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AAMC Practice Exam 3

Terms in this set (98)

energy stored in a capacitor
U = 1/2CV^2
charge stored in a capacitor
Q = CV
Suppose that the railcar passes by a horn that is emitting a sound with frequency f. Which of the following describes the frequency f' that the person on the railcar hears?
f' > f before passing the horn f' < f after passing it
Doppler effect
An observed change in the frequency of a wave when the source or observer is moving
total power
P = Fv
The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data?
Heats of combustion

-The relative thermodynamic stability of isomers can be determined based on the amount of heat produced when the compounds are combusted; less heat = greater stability
Ideal gas law
PV = nRT
HCO3- is best categorized as a:
base since Kb > Ka for this ion
The energy of activation for the reaction is described as the energy of:
the activated complex minus the energy of the reactants
activation energy
the minimum energy barrier necessary to be overcome by the reactants on the path to products
Celsius to Kelvin conversion
K = C + 273
energy of a photon
E = hf
That the electric field is uniform between the electrodes means that the electric field lines:
are equally spaced at both electrodes and between them.
FAD
cofactor oxidant
steroid
four fused ring structure
The pH of a 1 L phosphate buffer solution was measured as 7.6, but the experimental procedure calls for a pH 7.2 buffer. Which method will adjust the solution to the proper pH?
Alter the ratio of monosodium/disodium phosphate added to favor the monosodium species.

-To lower the pH of a buffer, the proportion of acidic buffer component must be increased.
When two amino acids are joined via a peptide bond, what is the mass of the byproduct of this reaction?
18 amu.

Formation of a peptide bond is accompanied by the formation of water as a byproduct and the mass of water is 18 amu.
Which experimental condition is NOT necessary to achieve reliable data for Michaelis-Menten enzyme kinetics?

A) Initial velocity is measured under steady state conditions.
B) Solution pH remains constant at all substrate concentrations.
C) The concentration of enzyme is lower than that of substrate.
D) The reaction is allowed to reach equilibrium before measurements are taken.
D) The reaction is allowed to reach equilibrium before measurements are taken.

The answer to this question is D because once the reaction reaches equilibrium, measurement of Vo will be impossible and the kinetic data will look the same regardless of substrate concentration. Hence, response D is not necessary (nor desirable) to achieve reliable data for Michaelis−Menten enzyme kinetics. In contrast, Distractors A−C are essential to obtain reliable Vo versus substrate concentration data to calculate KM and Vmax using Michaelis−Menten enzyme kinetics.
Which atom is most likely involved in the coordination of calcium ions found in HRP?
A) Hydrogen
B) Carbon
C) Nitrogen
D) Oxygen
D) Oxygen

An atom must be a Lewis base to coordinate to calcium ions, and oxygen is the only Lewis basic atom present in the side chains or backbones of the listed amino acids that has either a partially negative charge or a negative charge.
heme
The cofactor is heme, which is a porphyrin.

The basic unit of a porphyrin is the pyrrole ring, a five-sided heterocycle containing one nitrogen atom.
resistivity
inverse of conductivity

r = 1/c
Which two classes of enzymes are needed in the two-step conversion of cytosine to 5hmC?
A) Transferase and oxidoreductase
B) Hydrolase and ligase
C) Oxidoreductase and hyrolase
D) Transferase and ligase
A) Transferase and oxidoreductase

The first step involves the transfer of a methyl group to cytosine, and the next step involves hydroxylation of that methyl group.

Therefore, the two classes of enzymes needed are a transferase and oxidoreductase.
A common column material used in size-exclusion chromatography is dextran, a polysaccharide of glucose. Which type of interaction most likely occurs between proteins and the dextran column material?
A) Aromatic
B) Hydrophobic
C) Salt bridge
D) Hydrogen bonding
D) Hydrogen bonding

A polysaccharide of glucose has numerous hydroxyl groups that can hydrogen bond to the polar side chains that are typically exposed on the protein surface.
Which halogen has the highest first ionization energy?
A) Iodine
B) Bromine
C) Chlorine
D) Fluorine
D) Fluorine

Fluorine is the smallest halogen and appears at the top of Group 17. With fewer electrons to shield the valence electron from the nucleus, fluorine will exhibit the highest first ionization energy.
Which of the following properties of a 2.3 MHz ultrasound wave remains unchanged as it passes into human tissues?
A) Frequency
B) Wave speed
C) Amplitude
D) Wavelength
A) Frequency

Frequency of a wave is not affected by the medium through which it propagates.
speed of a wave
v = fλ
Calcium and magnesium belong to what group on the periodic table?
A) The alkali metals
B) The metalloids
C) The alkaline earth metals
D) The halogens
C) The alkaline earth metals

Magnesium and calcium both appear in Group 2 of the periodic table of elements (alkaline earth metals).
If a reaction is spontaneous, the value of K must be:
A) greater than 1
B) equal to deltaG
C) less than 1
D) equal to 0
A) greater than 1

A spontaneous reaction is one that exhibits ΔG < 0. Since ΔG = -RTln(Keq), this means that Keq must be > 1.
Which of the following molecules has an octahedral geometry?
A) SF6
B) CBr4
C) XeF4
D) BrF3
A) SF6

SF6 is an AX6 system with no lone pairs. As a result, it will adopt an octahedral bonding arrangement to minimize repulsive interactions of the bonding domain electrons.
Which of the following is a second period element that is a covalent network solid in its standard state?
A) Carbon
B) Phosphorus
C) Oxygen
D) Iodine
A) Carbon

Carbon is a second period element that is a covalent network solid (graphite) in its standard state.
Individual M has longer limbs and muscles than Individual N. Both individuals lift the same amount of weight from the ground to their shoulders an equal number of times. If all repetitions were completed in synchrony, which statement about the amount of work completed by the individuals is true? At the end of the workout:
Individual N will have done less work because the object was moved a shorter distance.
What are the relative potentials for force and power generation by a slow-twitch muscle fiber and a fast-twitch muscle fiber of the same diameter?
The fast-twitch fiber is capable of generating more power than the slow-twitch fiber, while the potential for force generation is the same.

-Similar sized fibers would generate similar force, regardless of fiber type. However, the fast-twitch fiber would generate the same force with greater velocity, generating more power.
Which of the following is LEAST likely to occur in a muscle fiber that is metabolizing anaerobically?
A) Fermentation of glucose to lactic acid
B) Phosphorylation of ADP within the electron transport chain
C) Depletion of stores of glycogen
D) Acidification of the cytoplasm
B) Phosphorylation of ADP within the electron transport chain

The electron transport chain only provides ATP aerobically. Lack of oxygen effectively shuts down the Krebs cycle and the electron transport chain.
According to the passage, relative to slow-twitch fibers, fast-twitch fibers are likely to exhibit which property?
A) Greater Ca2+-pumping capacity
B) Increased capillary density
C) More mitochondria
D) Higher levels of oxygen-binding proteins
A) Greater Ca2+-pumping capacity

-Slow-twitch fibers are adapted for aerobic exercise which suggests they are likely, relative to fast-twitch fibers, to have increased capillary density, larger numbers of mitochondria, and higher levels of oxygen-binding proteins.
disulfide bonds
formed between cysteine residues
Which of the following animal pairs best illustrates the outcome of convergent evolution?

A) The dolphin and shark
B) The domestic sheep and the mountain goat
C) The polar bear and the panda bear
D) The light-colored and the dark-colored forms of the peppered moth
A) The dolphin and shark

Convergent evolution is defined as the process whereby distantly related organisms independently evolve similar traits to adapt to similar needs.
Assume that a certain species with sex chromosomes R and S exists such that RR individuals develop as males and RS individuals develop as females. Which of the following mechanisms would most likely compensate for the potential imbalance of sex-chromosome gene products between males and females of this species?

A) Inactivation of one R chromosome in males
B) Doubling transcription from the S chromosome in females
C) Inactivation of the R chromosome in females
D) Doubling transcription from the R chromosomes in males
A) Inactivation of one R chromosome in males

Males of the species have two copies of the R chromosome, whereas females have one R chromosome and one S chromosome. Therefore, in order to compensate for a potential imbalance of sex chromosomes between females and males, one R chromosome should be inactivated in males.
Kallman Syndrome is a disease in which gonadotropin-releasing hormone producing neurons fail to migrate from the olfactory area to the hypothalamus during embryonic development. Which endocrine axis is disrupted in individuals with Kallman Syndrome?

A) The stress axis
B) The growth hormone axis
C) The thyroid axis
D) The reproductive axis
D) The reproductive axis

Gonadotropin-releasing hormone regulates pituitary gonadotropin (luteinizing hormone and follicle-stimulating hormone) secretion. Thus, if gonadotropin-releasing hormone is not able to regulate luteinizing hormone and follicle-stimulating hormone secretion from the pituitary, the reproductive axis will remain quiescent.
Which statement correctly identifies an enzyme involved in DNA replication and describes its primary function?


A) Ligase catalyzes the binding of RNA primers to DNA via phosphodiester bonds.
B) Primase catalyzes the replacement of RNA primer nucleotides with DNA nucleotides.
C) Helicase catalyzes the separation of the parent DNA strands at the origin of replication.
D) Topoisomerase catalyzes the joining of adjacent Okazaki fragments into a continuous strand of DNA.
C) Helicase catalyzes the separation of the parent DNA strands at the origin of replication.

-Helicase catalyzes the unwinding and separation of the parental DNA strands, so that each can be replicated.
Cells that contain a large amount of phosphorylated p38 are most likely:
A) increasing in size
B) replicating their DNA
C) dividing
D) undergoing growth arrest
D) undergoing growth arrest

-p38 phosphorylation levels correlates with apoptotic signaling, which most likely leads to growth arrest.
Which action(s) could contribute to the positive inotropic effect of digoxin on cardiac myocytes?

I. Decrease transport of Ca2+ to the extracellular environment.
II. Increase availability of intracellular Ca2+ to bind to troponin.
III. Increase overall Ca2+ stores in the sarcoplasmic reticulum.
I, II, and III.

All of these actions will lead to an increase in intracellular calcium levels, resulting in enhancement of the contractile force of the heart.
Which type of membrane transport is directly affected by cardiac glycosides?
A) Simple diffusion
B) Facilitated diffusion
C) Primary active transport
D) Secondary active transport
C) Primary active transport

The Na+/K+ ATPase is an example of primary active transport.
In the absence of digoxin treatment, hydrolysis of one molecule of ATP results in which combination of ion movements across the myocardial cell membrane?
3 Na+ out; 2 K+ in

Na+/K+ ATPase transports 3 Na+ outside of the cell and 2 K+ inside of the cell per molecule of ATP hydrolyzed.
HDACS (which counter the affects of acetyltransferases) change chromatin by:
increasing its condensation and inhibiting transcription.

-As histone acetylation typically promotes transcription by modifying chromatin structure, HDACs would inhibit transcription by condensing chromatin structure.
If HDAC inhibition by βOHB is a physiological response in living animals, the information in the passage indicates it is likely to occur when:

A) there is sustained fatty acid oxidation.
B) the pentose phosphate shunt is activated.
C) there is increased gluconeogenesis.
D) the Cori cycle is occurring.
A) there is sustained fatty acid oxidation.

-Fasting leads to glycogen breakdown and gluconeogenesis, then continued fasting leads to the production of ketone bodies by sustained fatty acid oxidation.

-βOHB is a component of ketone bodies, so serum levels of βOHB are elevated when there is sustained fatty acid oxidation.
The adrenal medulla is part of which branch(es) of the peripheral nervous system?
The sympathetic branch of the autonomic nervous system only.

-The adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress. Reaction to short-term stress are mediated by the sympathetic branch of the autonomic nervous system.
Allosteric inhibition of an enzyme involves which of the following?
Binding of an inhibitor to a site other than the substrate binding site
Which of the following best describes the chemical energy that is derived from the Krebs cycle? Energy is produced in the form of:
ATP, which directly supplies energy for many cellular processes, and NADH, which supplies energy for the electron transport chain.
What are the effects of hypoxia on energy metabolism? In hypoxia:

A) the citric acid cycle is induced to produce more NADH.
B) lactic fermentation is induced to regenerate NAD+.
C) the electron transport chain is induced to consume more NADH.
D) glycogenesis is induced to regenerate NAD+.
B) lactic fermentation is induced to regenerate NAD+.

In glycolysis is activated, while mitochondrial functions are attenuated. This metabolic reprogramming leads to increased concentration of NADH inside the cell.

For glycolysis to proceed, NADH must be converted back to NAD+ through lactic fermentation.
imprinted genes
expressed in a parent-specific manner
Certain viruses contain RNA as their genetic material. One of the ways these RNA viruses replicate themselves is to:
code for or carry a transcriptase that copies viral RNA.

-RNA viruses require a type of transcriptase (reverse transcriptase) to replicate themselves.
Large amounts of protein are found in the urine of a patient. Based on this information, which portion of the nephron is most likely malfunctioning?
Glomerulus

In healthy individuals, the structure of the glomerular capillaries prevents the entry of large molecules, such as proteins, into the filtrate.
The rate of a typical enzymatic reaction is increased by which of the following changes?

A) Decrease in a substrate concentration
B) Increase in pH from 6.8 to 7.4
C) Increase in the energy of activation
D) Increase in temperature from 20°C to 37°C
D) Increase in temperature from 20°C to 37°C
Mucous secretions in the respiratory tract inhibit microbial infections. These secretions are produced by which of the following tissue types found in the lungs?
A) Smooth muscle
B) Epithelial
C) Nervous
D) Connective
B) Epithelial

Epithelial cells are specialized cells for secretion and are present in the respiratory tract.
Which of the following ways is the action of serotonin on postsynaptic neurons most likely terminated?
Transportation of released serotonin back into the presynaptic terminal
SSRIs most likely relieve depression by increasing the:
amount of time that serotonin is present in the synaptic space

-SSRIs function to treat depression by blocking serotonin reuptake in the presynaptic neuron.

-Blocking the reuptake of serotonin into the presynaptic neuron would increase the amount of time that serotonin is available in the synaptic cleft to bind to postsynaptic neurons
One consequence of advanced malnutrition is reduced amounts of plasma proteins in the blood. This condition would most likely cause the osmotic pressure of the blood to:
decrease, resulting in an increase of fluid in the body tissues.

-Large plasma proteins, such as albumin, in the blood increase the osmotic pressure of the blood, which in turn, increases the return of fluid to the circulatory system from the blood tissues.
Within the intestines, unabsorbed fats are broken down into fatty acids by intestinal bacteria. Given this, excess unabsorbed fats most likely have which of the following effects within the intestines?
They increase the osmotic pressure within the intestines, leading to diarrhea.
One potential complication of celiac disease is osteoporosis, which can occur as the body utilizes bone tissue to maintain adequate levels of calcium in the blood. The most effective way for the body to utilize bone tissue to increase blood calcium levels would be to simultaneously:
increase osteoclast activity and decrease osteoblast activity.

-Osteoblasts function to build and repair bone, osteoclasts break down bone.
A certain drug blocks the activity of enzyme A by reversibly binding the enzyme's active site. Given this, the drug most likely inhibits enzyme A's activity by:
competitive inhibition
Which series shows the order in which filtrate passes through the tubular regions of a nephron?
Bowman's capsule --> proximal tubule --> loop of Henle --> distal convoluted tubule --> collecting duct
Considering the research on interpersonal attraction, which variable is LEAST likely to predict whether two participants will select each other for a coalition in Study 2?

A) The similarity between the participants in terms of activities they enjoy
B) The physical attractiveness of the participants
C) The number of times the participants have run into each other prior to participating in the study
D) The participants' scores on a personality test that assesses neuroticism
D) The participants' scores on a personality test that assesses neuroticism

Personality traits like neuroticism do not predict interpersonal attraction.
Which of the following findings would suggest that the empathy questionnaire is NOT a valid measure?
A negative correlation between scores on the empathy questionnaire and the personal distress questionnaire.

-If people who got high scores on the empathy questionnaire got low scores on the psychological distress questionnaire, the validity of both could be called into question.
flashbulb memory
subjectively vivid, compelling memories of details associated with reception of news about emotionally arousing events
episodic memory
stores personally experienced episodes with tags for context and time
Which critique of laboratory research on memory for emotional events is concerned with generalizability?
The memories and emotional experiences in real life are very different from those generated in laboratory studies.

-Generalizability refers to external validity, which is the extent to which the results of a scientific investigation would generalize to other settings and populations.
Individuals with impaired color perception, such as an inability to distinguish between red and green, are most likely to show improper functioning of which part of the visual system?
cones

-Cones are the sensory receptors responsible for initial detection of color information.
A 45-year-old man presents himself at a hospital emergency room. Symptoms include a pounding heart, chest pain, shortness of breath, sweating, and feeling dizzy. Medical tests reveal that the man did not have a heart attack. Which psychiatric diagnosis provides the most likely explanation for the man's symptoms?
Panic disorder
Every time a volunteer in a sleep study begins to exhibit rapid eye movements (REM), the experimenter wakes the person up. On the following night, when his or her sleep is uninterrupted, the person will most likely:
have more REM sleep than usual

-After being REM-deprived the night before, the volunteer is going to exhibit "REM rebound".
The cycle of worrying described in the passage is an example of:
self-fulfilling prophecy
When designing a study to test the hypothesis that controlling for SES should reduce racial differences in stress, which data would a researcher be LEAST likely to include in an aggregate measure of SES?

A) occupational status
B) income sources
C) social capital
D) educational attainment
C) social capital

-Social capital refers to the benefits provided by social networks. The other options refers to the main components of SES.
If certain stressors lead to an emotional response of anger and hostility, which consequence is more likely for individuals from lower socioeconomic positions?

A) Increased incidence of heart disease
B) Stronger reliance upon coping mechanisms
C) Reduced external locus of control
D) Fewer depressive symptoms
A) Increased incidence of heart disease

Certain stressors are related to anger and hostility, which have found to be associated with increased risk of heart disease.
In response to stress, what part of the brain initiates signals to the endocrine system?
Hypothalamus

-The hypothalamus is the brain structure that controls the pituitary gland, initiating the stress response.
Which category of behavioral and emotional problems includes measures that are most directly related to assessing the presence of a depressive disorder in a child?
A) Interpersonal problems
B) Externalizing problems
C) Learning problems
D) Internalizing problems
D) Internalizing problems

-Internalizing problems, which were assessed by measures of anxiety, loneliness, low self-esteem, and sadness, are best suited for evaluating whether a depressive disorder is potentially present in a child.
self-fulfilling prophecy
an observer's expectations either directly or indirectly lead to the expected attributes or behavior
fundamental attribution error
occurs when a person's explanations of someone else's behavior emphasizes personality or dispositional traits, minimizing possible influence of situational contingencies
The standard version of a dichotic listening task involves:
presenting two different auditory messages, one to each each
The frequency with which students completed problems decreased after their teacher stopped rewarding completed problems with candy. This observation is an example of which phenomenon?
Extinction

-Without continued reinforcement of an established operant behavior, the frequency of the behavior decreases.
Public health campaigns often target behaviors that are formed in adolescence. For example, alcohol, tobacco, and drug use interventions are often designed to prevent or delay risky behaviors because patterns established in adolescence are associated with disorders in adulthood. This example is best described as using which approach to health?
A life course perspective on health

-Attending to life stages is a major characteristic of life course perspective.
Which imaging technique is best suited for localizing brain areas in studies of neural activity?
PET
Which statement best applies conditioning principles to explain the progression from alcohol experimentation in adolescence to alcohol dependence in adulthood?
Early alcohol use begins with positive reinforcement, while later use is maintained by negative reinforcement.

Positive reinforcement (during alcohol use initiation) and negative reinforcement (during later alcohol dependence)
Based on the discussion of experimentation with alcohol, which description of social influence provides the most likely pattern of interaction for establishing alcohol use in adolescence?
Conformity with a primary group

-Establishing alcohol-related behaviors is specified in the passage as occurring in peer groups, which is a type of primary group (referring to more intimate social ties).

-In addition, the reference to peer groups implies that experimenting with alcohol is likely due to conformity with peers (again, a primary group).
In an extension of the research, ten individuals were recruited for an information session on the energy-saving program. Six of the ten individuals were colleagues and unanimously agreed to the program. The remaining four individuals also agreed to the program. Which concept is best represented by this scenario?
Groupthink

The researchers were testing whether individuals, when they are part of a cohesive in-group, will agree to the same behavior, which is an example of groupthink.
In a follow-up research study, a focus group of individuals who are not supportive of environmental protections is assembled to discuss the energy-saving program. As they discuss the program, the individuals become even more convinced that it is not a good program. This outcome is evidence of what concept?
Group polarization
Researchers interviewed an individual who participated in the energy-saving program. The participant mentioned that, as a child, her parents engaged in energy-saving practices such as turning off lights in rooms when not in use and insulating windows. As an adult, she does the same. This is most likely due to
observational learning
In response to the findings of this study, a religious leader sets up a website to attract young people to his or her congregation. Which sociological application of the findings best describes the leader's response?
There are cohort differences that impact individual behavior, and by responding to those differences, the religious leader may be able to attract young people.
A transient shortage of oxygen (global ischemia) releases excess glutamate into the extracellular fluid of the brain. This causes neuronal death by hyperexcitation to a greater extent in the hippocampus than in the cortex. Which reason best explains why the hippocampus is selectively vulnerable during global ischemia?
The expression of NMDA receptors is more abundant in hippocampal than cortical neurons.

-Higher expression of NDMA receptors in the hippocampus than the cortex would render the hippocampus more vulnerable to the excess release of extracellular glutamate.
When an individual moves from one social class to another over the course of his or her lifetime, this process is defined as:
intragenerational mobility
Pairs of research participants interacted for 10 min. They rated themselves and their partners on personality traits and then rated the accuracy of their partners' ratings of them. The partners' ratings were rated as more accurate if they were close to participants' own self-ratings. This finding illustrates:
self-verification
self-verification
refers to the tendency to seek out (and agree with) information that is consistent with one's self-concept.
serotonin
involved in the regulation of both mood and appetite
role strain
refers to stress from different expectations associated with a single role
Which response represents a symbolic interactionist's interpretation of the research findings in the passage?
The practices and rituals of the holiday celebrations are in some way correlated with the spike in holiday deaths.
When studying education as a social institution, the hidden curriculum constitutes:
latent function of schools
latent functions
aspects of a social institution that may serve an unacknowledged purpose
In order to balance on one foot, many people need to have their eyes open. This is an example of:
sensory interaction
sensory interaction
idea that one sensory modality (ex. vision) may influence another (ex. balance)
The phenomenon that occurs when people mistakenly read the letter "C" as the letter "O" illustrates which Gestalt principle of perceptual grouping?
Closure

-refers to one of the Gestalt principles of perceptual grouping, occurs when people perceive objects that are incomplete as complete.
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