MCAT TPR practice test #2

define Kd

, quantifies the dissociation of the ligand-protein complex. Therefore, the substance that binds most strongly will have the smallest value for Kd.

Similarities that exist between protists and bacteria include all of the following except: A. Organelles B. Double-stranded DNA C. Unicellularity D. Flagellar motility

A. Bacteria do not have organelles while protists exhibit the organelles typical of animal cells (answer choice A is correct). While bacterial store genetic information in circular DNA and protists have linear chromosomes, both forms of DNA are double-stranded and, thus, this is a similarity between bacteria and protists (answer choice B is incorrect). Bacteria are unicellular and protists typically are, as well (answer choice C is wrong). Some protists exhibit amoeboid movement but both protists and bacteria often exhibit flagellar movement (answer choice D is wrong).

One of the modifications that Milgram made to his original shock experiment was to test the possible effects of conformity on obedience. The basic experiment tests the conditions under which a research subject, the "teacher", will administer an electric shock to the "learner" (a confederate member of the research team). The teacher receives instructions from an authoritative "experimenter" (a research team member) to administer the shock under certain circumstances. Which of the following experimental modifications would in fact test for the effects of conformity on obedience? Adding another teacher (a confederate) to the shock administration room Adding a window to the room so that the teacher can see the learner Increasing the proximity of the teacher to the learner A. I only B. II only C. I and II only D. II and III only

A. To assess the possible effects of conformity on obedience, one must determine whether and to what extent subjects conform their behavior to the actions of others who appear to be similarly situated (i.e., other "teachers") when determinig whether or not to obey the experimenter who instructs them to administer shocks. Item I is true: adding another confederate teacher to the shock administration room would test whether the naive subject would conform to the actions of the other "teacher" when determining whether or not to obey. Item II is false: adding a window to the room wherein the learner will receive the shock would not test for the effects of conformity on obedience because it would not include a similarly situated figure (choices B and C can be eliminated). Item III is false: similarly, merely increasing the proximity of the teacher to the learner would only test obedience, as there is no other person present to whose behavior the subjects might conform their actions (choice D can be eliminated, choice A is correct).

It has been observed that when an alpha particle and a beta particle are given equivalent initial kinetic energies, the beta particle will travel a significantly greater distance in air before losing its energy. Of the following, which is the most likely explanation for this observation? A. The alpha particle's greater size and charge results in a greater number of interactions, which cause it to dissipate its energy faster. B. Beta particles have greater momentum. C. The beta particle's smaller size causes it to have more elastic collisions with air molecules, allowing it to travel farther. D. The greater velocity of the alpha-particle relative to the beta-particle results in an erratic, shorter mean free path for the alpha particle.

A. Choice B is false since the equation relating momentum, p, to kinetic energy, K, is p =Start Square root: 2 times: kinetic energy or K: times: mass or m: End Square root. Since the alpha and beta particles have the same K, the one with the smaller mass (the beta particle) has the lower momentum. Choice C is false since a smaller particle would tend to have fewer collisions, not more. Choice D can be eliminated because the greater mass of the alpha particle means it has a lower velocity than a beta particle of equal kinetic energy.The alpha particle would experience a greater electric force and a greater gravitational force than an equally-energetic beta particle, not because of its lower velocity, but because of its greater charge and its greater mass. [In fact, it can be shown the energy lost per unit distance for a particle of charge q and mass m moving through matter is proportional to q2m / K.] Choice A is correct and describes why alpha particles have shorter ranges than beta particles.

The first daughter nucleus in the 238U decay series is thorium-234. If the next four decays are two β- and two α decays, what is the resulting radionuclide? A. Radium-226 B. Polonium-226 C. Radon-228 D. Thorium-230

A. Each β- decay increases the number of protons by 1, but leaves the total number of protons and neutrons unchanged. Each α decay decreases the number of protons by 2 and decreases the total number of protons and neutrons by 4. Thus, after two β- and two α decays, thorium-234 becomes radium-226

Suppose a parent group accuses a school of maintaining a hidden curriculum that gives boys an advantage in subjects requiring mental rotation, such as geometry. The school makes changes that are later characterized by a local paper as tokenism. Which of the following scenarios is most illustrative of this vignette? A. The school hired one female geometry teacher to join an existing staff of 9 male geometry teachers. B. The school required its geometry teachers to disclose curriculum expectations at the start of the school year. C. The school instituted a reward system to provide incentives to female students to improve their geometry scores. D. The school rewarded geometry teachers who ensured that boys and girls received equal time to ask questions in class.

A. Hidden curriculum refers to social messages conveyed in schools that may impact performance of different groups. Through teachers' language, test formats, classroom procedures, or other factors, implicit messages about the value, abilities, or importance of different groups may be internalized by students. An example of a hidden curriculum may be a disproportionate number of male geometry teachers versus female teachers. In such a case, students may "learn" that men are typically better at geometry than women. By hiring a single female teacher, however, the school may be engaging in tokenism. Tokenism refers to an organization's inadequate remediation of problems of inequality while exploiting minimal improvements. Such an approach is likened to giving a low-cost token to equality advocates in order to quell their demands for substantial reform. Thus, emphasizing its hiring of a female geometry teacher despite a disproportionate number of male geometry teachers could be characterized as "tokenism" (choice A is correct). Hidden curriculum does not pertain to maintaining secrecy about curriculum objectives (choice B is wrong). The institution of a system of tangible rewards in exchange for desired behavior is known as a "token economy," not "tokenism" (choices C and D are wrong).

Retinal isomerase is used to alter the conformation of retinal. Retinal isomerase is most likely manufactured by: A. dehydration synthesis. B. hydrolytic synthesis. C. oxidation. D. glycosidic anabolism.

A. Retinal isomerase, an enzyme, is a protein, and proteins are synthesized by the condensation of amino acids. Condensation involves dehydration.

For a future study, the researchers wanted to design an experiment to examine the effects of social support on specific types of illness, such as heart disease, cancer, diabetes, and dementia. Which would be the best way to examine these variables? A. Use the illnesses as the dependent variable, and make social supports the independent variable. B. Use the social supports as the dependent variable, and make the illnesses the independent variable. C. Use two dependent variables: illness and type of social support. D. Use two independent variables: illness and type of social support.

A. The dependent variable in an experiment is the one that will be affected by the independent variable. In this experiment, researchers would want to see how illness, the dependent variable, is affected by various types of social support, the independent variable (choice A is correct). The independent variable is the variable that does not change or is not affected by the dependent variable. According to the question stem, the researchers do not want to measure the effect of disease on social support groups—that would be a different research project (choice B is wrong). The use of two dependent or independent variables would not follow the scientific method by which we keep one variable constant and look at a changing variable to see the effect (choices C and D are wrong)

Rank the following bonds in order of increasing polarity: I. C—Cl III. Cl—Cl II. Si—Cl IV. P—Cl A. III < I < IV < II B. III < IV < II < I C. I < II < IV < III D. II < IV < I < III

A. The polarity of a bond depends on the difference in electronegativity between the two bonding atoms: The larger the difference, the more unequal the sharing of electrons, and the more polar the bond. Thus, the Cl—Cl bond is completely nonpolar, eliminating choices C and D. To find the final answer, look at the other extreme of the ranking problem for the remaining answer choices. Carbon is more electronegative than Si, therefore Cl, which is the most electronegative element depicted, will show the greatest electronegativity difference with Si. Therefore, of the four bonds, the Si—Cl bond should be the most polar (eliminate choice B).

A healthy woman has a respiratory minute volume (the amount of air inhaled and exhaled in one minute) of about 6 L. Suppose the breathing tube she uses has a cross-sectional area of 1 cm2. What is the average flow speed through the tube? A. 1 m/s B. 3.1 m/s C. 100 m/s D. 310 m/s

A. The volume flow rate (volume of air flowing per second) is given by the equation f = Av, where A is the cross-sectional area of the cylinder and v is the average speed of the flow. The flow rate in this case is f = 6 L/min × (1 m3 / 1000 L) × (1 min / 60 s) = 1 × 10-4 m3/s. The cross-sectional area is 1 cm2 × (1 m / 100 cm)2 = 10-4 m2. Thus v = f / A = (1 × 10-4 m3/s) / (10-4 m2) = 1 m/s.

describe function of Ach on cardiac muscle

Acetylcholine has an inhibiting effect on cardiac muscle and therefore would cause a decrease in heart rate. Thus, group A members would have a greater concentration of acetylcholine present around their cardiac tissue since they had a lower heart rate

HIV, the virus that causes AIDS, is a retrovirus. Retroviruses have an RNA genome that, after entry into the host cell, is reverse transcribed to DNA, then incorporated into the host genome. RNA copies of the viral genome are produced using the normal host machinery, then packaged into viral capsid proteins for release. Which one of the following is most likely to contribute to the development of drug-resistant HIV? A. Mutation of the virus after insertion into the host-cell genome B. Frequent random errors in transcription by host-cell enyzmes C. Viral proteins folding differently in the presence of drug than in its absence D. Changes in the tertiary structure of viral RNA by drug

B. Drug resistance develops as mutant versions of the virus are produced and begin infecting new host cells. The change must be able to be passed on to viral progeny. If the viral proteins fold differently in the presence of drug than in its absence, this might account for the mechanism of action of the drug, but does not explain how drug resistance develops, nor could this be a heritable change (choice C is wrong). Changes in the tertiary structure of the viral RNA by the drug is another temporary, non-heritable change (choice D is wrong). Choices A and B are both plausible mechanisms for creating new, heritable versions of the virus. However, mutation of the virus after insertion into the host-cell genome would require that an error in DNA replication be made—a rather unlikely event, given the proofreading ability of DNA polymerase. Viral progeny are produced through transcription (creating a new RNA viral genome off the permanent DNA version inserted into the host-cell genome), and the question states that this occurs using the normal host machinery. Since the normal host RNA polymerases have no proofreading function, it is more likely that errors will occur here, leading to mutant virus (choice B is better than choice A).

Which of the following is employed by many organisms in order to reduce the two-fold cost of sexual reproduction? A. Foraging B. Pheromones C. Social aggression D. Inclusive fitness

B. Pheromones are chemicals released by organisms that trigger a social response through detection by other members of the same species. They are often used as signals in sexual reproduction and to assess reproductive compatibility and fitness, reducing the two-fold cost (choice B is correct). Foraging is the search for wild food resources, which does not address the two-fold cost (choice A is wrong). Aggressive behavior towards other members of the species would not make it easier to find individuals to mate with or help pass on a higher percentage of genes (choice C is wrong). Inclusive fitness may help increase an individual's likelihood of survival within a group, but this does not reduce either of the two components of Smith's two-fold cost: passing on fewer genes and the challenges of finding a mating partner (choice D is wrong).

All of the following are components of plasma EXCEPT: A. fibrinogen. B. erythrocytes. C. potassium. D. immunoglobulins

B. Plasma is the cell-free portion of blood. Proteins and salts are present in plasma, but cells—such as erythrocytes—are not, by definition

The bicarbonate buffering system protects the blood against large pH swings from its normal level at 7.4 and is based in the following equilibria: H2O(l) + CO2(g) equilibrium arrow H2CO3(aq) equilibrium arrow H+(aq) + HCO3-(aq) If a subject were to be placed in an environment enriched in CO2, which of the following is a reasonable expectation for his/her blood pH? A. 7.4 B. 7.1 C. 8.6 D. 7.9

B. The question details the fact that H2O and CO2 react to form H2CO3. Assuming the hypothetical test subject was equilibrated in a normal environment, his/her blood would have a normal pH of 7.4. If the concentration of CO2 inhaled by the subject was increased, all of the equilibria would shift to the right, slightly increaing the [H+] of the blood and thus slightly decreasing the pH of the blood. The only answer possible is choice B.

During oxidative stresses, HbS can cause the affected red blood cells to sickle. The spleen is very vascular and is responsible for removing old or damaged red blood cells. Recurrent sickling can cause blockage of blood flow in the spleen, resulting ultimately in death of splenic cells. Which of the following would result from destruction of the spleen? A. Impaired ability to synthesize red blood cells B. Impaired ability to fight off encapsulated bacteria C. Impaired digestion D. Increased red blood cell destruction

B. The spleen is one of the major organs of the immune system. It is rich with lymphocytes, both B and T, and serves a major resource in the body's natural defenses against pathogens, especially encapsulated bacteria (choice B is correct). The spleen is not the site of red blood cell synthesis; the bone marrow is (choice A is incorrect). The spleen is not involved in digestion (choice C is incorrect). The spleen also removes damaged or old red blood cells. If the spleen is damaged, or infarcted, then there will be less destruction of red blood cells (choice D is incorrect).

If 99% of the H+ ions in a solution of pH 1.3 were neutralized, what would be the final pH? A. 0.3 B. 3.3 C. 5.3 D. 6.9

B. If only 1% = 1/100 of the H+ ions remained, then the number of H+ ions would drop by a factor of 10^2. Therefore, the pH would increase by log(10^2) = 2 units. In this case, the pH would rise from 1.3 to 1.3 + 2 = 3.3.

A researcher proposed to block the leptin receptor in order to treat hypertension in obese patients. Which of the following detection methods would work best to identify the receptor in the different tissues affected by leptin? Northern blot Western blot Southern blot A. I only B. II only C. I and III only D. I, II, and III

B. Item II is true: The leptin receptor is a protein and located in the cell membrane of different tissue types. Detection of a protein can be done using a Western blot. Items I and III are false: a Northern blot is designed to detect specific RNA sequences, and a Southern blot is designed to detect specific DNA sequences. Neither one of these two methods will assure that the final protein product will be formed in the cells tested.

The following characteristics are shared between skeletal and smooth muscle with the exception of: A. Upstroke in action potential is secondary to inward Na+ current B. Potential exhibits a plateau C. Action potential opens voltage gated Ca2+ channels D. Ca2+ is the primary substrate for triggering contractio

B. Neither skeletal nor smooth muscle contraction is initiated by an action potential with a plateau; this feature is only characteristic of cardiac action potentials (answer choice B does not indicate a similarity and is the correct answer). The upstroke in the action potential for both skeletal and smooth muscle is triggered by an inward Na+ current (answer choice A states a similarity and is not the correct answer). Once received by either skeletal or smooth muscle, the action potential does, indeed, cause voltage-gated Ca2+ channels to open; in skeletal muscle, these channels are located on the sarcoplasmic reticulum while, in smooth muscle, they are located in the cell membrane (answer choice C is wrong). Indeed, Ca2+ is the molecular substrate for triggering contraction in both skeletal and smooth muscle; binding with troponin triggers skeletal muscle contraction and calmodulin binding activates myosin light-chain kinase in smooth muscle (answer choice D is wrong).

The tertiary structure of a hydrophilic sodium-hydrogen transport channel would best accommodate which of the following substances? A. Anions B. Cations C. Phosphoric acids D. Neutral compounds

B. Proteins transporting ions through the plasma membrane are typically highly selective in the ions they transport. Both H+ and Na+ are cations, so choice B is the best option.

If an organic nerve toxin (acting at the neuromuscular junction) renders the ion channel of postsynaptic acetylcholine receptors permanently open, the toxin would be most likely to: A. cause prolonged hyperpolarization of the postsynaptic membrane. B. cause prolonged depolarization of the postsynaptic membrane. C. block the release of vesicles containing acetylcholine. D. prevent muscle contraction.

B. The acetylcholine receptor in the neuromuscular junction is a ligand-gated sodium channel. When it binds acetylcholine, it opens to allow sodium to flow down a gradient into the cell, depolarizing the muscle cell. The more that the channel is open, the greater the depolarization (B is correct). Hyperpolarization would require positive charges to leave the cell, not enter (A is wrong). The toxin acts on the acetylcholine receptor, so there is no reason to believe that it will block acetylcholine release (C is wrong). The result of prolonged depolarization will be excessive excitation of skeletal muscle, not a block on contraction (D is wrong).

Creatine phosphate is a high-energy buffer that helps maintain the level of available high-energy phosphates such as ATP. During intense muscular exertion, creatine phosphate replenishes the muscle's ATP by releasing a relatively larger amount of energy in transferring its phosphate group to ADP. ATP is able to accept this phosphate group from creatinine phosphate and serve as a convenient carrier of energy because: A. it releases more energy upon hydrolysis than any other molecule in the body. B. it has phosphate groups with an intermediate transfer potential. C. it has such a specific and limited role. D. it is present in selected cells.

B. What makes ATP a particularly good energy carrier is that it has an intermediate transfer potential. This allows higher energy phosphate carriers (like creatine phosphate) to drive the synthesis of ATP by transferring their phosphate groups to ADP (choice B is correct). ATP's hydrolysis does not release the largest amount of energy of any molecule in the body, since creatine phosphate can drive ATP synthesis (choice A is wrong). ATP has a varied role in the body, as an energy carrier and also as a nucleotide for RNA and DNA (choice C is wrong), and ATP is present in every cell in the body (choice D is wrong)

Suzanne was in the middle of deep sleep and was suddenly jolted awake and alert by her alarm clock. Suzanne's brain wave state has most likely quickly shifted from: A. alpha wave to delta wave. B. delta wave to beta wave. C. theta wave to alpha wave. D. beta wave to theta wave.

B. delta to beta waves This question calls for knowledge of four brain wave states. Beta waves are associated with alert wakefulness, while alpha waves are associated with relaxed wakefulness or drowsiness. Theta waves are active during drowsiness or sleep, and delta waves are associated with deep sleep. The question described Suzanne as being jolted from deep sleep to alert wakefulness, which corresponds to a shift from delta wave to beta wave activity (choice B is correct; choices A, C, and D are wrong)

All of the following are true about photoreceptors in the retina EXCEPT: A. rods function best in reduced light. B. rods are highly sensitive to visual detail. C. cones process color information in bright light. D. cones are the only photoreceptor found in the fovea.

B. rods are highly sensitive to visual detail. Although rods are more sensitive to lower levels of light than are cones, rods are not sensitive to detail and instead are generally involved in peripheral vision in normal or bright light (choice B is false and therefore correct). Due to their sensitivity to photons, rods do most, if not all, of their photoreception in dark situations (choice A is true and therefore wrong). Cones process color information in all settings, including bright light (choice C is true and therefore wrong). The fovea, the middle section of the retina on which images are generally focused, contains only cones (choice D is true and therefore wrong).

In glycolysis, how many moles of inorganic phosphate are consumed in the oxidation of 3 moles of glucose to pyruvate, as pictured in Figure 1? A. 1 B. 3 C. 6 D. 9

C. For every glucose molecule, 2 molecules of glyceraldehyde-3-phosphate are produced. Every molecule of glyceraldehyde-3-phosphate requires one molecule of Pi to be converted into 1,3-bisphosphoglycerate. For 3 moles of glucose, 6 moles of glyceraldehyde-3-phosphate are produced, requiring 6 moles of Pi.

Glucose-6-phosophate dehydrogenase (G6PDH) deficiency is an inheritable metabolic disorder that can result in the destruction of red blood cells, and in severe cases, can lead to kidney and liver failure. Which of the following best describes the reason why G6PDH deficiency can result in premature red blood cell destruction? A. G6PDH deficiency results in a buildup of glucose-6-phosphate, increasing the solute concentration in the intracellular environment, causing the cell to swell and lyse. B. G6PDH deficient cells are recognized as abnormal and are targeted for destruction by macrophages. C. G6PDH deficiency results in a deficiency of NADPH, which results in increased damage from reactive oxygen species and causes premature cell death. D. G6PDH deficiency results in an increased intracellular pH, which denatures proteins and triggers apoptosis.

C. Glucose-6-phosphate dehydrogenase (G6DPH) catalyzes the first step in the pentose phosphate pathway, where NADPH is produced. NADPH plays a major role in preventing damage due to oxidative stress/reactive oxygen species. A deficiency of G6PDH prevents the production of NADPH, thus individuals with this deficiency would experience increased damage from reactive oxygen species (choice C is correct). G6PDH deficiency would not be expected to alter the intracellular osmolarity (choice A is incorrect) or to increase the intracellular pH (choice D is also incorrect). Choice B is incorrect: macrophages are not involved in the death of red blood cells in G6PDH cells.

Which of the following, if true, does NOT challenge the assertion that males' mental rotation advantage is purely biological in nature? A. There is no significant relationship between performance and endogenous levels of male sex hormones. B. There is a positive correlation between degree of men's confidence and performance. C. There is no significant difference on geometry test scores between girls taught by a female teacher and those taught by a male teacher. D. There is a negative correlation between girls' level of internalization of negative stereotypes and performance.

C. If gender differences in performance were attributable exclusively to biological factors, then exposure to a female role model proficient in mental rotation tasks would not be expected to affect the trend. Accordingly, no significant differences between girls taught by a female teacher and those taught by a male teacher would be expected (choice C does not challenge the assertion and is therefore correct). If biological differences alone accounted for trends in male versus female performance on mental rotation tasks, one would expect that the level of male sex hormones to be associated with greater performance on such tasks. If no such association were found, the notion that performance differences are due exclusively to biology would be called into question (choice A would challenge the assertion and is therefore wrong). A finding that another variable, such as degree of confidence or level of internalization of stereotypes, is correlated/associated with performance would suggest that gender differences may be attributable to factors other than biology (choices B and D would challenge the assertion and are therefore wrong).

Which of the following could cause a metabolic acidosis? Anaerobic metabolism Vomiting Ethylene glycol A. III only B. I and II only C. I and III only D. I, II, and III

C. Item I is true: anaerobic metabolism results in the formation of lactic acid and this creates a metabolic acidosis (choice A can be eliminated). Item II is false: vomiting causes the loss of hydrochloric acid from the stomach. This in turn causes the parietal cells to avidly take H+ from the blood-side of the cell to create new HCl. By removing H+ from the blood, an imbalance between H+ and HCO3- exists, with greater HCO3- than normal. This results in a metabolic alkalosis (choices B and D can be eliminated, and choice C is correct). Note that Item III is in fact true: the passage states that ethylene glycol (antifreeze) can cause a metabolic acidosis.

In gastroesophageal reflux disease (GERD), gastric secretions exit the stomach via the lower esophageal sphincter and come in contact with the lower part of the esophagus. How would this affect the esophageal epithelium? Increased proliferation of the stratified squamous epithelium Conversion to columnar epithelium similar to that in the stomach Introduction of bicarbonate-secreting cells A. I only B. II only C. I and II only D. I, II, and III

C. Item I is true: in the short term, gastric acid would corrode the outermost layer of epithelium in the lower esophagus, increasing the production of cells (choice B can be eliminated). Item II is true: over time, the acid will destroy the epithelium and expose the submucosa. Columnar epithelium found in the stomach will gradually encroach on this area and become the dominant form of epithelium, since it is not sensitive to acid (choice A can be eliminated). Item III is false: There are specialized areas known as Brunner's glands in the proximal duodenum that produce bicarbonate to neutralize the acidic chyme as it passes from the stomach to the duodenum. However, there is no reason to assume that these cells would traverse the stomach to the lower esophagus (choice D can be eliminated and choice C is correct).

Which of the following scenarios best exemplifies modeling of deviant behavior? A. Because drug use is more common among cigarette smokers, smoking is considered a "gateway drug" B. Smoking is stigmatized both formally and informally in US society C. A teenager begins smoking cigarettes after repeatedly observing his older brother smoking D. Insurance companies charge a higher premium for smokers than for non-smokers

C. Modeling, according to social learning theory, occurs when an individual observes someone else's behavior and then behaves in a similar way. This is also known as observational learning or vicarious learning. If an individual observes his brother engaging in a deviant behavior (smoking), and then begins to engage in that behavior himself, this best demonstrates modeling of a deviant behavior (choice C is correct). While both drug use and smoking are generally considered deviant behaviors in society, this choice does not demonstrate modeling of deviant behavior (choice A is wrong). Deviant behavior, such as smoking, often is stigmatized both formally (through laws preventing smoking in certain places) and informally (through judgmental looks and comments from others) in US society, but this choice does not demonstrate modeling of deviant behavior (choice B is wrong). Similarly, insurance companies charging a higher premium for smokers could also be considered a form of stigmatization, but this choice does not demonstrate modeling of deviant behavior (choice D in wrong).

Take The First (TTF) heuristic, whereby an individual simply chooses the first solution that comes to mind. TTF could accurately be described as: A. a foundation for the representativeness heuristic. B. the result of syllogistic reasoning. C. a subtype of the availability heuristic. D. an indication of executive dysfunction.

C. The availability heuristic is a problem-solving strategy whereby the most salient information seemingly applicable to a problem is selected to produce a solution. For example, if people were asked whether there are more words with the letter "M" as the first letter than those with "M' as the fourth letter, they would likely respond that there are more words with "M" as the first letter; this is the case simply because such words are more easily recalled. Similarly, the TTF heuristic entails one's use of information that comes immediately to mind (choice C is correct). The representativeness heuristic is a strategy whereby a person chooses an option that appears most typical, or representative, of the solution. Such an approach is only possible when one is presented with multiple options, not when one must generate those options. Furthermore, this approach to problem solving is not a prerequisite to the TTF heuristic, which simply requires a person to select the first option that comes to mind (choice A is wrong). Syllogistic reasoning is a systematic process of logical thinking such that if A is related to B in X way, and if C is an example of A, then C will also be related to B in X way (choice B is wrong). While impulse-control problems may reflect a deficit in the executive system that regulates attention and behavior, the TTF heuristic is a strategy of deliberately choosing what comes to mind first, not a thoughtless or impulsive decision (choice D is wrong)

Which of the following is NOT a component of Baddeley's model of working memory? A. Episodic buffer B. Long-term memory C. Multi-store model D. Phonological loop

C. The multi-store model was a model of memory developed by Atkinson & Schiffrin (1968). Baddeley's model of working memory was designed to improve upon the multi-store model's conception of short-term memory (choice C is correct). The episodic buffer mediates between the long-term memory and the central executive in Baddeley's model, and helps give chronological order to memories and stories (choice A is wrong). Long-term memory is a component of both Baddeley's model and the multi-store model (choice B is wrong). The phonological loop is a component of Baddeley's model. It helps to store and retrieve auditory memories and stimuli (choice D is wrong).

Which of the following is true for Reaction 2, once it is allowed sufficient time to achieve equilibrium? reaction 2 has a negative ΔG° A. ΔG < ΔG° B. ΔG = ΔG° C. ΔG > ΔG° D. ΔG = RT

C. At equilibrium ΔG = 0. Since reaction 2 has a negative value of ΔG°, it must be true that ΔG > ΔG°.

The tertiary structure of proteins is partially due to disulfide bonds between cysteine residues. These bonds can be broken by treatment with a mild reducing agent as shown below: This image is too complex to describe in a useful or meaningful way. Which one of the following could be such a reagent? A. CrO3 B. H2SO4 C. NaBH4 D. CH3CH2OH

C. CrO3 is a good oxidizing agent (eliminate choice A) while H2SO4 (sulfuric acid) is a strong acid (eliminate choice B). CH3CH2OH (ethanol) is a poor nucleophile and has no reducing abilities (eliminate choice D). NaBH4 is a reducing agent since it has hydrogen present in the form of hydride.

Theorists using the conflict perspective to address questions of health, illness, and medicine are LEAST likely to consider: A. the commodification of health care delivery. B. the presence of disparities in health and health care. C. the power of professionals in patient-provider relationships. D. the dependence of medical institutions on profit.

C. Each of the main sociological perspectives—structural functionalism, conflict theory, and symbolic interactionism—is expected to approach health and health care differently. The conflict theory approach considers the competition for limited resources. According to this theory, limited resources, a negative result of capitalism, cause inequalities and power differentials in society. This concept can be extended to the medical institution. Furthermore, Karl Marx, the founding conflict theorist, focused on the internal tensions produced in capitalistic societies. Thus, it is expected that the conflict perspective would consider the commodification of health care and the dependence of institutions on profit (choices A and D can be eliminated). Health care can thus be purchased and sold in a marketplace, which allows those with resources and influence to control pertinent decisions, thus maintaining inequalities. Furthermore, these social inequalities determine the distribution of health care access and resources. Thus, it is expected that the conflict perspective would consider the resultant disparities in health and health care (choice B can be eliminated). However, while conflict theorists are interested in the creation and maintenance of power differentials, as proponents of a macro-sociological perspective, this interest is applied to social structures as a whole. The patient-provider relationship would perhaps be of more interest to symbolic interactionists, as symbolic interactionism is a micro-level perspective focused on the transfer of information through communication between individuals (choice C is not an expected focus of conflict theorists and is the correct answer). Furthermore, it is possible that a power differential is inherent in the provider-patient relationship as a result of the expertise required for medical professionals, thus making an egalitarian relationship difficult to create.

The sound level of a sound wave that is striking an eardrum is increased from 35 dB to 55 dB. By what factor has the intensity of the sound increased? A. 2 B. 20 C. 100 D. 200

C. For each increase by 10 in the decibel level, the intensity of the sound increases by a factor of 10. In this case, the decibel level has increased by two units of 10 (since 55 - 35 = 20 = 10 + 10), so the sound intensity increases by two factors of 10, that is, by a factor of 102 = 100.

Brown fat will increase energy expenditure in the form of heat better than any other adipose tissue in the body. In brown fat, leptin indirectly activates uncoupling protein 1 (UCP-1) located in the inner mitochondrial membrane. UCP-1 activation will dissipate the proton gradient across the inner mitochondrial membrane and STOP which of the following reactions in mitochondria? A. Electron transport chain B. Krebs cycle C. Oxidative phosphorylation D. NAD+ reduction

C. In the absence of the proton gradient across the inner mitochondrial membrane no electrochemical gradient has been built and oxidative phosphorylation, i.e. the formation of ATP by ATP synthase, will not proceed (C is correct). The electron transport chain will continue and pass electrons along the transport chain, but the pumped protons will return to the matrix of the mitochondria with the help of UCP-1 activation (choice A will continue and can be eliminated). The Krebs cycle provides NADH and FADH2 as substrates to the electron transport chain and receives NAD+ and FAD for continuation of its chemical cycle. This action can proceed unhindered during UCP-1 activation and choice B can be eliminated. Reduction of NAD+ in the mitochondria takes place in the Krebs cycle and the pyruvate dehydrogenase complex reaction and occurs prior to the action of events induced by UCP-1 (choice D will continue and can be eliminated).

Sociologists refer to women's role as family caregivers in addition to their role as professionals as the "second shift". How might the "second shift" be interpreted as a psychosocial stressor? A. It increases women's sense of self-efficacy in the workplace. B. It results from prejudice against working women. C. It may lead to identity interference. D. It is a function of the "glass ceiling", which leads to a lower standard of living.

C. It may lead to identity interference. By definition, women's "second shift" refers to an ongoing duality of roles (the role of a working professional and the role of the family caregiver). When the demands of these roles conflict in terms of time and energy, tension results. Identity interference is the principle that states that people experience stress when two aspects of their identity are in conflict. Thus, the "second shift" could be understood as a cause of identity interference, which then constitutes a psychosocial stressor (choice C is correct). There is nothing to indicate that the "second shift" is the result of prejudice against working women (choice B is wrong). Self-efficacy is Albert Bandura's term for an individual's feelings of capability regarding the accomplishment of a given task; compounding one's roles would not increase self-efficacy in the workplace (choice A is wrong). The "glass ceiling" refers to unofficial limits on women's advancement in the workplace and does not directly relate to their additional roles outside the workplace (choice D is wrong).

During strenuous exercise, aerobic metabolism often converts to anaerobic metabolism with the consequent buildup of lactate. Which of the following will result? A. Respiratory acidosis B. Respiratory alkalosis C. Metabolic acidosis D. Metabolic alkalosis

C. Lactate is the ionized/deprotonated form of lactic acid. Therefore, an acidosis is expected to develop. Since lactate is generated through a metabolic process (anaerobic respiration) and not a function of breathing rate, it is expected to cause a metabolic acidosis (choice C is correct). Respiratory acidosis is secondary to an increased CO2 concentration, typified by decreased respiratory rate (choice A is incorrect). An alkalosis would result in increasing the pH of the blood (choice A is incorrect). If it is metabolic in origin, then there is an increased concentration of HCO3-, whereas if it is respiratory, then there is a decreased concentration of CO2 (choice D is incorrect).

A sample of 222Rn is collected in a sealed glass container and allowed to stand for 11.5 days. After this time, approximately what percentage of the original 222Rn remains? half life of 222Rn is approx 4 day A. 3% B. 6% C. 12% D. 25%

C. Since the passage states that the half-life of 222Rn is a little less than 4 days, a time period of 11.5 days is approximately 3 half-lives. After 3 half-lives have elapsed, the amount of radioisotope remaining is (1/2)3 = 1/8 = 12.5%, so choice C is best.

The following measurements were obtained by an investigator who observed a light ray that propagated across a boundary between air and Material X: speed of light in air = 3.0 × 108 m/s frequency of light in air = 5.0 × 1014 Hz angle of incidence = 30.0° angle of refraction = 23.5° density of Material X = 5.0 g/cm3 At what speed does light propagate through Material X? (Note: sin 23.5° = 0.4) A. 1.4 × 108 m/s B. 1.7 × 108 m/s C. 2.4 × 108 m/s D. 3.7 × 108 m/s

C. Snell's Law gives n1 sin θ1 = nX sin θX → (1) sin30° = nX sin(23.5°) → 0.5 = nX(0.4) → nX = 5/4. Since the index of refraction of Material X is 5/4, then, by definition, the speed of light is reduced by a factor of 5/4 from its speed in vacuum (or air). Thus, vX = (4/5)c = (4/5)(3 × 108 m/s) = 2.4 × 108 m/s. (Note that choice D can be eliminated immediately since it is greater than c = 3 × 108 m/s.)

Which of the following scenarios best exemplifies the phenomenon known as social loafing? A. A group of excellent individual rowers perform worse in a group race than expected due to an inability to coordinate. B. An elderly woman trips and falls in a busy street, yet no one comes to her aid. C. Blindfolded individuals shout louder when they are told that they will be shouting alone than when they are told that they will be shouting in a group. D. A soccer player performs better when being watched by a large crowd than when alone

C. Social loafing is the phenomenon whereby people exert less effort to achieve a goal when they work in a group than when they work alone; therefore, blindfolded individuals who shout louder when they are told that they will be shouting alone than they do when they are told that they will be shouting in a group best demonstrate social loafing (choice C is correct). The reduced group output in social loafing occurs because everyone assumes someone else in the group will put forth effort, so all of the individuals put forth less effort themselves; this is different from an impaired performance resulting from a loss of coordination in a group of excellent rowers (choice A is wrong). The phenomenon whereby people are less likely to provide needed help when they are in groups than when they are alone is known as the bystander effect; this explains why an elderly woman who trips and falls in a busy street is aided by no one (choice B is wrong). The phenomenon whereby an individual performs better on a task when being watched is known as social facilitation; this explains why a soccer player might perform better when being watched by a large crowd (choice D is wrong).

An object with a height of 6 cm is placed at a distance of 20 cm from a concave mirror with a focal length of 12 cm. If the mirror produces a real, inverted image at a distance of 30 cm, the height of the image is: A. 4 cm. B. 6 cm. C. 9 cm. D. 12 cm

C. The linear magnification m is given by the expression -i/ o. In this case, m = -(30 cm) / (20 cm) = -1.5, so the image is 1.5 times taller than the object. Therefore, if the object is 6 cm tall, then the image is 1.5(6 cm) = 9 cm tall. (Note: The minus sign on msimply signifies that the image is inverted, as stated in the question.)

What is the correct relationship between the first ionization energies of the elements mercury, thallium, and lead? A. Hg > Tl > Pb B. Tl > Pb > Hg C. Pb > Tl > Hg D. Hg > Pb > Tl

D In Hg, all orbitals are full, which is relatively stable. It is the least likely atom to give up any electrons, and therefore it has the highest ionization energy (eliminate choices B and C). Tl is the opposite. If Tl gives up a single electron, it would result in the electron configuration of Hg, which is more stable. Therefore, Tl has the lowest ionization energy of the three, making the answer choice D.

A scientist wants to test the heritability of sexual attractiveness in college-age females. This could be best accomplished by: A. using monozygotic twin studies to measure the percentage of sexual attractiveness caused by genes. B. using dizygotic twin studies to measure the percentage of sexual attractiveness caused by genes. C. using dizygotic twin studies to measure the percentage of variation in sexual attractiveness attributable to genetics. D. using monozygotic twin studies to measure the percentage of variation in sexual attractiveness attributable to genetics.

D. Heritability is best tested with monozygotic twin studies, since monozygotic twins share the same genes. Also, heritability is defined as the proportion of observable differences in phenotype attributable to genetic causes (choice D is correct). Heritability does not measure the percentage of an observable trait caused by genes, but only has meaning within the context of proportion attributable to variation (choice A is wrong). The other two answer choices can be eliminated because heterozygotic twin studies do not measure heritability as well as monozygotic twin studies do (choices B and C are wrong).

It was observed under the microscope that a small section of bone consisted of concentric rings of fibrous material surrounding an open circular region. The bone section was identified as an osteon. The circular region is expected to contain: A. mature osteocytes. B. maturing chondrocytes. C. large blood cell precursors. D. blood vessels.

D. In compact bone, the osteon is the basic unit of structure. Concentric rings surround the central circular region that contains blood or lymph vessels (choice D is correct). Osteocytes can be found in small spaces along channels branching away from the central channel (choice A is wrong). Bone is the site of the marrow in which blood cell precursors are found, but bone marrow is found in spongy bone and not in compact bone where osteons are found (choice C is wrong). Chondrocytes are found in cartilage (choice B is wrong).

During the research period, 16% of wives with moderate forecasts and 12% of wives with positive forecasts divorced. Despite high divorce rates, many couples decided to forgo professional relationship counseling. This can be attributed to a number of factors, including the social stigma surrounding such services. Which of the following is true of stigma? It is applied to deviant character traits rather than external deformities. It is defined as disapproval resulting from actual or perceived social deviance. It can lead to demeaning labels that are applied to entire social groups. A. II only B. III only C. I and II only D. II and III only

D. Item I is false: social stigma is a negative reaction to a person or group. This can result from the perception, correct or incorrect, of the presence of numerous characteristics; these include personal or behavioral traits, such as in certain mental illnesses, or external deformations, such as visible manifestations of eating disorders (choice C can be eliminated). Item II is true: deviance is the violation of social norms, which is seen as unacceptable by the society at large (choice B can be eliminated). Item III is true: labels are often applied to individuals deviating from the social norm, thus perpetuating social stigma (choice A can be eliminated and choice D is the correct answer). For example, social stigma is a widespread problem in mental health; a demeaning label applied in this context might be "crazy" or another related word.

When asked to indicate what contributed to their desirability ratings, none of the daters mentioned the issue of whether the individual whom they were rating approached them or remained stationary. Moreover, all of the daters instead focused upon the individual's perceived personality and character traits. In light of the findings stated in the passage and the data in Figure 1, this might be an example of: A. a self-fulfilling prophecy. B. stereotyping. C. socialized identity formation. D. the fundamental attribution error.

D. The fundamental attribution error is the tendency to interpret others' behavior in terms of personal attributes, as opposed to situational factors. In this case, the daters may have tended to interpret what they perceived as desirable or undesirable behavior during the speed dating interactions as dispositional, rather than simply the result of the structured situation (choice D is correct). A self-fulfilling prophecy occurs when the expectation of an event leads directly or indirectly to that event happening (choice A is wrong). Stereotyping involves viewing members of a social group in a distorted and often negative way based on preconceptions about the characteristics of that group (choice B is wrong). Socialized identity formation is the establishment of a distinct personality based on interactions with others (choice C is wrong).

To produce the maximum number of ATPs, post-glycolytic pathways in aerobes must receive from glycolysis: A. ADP and NADH. B. ATP and NADH. C. NADH and glucose. D. NADH and pyruvate

D. The post-glycolytic pathways are the Krebs cycle and electron transport, which require oxygen, NADH, and pyruvate. Pyruvate is converted into acetyl-CoA to enter the Krebs cycle (choice D is correct). The Krebs cycle does not require either ADP or ATP from glycolysis and does not need glucose, only the pyruvate that is derived from glucose.

During times of starvation: A. triacylglyceride stores in adipocytes are anabolized by lipase. B. fatty acids are broken down via oxidation, hydration and cleavage reactions, to generate NADPH, and to oxidize FADH2. C. glycerol is converted to DHAP, a glycolysis intermediate, which is then used to generate lactate and ethanol via fermentation. D. fatty acids are transported in the blood via binding to blood proteins like albumin, then are broken down via β-oxidation in target tissues.

D. During times of starvation, sugar, protein and fat stores are degraded to provide the body with sufficient energy. Triacylglycerides are catabolized (not anabolized) in adipocytes via lipase (eliminate choice A). The glycerol backbone is converted to DHAP, a glycolysis intermediate, which is then converted to pyruvate and put through Krebs cycle and ETC to make energy, or is used in gluconeogenesis to make glucose-6-phosphate. Fermentation can generate lactate or ethanol, but not both, and is only done in anaerobic conditions (eliminate choice C). Fatty acids are transported in the blood via binding to blood proteins like albumin. Once at the target tissue, they are activated, shuttled into the mitochondria and broken down via β-oxidation. This generates acetyl-CoA (via cleavage of the carbon backbone), as well as NADH and FADH2 (via reduction of NAD+ and FAD respectively, eliminate choice B and choice D is correct). Note that NADPH is made via the pentose phosphate pathway, not during fatty acid oxidation.

Ghrelin, the "hunger hormone," is released when the stomach is empty. It increases hunger and promotes secretion and motility in the digestive tract. The receptor for ghrelin is found on the same cells in the brain as the receptor for leptin. Which of the following is a true statement? A. The interaction of leptin and ghrelin can be considered competitive inhibition because they produce antagonistic effects. B. The interaction of leptin and ghrelin is considered to be allosteric inhibition. C. The interaction of leptin and ghrelin is considered uncompetitive because ghrelin only binds when leptin is already bound. D. There is no interaction between leptin and ghrelin because they operate on separate receptors.

D. Even though they bind to the same cells in the brain, the fact that leptin and ghrelin bind to separate receptors means that there cannot be any kind of inhibition or interaction between them (choice D is correct). For competitive inhibition to occur, two things must be trying to bind to one site; for example, if both leptin and ghrelin bound to the same site on the same receptor. The fact that they have separate receptors prevents this (choice A is wrong). Likewise, allosteric inhibition requires that the inhibitor bind to a separate site on the same enzyme or receptor (choice B is wrong), and there is nothing in the question stem or passage to suggest that ghrelin can only bind when leptin is bound (choice C is wrong).

Rogerian psychological theory, as developed by Carl Rogers, differs from Freudian theory in that: A. The Rogerian psychotherapeutic process focuses more upon early childhood events and conflicts than does the psychoanalytic process. B. Freudian theory emphasizes social influences, while Rogerian theory focuses on biological impulses. C. Freudian theory suggests that people are motivated by the need to become self-actualized, whereas Rogers posited that people are motivated to avoid anxiety. D. Freudian theory emphasizes innate biological drives and focuses on the conflict between the individual and societal demands, while Rogerian theory focuses on the individual's experience within the social environment and posits that individuals are motivated to become self-actualized.

D. Freud posited the existence of the id, which contains the biological impulses and unconscious desires, and emphasized that the superego and the ego formed in order to manage the individual's interactions with society. Carl Rogers also recognized the importance of the interaction of the individual with society, but, unlike Freud, posited that people are motivated by the desire to become actualized as the best possible versions of themselves (choice D is correct). Unlike Rogerian psychotherapy, the Freudian psychoanalytic process focuses largely upon the events and conflicts of early childhood (choice A is wrong). Freudian theory emphasizes biological, or innate, impulses, while Carl Rogers did not primarily emphasize biology (choice B is wrong). Rogerian theory (not Freudian theory) suggests that people are motivated by the need to become self-actualized, and Freud (not Rogers) posited that people are motivated to avoid anxiety (choice C is wrong).

Hypothetically, if Reaction I was found to be spontaneous at standard state and higher temperatures, but nonspontaneous at low temperatures, the reaction must result in: A. decreasing entropy and decreasing enthalpy. B. decreasing entropy and increasing enthalpy. C. increasing entropy and decreasing enthalpy. D. increasing entropy and increasing enthalpy.

D. From the equation ΔG = ΔH - TΔS, we can eliminate choice B since ΔH > 0 and ΔS < 0 would always give ΔG > 0 (nonspontaneous) no matter what the temperature, and we can eliminate choice C since ΔH < 0 and ΔS > 0 would give ΔG < 0 (spontaneous) regardless of temperature. Choice A is false since at sufficiently high temperatures, the T ΔS term would become more negative than ΔH, leading to a positive ΔG, contradicting the statement in the question that the reaction is spontaneous at high temperatures. This leaves choice D.

Margaret was more afraid of dying in a terrorist attack than dying from dangers lurking in her own neighborhood because she was watching so many news reports of deaths by terrorist attack. This is an example of what psychological construct? A. Normative influence B. Fixation C. Attribution theory D. The availability heuristic

D. The availability heuristic states that a person will make a decision based on the information most readily available in memory. If Margaret has been watching many reports of terrorist dangers on the news, she will be more likely to worry about those than the dangers lurking in her own neighborhood about which she has heard little (choice D is correct). Normative influence refers to a group effect that results from individuals' desire to be liked and to win the approval of others, which does not explain Margaret's fear of terrorist attacks (choice A is wrong). Fixation refers to a state wherein an individual is attached to things or behaviors more appropriate to an earlier stage of psychosexual developmental (choice B is wrong). Attribution theory describes a social-cognitive approach to creating cause-and-effect relationships. Informational influence means that she is using the information in an attempt to be correct. That is not her motivation; rather, she is creating cause-and-effect connections between the information she hears and the decisions she makes. She is not worried about being right (choice C is wrong).

The iron law of oligarchy: A. asserts that, because of the constant struggle between the labor class and the ownership class, democracy will be inevitably replaced by socialism. B. explains how formal social norms are codified into laws. C. describes the process whereby tasks are broken down into component parts to be completed by different workers in an organization. D. suggests that democracy is not possible in large groups or organizations.

D. The iron law of oligarchy is a theory in sociology that states that regardless of how democratic an organization is, all organizations will eventually and inevitably end up with a majority of the power in the hands of a few, thus leading to an oligarchy. The iron law of oligarchy suggests that democracy is practically and theoretically impossible, particularly in large and complex organizations (choice D is correct). Karl Marx asserted that, because of the constant struggle between the labor class and the ownership class, capitalism (not democracy) will be inevitably replaced by socialism (choice A is wrong), but this has nothing to do with the iron law of oligarchy. The iron law of oligarchy does not explain how formal social norms are codified into laws (choice B is wrong). Rationalization, which is a major component of bureaucracy, describes the process whereby tasks are broken down into component parts to be completed by different workers in an organization (choice C is wrong)

The ratio of products to reactants at equilibrium for Reaction 1 will change with a change in the: A. concentration of ATP. B. ΔG°. C. pressure. D. temperature

D. The only way to change a reaction's equilibrium constant is to change the temperature.

The trimerization of adenovirus protein fiber monomers is an example of what type of protein structure? A. Primary B. Secondary C. Tertiary D. Quaternary

D. Trimerization implies the interaction of multiple protein subunits to form a complex, which is an example of quaternary structure (choice D is correct and choices A, B, and C are wrong).

function of western blot

Detection of a protein

define stiffness and how it relates to dipness of a potential energy graph

Stiffness is a measure of how much energy must be applied to change the bond length. A very narrow dip in the potential energy plot means that stretching the bond a little requires a lot of energy. This is different than the bond energy, which is indicated by how deep the dip in the plot is. a bond has a relatively wide dip, meaning that application of only a little energy can change the bond a good deal.

relationship between dependent and independent variable

The dependent variable in an experiment is the one that will be affected by the independent variable. The independent variable is the variable that does not change or is not affected by the dependent variable.

independent variables

The independent variable is the variable that the experimenter controls or manipulates, or which is already fixed in advance; the independent variable is thought to have some effect on the dependent variable

what effects does the vagus nerve have on cardiac muscle?

When activated, the vagus nerve causes a decrease in heart rate and is part of the parasympathetic nervous system.

wernicke's area

area responsible for speech comprehension

broca's area

area responsible for speech production

function of southern blot

detect specific DNA sequences

function of northern blot

detect specific RNA sequences

The Yerkes-Dodson law refers to

how stress and arousal affect performance; a moderate level of stress helps people perform at their best

define prejudice

involves biased opinions and thoughts about members of another group (such as a racial/ethnic out-group), but does not involve acting on those thoughts

define Groupthink

involves the notion that members of groups, especially those groups that value cohesiveness among members, will conform in order to eliminate disharmony, which leads to a faulty decision-making process.

define discrimination

is prejudicial treatment of an individual by another individual based on perceived membership in a certain social group

stroke to wernicke's area

lacking ability to comprehend speech OR leads to fluent aphasia (non-sensical speech)

stroke to broca's area

lacking ability to produce speech

will a compound with the highest or lowest K sp (solubility product) precipitate first?

lowest K sp compound will precipitate first

define Group polarization

occurs when, after pertinent discussion or argument, a group adopts a more extreme position than the positions to which the individual members adhere.

define Normative influence

refers to a group effect that results from individuals' desire to be liked and to win the approval of others

define Tokenism

refers to an organization's inadequate remediation of problems of inequality while exploiting minimal improvements. Such an approach is likened to giving a low-cost token to equality advocates in order to quell their demands for substantial reform.

define availability heuristic

states that a person will make a decision based on the information most readily available in memory.

The social facilitation effect states

that people perform better on simple tasks when others are watching