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About This Quiz
Biology, psychology, biochemistry, general chemistry, sociology, physics and organic chemistry. These are some of the subjects a pre-med student needs to know in depth! Just in case you're serious about taking the Medical College Admission Test (MCAT) this quiz contains sample questions and answers gathered from two sources, the Kaplan Test Prep website and the M Prep site at www.mcatquestion.com with 2015 exam questions. This version is important to note since new content was added in 2015, specifically psychology and sociology curriculum. The MCAT now contains four sections, each scored on a scale of 118 to 132 for a cumulative score range of 472 to 528.
To put it simply, a pre-med student needs to know all things science-related. In other words, most everything. In this quiz there are questions about what is the response of the immune system to downregulation of MHC molecules on somatic cells (natural killer cells induce apoptosis of affected cells.) As well as physics questions such as how much work is done by a six-foot man lifting a 100 lb weight one foot above his head (700 foot pounds). Are you still up for the challenge? Then student, teach thyself, by taking this quiz. If you get 29 out of 35 on this quiz, you can fake your way through med school!
Which is not a characteristic of proteins?
Can self replicate
Proteins have numerous functions in the body; they can be hormones (chemical messengers), enzymes (catalyze chemical reactions), structural proteins (physical support), transport proteins (carriers of important materials), and antibodies (which bind foreign particles). However, proteins cannot self-replicate; DNA is the only molecule capable of self-replication.
Cannot self replicate
Acts in cell membrane trafficking
Can bind foreign materials
A drug is used that prevents the conversion of angiotensin I to angiotensin II. What is a likely effect of this drug?
Increased sodium re absorption
Increased potassium re-absorption
Normally, angiotensin II causes secretion of aldosterone from the adrenal cortex. Aldosterone serves to increase reabsorption of sodium, while promoting excretion of potassium and hydrogen ions. Thus, blocking the release of aldosterone should result in decreased reabsorption of sodium, while decreasing excretion of potassium and hydrogen ions.
Increased blood pressure
Increased blood pH
For a particular population, the crude death rate (per 1000) individuals is found to be 8.6 in 2016 and drops to 5.8 in 2017. If the population size is 46,000,000 individuals and the death rate is expected to decline at a linear fashion at the same rate, how many individuals will be expected to die in 2018?
56,000
92,000
112,000
138,000
The crude death rate describes the number of deaths per a certain number of individuals (here this happens to be 1000). Crude death rate is 8.6 in 2016, 5.8 in 2017, and would be predicted to be 3.0 in 2018 if the decline is linear and predictable. To calculate the total number of individuals expected to die, we take the product of 3/1000 * 46,000,000 = 3*46,000 = 138,000 individuals.
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Which of the following is/are true with regard to neurulation? I. The neural tube differentiates from endoderm. II. The neural tube becomes the peripheral nervous system. III. Neural crest cells migrate from their original site.
I only
III only
Neurulation occurs when the notochord causes differentiation of overlying ectoderm into the neural tube and neural crest cells. The neural tube ultimately becomes the central nervous system (brain and spinal cord), and neural crest cells migrate to other sites in the body to differentiate into a number of different tissues.
II and III only
I, II and III
Where is this process completed? C6 H12 O6 +O2 --> CO2 + H2O
In the cytoplasm
In the area of the cell membrane
In the mitochrondria
The process presented in the question stem is respiration; overall, in the presence of oxygen, a glucose molecule is broken down so as to give energy in the form of ATP, and two byproducts - carbon dioxide and water. Respiration begins in the cytoplasm but is completed in the mitochondria. The first step of respiration is glycolysis, which occurs in the cytoplasm.
In the area around the ribosones
What is the response of the immune system to downregulation of MHC molecules on somatic cells?
B cells are activated and antibodies are released.
T cells are activated, resulting in cytotoxic response.
Natural killer cells induce apoptosis of affected cells.
Healthy cells exhibit MHC class I molecules. Natural killer cells monitor the expression of MHC molecules on the surface of cells. Viral infection and cancer often cause a reduction in the expression of MHC class I molecules on the cell surface. Natural killer cells detect this lack of MHC and induce apoptosis in the affected cells.
Macrophages engulf the pathogen and display its antigens.
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A person suffers from food poisoning after eating a spoiled lemon, and later finds that the smell of limes and other citrus fruits make her nauseous. This is an example of:
Acquisition
Generalization
Generalization is the process by which similar stimuli can produce the same conditioned response. Here, the response to the taste and smell of lemons has generalized to that of all citrus.
Discrimination
Negative Reinforcement
How many different types of gametes would be produced by an organism of genotype AabbCcDdEE, if all of the genes assort independently?
6
8
The number of genetically unique gametes produced by a given individual can be determined by using the formula "two to the nth power", where "n†is the number of heterozygous gene pairs that the individual has (23 = 8).
10
16
A woman comes to the doctor with a two-week history of complete paralysis of her left arm. She has had no injury to the extremity, and full neurological workup fails to demonstrate any underlying cause. She seems surprisingly unconcerned about the paralysis, and seems more worried about an argument she had one month ago in which she hit her daughter. Based on this information, the woman's most likely diagnosis is:
Conversion Disorder
Conversion disorder is marked by a motor or sensory symptom in the absence of an underlying physical or neurological cause. It is associated with an inciting event that, in this case, may have been the argument with her daughter. Her lack of concern over the deficit is referred to as la belle indifférence.
Generalized Anxiety Disorder
Illness Anxiety Disorder
Histronic Personality Disorder
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A 6 ft man lifts a 100-lb weight from the floor to a height 1 ft above his head.How much work is done in lifting the weight?
0 foot pounds
6 foot pounds
600 foot pounds
700 foot pounds
Recall the equation used to determine work, W = Fd cos θ, where F is the force, d is the displacement, and θ is the angle between the force and the displacement. In this case, the direction of the force and the direction of the displacement are the same, so that θ = 0° which means that cos θ = 1. So we have W = Fd. Now we note that the force required to lift an object is simply the weight of the object. So we have W = (100 pounds)(6 ft + 1 ft) = 700 ft-pounds.
Which statement about cyclic AMP (cAMP) is NOT true?
cAMP is formed from ATP.
The enzyme that catalyzes the formation of cAMP is adenylate cyclase.
The enzyme that catalyzes the cAMP formation is generally located in the cytoplasm.
cAMP is responsible for carrying the chemical stimulus into the cytoplasm and triggering a response; it is generally referred to as a second messenger because it is mobilized after a receptor binds a ligand. Ligands (such as hormones and neurotransmitters) bind their membrane receptors, activating them. Through a G-protein intermediate, the enzyme adenylate cyclase is activated, and converts ATP into cAMP. Adenylate cyclase is attached to the inner layer of the phospholipid bilayer; it is not located in the cytoplasm, which means that choice (C) is a false statement, and therefore the correct answer for this question.
cAMP is regarded as a second messenger, since it can trigger a cascade of intracellular reactions when a hormone binds to a cell membrane.
A patient who resides in the United States says, "I love you,†and hugs his doctor after every routine visit. This behavior violates which of these?
Personal beliefs
Patient autonomy
Social values
Social norms
In the United States, it is not a common practice to say, "I love you," and hug one's physician after each routine checkup; therefore, this behavior could be considered deviant, going against the social norm. Values are what an individual deems to be important.
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Which of the following best describes the populations targeted by Medicare and Medicaid, respectively?
Medicare: mostly patients without an employer-guaranteed health care; Medicaid: mostly patients who have recently immigrated
Medicare: mostly patients who have recently immigrated; Medicaid: mostly patients without an employer-guaranteed health care
Medicare: mostly patients in an older age group; Medicaid: mostly patients with low socioeconomic status
Medicare covers patients over the age of 65 (older age groups), those with end-stage renal disease, and those with amyotrophic lateral sclerosis (ALS). Medicaid covers patients below a certain socioeconomic level.
Medicare: mostly patients with low socioeconomic status; Medicaid: mostly patients in an older age group
The RAG complex in somatic recombination is essential to producing the high variability in V(D)J antibodies in T and B cells. A person with a mutation in the RAG complex which renders the complex nonfunctional is likely to experience which one of the following problems?
Autoimmune attack of the pancreatic insulin-producing cells
Severe allergic responses
No adaptive immune response
T and B cells are the effector cells of the adaptive immune response. Thus, a mutation which abolishes the diversity of the T and B cell recognition antibodies will negate their potential to bind antigens and elicit responses. Thus, the person will have no adaptive immune response. Autoimmune attacks, severe allergic responses, and somatic hypermutation are only possible in individuals with functional somatic recombination mechanisms.
Overcompensation of somatic hypermutation in B cells to compensate for the loss of somatic recombination
Which of the following best describes the population where genetic drift would play the most important role in evolution?
A population of thermophiles (microbes) near an undersea hydrothermal vent
A seabird population afflicted by the effects of an oil spill
A bear population on an island in a large, inland Canadian lake
Genetic drift describes the change in the frequency of alleles in a population due to the random sampling of organisms. The bear population described is somewhat close to a bottleneck, where the population becomes somewhat isolated and/or is reduced in size. In this case, the odds for survival of any member of the bear population are purely random, meaning the odds are not at all improved by any particular inherent genetic advantage, and this can exacerbate genetic drift, since there can be noticeable or even extreme changes in allele frequencies, completely independent of selection.
A bacterial population currently under experimental antibiotic conditions
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Which of the following would be expected in a population of eukaryotic cells under low-oxygen stress?
Increase in presence of oxidative radicals
A higher pH in the mitochondrial intermembrane space
The decrease in oxygen negatively impacts the ability of the ETC to pump protons into the intermembrane space, resulting in a lower H+ concentration and therefore an increase in the pH.
Decrease in fermentation processes
pregulation of the Krebs cycle
Which of the following does the change in entropy of a system NOT depend on?
Volume
Moles
Pressure
None of the above
The Boltzmann equation shows that entropy is directly proportional to internal energy, volume, and moles. While it seems logical that entropy is not dependent on pressure, we must realize that in order to change pressure, we must change internal energy, volume or moles. Therefore, change in entropy for a system does indeed rely on volume, moles, and pressure.
Which of the following contents of HIV is most vital for the ability of HIV to insert its genomic data into the genome of the host?
A spherical capsid
Single stranded DNA, rather than double stranded
Both DNA and RNA
Reverse transcriptase
Reverse transcriptase transcribes DNA from RNA. HIV is an RNA virus, and thus for its genomic data to enter the genome of the host, it requires reverse transcriptase to convert its data into DNA, which can then be transcribed and translated by the host.
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In the Krebs cycle, malate and NAD+ are converted to NADH and oxaloacetate. The malate converts to oxaloacetate by having one of its alcohol groups converted into a carbonyl. From the perspective of malate, this type of reaction is an example of which of the following?
Reduction
Oxidation
The conversion of an alcohol to a carbonyl group involves the loss of H2. In organic chemistry, this suggests an oxidation reaction. Additionally, the increase in the number of bonds to the oxygen atom (from C-O of the alcohol to C=O of the carbonyl) is also suggestive of oxidation. NAD+ is reduced to NADH.
Dehydration
Condensation
Immunoglobulin antibodies perform which of the following processes?
Cleave exotoxins
Stimulate exocytosis of viruses from infected cells
Aid in phagocytosis of foreign bacteria
Antibodies aid in the phagocytosis of foreign bacteria by coating the bacteria as they bind to specific sites on the bacteria. This process exposes the Fc region of the immunoglobulin, which facilitates the endocytosis of the bacteria by increasing the affinity of the phagocyte for the bacteria.
Chelate toxic heavy metals
Which of the following is correct regarding prions?
They are entirely composed of proteins.
Prions are proteins which are capable of folding in various ways. These proteins can fold in such a configuration that allows them to bind to other prion proteins and cause these other proteins to fold in that same particular pattern. This allows for transmission of the protein folding pattern and can result in disease (e.g., Creutzfeldt-Jakob disease).
They are not involved in diseases in humans.
They describe viral proteins capable of introducing viral DNA into host DNA.
They are proteins which may bind to other proteins and result in the protein's degradation.
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Which of the following is an inaccuracy regarding peptide bonds and polypeptide structure?
Polypeptides are formed through a condensation reaction between two amino acids.
At times, the peptide bond is composed of disulfide bond, as in the case of cysteine.
This question requires a fairly in-depth understanding of peptide bonds and their formation. They form through a condensation reaction (i.e. water is released as a product). In the reaction, the ammonia group acts as a nucleophile and attacks the carboxyl-carbon. You should know that peptide bonds are NEVER composed of disulfide bonds. Disulfide bonds form between the chain groups of amino acids and are very distinct from peptide bonds.
Peptide bonds with a polypeptide are broken through a hydrolysis reaction.
The carboxyl-carbon on one amino acid acts as the electrophile the hydrolysis reaction.
With respect to IR spectroscopy, a hydroxyl group typically contributes which of these? I. narrow peak. II. broad peak. III. peak around 3300 cm-1. %0D IV. peak around 1600 cm-1.
I and III
I and IV
II and III
Hydroxyl groups have an absorption which forms a broad peak around 3300 cm-1.
II and IV
Certain functional groups will absorb at multiple different wavelengths in infrared spectroscopy. This absorbance at multiple wavelengths is due to
Different types of bond motions including vibrations and stretches
Various functional groups have multiple degrees of freedom for their motion (wag, stretch, bend, rock, etc.) each of which can be excited at a particular wavelength.
Intramolecular interactions of other functional groups
Resonant absorbance frequencies
Conjugation in the molecule
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A ball of weight 20N sits at the bottom of a 100m pool. Buoyancy force is calculated and is determined to be 30N. Approximately how long will it take for the ball to rise to the surface?
4 seconds
6 seconds
We first need to calculate the mass of the object. We know that weight is 20N, which is equal to m*a, with a=9.8 m/s2, thus mass is approximately 2 kg. We can calculate the net force, which is 10N in the upward direction. From this, we know F=ma, thus 10N = 2*a, thus acceleration is 5 m/s2. Because initial velocity is zero, we can use the kinematics equation d=at2/2, thus 100 = 5t2/2. Thus t2=40, thus t is approximately 6 seconds.
8 seconds
10 seconds
Histone methylation that weakens the association of histones with DNA results in which of these?
An increase in transcription
Histones interact with DNA in chromatin, where the DNA is wound around the histone proteins in tightly-packed coils, aiding in the organization of the chromosome. Dense chromatin has little space for transcription to occur, and thus gene silencing can occur by increasing chromatin density. If the interaction between histones and DNA is weakened, the coils can unwind and the chromatin becomes less dense. Thus there should be an increase in transcription.
A decrease in RNA stability
A decrease in protein concentration
An increase in chromatin density
In the hydrolytic reaction between deuterated water (D2O) and a peptide, deuterium will be found on the products in which of the following bonds?
-OH as -OD; -NH2 as -ND2
OH as -OD; -NH2 as -NHD
Hydrolytic reactions involve the addition of water to break bonds. Since the starting peptide nitrogen already has one H on it, only one D is added to produce -NHD. On the carbonyl carbon, O is added to replace the N. Since O comes protonated, this results in -OD addition to the carbonyl carbon. Hence the total products are -OD and -NHD.
-OH as -OD only
-NH2 as -NHD only
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Which of the following amino acid substitutions would likely have the greatest impact on the 3-dimensional structure of a protein?
Valine to leucine
Isoleucine to leucine
Tyrosine to phenylalanine
Aspartic acid to lysine
Aspartic acid has a relatively small, negatively charged R group while lysine has a much larger, positively charged R group. These opposing charges would have a substantial impact on their surroundings and would thus be most likely to impact the 3-dimensional structure of the protein.
Which of the following is the best explanation for why animal fats (but not vegetable oils) are solid at room temperature?
Animal fats have more double bonds than vegetable oils do.
Animal fats have fewer double bonds than vegetable oils do.
Animal fats are largely comprised of saturated triglycerides, which are solid at room temperature due to the presence of sigma bonds (not double bonds), as this allows for straight "packaging" or the molecules, which more easily forms a solid. Conversely, vegetable oils, which have double bonds as part of their structure, are not solid at room temperature, and this is due to the double bonds introducing "kinks" into the packaging system, so these fats are more fluid and thus not solid at room temperature.
Animal fats have shorter fatty-acid tails than vegetable oils have.
Animal fats have a lower concentration of sterols.
RNA interference (RNAi) is a mechanism by which short RNA sequences bind onto specific targets of RNA molecules. One of its consequences is the targeting of RNA molecules for intracellular destruction. This protects cells against viral and other infectious RNA molecules. In this capacity, RNAi's function is analogous to which of the following?
Macrophages
Cytotoxic T cells
Antibodies
Antibodies are proteins which bind to antigens, or structures the immune system has targeted. The antibody-antigen relationship is highly specific, with antibodies generally targeting a specific site on the antigen. Antigens that have been bound by antibodies are easier to capture and destroy by the immune system. This is analogous to the function of RNAi wherein RNA sequences bind onto specific target RNA sequences for destruction like infections molecules.
Apoptosis
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A box sits atop a frictionless ramp and then from rest, slides down it, achieving some speed at the very bottom (before it hits the floor). For that same box to achieve a speed (at the bottom of the ramp) twice as fast as the original, how much taller should a new ramp be?
The new ramp should be the same height as the original, but with a more gradual slope.
The new ramp should be twice as high as the original.
The new ramp should be three times higher than the original.
The new ramp should be four times higher than the original.
Per the conservation of energy (mgh = � mv2), the loss in potential energy is equal to the gain in kinetic energy, which is proportional to the square of the block�s speed at the bottom of the ramp. The "2" means squared in this equation. Since all else is constant, this velocity is proportional to the height of the ramp, which must be four times higher than the original ramp in order to account for a doubling of velocity.
Which of the following is NOT a plausible way that a virus could evolve to gain resistance to an antiviral agent?
Encode a different protease enzyme
Contain a capsid which contains different cell surface receptor proteins
Encode a different integrase enzyme
Encode virion progeny which do not contain a capsid
Viruses cannot survive without a capsid. It is absolutely essential to their survival. All of the other mechanisms are ways that viruses can evade typical antiviral agents, which may target proteases and integrases. Encoding for different such proteins could possibly render the drugs inefficient as they may be unable to bind to the enzyme of interest.
Crystallography is a visualization technique to determine the arrangement of atoms in solids. It has been incredibly useful in discovering the structures of many proteins, such as hemoglobin. Difficulties arise when crystallography is attempted on non-polar molecules, such as proteins high in valine or alanine. Using this information, which of the following would be most difficult to visualize using crystallography?
A ribosome
A viral protein from HIV
A trans-membrane protein
Trans-membrane proteins must, as their name implies, span through the membrane. The inter-membrane region is highly nonpolar, since it is composed of hydrophobic tails from the membrane lipids. A trans-membrane protein must also contain such hydrophobic, non-polar regions to be able to stably rest inside of the membrane (remember that like dissolves like).
A digestive protease
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Two containers of equal volume have the same pressure but different temperatures. Which of the following must be true of the containers?
The container with the higher temperature has fewer moles of gas.
Given PV = nRT, if the two containers have the same volume and the same pressure, the two variables remaining are the number of moles and the temperature. If one has a higher temperature it must also have fewer moles in order for the pressure and volume to be the same as the other container.
The container with the higher temperature has more moles of gas.
The two containers have the same number of moles of gas.
The answer cannot be determined from the given information.
Striations, as are seen in skeletal muscle tissue (as opposed with smooth muscle tissue), signify what?
Aligned thick and thin filaments within muscle tissue
Striations are due to the alignment of thick and thin filaments which cause a dark, banding pattern under light microscopy. Smooth muscle tissue does not have such an organized alignment thus striations are not visible.
Support proteins which hold up the stability of the sarcomere
Large regions of muscle which do not have actin filaments within them
Homogeneously contracted muscle cells
You Got:
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