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MCAT Question Mix Bowl #2

Terms in this set (37)

Radioactive element I-131 can cause thyroid cancer. A group of researchers choose to study these thyroid cancer cases in children rather than adult. What is one possible explanation?
A. Thyroid cancer is not present in children
B.children receive a higher relative dose of I-131 at the same contamination level
C.children receive a lower relative dose of I-131 at the same contamination level.
B; bc children weigh less than adults, the same quantity of external I-131 would result in a higher concentration of isotope in body --> (+) chance of DNA damage and cancer.
Which of the following more likely to result in ankle injury?
A.an anterior force of 450 N at the pivot point of the angle
B.an anterior force of 450 N at a distance of 10 cm from the pivot point of the ankle.
B; bc there is also force caused by torque
A book rests horizontally on a table, and it experienced a gravitational force of mg due to Earth's gravity. According to Newton's third law:
A. the book experience a normal force of mg pushing up due to the table
B. the earth experience a gravitational force of mg from the book
C.the table exerts a gravitational force of mg on the earth
D.the earth exerts a normal force up on the table equal to mg plus the weight of the table.
Answer: B
-Newton's Third Law: F_A on B = -F_B on A
-While A is true, this is not what the Third Law say.
Nitrogen primarily exists in the atmosphere as a diatomic gas. Which of the following is true about this form of nitrogen?
A.the presence of a lone pair of electrons on each nitrogen atom in the molecule allows it to act as a strong Lewis base
B.the triple bond of the electrons creates a region of high electron density that allows N_2 to be very reactive as a nucleophile
C.diatomic nitrogen gas is relatively inert and can be used as the atmosphere in laboratory conditions to prevent unwanted side reactions.
D.atmospheric nitrogen will react spontaneously with carbon dioxide,which keeps atmospheric CO2 levels to the relatively low 0.04% (on a molar basis) of the atmosphere.
Answer: C
Triple bond means that it is very stable with no significant chemical reactions
D is Incorrect bc CO_2 level is determined primarily by the seasons(in spring, lots of plant, pulls CO_2 out of atmosphere)
Given that the standard reduction potential for rxn involved in the Electron transport chain, NADH+/NADH, Fe3+/Fe2+ in cytochrome c, and FMN/FMNH2 are -0.32 V, +0.22 V and -0.22 V, respectively. What is the likely standard voltage change for the (1/2)O2/H2O redox pair?
A.+0.82 V
B. +0.14 V
C. -0.18 V
D. -0.45 V
A;
standard voltage is a measure of the ability of the substance to attract electron, and a higher (+) voltage correlates with a greater electron-attracting (oxidizing ability). Since O2 is the final electron acceptor, it therefore should have the largest redox voltage.
Transcription factor AP-1 is a heterodimer consisting of c-jun and c-fos. C-jun and c-fos are soluble proteins that can be localized to eiether the cytosol or nucleus of a cell. C-jun and c-fos dimerize through a leucine zipper motif. In a leucine zipper motif, every 7 amino acid residues, or 2 full turns of an alpha helix, are leucine residues. Which of the following solvent would be the least favorable for c-fos/c-jun dimerization?
A.hexane
B.ethanol
C.water
D.phosphate-buffered saline
A; because it is the least polar and can interact with the hydrophobic face of the leucine zipper.
What effect will the addition of a fluorine substituent have on carbocation stability?
A.the fluorine group is destabilizing because it is highly electronegative
B. the fluorine group is stabilizing bc it has additional lone pair electrons
D. the fluorine group is stabilizing bc it has additional lone pair electrons
A;
carbocation is stabilized by Electron-donating group
When the solution-filled ITO glass plates of the flow chamber were connected to the AC generator,a 1.5 V potential difference between the plates was sustained for 3 hrs. the plates functioned most like which of the following electrical components?
A. a resistor
B. a capacitor
C.a galvanic cell
D. an electrolytic cell
B; the sustaining of potential difference indicates that it is storing charges
A galvanic cell (battery) is a device that uses a spontaneous redox reaction to produce an electrical potential
An electrolytic cell is a device that uses an electrical potential to drive a nonspontaneous redox reaction.
Vinblastine is a microtubule disrupting drug that inhibits tubulin polymerization. Which of the following processes would be directly inhibited upon vinblastine treatment?
I.phagosome fusion with lysosome
II.mitosis
III.meiosis
IV.electron transport
I,II,and III
microtubules are involved in vesicle transport, mitosis, and meiosis.
Stimulation of the iris dilator muscle is a result of activation of:
A.sympathetic motor neurons
B.parasympathetic motor neurons
C.the fifth cranial nerve
D.sympathetic sensory neurons
A
A student finishes an experiment involving several bacteria which are highly pathologic in humans. She wishes to dispose of the agar plates and micropipette tips she used. Which of the following procedures should she carry out?
A. microwave all materials for more than 60 seconds
B.wipe down all materials with a 100% ethanol solution
C.place all materials in a biohazard bag and autoclave the bag
D.place all materials under a UV light for 90 seconds
C; autoclave is the most effective sterilizing technique which bring the materials to a temperature over 120 degree Celsius and pressure over 2 atm.
If we start with the molecule (boxed in the pic) instead of palmitic acid, which step of the beta-oxidation will be interrupted and which enzyme will be used to correct the issue?
A. step 1, phosphotase
B.step 1, isomerase
C.step 2 , reductase
D.step 2 , kinase
B; just need to form the version of palmitic acid in step one by switching the double bond between alpha and beta carbon, which can be done through the usage of isomerase (bc these two molecules differ only in the configurations of their atoms, thus they are isomers)
In a population of Amish people, the frequency of recessive autosomal allele for polydactyly is 1.2%. What percent of the population are carriers for this gene?
A.0.0144%
B.1.19%
C.2.37%
D.97.6%
C
Which of the following do NOT have proteins with a nuclear localization signal?
I.E.coli
II. Homo sapiens
III.Fungi
IV. Archaea
I and IV
bc they are consisted of prokaryotic cells that lack nucleus.
A drive-reduction and cognitive theorist would argue that depression is most strongly correlated with a deficiency in which component of fulfillment?
A. socialization
B.stigma
C.arousal
D.self-efficacy
C;
Drive-reduction theories suggest that depression stems from a reduction in the motivating forces of arousal, while a cognitive theorist would say that arousal is essential to maintain most behaviors.
Abnormal functioning of which brain region(s) plays a role in the development of depression?
I.frontal lobe
II.Limbic system structures
III. hypothalamus
I,II,and III
frontal lobe is involved in the ability to project future consequences of current actions; limbic system regulate emotion and memory, and the hypothalamus coordinate many hormones(some of which is involved in mood regulation).
Which of the following statistics would give information about new cases of a disease in a community over the past year?
A.incidence
B.risk ratio
C.prevalence
D.mortality
A; incidence describes the number of new cases of a disease during a specific time interval
Risk ratio compares the risk of the disease between two groups
-prevalence describes how common a disease is.
What type of conformity do medical students experience when they engage in behavior that they privately feel is unacceptable and unethical, but that is considered normative in medical school?
A.compliance
B.internalization
C.identidication
D.informational social influence
A
Internalization is both public and privately conform to a behavior
-identification refers to situation where the medical student would conform to a behavior bc they like or respect the person who exhibit it
-informational social influence: medical school student would conform by turning to others in their group for info about what is correct.
What type of conflict are jurors likely experience when they have to make a decision if they are unsure of the defendant's guilt?
A. approach-approach conflict
B.avoidant-avoidant conflict
C.approach-avoidance conflict
D.double approach-avoidant conflict
D;
double-approach-avoidant conflict consist of two options with both appealing and negative characterisitcs ---- if jurors ruled the defendant guilty, they could be punishing the criminal (approach) or maybe punishing an innocent person (avoidant); if rule unguilty, could let criminal walk away (avoidant) or freeing an innocent (approach).
The following base sequence is given for the DNA coding strand: 5' ACTGTTACATTG 3'. Insertion of the base thymine (T) between the 8th and 9th base may affect how many amino acids?
A.0
B.1
C.2
D.3
C
What is the difference in the number of potential RNA combinations that can exist with a single-base RNA code and a three-base RNA code?
Please choose from one of the following options.
A.4
B.16
C.60
D.64
C
Assuming that it is a third-class lever, which of the following graphs accurately represent how the lever arm changes with respect to the biceps muscle's angle of application (ϴ)?
Answer: the last graph
Torque is the product of force and lever arm.Torque = F x d sin ϴ
The equation for lever arm:LEVER ARM = d sin ϴ takes on the general form of y =A sin ϴ. A represents the amplitude of the graph which is equal to d.
So, as the angle increases, the lever arm also increases (until level off)
[Note: x-axis = the degree of angle; y-axis: the magnitude of lever arm]
(1)If the mass of M1 > the mass of M2, and the sarcomere is moving with constant velocity, what can be said about the tension in both actin sections? (2)If the mass of M1 > the mass of M2 and the sarcomere is accelerating to the right, how will the tensions in the actin sections compare?
A.TA is larger than TB since the mass of M1 is larger than the mass of M2
B.TA is smaller than TB since actin B has to pull the mass of both boxes
C.Both tensions TA and TB are equal and are not equal to zero
D.Both tensions are the same and are zero
Answer:(1) D (2)B
(1)The sarcomere is moving with constant velocity
Since the sarcomere is moving with constant velocity there is no acceleration
: Since there is no acceleration the net force on the both myosin sections must be zero
Since the net force must be zero, and there's no friction, the tension in actin A must be zero, which means the tension in actin B must also be zero
(2)Use ΣF=ma for the horizontal forces on the masses
The only horizontal force on the 60kDa mass is the tension from the actin A
Actin B has to pull the mass of both myosin sections so TB is greater than TA
Which of the following traits MUST be present in a Fourier transform of Figure 3?
A.A peak at 2 hz
B.A peak with amplitude 1 V
C.A peak with amplitude 2 V
D.A peak at .5 hz
A
Two of the answer choices have the wrong units
Because the signal repeats every .5 seconds, there must be a 2 hz peak in the Fourier transform.
In one of the UNICEF's open defecation pilot communities, a community member said: "Toilet is more than a necessity. It's a pride." Which of the following sociological concepts best reflects the concept behind this quote?
A.Cultural relativity
B.Symbolic interactionism
C.Economic rationalism
D.Normative behavior
B.
The toilet here is more than an object, it has meaning attached.
Hint #2
The toilet is viewed no longer as a mere necessity, but as a symbol of pride.
Hint #33 / 3
Symbolic interactionism highlights the processes through which humans interact with objects take on particular symbolic meanings.
Critics of Study B argue that the lack of engagement in aggressive behavior does not mean that the children and adolescents in China did not learn aggressive behavior. Which of the following theories supports their notion?
A.Learning-performance theory
B.Terror management theory
C.Drive theory
D.Attribution theory
Answer: A
Drive theory is based on the idea that behavior is driven by psychological needs.

Terror management theory involves the fear of inevitable death.

Learning-performance theory involves learning something without actually performing the behavior.
The results of their experiments show that the reaction of the intestinal microbiota to saccharin interferes with glucose metabolism. Which other body functions are likely to be affected with disruption of the intestinal microbiota?
A.Leukopoiesis
B.Hemoglobin saturation
C.Coagulation
D.T lymphocyte maturation
Answer: C
Hemoglobin saturation is determined by blood oxygen levels.

T lymphocyte maturation occurs in the thymus.

Leukopoiesis is production of white blood cells.

Vitamin K is a precursor for factors linked with the coagulation cascade, its absorption is linked to the intestinal microbiota.
Which of the following properties increases during exhalation?
A.The amount of oxygen in the bloodstream
B.The intermolecular forces acting on individual oxygen molecules
C.The solubility of oxygen in the bloodstream
D.The surface area of the alveoli into which oxygen can diffuse
C
bc during exhalation, the pressure in the lung (+), which in term (+) the solubility of the oxygen.
An object is placed at point B and the convex lens creates a real image of that object. (1) Which position could be the location of that real image? (See pic:Given that each interval is 10 cm, and f = 20 cm)
A.To the right of point I
B.In between D and E
C.In between B and C
D.To the left of point A
(2) What is the power of the lens?
(1)Answer: A
Real images are formed when light rays actually cross at the location of the image.
Light rays must travel through a lens.

Since a real image must be formed on the opposite side of a lens as the object, the only reasonable option is "to the right of point I.
(2)Lens strength is given by P=1/f
Make sure you convert all lengths to meters
P = 1/f = 1/0.2m = 5 D
If the researcher in the passage is correct about increased albumin concentration in the interstitial fluid of the brain following focal ischemia, which of the following interactions would most likely be affected?
A.Astrocytes and blood vessels
B.Schwann cells and axons
C.Microglia and lymphocytes
D.Ependyma and cerebrospinal fluid
A
Schwann cells form the myelin sheath around axons of neurons in the peripheral nervous system.
Hint #2
Microglia present antigens to lymphocytes.
Hint #33 / 3
Astrocyte end feet surround blood vessels of the central nervous system to contribute to the blood brain barrier.
Which cell type normally maintains homeostasis of the interstitial fluid in the brain, including the concentration of potassium ions?
A.Neurons
B.Ependyma
C.Microglia
D.Astrocytes
Answer: D
The ependyma is a leaky barrier composed of ependymal cells between the cerebrospinal fluid and the interstitial fluid of the central nervous system.
Hint #2
Neurons process and transmit information in the nervous system.
Hint #33 / 3
Astrocytes maintain homeostasis of the interstitial fluid of the central nervous system.
If the researcher wanted to study the concentration of albumin in the brain after ischemia over time, what technique would she likely use?
A.Northern blot
B.Southern blot
C.Eastern blot
D.Western blot
D;
Albumin is a protein.
Hint #2
Northern and southern blots measure nucleotide concentration.
Hint #3
Eastern blots analyze protein post-translational modifications.
Hint #44 / 4
Western blots measure protein concentration and would therefore be used in this experiment.
Why is it always important to consider the minimal threshold for clinical detection when measuring protein concentrations?
A.Minimal thresholds indicate when protein levels reach a concentration that indicates that injury has occurred.
B.The threshold level is equivalent to the control group concentration.
C.Minimal thresholds provide an indicator so one can measure several different protein concentrations relative to one another.
D.Every assay has a threshold below which concentrations cannot be accurately measured.
Answer: D
Minimal thresholds are not indicative of injury.
Hint #2
Minimal thresholds do not allow one to compare different protein concentrations to one another nor do they act as a control group measurement.
Hint #33 / 3
Every assay has a minimal threshold below which concentrations cannot be accurately measured.
Physics Question: See pic
An orbiting object is undergoing free-fall.
Hint #2
Free-fall (in the absence of air resistance) is formally equivalent to zero-gravity.
Hint #3
[ANSWER] The total load on the astronaut's muscles is zero during orbit.
Which of the following would be the most effective exercise to induce dissonance in the dissonance program?
A.The smokers are told to watch a video at home about living with lung cancer.
B.The smokers are asked to try deep breathing exercises instead of smoking.
C.The smokers admit they are addicts and surrender themselves to a higher power.
D.The smokers give a speech to the group about the negative effects of smoking.
Answer: D
Dissonance is induced when a person becomes aware of the inconsistencies between their behavior and attitudes.
Hint #2
Admitting to addiction and surrendering to a higher power is a typical exercise for a 12-step program.
Hint #3
The act of watching a video is passive and might not lead to behavioral change.
Hint #44 / 4
Publicly speaking about the negative effects of smoking is a behavior that would directly challenge their current attitudes about smoking. This would probably induce dissonance.
One smoker from the twelve step treatment stated that while he was in the program he was influenced by the sobriety of those around him and felt he had to comply with the no smoking standards, but once the group was over he started smoking again, because he really didn't believe smoking was hurting him or that quitting completely was the right decision. What likely influenced his decision to start smoking again?
A.Subjective norms
B.Classical conditioning
C.Normative beliefs
D.Perceived behavioral control
Answer: A
Normative beliefs, or a smoker's perception of social normative pressures not to smoke, probably led to his cessation while in the program.
Hint #2
Perceived behavioral control, or how easy or difficult a person believes quitting smoking will be, was not mentioned as a factor in the smoker's decision to quit or to start smoking again.
Hint #33 / 3
In this case, subjective norms are a smoker's perception about smoking - because he didn't believe quitting completely was important, he began smoking again.
How many different gametes can the person whose karyotype is pictured in Figure 2 produce? (In regards to chromosome 14 and 21?
A.4
B.8
C.2
D.6
D
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