. C: This is an example of reducing crime through strain theory. D: This is a behavioral approach to reducing crime.

At physiological pH, what will be the principal interactions between Arg681 and Cys683? A. Ion-dipole interactions between two chain B residues B. Dipole-dipole interactions between chain A and chain B residues C. Hydrogen bonds between a chain A and a chain B residue D. Disulfide bonds between two chain B residues

A is correct. According to paragraph 2, "Arg681 engages in two direct interactions: a salt bridge with Asp145 of chain A and an intra-subunit interaction with Cys683." Since the passage describes the interaction between Arg681 and Cys683 as "intra-subunit," the two residues must be located on the same chain (eliminate choices B and C). In order for arginine to participate in a salt bridge, it must be ionized, indicating that a nitrogen of the side chain guanidinium group must be protonated. Cysteine is not ionized at physiological pH (~7.4), but it is polar. Thus, its interactions with the other residue are most likely to involve ion-dipole interactions. This is sufficient information to eliminate all answer choices other than A. B, C: Arg681 and Cys683 are both located on chain B.

The AAVrh.10 viral vector was most likely which kind of virus? "Researchers developed an alternative strategy to deliver the coding sequence for an anti-EGFR antibody directly to the CNS via an adeno-associated virus serotype rh.10 (AAVrh.10) gene transfer vector." A. A DNA virus B. A positive-sense RNA virus C. A negative-sense RNA virus D. A retrovirus

A is correct. Based on the passage, DNA coding for the antibody cetuximab was spliced into the viral vector, resulting in AAVrh.10CetMab. The only way that this splicing process could take place is if the viral genetic material were made of DNA.

If a modern portable defibrillator uses as 12 V battery and a 20 μF capacitor, what is the total charge stored on the plates of the capacitor? A. 0.24 mC B. 24 mC C. 24 C D. 60 C

A is correct. Capacitance (C, measured in farads) is the amount of charge stored per volt, expressed with the equation C = q/V. This means that charge (q) = VC. (Do you remember the home shopping network, QVC?) The capacitance is given as 20 x 10-6 F. Substituting the voltage (12 V) and capacitance into the equation gives us the charge (in coulombs). (20 x 10-6 F)(1.2 x 101 V) = 24 x 10-5 C = 2.4 x 10-4 C = 0.24 x 10-3 C = 0.24 mC Remember when making the exponent larger, we must make the coefficient smaller by the same factor.

Cell differentiation is mediated primarily by: A. gene expression levels. B. differing genetic material. C. location within an organism. D. DNA ethylation.

A is correct. Cell differentiation occurs primarily through different gene expression levels. B: Nearly all cells share the same genome, so differences in the genetic material isn't a realistic explanation. C: Location within the body is not responsible for cell differentiation. A skin cell transplanted to the liver, for example, will not become a liver cell. D: It is DNA methylation, not ethylation, which plays a major role in gene expression and, consequently, cell differentiation.

The individual thermodynamic contribution of W (RM)chain A was found to increase the interaction energy of the MKR681H dimer. If so, what must be true for chain A? " W (RM)int = W (RM)dimer - W (RM)chain A - W (RM)chain B Equation 1 where W (RM) is the effective energy of a protein with coordinates RM in solution. W (RM) is given separately by the equation: W (RM) = Hintra + ΔGsolv Equation 2 " A. ΔGsolv < 0 B. ΔGsolv = 0 C. W (RM)chain A > 0 D. Hintra < 0

A is correct. Consider the following expression: W (RM)int = W (RM)dimer - W (RM)chain A - W (RM)chain B If W (RM)chain A increases the interaction energy of the MKR681H dimer, W (RM)int, W (RM)chain A must be a negative quantity, such that the -W (RM)chain A term in the equation becomes a positive value. Equation 2 also tells us that W (RM) = Hintra + ΔGsolv. If W (RM)chain A < 0, then one or both of the terms Hintra and ΔGsolv must be negative. According to the passage, the intramacromolecular enthalpy term Hintra accounts for positive terms. For this reason, it must be true that ΔGsolv < 0.

When an odorous molecule binds to olfactory receptors, the cell transduces the information into an electrical signal that travels to the brain for processing. Which of the following accurately describes the state of the voltage-gated channels on this cell during the relative refractory period? A. Na+ channels are de-inactivated, and K+ channels are activated. B. Na+ channels are inactivated, and K+ channels are activated. C. Na+ channels are de-inactivated, and K+ channels are inactivated. D. Na+ channels are inactivated, and K+ channels are inactivated.

A is correct. First, we need to understand the difference between the absolute and relative refractory periods. The absolute refractory period lasts nearly the entire duration of an action potential, during which time a second action potential cannot be generated. During this time, voltage-gated sodium channels are "inactivated." If this term is not familiar, note that voltage-gated sodium channels have two gates that must be open for sodium to flow inward and depolarize the cell membrane. If the "inactivation gate" is closed, the channels are inactivated. If the inactivation gate is open but the activation gate is closed, the channel is "de-inactivated" — it isn't inactivated, but it is not yet open either. This "de-inactivation" occurs once the action potential nears its end and the membrane voltage becomes sufficiently low (generally during the hyperpolarization phase). At this time, the inactivation gate opens and the activation gate closes. Since the channel is not inactivated, a stimulus could theoretically produce an action potential, but since the cell is hyperpolarized, this stimulus would need to be larger than normal. This interval is termed the relative refractory period, which is what this question asks about. At this time, again, sodium channels are de-inactivated; potassium channels are still activated, allowing potassium to continue flowing out of the cell to finish the action potential.

Which of the following statements is NOT true concerning the element that it describes? A. Lithium has the second-largest atomic radius in period 2. B. Iodine has the highest electronegativity in period 5. C. Iron is a transition element. D. Neodymium is a rare earth element.

A is correct. Lithium (atomic symbol Li) is in group 1, which is sometimes called the alkali metal group. This group has the largest atomic radii of the periodic table. Thus, lithium has the largest (not the second-largest) atomic radius in period 2, and choice A is the correct answer to this NOT question. Group 2 elements, such as magnesium and calcium, are known as the alkaline earth elements and would have the second-largest atomic radii.

Which of the following, if true, would weaken one of the arguments made in the passage? A. The R squared value was not statistically significant in the chart comparing twins' verbal measure scores. B. The R squared value was not statistically significant in the chart comparing siblings' verbal measure scores. C. There was a statistically significant difference between age groups in number of syntactic constructions in 1990. D. There was a statistically significant difference in overall number of syntactic constructions between years across all age groups.

A is correct. One of the main ideas of the article is that language acquisition is biologically based. Evidence to support this was that language acquisition is genetically based, as supported by twin studies. If there were not significant findings of correlation between twins, that would weaken the argument. B: The goal of the study with results shown in Figure 2 was to compare the correlation between twin verbal ability with that of sibling verbal ability. Implicit in this design is the assumption that twin verbal ability will be more highly correlated than sibling verbal ability, since (identical) twins share more genetic information than siblings. Thus, it does not weaken a passage argument if siblings' verbal measure scores are not correlated to a statistically significant degree. C: This simply indicates that different age groups form different numbers of syntactic constructions. This does not weaken a passage argument, and in fact makes logical sense (for example, if older children tend to form more syntactic constructions). D: This supports the data shown in Figure 1, where the number of unique syntactic constructions is shown to increase from 1990 to 2000 to 2010.

In Figure 1, Korsakoff's syndrome patients showed a marked increase in: A. confabulation. B. declarative memory. C. procedural memory. D. aggression.

A is correct. One of the symptoms of Korsakoff's syndrome is confabulation - making up memories to fill in gaps and then believing that those memories are true. When asked to recognize sentences, Korsakoff's patients (at a rate vastly higher than normal) picked incorrect sentences, suggesting they were confabulating the memory of having heard those sentences. B: Declarative (or explicit) memory is the memory of facts and events. The sentence recall/recognition task in Figure 1 is a test of declarative memory. Korsakoff's patients perform much worse on this test than do normal patients, so we would not say that Korsakoff's patients showed an increase in declarative memory. C: Procedural memory relates to the origami task in Figure 2, not Figure 1 (which this question asks about). D: No evidence is given in the passage that the Korsakoff's patients behaved aggressively.

How many liters of carbon dioxide at STP are produced by reacting 100 g of calcium carbonate with an excess of hydrochloric acid? A. 0.0 L B. 11.2 L C. 22.4 L D. 44.8 L

C is correct. The balanced chemical reaction is: CaCO3 (s) + 2 HCl (aq) → CO2 (g) + H2O (l) + CaCl2 (aq) From the periodic table, the formula weight of calcium carbonate is 40 + 12 + 3(16) = 100 g/mol. 100 g of calcium carbonate therefore represents one mole, and based on the reaction, this will produce one mole of carbon dioxide gas. Remember, one mole of any gas at STP (standard temperature and pressure) has a volume of 22.4 L! Thus, the volume of gas produced will be 22.4 L at STP.

Which of the following would have likely lessened the effects observed in the study? I. One guard stating that the treatment of prisoners was too harsh II. Giving information that past participants acted in similarly harsh ways III. Assigning roles based on a personality profile A. I only B. II only C. I and II only D. I and III only

A is correct. Option I alone is correct. Compliance was shown to be severely weakened when just one person disagrees with the group. II: This would likely increase the effects, as it would normalize the behavior. III: Using some qualitative assessment of personality to determine role in the study would result in having similar peoples assigned to the same role. This would likely have increased the harsh treatment, as groups that view themselves as more homogeneous are harsher on outsiders.

The researchers interviewed one of the participants in the study, who, at 50 years of age, recently experienced her first year of poverty. When asked to explain her financial history, she credits her hard work and determination for her success despite being from a low-income neighborhood, and attributes her recent financial struggles to her employer's refusal to give her a raise. Her story is an example of: A. self-serving bias. B. fundamental attribution error. C. prejudice. D. ethnocentrism.

A is correct. Self-serving bias is the tendency to attribute good outcomes with internal factors (for example, hard work), and ascribe bad outcomes to external factors (boss not giving a raise). B: Fundamental attribution error describes the tendency for individuals to overemphasize internal characteristics, such as personality, in attempting to explain someone's behavior at the expense of situational factors. This is not an example of fundamental attribution error. C: Prejudice describes attitudes towards particular groups that do not have a basis in reality. Without more knowledge of the boss's reasons for not giving her a raise, we cannot ascribe this example to prejudice. D: Ethnocentrism means judging another culture by one's own cultural values. The participant's story does not really hint at any cultural factors, so this is not a likely answer.

It has been shown that pheromones induce the body to secrete sex hormones more readily. All of the following are expected effects of sex hormones EXCEPT: A. testosterone causes the Leydig cells in the seminiferous tubules to produce sperm. B. estrogen causes the endometrial lining to thicken. C. estrogen inhibits bone resorption. D. testosterone causes the development of secondary sex characteristics in boys.

A is correct. Sperm is produced by the Sertoli cells of the seminiferous tubules, not the Leydig cells. The seminiferous tubules and their location in the testes of the male reproductive system are shown below. B: This is true; estrogen and progesterone together cause the endometrium to thicken. Estrogen produced from the developing follicles stimulate endometrial growth, and progesterone is responsible for converting the estrogen-primed endometrium into a receptive state. C: Estrogen does inhibit bone resorption; in fact, this is the reason why post-menopausal women experience significant declines in bone density. D: This is also an accurate statement; testosterone causes secondary sex characteristics to develop during puberty in boys.

Based on passage information, medication for which other disorder might cause symptoms of schizophrenia? A. Parkinson's disease B. Major depressive disorder C. Antisocial personality disorder D. Dissociative personality disorder

A is correct. The passage states that schizophrenia is thought to be at least partially caused by dopamine overactivity. Parkinson's disease, in contrast, is caused by insufficient dopamine transmission in the substantia nigra. Therefore, treatments for Parkinson's include medications designed to increase dopamine levels. Too large a dose and/or administration of such medications to a susceptible individuals might therefore increase the risk of experiencing symptoms of schizophrenia. B: Major depressive disorder is thought to be linked to serotonin dysregulation, not dopamine levels. C, D: Personality disorders are not thought to be linked specifically to levels of any given neurotransmitter; nor are they treated through simple medications.

Which of the following is least likely to be observed in a patient experiencing hyperventilation? A. Hypoxia B. Net exhalation of CO2 C. Increased blood pH D. Increased hemoglobin O2 affinity

A is correct. This question asks us to determine the effects of hyperventilation. During hyperventilation, there is a loss of CO2 and an increase in O2 in the blood. Hypoxia is another term for oxygen deprivation. B: During hyperventilation, CO2 is lost due to excess exhalation. C: Loss of CO2 corresponds with increased blood pH. D: Loss of CO2 corresponds with increased hemoglobin affinity for O2.

The instance of nondisjunction for the X chromosome in females over the age of 30 is about one out of every 130 live births. If a woman over 30 gives birth to a viable baby, assuming the risk of nondisjunction from the father is negligible, what is the likelihood that it will have a normal phenotype? A. 99.2% B. 99.6% C. 0.6% D. 0.4%

A is correct. This question asks us to find the probability of a mother giving birth to have a phenotypically normal child. The chances of nondisjunction are 1/130 (0.008), or about 0.8%. If nondisjunction occurs, there is a 100% chance that she will pass on either no copies of her X chromosome and have a child with Turner syndrome (XO) or pass on two copies of the X chromosomes and have a baby with Trisomy X (XXX) or Klinefelter syndrome (see the Punnett square below). The only viable monosomy is the XO genotype. A YO genotype is not viable, meaning we cannot include it in our calculations, since the question asks us to assume a viable birth. Therefore, we simply take 1 - (probability of nondisjunction) = 1 - 0.008 = 0.992 = 99.2%.

If sodium sulfate was added to the mixture containing silver ions and the yellow precipitate, what might be observed after a significant amount of time elapsed? A. Little to no silver sulfate formation, because the Ksp of silver sulfate is very large compared to the Ksp of the yellow precipitate. B. Little to no silver sulfate formation, because sodium sulfate cannot be dissolved at all in water. C. Significant silver sulfate formation, because the solubility of sodium sulfate releases sodium ions which catalyze the necessary reactions. D. Significant silver sulfate formation, because the solubility of sodium sulfate releases sulfate ions which catalyze the necessary reactions.

A is correct. This question is asking us to find a possible outcome and explanation for the outcome when adding sodium sulfate to the silver/yellow precipitate mix. This means we need to choose the answer that has a valid outcome and a proper explanation for that outcome. The Ksp, or solubility product, of a substance is defined as the product of each of the substance's dissolved ion concentration raised to the power of its stoichiometric coefficient. For silver sulfate, the dissolution reaction is: Ag2SO4 (s) → 2 Ag+ (aq) + SO42- (aq) which means that the Ksp equation is: Ksp = [Ag+]2[SO42-] A large Ksp suggests that a substance is more soluble than a substance with a lower Ksp. It is not certain, given that the coefficients might be different and might affect the power to which the ion concentrations are raised. However, it provides a better possible explanation than the other answer choice options (and the phrasing of the question prompt, using the words "might explain," notes that there is some uncertainty involved).

The electrical resistance of dry skin is 100 kΩ, but can be lowered to 20 Ω if electrode contact area is large and conducting gel is used on the skin. If Vmax of the defibrillatror 500 V and lasts 0.01 s, what is the maximum possible current delivered to the heart during defibrillation? A. 2.5 × 101 A B. 2.5 × 10-2 A C. 5.0 × 10-2 A D. 5 A

A is correct. We are given R, V, and time, and the question asked us to determine current (charge/time, or C/s). We do not need to use the time since we should know Ohm's law, V = IR. TIME DOES NOT EFFECTS OHMS LAW If I = V/R and the question asks for the maximum current, we should use the smallest available resistance. I = V/R = (500 V) / (20 Ω) = (50) / (2) = 25 amps = 2.5 × 101 A

In condition 3, the simultaneous application of succinate-rich MDM and rotenone: (complex 1 inhibitor) A. isolates the activity of the ETC beginning at complex I. B. isolates the activity of the ETC beginning at complex II. C. stimulates ATP production in normal and mdx mitochondria. D. stimulates complex II activity only in normal mitochondria.

B is correct. In condition 3, the application of succinate and rotenone causes stimulation of the ETC beginning at complex II instead of complex I, because the ETC is being fed at the former and inhibited at the latter. As a result, the MAPRs observed represent the activity of the ETC beginning at complex II.

A principal of a high school seeks to establish rules and systems in the school that reflect a meritocracy. Which of the following goals must these systems achieve if the principal is to successfully establish a meritocracy? I. Outcome equality II. Skill equality III. Opportunity equality A. I only B. III only C. II and III only D. I and III only

B is correct. A meritocracy is a society of people whose progress within the society is based on ability and talent rather than on class privilege or wealth. This requires that everyone be afforded the same opportunities to advance yet only be rewarded based upon individual outcomes due to their individual talents and/or abilities, which can vary between persons.

What is the pH of a 0.10 M aqueous solution of acetylsalicylic acid? "Subsequently, drugs have been developed to reduce these effects. Aspirin (180 g/mol; pKa = 3.5) is easily prepared by reacting salicylic acid (138 g/mol; pKa = 2.97)" A. 1.0 B. 2.3 C. 3.5 D. 4.1

B is correct. Acetylsalicylic acid is a weak acid, with a pKa of 3.5. Therefore, the pH of this solution must be less than the pKa, because the compound is primarily in its acid form and a pH of 3.5 would mean that the concentration of weak acid and conjugate base were equal (a buffer). Choices C and D can be eliminated. A pH of 1.0 for an acid whose concentration is 0.10 M would require complete dissociation (as in a strong acid), eliminating choice A. Alternatively, the pH can be determined from the equilibrium expression: Ka = [H+][A-]/[HA] 10-3.5 = x2/(0.1-x) Since x will be small, we can approximate 0.1-x ~ 0.1, giving: 10-3.5 = x2/(0.1) 10-3.5(0.1) = x 2 10-4.5 = x2 [10-2.25][10-2.25] = x2 10-2.25 = x Since x equals the hydrogen ion concentration, taking the -log(10-2.25) = 2.25.

Which of the following is NOT considered an organic acid? A. Folic acid B. Carbonic acid C. Ascorbic acid D. Citric acid

B is correct. An organic compound must contain carbon and hydrogen in its formula. Furthermore, there must be a covalent bond between a carbon and hydrogen atom in the molecular structure. Organic acids are weak acids, generally having formulas of R-CO2H, with the acidic hydrogen bonded to an oxygen atom. Even knowing this information, you may be intimidated, as you may not be familiar with the structures of all of these choices. However, you can begin with the most familiar compound, carbonic acid. The Lewis structure of this compound is shown below. H2CO3 (equivalently OC(OH)2). From this structure alone, we can see that neither hydrogen atom is directly bound to carbon, so carbonic acid is not an organic acid and must be the correct answer here.

Which of the following is a characteristic of creativity? A. Convergence B. Flexibility C. Gender differences D. Rigid personality factors

B is correct. Creativity requires several characteristics, including openness to experience, new ideas, an internal locus of evaluation, an ability to toy with elements and concepts, perceiving freshly, concern with outside and inside worlds, ability to defer closure and judgment, and skilled performance of the traditional arts, among others. A: Convergence theory has its roots in the functionalist perspective, which assumes that societies have certain requirements that must be met if they are to survive and operate effectively. This is not a trait among creative individuals. C: This is not a trait among creative individuals. D: Rigidity means the person is unwilling to adapt or change to accommodate new situations. This is not a trait among creative individuals.

At very low CTP concentrations, kinetic data fitted to the Michaelis-Menten equation predicts that the initial rate of the CCT-catalyzed reaction is most nearly what order with respect to CTP? A. Zero order B. First order C. Second order D. Third order

B is correct. For an enzyme-catalyzed reaction with a very low initial substrate concentration, and where Km >> [S], the Michaelis-Menten equation may be approximated as V = Vmax [S] / Km, where Vmax / Km is a constant of the reaction. Under these conditions, the reaction is approximately first order with respect to S. This can be seen graphically in Figure 1, where at low initial CTP concentrations, the enzyme activity (and the reaction velocity to which it is proportional) increases in a roughly linear fashion with CTP concentration. A generic Michaelis-Menten curve is shown below. Note that at low substrate concentrations, the reaction approximates first-order kinetics, as described above. In contrast, at very high substrate concentrations (where the enzyme is nearly or entirely saturated), the reaction approximates zero-order kinetics, since reaction rate ceases to depend on substrate concentration.

A defect in the absorption of certain nutrients in the small intestine has been linked to an abnormally-delayed initiation of differentiation. If the levels of HER2, PTEN, and Akt protein can be estimated accurately, what is the earliest point in development at which the defect could be evaluated? A. 14 weeks B. 16 weeks C. 20 weeks D. 24 weeks

B is correct. From Figure 1, it is clear that the initiation in differentiation results from the downstream signaling from Akt, and, thus, differentiation would not occur until the levels of Akt expression increase. From Figure 2, it should be noted that Akt levels are first noticed in the small intestine during week 16; thus, you would not expect differentiation to occur before week 16.

Efforts to treat lactic acid buildup in muscles were attempted using dissected muscle specimens in the laboratory. One of these experiments involved ammonium formation from dissolved ammonia. Under conditions of excessive lactic acid: A. the final concentration of ammonium will be higher than otherwise due to higher pH. B. the final concentration of ammonium will be higher than otherwise due to lower pH. C. the final concentration of ammonium will be lower than otherwise due to higher pH. D. the final concentration of ammonium will be lower than otherwise due to lower pH.

B is correct. In an acidic environment, a base such as ammonia (NH3) will dissolve into its conjugate acid, ammonium (NH4+), to a greater extent than would have been the case in a neutral or a basic environment. An environment with lower pH is an environment that is more acidic.

In a follow-up study, the emission spectra of both bound states of Y32 were shifted to longer wavelengths than the excitation spectra shown in Figure 2. What is the most likely cause of this shift? A. The emission intensity peak is usually lower than the excitation peak. B. There is a loss of vibrational energy when electrons move from the excited to the ground state. C. A fluorophore typically excited at a wavelength at the peak of the excitation curve. D. Emission detection was selected at the peak of the emission curve.

B is correct. Longer-wavelength light corresponds to lower-energy light. If the energy required to excite electrons present in the CPV fluorophore exceeded that which is emitted when the electrons relaxed, then energy must have been lost during the return to the ground state following excitation separately from the energy of the emission. Only choice B, which states that there is a loss of vibrational energy during the transition, provides a possible explanation consistent with this requirement.

What additional evidence was given to support that the creole languages that evolved in newly established communities were biologically based? A. The languages evolved as groups needed to communicate. B. The syntax of the languages was similar across different, unrelated communities. C. Deaf people generated languages as well as hearing people. D. Creole languages evolved from pidgin languages.

B is correct. That the syntax of the languages was similar across different unrelated communities suggests that there is some innate understanding of language contained within people. A: This does not necessarily indicate that creole language development was biologically based. On the contrary, the fact that the languages evolved in response to people's needs could indicate that language development was not biologically inherent. C: This was never stated in the passage, nor does it necessarily support creole languages being biologically based. D: This is simply a fact about the terminology of these languages and tells us nothing about the factors behind their development.

Researchers conduct an experiment to test the Cannon-Bard theory of emotional arousal. A simulated car crash is used in which the subjects were shown video of an oncoming vehicle. Which of the following results best supports the Cannon-Bard theory? A. Subject spots oncoming vehicle → Subject feels fear → Subject heart rate rises B. Subject spots oncoming vehicle → Subject feels fear and subject heart rate rises C. Subject spots oncoming vehicle → Subject heart rate rises → Subject feels fear D. Subject feels fear → Subject heart rate rises → Subject thinks "I am afraid"

B is correct. The Cannon-Bard theory states that emotion arousing stimuli simultaneously triggers 1) physiological responses and 2) the subjective experience of emotion. A: This incorrectly shows emotion and physiology occurring separately. C: This is an example of the James-Lange theory, which states that experience of emotion is in response to awareness of physiological response to arousing stimuli. D: This is unrelated to the Cannon-Bard theory. Cognitive labels such as "I am afraid" are part of two-factor theories, not Cannon-Bard.

Which of the following forms of bias could best explain the relationship seen between MHAs and welfare distribution? A. Egocentric bias B. Attributional bias C. Framing bias D. Automation bias

B is correct. The study showed that MHAs significantly increased during weeks of welfare distribution. The cops could be assuming that welfare recipients are more prone to mental diseases due to their low social standing and thus more deserving of an MHA. In psychology, attributional bias is a cognitive bias that refers to the systematic errors made when people evaluate or try to find reasons for their own and others' behaviors. People constantly make attributions regarding the cause of behaviors; however, attributions do not always accurately mirror reality. Rather than operating as objective perceivers, people are prone to perceptual errors that lead to biased interpretations of their social world. If police know the welfare schedule and they make harsher judgements based on their perceptions of those on welfare, this would be attributional bias. A: Egocentric bias is the tendency to overstress changes between the past and present in order to make oneself appear more worthy or competent than one actually is. According to the results from several conducted studies, individuals are also more likely to favor circumstances that are beneficial to themselves compared to those that favor the people around them. C: In the social sciences, framing comprises a set of concepts and theoretical perspectives on how individuals, groups, and societies organize, perceive, and communicate about reality. Framing involves social construction of a social phenomenon - by mass media sources, political or social movements, political leaders, or other actors and organizations. It is an inevitable process of selective influence over the individual's perception of the meanings attributed to words or phrases. D: Automation bias is the tendency to excessively depend on automated systems, which can lead to erroneous automated information overriding correct decisions. While this may lead to MHAs where they are not needed (if the police just rote followed protocol), it would not explain the apparent relationship between MHAs and welfare check distribution.

Which of the following would likely decrease an individual's self-efficacy in regard to a particular task? A. Seeing a task performed successfully B. Feeling that past failures were due to other individuals C. Being offered positive encouragement by others D. Learning stress-reduction techniques in regard to the task

B is correct. This is an example of an external locus of control, which might increase an individual's self-esteem, but would be expected to have a negative effect on self-efficacy. A, C, D: Ways to increase self-efficacy include social modeling, social persuasion, and modifying psychological responses, as well as mastery of tasks. These choices are all examples of one of these methods.

Conn's syndrome, also known as primary hyperaldosteronism, is most likely to cause which symptom? A. High renin concentration B. Low blood potassium C. Low blood sodium D. Hypotension

B is correct. This question is asking you to recall the effects of aldosterone and how it achieves those effects. Aldosterone increases H2O and Na+ reabsorption from the kidney while exchanging K+ ions for Na+ ions. The triggers for and results of aldosterone secretion are shown below.

Which of the following findings in the study of sibling language ability would strengthen the conclusion that language acquisition is a biological process? A. Finding that siblings closer in age had more similar scores B. Finding that gender had no impact on score similarity C. Finding that monozygotic twins had more similar scores than dizygotic twins D. Finding that half-siblings raised in the same environment had scores similar to siblings with the same parents

C is correct. Monozygotic, or identical, twins having more similar scores than dizygotic, or fraternal, twins suggests that language is biologically based because identical twins are more biologically similar than fraternal twins.

If a scientist chooses not to employ a SEC column, but wishes to fractionate a protein sample on the basis of only molecular weight, what technique would be most appropriate? A. Affinity chromatography B. Ion-exchange chromatography C. SDS-PAGE D. NMR spectroscopy

C is correct. SDS-PAGE is an electrophoretic technique which involves the binding of the anionic detergent SDS to a polypeptide chain. SDS binding denatures and imparts an even distribution of charge per unit mass to the protein, resulting in fractionation by approximate size alone during electrophoresis.

Which of the following conclusions is NOT supported by the results of the research study? A. Disability is more likely to be associated with poverty than with extreme poverty. B. Income inequality has increased since 1968. C. Americans ages 55-64 are less likely to experience a year of poverty than Americans ages 25-34. D. Marital status is a stronger predictor of poverty than all other predictors of poverty that were studied.

B is correct. This question is best tackled by process of elimination. We're looking for the conclusion that is not supported by the passage, so we can eliminate each answer choice that is supported. Choice A is the first option that can be eliminated, since Table 2 shows that the odds ratio for disability and poverty is greater than the odds ratio for disability and extreme poverty. Moving on to option C, Table 1 says that 46.9% of Americans ages 25 to 34 have experienced at least one year of poverty, whereas only 38.9% of Americans ages 55 to 64 have experienced the same. Thus, this answer choice is supported by the passage. Finally, for choice D, Table 2 shows us that not being married has an odds ratio of 6.99 for poverty and an even larger odds ratio for extreme poverty. This means that not being married results in a higher probability of experiencing poverty than any other factor in that table. This answer choice is supported by the passage. Choice B is the only answer choice remaining. The passage never addresses income inequality; since it is based on lifetime poverty years rather than being a cross-sectional study, it can't tell us anything about differences in income structure between 1968 and the present day.

A student determined that her yield of aspirin was 3.9 g. What was her percent yield? "Using a graduated cylinder, add 7 ml of acetic anhydride (d = 1.08 g/cm3) to the Erlenmeyer flask. " "Weigh out 5 g of salicylic acid (C7H6O3) and place it in a 125-ml Erlenmeyer flask." A. 45% B. 60% C. 78% D. 92%

B is correct. We first need to determine if there is a limiting reagent and then determine the theoretical yield. The moles of acetic anhydride can be determined by using the volume and density information in step 2 of the procedure and the molecular weight given in the passage. 7 mL x 1.08 g/mL x 1 mol/102 g ~ 7 x 10-2 mol We can also calculate the moles of salicylic acid from the number of grams used in step 1 and the molecular weight given in the passage. 5.0 g x 1mol/138 g ~ (5/1.4) x 10-2 ~ 3.5 x 10-2 mol Since the stoichiometry is 1:1 from Reaction 1, the acetic anhydride is in excess and the limiting reagent is the salicylic acid. The stoichiometric ratio between salicylic acid and the acetyl salicylic acid is also 1:1; therefore, the theoretical yield can be calculated using the molecular weight from the passage. 3.5 x 10-2 mol x 180 g/mol ~ 3.5 x 2 x 10-2 x 102 ~ 7 g Since the question indicates that the actual yield was 3.9 g, which is about 4 g, the percent yield is (4/7) x 100 ~ 60%.

The results of the study indicate that to improve the mental health ED care in Seattle, changes should be made to all of the following EXCEPT: A. ED staffing schedules. B. ED patient surge capacity planning. C. social policies regarding welfare payment sizes. D. public policies regarding welfare payment schedules.

C is correct. According to paragraphs 4 and 5 and the data in Figure 1, researchers found an association between ED visits, MHA incidents, and the timing of welfare payments. These findings would indicate that potential improvements could be made if ED staffing models (choice A), ED surge capacity planning (choice B), and even public and social policies regarding payment schedules (choice D) take these associations into account. There is nothing in the study results to suggest that the size/amount of the welfare payments will affect the rate of MHAs or ED visits due to mental health issues. A, B, D: Again, the findings suggest that all of these could be changed to improve mental health ED care.

The passage data regarding the thermal stability and enzyme activity of MKR681H is most consistent with what conclusion regarding the role of Arg681 in CCT? A. Arg681 replacement reduces the CTP binding affinity of MKR681H. B. Arg681 provokes increased heat sensitivity in the dimer. C. Arg681 is engaged in the catalytic function of the enzyme. D. Arg681 absence promotes dissociation of the CCT dimer.

C is correct. Be careful. This question is NOT asking about the mutant. R681H denotes that amino acid 681 (arginine, R) is changed to a histidine (H). The question is asking what we can conclude about the wild-type enzyme given the data presented in the passage. Examining Figure 1 for the enzyme activity data plotted for MKR681H and MKWT shows that substitution of arginine by histidine decreases maximum enzyme activity. Enzyme activity depends principally on an enzyme's intrinsic catalytic efficiency, its concentration, the initial substrate concentration, the presence of inhibitors or allosteric activators, temperature, and pH. In the experiment performed in the passage, all of these factors were controlled for between the enzyme variants other than their intrinsic activity. Of the choices given, this most strongly suggests that Arg681 is involved in the catalytic function of the normal enzyme.

When does a runner output the most additional energy to keep the ground reaction forces most nearly vertical and through her body's center of mass? "Pitch can be minimized if the body applies counter-acting forces to ensure ground reaction forces are approximately vertical through the center of mass. In this case, the force and energy required to maintain such a stance are: where F x is the horizontal force required, Fz is the ground reaction force, Δz is the vertical displacement of a single step, and φ is the angle of ground reaction forces with the vertical, related to the angle at which the body is leaning forward (i.e., the tendency to pitch is greater at higher angles, requiring higher counter-acting forces). " A. When she takes high, bouncing strides and keeps her spine fairly vertical B. When she takes long, low strides and keeps her spine fairly vertical C. When she takes high, bouncing strides and leans her upper half into her run D. When she takes long, low strides and leans her upper half into her run

C is correct. Both the vertical displacement of the runner's steps and the angle of her body from the vertical increase the energy required to realign the ground reaction forces. Recall that tanθ = sinθ/cosθ, so when θ is close to zero, so is tanθ. When θ is close to 90°, tanθ becomes arbitrarily large. The more the runner leans into the run, the greater (or closer to 90°) tanθ is, and the greater the work expended by the runner must be, according to the work equation given in the passage (Wx = Fz tan(θ) Δz). Also, in this equation, the passage states that Δz represents the vertical displacement of a single step. Thus, the higher the vertical displacement ("high, bouncing strides..."), the greater the energy expenditure.

Underproduction of pulmonary surfactant in IRDS leads to decreased compliance of alveolar tissue. Based upon this information, which of the following must be true regarding pulmonary surfactant? A. Its adsorption to the water-alveolar interface increases surface tension, preventing alveolar collapse due to intra-thoracic pressure. B. Its absence decreases the minimum radial size of alveoli able to avoid collapse at a given pressure of inspired air. C. Its adsorption to the water-alveolar interface decreases surface tension, decreasing the pressure difference required to inflate the airway. D. Its presence increases the efficiency of gas exchange across the alveolar membrane by decreasing the surface area of the alveolus at a given pressure of inspired air.

C is correct. During inspiration, contraction of the diaphragm and external intercostal muscles leads to expansion of the thoracic cavity and a decrease in intrapleural pressure. This negative pressure, relative to atmospheric pressure at the entry of the upper airway, generates airflow through the respiratory tree and to its terminal extension—the alveoli. The elastic recoil force of the airway and the surface tension of the water lining the airway oppose expansion of the alveoli due to the influx of atmospheric pressure. Pulmonary surfactant adsorbs to the air-water-alveoli interface, reducing surface tension and the total force resisting expansion. This increases pulmonary compliance—a measure of lung volume change at a given pressure of inspired air—and decreases the work required to expand the lungs at a given atmospheric pressure. This is consistent with choice C. In general, surfactant molecules are amphipathic, meaning that they contain both hydrophobic and hydrophilic regions. The diagram below shows surfactant molecules surrounding a micelle of oil. The hydrophobic tails of the surfactant molecules mix well with the hydrophobic oil, while the hydrophilic heads point away from the oil droplet. Tension = Bad

Y32 is pH-sensitive. This can be a problem when employing it to monitor changes in the energy balance of a cell because: A. pH can differ between cells. B. the ATP-to-ADP ratio of a cell depends on pH. C. pH may change over time in the same cell. D. decreased pH favors the CPV B-state.

C is correct. If the biosensor is pH-sensitive, then changes in cellular pH over the course of a measurement could confuse changes in the energy balance of the cell, as reflected by the cell's ATP-to-ADP ratio.

A student assisting with the experiment would observe all of the following about the electron transport chain EXCEPT: A. Electrons are passed from carriers with lower reduction potential to those with higher reduction potential. B. Complex I is also a proton pump. C. All electron carriers are mobile and hydrophobic. D. The electron carriers can transport a maximum of 2 electrons.

C is correct. In the ETC, carriers travel inside the inner mitochondrial membrane, passing electrons from one to another and pumping protons across the inner mitochondrial membrane. Therefore, they are mobile. In order to travel inside the hydrophobic interior of the membrane, we would expect them to all be hydrophobic. However, cytochrome c is a highly water-soluble protein, unlike other cytochromes. Thus, answer choice C is correct. A: Electrons are passed from carriers with lower reduction potential to those with higher reduction potential. B: An electron from NADH is first accepted by the protein complex NADH-Q reductase, also known as the NADH dehydrogenase complex. H+ ions are pumped through this complex, which spans the membrane, and out of the matrix. D: Each member of the electron transport chain can carry one or two electrons at a time.

A person experiences a prolonged deficiency of thiamine and as a result may develop which of the following neurological disorders? A. Down syndrome B. Alzheimer's disease C. Korsakoff's syndrome D. Schizophrenia

C is correct. Korsakoff's syndrome is a neurological disorder that is most often seen in people who have severe prolonged alcoholism, as a result of which they experience severe thiamine deficiency. Thiamine, also known as thiamin or vitamin B. A: Down syndrome is trisomy 21, in which the individual's cells have three copies of chromosome 21 instead of two. Down syndrome does not result from thiamine deficiency. B: Alzheimer's disease has no known relationship with thiamine deficiency. D: Schizophrenia is not known to develop due to thiamine deficiency, or nutritional imbalances in general.

Which regions of Figure 1 are most likely to be explained by the movement of sodium ions into a cardiac neuron? I. P II. Q III. R IV. T "The P wave is associated with atrial depolarization. After a short interval, the Q and R portions are observed, which indicate ventricular contraction. The final portion, the T wave, is associated with repolarization. In some individuals, an additional repolarizing U-signal is detected after the T wave." A. I only B. II and III only C. I, II, and III only D. I, II, III, and IV

C is correct. Let's begin with RN I. As stated in the passage, the P wave is associated with the depolarization and contraction of the atria. A rest potential is created when sodium ions are pumped to the outside surface of the membrane of a cell. When ion channels open, the sodium ions spontaneously flow back into the cell, resulting in depolarization and an action potential. Roman numeral (RN) I is thus correct.

For the reaction below, which solvent will best promote an SN2 mechanism of reaction? A. H2O B. Methanol C. Acetone D. Toluene

C is correct. The SN2 mechanism is favored by polar aprotic solvents, such as acetone or DMSO. The structure of acetone is shown below; note that it has a dipole moment ("polar"), but does not contain O-H or N-H bonds ("aprotic").

A second student repeated the experiment using glucose and the equivalent enzymes of glycolysis instead of starches. How would his results compare to those shown in Figure 3? ( iodine binds selectively to linear-chain polysaccharides and turns purple) A. Purplish color with higher initial current B. Purplish color but no current because of incomplete glycolysis C. Brownish color with higher initial current D. Brownish color with lower initial current

C is correct. The first difference between the first student and the second is the use of glucose, a monosaccharide (shown below), as the fuel. Paragraph 2 states that iodine binds selectively to linear-chain polysaccharides. As a result, the iodine will NOT bind the glucose, causing the solution to remain brown. We can eliminate choices A and B. Next, we must determine the effect of using glucose and the glycolytic enzymes on the current generated by the battery. From Figure 1, we can infer that the amount of current generated should be directly related to the production of NADH. Unlike in the biostarch battery, glycolysis does not require the breakdown of starch. Thus, NADH is generated directly and more quickly via the conversion of glyceraldehyde 3-phosphate (GAP) to 1,3-bisphosphoglycerate (1,3-BPG). The enzymes should produce 1 NADH per GAP molecule, or 2 NADH per glucose molecule (since each unit of glucose breaks down into two GAP molecules). The original experiment only produced 1 NADH per glucose conversion to phosphogluconate, so we can conclude that the second student should observe a higher initial current than the first.

What is the standard cell potential for the starch battery created? A. -1.136 V B. -0.916 V C. 0.916 V D. 1.136 V

C is correct. The passage states that the cell is meant to act like a galvanic cell, meaning that it proceeds in a spontaneous fashion. Since galvanic cells always have cell potentials that are greater than 0, we can eliminate any negative options (choices A and B) immediately. To decide between C and D, we need more information, namely the reduction potentials of the species involved. Paragraph 1 gives E°reduction of O2 as 0.816 V and E°reduction of AQDS as -0.10 V. Since both species cannot reduce at once, we must reverse the sign of one of the reduction potentials to find the oxidation potential of the relevant reaction. For galvanic cells, reverse the less positive reduction potential, which is -0.10 V here. The associated oxidation potential, then, is +0.10 V. Finally, since we now have a reduction and an oxidation, we can simply add the values directly to yield 0.816 V + 0.10 V = 0.916 V.

If a LCFA is synthesized with isotopically labeled carbons at the C2 and C3 positions, in which product(s) of the initial cycle of its β-oxidation will an isotopically-labeled carbon be found? A. A fatty acyl-CoA molecule only B. An acetyl-CoA molecule only C. Both a fatty acyl-CoA and an acetyl-CoA molecule D. Neither a fatty acyl-CoA nor an acetyl-CoA molecule

C is correct. The products of the initial round of LCFA β-oxidation are 1) an acyl-CoA group that is two carbons shorter than the parent chain and 2) an acetyl-CoA molecule. According to the reaction pathway illustrated in Figure 1, the first and last reactions of which are pictured here, C2 and C3 carbons in an original LCFA will enter the mitochondria in the C2 and C3 positions of activated fatty acid-CoA derivatives (acyl-CoA). They will eventually become included in the C-2 and C-3 positions of 3-ketoacyl-CoA. According to the final reaction pictured in the pathway in Figure 1, thiolase cleaves the acyl-sulfur bond of the 3-ketoacyl-CoA thioester, producing an acyl-CoA molecule. This acyl-CoA unit contains the original C3 carbon as its carbonyl carbon. The original C2 carbon is contained in acetyl-CoA as the terminal methyl carbon.

The finding that Korsakoff's syndrome impairs declarative memory is most consistent with the fact that: A. it is caused by deficiency of a particular type of B vitamin. B. alcoholics are the most common patient population in the US who exhibit the syndrome. C. it is usually associated with lesions that can affect the functioning of the hippocampus. D. patients with Korsakoff's syndrome typically have a normal life expectancy if they receive treatment.

C is correct. The question asks you to find a fact consistent with damage to declarative memory. Here, the MCAT expects you to know about the central role played by the hippocampus in the functioning of declarative memory. Lesions that affect the hippocampus, as described in choice C, would be most consistent with memory impairment. A, B, D: Though these choices are all true facts about Korsakoff's, none of them directly relate to memory impairment as asked in the question.

If a 3-kg rabbit's leg muscles act as imperfectly elastic springs, how much energy will they hold if the rabbit lands from a height of 0.5 m and its legs are compressed by 0.2 m? A. -0.6 J B. 0 J C. 10 J D. 14.7 J

C is correct. This is a tricky question, because the passage states that nature has no perfectly elastic springs, which means energy cannot be completely conserved. This does not, however, mean that all the energy is lost, nor does it make sense for the potential energy stored in a spring to be negative (ruling out answer choices A and B). Then, to distinguish between choices C and D, we need to obtain an estimate of what the value would be if energy were completely conserved, since that could serve as a baseline. The potential energy of the rabbit at the peak of its height can be estimated as PE = (3)(10)(0.5) = 15 J. Since that value was calculated using the estimate of 10 m/s2 for g, instead of 9.81 m/s2, we should recognize that it is an overestimate. That is, the actual value that would be obtained if no energy was lost would be slightly less than 15 — therefore, answer choice D, 14.7 J, seems about right for how much we need to correct for our estimation of g. That is, choice D corresponds to the value that we would calculate if no energy was lost. Finally, we are left with choice C, 10 J, which corresponds to a non-trivial loss of energy due to inefficiency, which is what the question stem suggests that we should expect (because of the wording "imperfect spring").

.Selenocysteine is a non-standard amino acid that is present in all domains of life. It has the structure of cysteine, but the sulfur atom is replaced with selenium. The structure of selenocysteine is shown below: Nitrogen, C-Se, C-O(double bond), H What is the absolute configuration of the alpha carbon in selenocysteine? A. D B. L C. R D. S

C is correct. When assigning absolute configuration, imagine the molecule so that the lowest-priority group is facing away. In this case, it is the implicit hydrogen, which by the tetrahedral geomtry of the alpha carbon already happens to be facing away. Then, assign priority based on molecular weight of the attached atoms. Nitrogen > C-Se > C-O > H. Follow those atoms in a clockwise circle to assign the R configuration, as shown below.

What are the respective hybridizations of the imine nitrogen and carbonyl carbon of the CPV B-state as it is depicted in the passage? A. sp and sp2 B. sp and sp3 C. sp2 and sp2 D. sp3 and sp3

C is correct. When determining the hybridization of an atom, remember that each sigma bond in which that atom participates and every lone pair to which it is bound requires, in most situations, one hybrid orbital. The imine nitrogen of the CPV B-state is bound to two other atoms and has one lone pair. Accordingly, it requires three sp2 hybrid orbitals. The carbonyl carbon is bound to three other atoms. For this reason, it requires three sp2 hybrid orbitals.

A hospital purchases brand-new GKS-Co and GKS-X machines. Five years after installation, what is the expected ratio of the total atomic mass of material in the Co machine to that in the X machine, assuming both machines start with the same mass of radioactive material? A. 1:16 B. 1:5 C. 1:1 D. 5:1

C is correct. When reading questions, be careful not to read too quickly. In this case, fast but inefficient reading will lead us to assume that it is asking about the percentage of a certain isotope that is left after radioactive decay. However, the question is asking about atomic mass. While β-decay does cause a nuclear transmutation of protons to neutrons (β-plus) or neutrons to protons (β-minus), the atomic mass lost in these processes is negligible. This means that whether after one (Co) or five (X) half-lives, the atomic mass will be the same in both samples.

Besides aspirin, what is the other product of Reaction 1? C2H4O2 A. Ethanol B. Ethanoic acid C. Ethanal D. Methyl formate

C2H4O2 B is correct. The other product of Reaction 1 has a formula of C2H4O2. Ethanoic acid, a carboxylic acid, has this formula. The reaction between acetic anhydride will involve the acylation of the alcohol functional group of the salicylic acid, with the by-product being acetic acid, also known as ethanoic acid. A: Ethanol is an alcohol and has a formula of C2H6O, meaning that it cannot be the product that we're looking for. C: Ethanal is an aldehyde and has a formula of C2H4O; again, this is the incorrect formula. D: Methyl formate is an ester and does have the correct formula of C2H4O2. However, as mentioned above, Reaction 1 yields a by-product of ethanoic acid, which preserves the bond between the methyl group and the carbonyl carbon that was present in the acetic anhydride. For methyl formate to form instead, the methyl group would have to rearrange somehow (magic?) and bond to an oxygen atom to form the ester shown below:

A student theorizes that the differences in ATP-to-ADP ratios between cells detected in the experiment could be due to variations in Y32 expression rather than differences in the cells' metabolic conditions. Does information presented in the passage support this possibility? A. Yes, Y32 fluorescence intensity is proportional to the number of sensor molecules excited. B. Yes, Y32 expression levels can influence the cellular ATP-to-ADP ratio. C. No, the shape of the fluorescence excitation spectrum of Y32 is influenced by the bound state. D. No, the spectral ratio intrinsically normalizes for the amount of biosensor.

D is correct. According to the passage, the spectral ratio of the peaks of the excitation spectrum of a Y32-expressing cell directly reflects its cellular ATP-to-ADP ratio. The fact that a ratio is used is the key to the idea of intrinsic normalization. The peak absorbance of the B-state, which is favored in the Mg2+-ATP bound conformation, is near 500 nm, while the peak absorbance of the A-state, which favors the ADP-bound conformation, is near 420 nm. Thus, the ratio of the fluorescence emission intensities when Y32 is excited at 500 nm versus when it is excited at 420 nm serves as a direct indicator of the cellular ATP-to-ADP ratio. If, as stated in the passage, the fluorescence intensity is proportional to the number of sensor molecules excited, then excitation at both 500 nm and 420 nm would change proportionally with changes in biosensor expression, and would have no impact on determining the ratio in which ATP and ADP are present in the cell.

Which of the following represents a limitation to the design of this study? A. The age of the participants B. Lack of knowledge about OCD C. Ethical implications of delivering shocks to participants D. Using a non-clinical patient sample

D is correct. Any findings during this study would be more valid if the researchers could have gathered patients who had been diagnosed with OCD, instead of having participants that simply had obsessive-compulsive traits. An important note here is that this limitation specifically pertains to the goal of the study, which was conducted to investigate overgeneralization. In turn, paragraph 1 tells us that overgeneralization is linked to OCD. Therefore, conducting a study among participants with OCD, perhaps in addition to those with only obsessive-compulsive traits, would have strengthened the findings of the study. C: Conducting research ethically does not necessarily mean avoiding all techniques that might be uncomfortable for participants. In particular, delivering shocks to participants is a fairly common research method. Ethical considerations apply to the need to obtain informed consent and to conduct the procedure in the least harmful possible way that is consistent with the research goals (a concern that would be evaluated as part of IRB approval). However, using shocks is not inherently unethical.

The Rorschach inkblot test is often used to identify distinct personalities in those with DID. This test is best categorized as a: I. subjective personality assessment. II. objective personality assessment. III. projective personality assessment. A. I only B. II only C. II and III only D. I and III only

D is correct. Both RN I and III correctly describe the inkblot test. In subjective assessments, patients project their own subjective feelings, perceptions, and thoughts onto the assessment stimuli, yielding results that are open for inaccuracy. For example, physicians may reach a different conclusion despite seeing the same patient who says the same thing. Projective personality assessments require the participant to respond, and then their response is assessed for meaning. II: An objective personality assessment measures specific personality characteristics based on a set of discrete options, such as in the Meyers-Briggs personality assessment.

If a flat Petri dish containing a single layer of cells suspended in viscous culture medium is tapped, some cells will collide into each other. If cell 1 collides into cell 2 on such a plate, which of the following describes what happens to cell 2 after the collision, assuming an elastic collision and non-zero drag from the medium? I. Cell 2 continuously accelerates. II. Cell 2 moves with decreasing speed. III. Cell 2 moves with constant speed. IV. Cell 2 decelerates until it reaches a velocity of 0 m/s. A. I only B. II only C. III only D. II and IV only

D is correct. Cell 2 can only accelerate while it is being pushed/in contact with cell 1, so statement I is false. Since the cells experience drag from the medium, cell 2 will decelerate after the collision, making statement II correct and statement III incorrect. The drag will cause cell 2 to continuously decelerate until it comes to rest.

All of the following are potential limitations of the research discussed in the passage EXCEPT: A. Seattle is a busy urban center, with some core regions of the city having a high concentration of inhabitants with mental illness and addictions. B. the impact of MHAs were not correlated to ED or police workload or flow. C. the increase in MHAs following income assistance payments may be related to other unknown and undetermined confounders. D. sociological activity, such as welfare check distribution, is known to be causally related to increased police or ED activity.

D is correct. If welfare check distribution were known to be an established causal element to the relationship observed between MHAs and welfare distribution, it would strengthen the implications of the study.

An individual with Wernicke's aphasia would likely have difficulty with what part of communication? A. Producing sound B. Constructing words C. Forming sentences D. Expressing meaning

D is correct. People with Wernicke's aphasia have difficulty connecting meaning to language. The diagram below depicts Wernicke's area (located in the temporal lobe) as well as Broca's area (located in the frontal lobe). A, B, C: These are all parts of communication related to the physical production of speech. As such, an individual with Broca's aphasia might have trouble accomplishing them, but an individual with Wernicke's aphasia would not. (For choice C, note that it says "Forming sentences," not "Forming meaningful sentences." As such, it refers to the physical production of sentences and is not the answer here.)

A person pushes horizontally on a 50-kg crate, causing it to accelerate from rest and slide across the surface. If the push causes the crate to accelerate at 2.0 m/s2, what is the velocity of the crate after the person has pushed the crate a distance of 6 meters? A. 1 m/s B. 2 m/s C. 3 m/s D. 5 m/s

D is correct. Since the crate is initially at rest, the Vi = 0 m/s, the acceleration a = 2.0 m/s2, and the displacement = 6 m. The appropriate kinematic equation is vf2 = vi2 + 2ad. Substituting the variables gives: vf2 = 02 + 2(2)(6) vf2 = 24 vf = ~5 m/s

Examining the results in Figure 2, the common ion effect accounts for: I. the increased yellow precipitate observed in Figure 2 when AgNO3 is added. II. the increased yellow precipitate observed in Figure 2 when K3PO4 is added. III. the decreased yellow precipitate observed in Figure 2 when Ba(OH)2 is added. A. I only B. II only C. III only D. I and II only

D is correct. The common ion effect occurs when a solution contains a salt that partially dissolves into ions, and an extra quantity of one of these ions is added. This results in the combination of this ion with existing dissolved ions, causing an additional quantity of the salt to precipitate out of solution. In this case, the partially-dissolved salt is Ag3PO4. Adding AgNO3 causes dissolution of extra Ag+ions, which then combine with already-present PO43- ions and precipitate out of solution into the yellow Ag3PO4 precipitate (identified with the mass spectrometer used in Figure 1). Similarly, adding K3PO4 results in dissolution of extra PO43- ions, which then combine with already-present Ag+ ions and precipitate into yellow Ag3PO4. I and II are therefore both correct.

When Y32 is expressed within a normal cell, what is true of its nucleotide binding site? "The biosensor can bind both Mg2+-ATP and ADP with very high affinity (Km ∼ 1 μM). In the cytosol of a normal cell, the concentrations of ADP and Mg2+-ATP range in the hundreds of μM and approximately 1 mM, respectively." A. It is most likely to be occupied by ADP. B. It is unlikely to be occupied by Mg2+-ATP. C. It is unlikely to be occupied by Mg2+-ATP or ADP. D. It is effectively always occupied by Mg2+-ATP or ADP.

D is correct. The passage indicates that the biosensor binds Mg2+-ATP and ADP with very high affinity (with a Km ∼ 1 μM). This concentration is much lower than the normal cytosolic concentrations of ADP and Mg2+-ATP (hundreds of μM and about 1 mM, respectively). Given this, it is quite likely that the nucleotide binding site of an Y32 molecule would be occupied by Mg2+-ATP or ADP under such conditions.

During the study discussed in the passage, different-sized circles were displayed before a shock was delivered to the participants. The shock and the resulting fear are examples of which aspects of classical conditioning, respectively? A. Unconditioned stimulus and conditioned response B. Conditioned stimulus and conditioned response C. Conditioned stimulus and unconditioned response D. Unconditioned stimulus and unconditioned response

D is correct. Unconditioned because you don't need to be conditioned or taught to have these responses to such obvious stimulus. The shock is an unconditioned stimulus because it triggers a naturally-occurring response, and the fear is an unconditioned response that naturally occurs when presented with a shock. A: Here, fear is an unconditioned response because it occurs naturally after a shock. B: A shock automatically tends to provoke a fear response, making the shock an unconditioned stimulus. C: A conditioned stimulus is a neutral stimulus, like the image of a circle, that (after being repeatedly presented prior to the unconditioned stimulus) evokes a behavior similar to the unconditioned response. The conditioned response is the acquired response, in this case fear, to the formerly neutral stimulus (the image of the circle).

What is the net charge on a phenylalanine molecule at pH 1? A. -1 B. 0 C. +0.5 D. +1

D. +1 At a pH1, which is very highly acidic, the only functional groups to think about are just the amino and acid parts of an amino acid. So the amino group (NH2) at a really super acidic pH is going to be NH3+ (so +1). And the acid part (COOH) is also going to be protonated. So the COOH is neutral. So you've got COOH neutral, NH3+1, and the phenylalanine side chain which is also neutral. This gives us a total net charge of +1. So the answer here would be (d) +1 charge.

The high-energy radiation produced by the γ rays has sufficient energy to: I. generate free radicals. II. excite electrons to higher energy levels. III. eject electrons from molecular orbitals. A. I only B. I and II only C. II and III only D. I, II, and III

D. I, II, and III D is correct. The second paragraph tells us that the radiation is strong enough to cause molecular electronic transitions by exciting electrons to higher energy levels in molecular orbitals. This indicates that that the radiation can either excite or eject electrons (depending on its energy) and can create free radicals (atoms with unpaired valence electrons). These properties correspond to Roman numerals I, II and III.

How much heat is produced from the complete combustion of 30.0 g of methane, if the enthalpy of reaction is -890 kJ/mol? A. 1.7 x 103 J B. 1.7 x 106 J C. 4.7 x 106 J D. 4.7 x 109 J

Enthalpy is the energy per mole B is correct. First, note that methane has a molecular formula of CH4. Thus, its molecular weight is approximately 12 + 4(1) = 16 g/mol. 30 g CH4 x (1 mol/16 g) x (890 kJ/mol) = 1.8 x 103 kJ (if we round 890 to 900 kJ/mol) Note that the answer options have units of joules (J), not kilojoules (kJ), and choice A should be eliminated. Converting the units gives: 1.8 x 103 kJ x (103 J /1 kJ) = 1.8 x 106 J A: This is the answer in kilojoules (kJ), but it includes units of joules (J), making it incorrect.

absolute configuration

S or R

Third order kinetics

Third Order Reaction. A reaction is said to be of third order if the rate is determined by the variation of three concentration terms. In other words, the minimum number of molecules necessary for the reaction to take place is three.

Differential Association Theory (Sutherland)

deviance depends on the amount of contact with others who reject conventional behavior differential association theory, individuals engage in criminal choices because they are exposed to it, while individuals who don't commit crimes have not been exposed to this type of behavior. Thus, a child going from an area in which he is likely to be exposed to crime to an area where he is not likely to be exposed will reduce the likelihood of this individual committing a crime.