FL Exam #3 Flashcards
(25 cards)
The rolling friction of the wheels and the internal friction between the wheels and axles contribute a continuous 1000 N decelerating force any time that the railcar is in motion. This system can generate a maximum braking force of 14,000 N.
If no braking occurs, a total of how much power would be required to keep the railcar moving at 40 m/s?
A. 16 kW
B. 40 kW
C. 600 kW
D. 800 kW
The answer to this question is B.
The power required must match the work done by the friction force that tends to slow down the railcar, which is equal to the decelerating force multiplied by the constant speed, so 1000 N × 40 m/s = 40 kW.
The relative thermodynamic stability of isomeric organic compounds can be inferred from which of the following types of experimental data?
A. Boiling points
B. UV–visible absorption spectra
C. Mass spectroscopic fragmentation patterns
D. Heats of combustion
The answer to this question is D.
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.
Radioactive tritium (3H) labeled guanine has been used to measure the rate of biochemical processes that involve its binding or incorporation.
Given that water is the solvent for this type of experiment, what is the best site for tritium labeling?
A. I
B. II
C. III
D. IV
The answer to this question is A.
The best site for tritium labeling would not exchange the tritium ions for protons in water.
All of the N−H sites (II−IV) would readily exchange tritium protons due to their lone pair-facilitating protonation and subsequent tritium exchange with water, but the C−H site (I), lacking a lone pair, would retain its tritium label.
The energy of activation for a reaction is given by the energy of:
A. the reactants minus the energy of the products.
B. the products minus the energy of the reactants.
C. the activated complex minus the energy of the products.
D. the activated complex minus the energy of the reactants.
The answer to this question is D.
The activation energy for a reaction represents the minimum energy barrier necessary to be overcome by the reactants on the path to products.
What additional substance is necessary for Reaction 2 to take place?
A. FAD
B. NADH
C. H2O
D. Acetyl-CoA
The answer to this question is A.
An oxidizing agent is required for Reaction 2 to proceed. Of the choices listed, only FAD is a cofactor oxidant.
The heme iron is coordinated by a single histidine residue, and the calcium ions are coordinated by various Asp, Ser, Thr, Val, Gly, and Ile residues through both side chain and backbone interactions.
Which atom is most likely involved in the coordination of calcium ions found in HRP?
A. Hydrogen
B. Carbon
C. Nitrogen
D. Oxygen
The answer to this question is D.
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 in the peptide backbone or side chain.
The only other Lewis basic atom present is nitrogen (distractor C), which has a partially positive chain in the peptide backbone due to resonance and is thus less likely to coordinate calcium ions.
The pH-dependent unfolding of each oligonucleotide solution was monitored using circular dichroism (CD) spectroscopy. The results are shown in Figure 1.
Based on the information in the passage and in Figure 1, what effect does epigenetic modification have on iM pH-dependent denaturation?
A. Both methylation and hydroxymethylation result in significantly decreased stability because cytosine is more readily deprotonated.
B. Both methylation and hydroxymethylation result in significantly decreased stability because cytosine is more readily protonated.
C. Only hydroxymethylation results in significantly decreased stability because cytosine is more readily deprotonated.
D. Only hydroxymethylation results in significantly decreased stability because cytosine is more readily protonated.
The answer to this question is C.
Because DNA unfolding occurs as the pH increases, it can be inferred that this is due to cytosine deprotonation.
The drop in pK of the transition denotes a decrease in stability. Since 5hmC-WT has the lowest pK, hydroxymethylation decreases stability by increasing the acidity of cytosine.
Which action(s) could contribute to the positive inotropic effect (increases the force of contraction) of digoxin on cardiac myocytes?
I. Decrease transport of Ca2+ to the extracellular environment.
II. Increase the availability of intracellular Ca2+ to bind to troponin.
III. Increase overall Ca2+ stores in the sarcoplasmic reticulum.
A. II only
B. III only
C. I and II only
D. I, II, and III
The answer to this question is D.
All of these actions will lead to an increase in intracellular calcium levels, resulting in enhancement of the contractile force of the heart.
To determine whether βOHB may also have HDAC inhibitor activity, researchers treated cells with different concentrations of βOHB.
After eight hours of βOHB exposure, histone acetylation levels were measured by immunoblot with antibodies specific to the H3 histone acetylated at lysine 9 (AcH3K9) or lysine 14 (AcH3K14). The antibody to AcTubK40 only binds to acetylated tubulin. The results are shown in Figure 1.
Which statement is best supported by the data using the anti-AcTubK40 antibody?
A. HDACs acetylates many types of target protein besides histones.
B. βOHB is not a general deacetylase inhibitor.
C. βOHB is present in the nucleus but not the cytoplasm.
D. βOHB inhibits different deacetylases compared to butyrate.
The answer to this question is B.
According to Figure 1, βOHB has no significant effect on tubulin deacetylase.
C is incorrect because βOHB was administered outside the cells, which means it must diffuse through both the plasma membrane and the cytoplasm to get into the nucleus and affect HDACs; therefore it is unlikely that βOHB is only in the nucleus.
Succinate modulates the level of hypoxia-inducible factor (HIF) by competitively inhibiting HIF hydroxylase, an enzyme that modifies HIF on specific amino acid residues and targets it for degradation.
Overexpression of which enzyme is likely to result in increased levels of HIF?
A. Succinyl decarboxylase
B. Succinyl-CoA synthetase
C. Succinate dehydrogenase
D. Succinate carboxylase
The answer to this question is B
Overexpression of succinyl-CoA synthetase, which results in the increased production of succinate, will enhance HIF levels.
Genetically, this mutation is transmitted in the germline and segregates with a benign form of neuroendocrine tumor known as paraganglioma, but only after paternal, not maternal, the transmission of the mutated allele. The estimated frequency of the mutated allele in the human population is 10%.
Which statement best accounts for the hereditary transmission of SDH-linked paraganglioma in a parent-specific manner? SDH is:
A. an imprinted gene.
B. a Y-linked gene.
C. an X-linked gene.
D. a tumor suppressor gene.
The answer to this question is A.
Imprinted genes are expressed in a parent-specific manner. B is incorrect because based on the passage both sexes may carry the mutated allele.
Certain viruses contain RNA as their genetic material. One of the ways these RNA viruses replicate themselves is to:
A. code for or carry a transcriptase that copies viral RNA.
B. infect microorganisms possessing RNA as their genetic material.
C. alter the host cell’s polymerase in order to synthesize progeny viral RNA from the viral RNA template.
D. stimulate the transcription of specific sequences of the host’s DNA, which, in turn, direct the assembly of viral particles.
The answer to this question is A.
RNA viruses require a type of transcriptase (reverse transcriptase) to replicate themselves.
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
The answer to this question is D.
While the optimum pH value varies greatly from one enzyme to another, the optimum temperature for enzymes is normally 37 °C.
A drug that inhibits the activity of which of the following enzymes would be most likely to relieve depression in some people, assuming the chemical reactions in Figure 1 are irreversible?
A. Aldehyde dehydrogenase
B. Monoamine oxidase A
C. L-aromatic amino acid carboxylase
D. Tryptophan-5-hydroxylase
The answer to this question is B.
Based on the data in Figure 1, monoamine oxidase A is involved in the oxidation and degradation of serotonin.
Therefore, a drug that inhibits the activity of monoamine oxidase A would be most likely to relieve depression.
SSRIs most likely relieve depression by increasing the:
A. amount of serotonin that is absorbed by the postsynaptic neuron.
B. release of serotonin by the presynaptic neuron.
C. rate of serotonin synthesis in the presynaptic neuron.
D. amount of time that serotonin is present in the synaptic space.
The answer to this question is D.
SSRIs function to treat depression by blocking serotonin reuptake in the presynaptic neuron.
Blocking the reuptake of serotonin into the presynaptic neurons 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:
A. decrease, resulting in a decrease of fluid in the body tissues.
B. increase, resulting in a decrease of fluid in the body tissues.
C. decrease, resulting in an increase of fluid in the body tissues.
D. increase, resulting in an increase of fluid in the body tissues.
The answer to this question is C.
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 body tissues.
Therefore, with malnutrition, the osmotic pressure of the blood would decrease resulting in an increase of fluid in the body tissues.
Events that evoke strong emotions when they occur are sometimes associated with vivid, detailed, and compelling memories.
Which term is used to refer to this type of memory?
A. Reproductive memory
B. Flashbulb memory
C. Prospective memory
D. Eidetic memory
The answer to this question is B.
The subjectively vivid, compelling memories of details associated with the reception of news about emotionally arousing events were referred to as flashbulb memories (Brown & Kulik, 1977).
In Study 2, participants described how they had heard about a disaster one day after it had occurred. They answered specific questions about key details.
The key details assessed in Study 2 were examples of which type of memory?
A. Episodic
B. Semantic
C. Procedural
D. Iconic
The answer to this question is A.
The episodic memory system (according to Tulving) stores personally experienced episodes with tags for context and time.
In Study 3, participants who viewed a sequence of slides involving a violent car accident remembered more central aspects of the event (for example, a car involved in the accident) and fewer peripheral details (for example, the street).
The finding from Study 3 is best explained by which mechanism? Increasing emotional arousal:
A. causes a restriction of the focus of attention.
B. improves memory, but only up to an optimal level of arousal.
C. impairs the encoding of peripheral details.
D. enhances the retrieval of encoded central details.
The answer to this question is A.
Emotional arousal seems to focus a person’s attention on the central features of an event.
The hypothesis (Easterbrook, 1959) that a person will notice information that elicits arousal, but fail to process other information, has been supported by studies in which memory for an (emotional) event’s “central” aspects (directly tied to the emotion elicitor) is compared to memory for “peripheral” aspects (removed from the source of the emotional arousal).
Thus, memory for the fundamental gist of the emotional event is retained, whereas memory for details (if they are encoded at all) either fades or undergoes changes.
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
The answer to this question is A.
Certain stressors related to anger and hostility have been found to be associated with increased risk of heart disease.
Which hypothetical finding would pose the greatest challenge to the theory that race/ethnicity is socially constructed?
A. During data collection for a large national survey, participants’ self-chosen racial/ethnic category often differed from the racial/ethnic designation made by in-person interviewers.
B. People who identified with one racial/ethnic group were found to have a significantly different genome than people who identified with another racial/ethnic group.
C. During data collection for an experiment on facial recognition, participants failed to consistently identify the racial/ethnic category of people from other parts of the world.
D. The medically evaluated health status of a representative sample of individuals from two different racial/ethnic groups was found to differ significantly between the groups.
The answer to this question is B.
The social construction of race refers to the idea that there is little biological basis for race (or ethnicity). Instead, racial/ethnic categories mostly result from history, culture, and society. If a significant biological basis (specifically for this question, a genetic basis) to racial categories were discovered, however unlikely that might be, it would challenge the idea that race is socially constructed. The remaining options would not contest the social construction of race to the same degree.
For adolescents who experiment with alcohol in peer groups, sensation-seeking behaviors may become associated with alcohol’s positive effects on mood. Some researchers hypothesize that dependence develops later in life when alcohol is consumed to alleviate negative emotions.
Which statement best applies conditioning principles to explain the progression from alcohol experimentation in adolescence to alcohol dependence in adulthood?
A. Early alcohol use begins with stimulus discrimination, while later use is maintained by stimulus generalization.
B. Early alcohol use is initiated by modeling, while later use is modified by shaping.
C. Early alcohol use begins with positive reinforcement, while later use is maintained by negative reinforcement.
D. Early alcohol use is an unconditioned response, while later use is a conditioned response.
The answer to this question is C.
The description in the passage is best explained by the mechanisms of positive reinforcement (during alcohol use initiation) and negative reinforcement (during later alcohol dependence).
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?
A. Bystander effect
B. Social loafing
C. Groupthink
D. Assimilation
The answer to this question is C.
In this example, 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.
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:
A. the self-fulfilling prophecy.
B. self-verification.
C. the self-serving bias.
D. self-efficacy.
The answer to this question is B.
Self-verification refers to the tendency to seek out (and agree with) information that is consistent with one’s self-concept.
