1. Can self replicate
   Cannot self replicate
2. Acts in cell membrane trafficking
   Can bind foreign materials

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.

1. Increased sodium re absorption
   Increased potassium re-absorption
2. Increased blood pressure
   Increased blood pH

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.

1. 56,000
   92,000
2. 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.

1. I only
   III only
2. II and III only
   I, II and III

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.

1. In the cytoplasm
   In the area of the cell membrane
2. In the mitochrondria
   In the area around the ribosones

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.

1. B cells are activated and antibodies are released.
   T cells are activated, resulting in cytotoxic response.
2. Natural killer cells induce apoptosis of affected cells.
   Macrophages engulf the pathogen and display its antigens.

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.

1. Acquisition
   Generalization
2. Discrimination
   Negative Reinforcement

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.

1. 6
   8
2. 10
   16

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).

1. Conversion Disorder
   Generalized Anxiety Disorder
2. Illness Anxiety Disorder
   Histronic Personality 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.

1. 0 foot pounds
   6 foot pounds
2. 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.

1. cAMP is formed from ATP.
   The enzyme that catalyzes the formation of cAMP is adenylate cyclase.
2. The enzyme that catalyzes the cAMP formation is generally located in the cytoplasm.
   cAMP is regarded as a second messenger, since it can trigger a cascade of intracellular reactions when a hormone binds to a cell membrane.

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.

1. Personal beliefs
   Patient autonomy
2. 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.

1. 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
2. Medicare: mostly patients in an older age group; Medicaid: mostly patients with low socioeconomic status
   Medicare: mostly patients with low socioeconomic status; Medicaid: mostly patients in an older age group

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.

1. Autoimmune attack of the pancreatic insulin-producing cells
   Severe allergic responses
2. No adaptive immune response
   Overcompensation of somatic hypermutation in B cells to compensate for the loss of somatic recombination

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.

1. A population of thermophiles (microbes) near an undersea hydrothermal vent
   A seabird population afflicted by the effects of an oil spill
2. A bear population on an island in a large, inland Canadian lake
   A bacterial population currently under experimental antibiotic conditions

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.

1. Increase in presence of oxidative radicals
   A higher pH in the mitochondrial intermembrane space
2. Decrease in fermentation processes
   pregulation of the Krebs cycle

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.

1. Volume
   Moles
2. 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.

1. A spherical capsid
   Single stranded DNA, rather than double stranded
2. 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.

1. Reduction
   Oxidation
2. Dehydration
   Condensation

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.

1. Cleave exotoxins
   Stimulate exocytosis of viruses from infected cells
2. Aid in phagocytosis of foreign bacteria
   Chelate toxic heavy metals

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.

1. They are entirely composed of proteins.
   They are not involved in diseases in humans.
2. 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.

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).

1. 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.
2. 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.

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.

1. I and III
   I and IV
2. II and III
   II and IV

Hydroxyl groups have an absorption which forms a broad peak around 3300 cm-1.

1. Different types of bond motions including vibrations and stretches
   Intramolecular interactions of other functional groups
2. Resonant absorbance frequencies
   Conjugation in the molecule

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.

1. 4 seconds
   6 seconds
2. 8 seconds
   10 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.

1. An increase in transcription
   A decrease in RNA stability
2. A decrease in protein concentration
   An increase in chromatin density

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.

1. -OH as -OD; -NH2 as -ND2
   OH as -OD; -NH2 as -NHD
2. -OH as -OD only
   -NH2 as -NHD only

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.

1. Valine to leucine
   Isoleucine to leucine
2. 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.

1. Animal fats have more double bonds than vegetable oils do.
   Animal fats have fewer double bonds than vegetable oils do.
2. Animal fats have shorter fatty-acid tails than vegetable oils have.
   Animal fats have a lower concentration of sterols.

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.

1. Macrophages
   Cytotoxic T cells
2. Antibodies
   Apoptosis

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.

1. 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.
2. 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.

1. Encode a different protease enzyme
   Contain a capsid which contains different cell surface receptor proteins
2. 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.

1. A ribosome
   A viral protein from HIV
2. A trans-membrane protein
   A digestive protease

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).

1. The container with the higher temperature has fewer moles of gas.
   The container with the higher temperature has more moles of gas.
2. The two containers have the same number of moles of gas.
   The answer cannot be determined from the given information.

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.

1. Aligned thick and thin filaments within muscle tissue
   Support proteins which hold up the stability of the sarcomere
2. Large regions of muscle which do not have actin filaments within them
   Homogeneously contracted muscle cells

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.