N/S FL 6 PSYCH/B/B

Mores Mores and taboos are unwritten rules in a society about what is considered right and wrong about important issues and are typically very broadly accepted within a given society (e.g. the incest taboo). Remember that on the MCAT, you can always eliminate two choices if they are functionally the same (since there can only be one right answer!).

not widely accepted

reference groups

people to whom an individual looks as a basis for self-appraisal or as a source of personal standards

group polarization

the enhancement of a group's prevailing inclinations through discussion within the group

Groupthink

the mode of thinking that occurs when the desire for harmony in a decision-making group overrides a realistic appraisal of alternatives

Expectancy theory "Expectancy theory" may sound tempting because stereotypes have to do with expectations, but in reality, expectancy theory propose that people make conscious choices to maximize pleasurable outcomes and minimize unpleasant outcomes. In psychology and sociology, we always have to be careful to operate with technical definitions, not impressionistic assessments of how terms sound.

we make conscious choices to maximize pleasure and to minimize unpleasant outcomes

social proof

influence tactic that relies on the tendency people have to behave in a particular way because others are doing so: B. II only Social proof, also known as informational social influence, is a psychological phenomenon where people assume the actions of others in an attempt to reflect correct behavior for a given situation. Informational social influence occurs most often when the situation is ambiguous. We have choices, but do not know which to select; there is a crisis and we have no time to think or experiment, as a decision is required now; others are experts. If we accept the authority of others, they must know better than us. If the first-year resident conforms because of informational social influences, he most likely does so because he assumes that the third-year residents know what they are doing, considers them experts, and thinks that he can trust that their opinion is correct (II).

Quiescent phase

total relaxation of atria and ventricles; Av valves fully opened and blood flows through passively

Bacteriophages have two distinct life cycles: lytic and lysogenic. During the lytic cycle, the bacteriophage essentially works to replicate at full speed, making full use of the host cell's machinery. Eventually, the host cell is filled with virions to the point that it bursts or lyses, and a tremendous number of new virions spill out into the environment.

Alternately, in the lysogenic cycle, bacteriophages can integrate themselves into the host genome, at which point they are referred to as a prophage or a provirus. In response to environmental signals, the prophage can re-emerge from the host genome and resume a lytic cycle. Non-bacteriophage viruses (e.g., those that infect humans) can exhibit a dormant stage that is similar to the lysogenic cycle. Examples of viruses with a prominent dormant stage include HIV and herpesvirus.

Opsonization

coating antigen with antibody enhances phagocytosis: Antigen presentation is a function of macrophages. B. opsonization. Opsonization is the process by which antibodies bind to and recognize antigens on the surface of a pathogen. The antibodies then attract macrophages to phagocytose the invader.

self schemata

cognitive representations of the self; one's sense of one's own characteristics

meta-analysis study

combining data from MANY different research studies to draw a conclusion

confounding variable

a factor other than the independent variable that might produce an effect in an experiment

self-concept

all our thoughts and feelings about ourselves, in answer to the question, "Who am I?"

Strong nucleophiles

Nucleophiles can often be recognized by the presence of at least one free pair of valence electrons, although nucleophilic attack can also take place using electrons from a pi or sigma bond. The factors that make a molecule a strong nucleophile include greater electron density—that is, more lone pairs and, if possible, more charge—and the lack of steric hindrance.

Social facilitation is the tendency that people have to perform simple tasks better or more efficiently when in the presence of other people. Inversely, when performing a complex or new task, the presence of others can hinder one's performance.

. In contrast, social loafing is the tendency that people have to put in less effort in a group setting, particularly if the group is being evaluated as a whole and not on an individual basis.

Gender schema is a cognitive theory of how individuals acquire and understand elements of gender and sex-linked characteristics from their surrounding culture and how those characteristics are transmitted inter-generationally.

A gender role is the set of normative behaviors viewed as acceptable (or desirable), for members of a given sex within a culture.

Social cognitive theory holds that our attitudes and behaviors are the result of observation of the attitudes and behaviors of others.

According to this theory, we learn through direct emulation of the other people and things that populate our environment. Albert Bandura introduced a concept he termed triadic reciprocal causation, in which behavior, personal factors, and environment all influence our attitudes. The interaction between these three factors is called reciprocal determinism.

Trans and cis fats

As shown in the image below, the hydrocarbon tails of trans fats are very similar to those of saturated fatty acids, meaning that they stack together more densely than the corresponding cis fats. This allows choices B and D to be eliminated. The denser, more stable stacking of trans fats means that they are more likely to be solids—and therefore less likely to be liquids—at room temperature. Thus, A is incorrect and C is correct. This property of trans fats makes them useful for inclusion in commercially produced baked goods, because the stable solid state of trans fats contributes to a longer shelf life. Unfortunately, trans fats have also been closely associated with an elevated risk of cardiovascular disease.

Many depressive patients experience a loss of pleasure in their daily lives. Which of the following is most closely associated with this symptom? A. Anhedonia Anhedonia is a symptom of depression and means "inability to feel pleasure." B. Alogia Alogia is the inability to speak.

Asociality Asociality is the lack of motivation or desire to engage in social activity. D. Avolition Avolition is a lack of interest in goal-directed behavior.

false negative

Assessment error in which no pathology is noted (that is, test results are negative) when one is actually present.

Dualism Dualism is a philosophical term that helped to form the field of psychology - it refers to the idea that the mind and the body are two separate entities.

Cognitive distortion A cognitive distortion is a phenomenon in which our mind convinces us that something is true when it isn't. There is no evidence of that here, so this choice is incorrect.

. Persuasion Persuasion is an active attempt to change another person's attitudes, beliefs, or feelings. Dr. Smith did not engage in persuasion.

Compliance is going along with an explicit request, whether or not you agree with it. Dr. Smith explicitly ordered the nurse to administer the medication, and she complied despite the fact that she did not feel it was the correct decision. Conformity Conformity refers to a change in a person's attitudes or behavior in response to pressure from others in a group. Herd mentality Herd mentality is not a type of social influence. 0.54%

lymphatic system

Composed of a network of vessels, ducts, nodes, and organs. Provides defense against infection. Content Foundations: Lymphatic System The lymphatic system can be thought of as being part of both the circulatory and immune systems. In a nutshell, it is a parallel circulatory system that drains interstitial fluid from the space surrounding the cells of the tissue. At any given moment, an adult human has about 10 liters of such fluid, which moves from the capillary beds into the extracellular space in the issues. In order to regulate fluid balance throughout the body, some of this fluid must always be in the process of being recycled through the circulatory system. Lymph capillaries collect this fluid and empty into lymph vessels, which converge into the right and left lymphatic ducts. These ducts in turn empty into the circulatory system at the intersection of the internal jugular veins and the right and left subclavian veins, respectively. The lymphatic system also has a connection with the digestive system because it is used to transport lipids, in the form of chylomicrons, to the circulatory system. Hundreds of lymph nodes dot the lymphatic system. These are organized clusters that can be thought of as filtration points for the lymphatic fluid where reservoirs of B and T cells are stored. Distinct clusters of lymph nodes are located in the head, neck, chest, underarms, abdomen, and groin, and are often palpated as a part of routine physical examinations because swollen lymph nodes may be a sign of conditions such as systemic infections or cancers.

IR spectrum ranges

Diatomic molecules (e.g. O2, N2, and Br2) do not return IR signals because no net change in the dipole moment occurs. Molecules respond to the influx of energy by either stretching or bending. Stretching is a result of changing distances in a bond between two atoms on the molecule. Bending is any change in the angle between two bonds on the molecule. The various types of vibrations and rotations absorb at different frequencies within the infrared region, resulting in unique spectral properties for different molecular species. The most high-yield IR spectra for the MCAT are those of carbonyl groups (C=O) and hydroxyl groups (OH). The figure below shows the IR spectra for these important functional groups.

The isoelectric point (pI) corresponds to the pH at which the average charge of an amino acid is exactly zero. An amino acid held at a pH equal to its pI will take the form of a zwitterion, which is an ion that contains multiple charged groups but has a net charge of zero. For example, the isoelectric point of glycine is approximately 6.0. When a solution of glycine is buffered at pH = 6.0, each glycine molecule tends to have a deprotonated, negatively-charged carboxylate terminal and a protonated, positively-charged amino terminal. Despite the presence of two charges on the molecule, its net charge sums to zero overall. For diprotic amino acids (i.e., those amino acids for which the side chain is neither acidic nor basic), the pI can straightforwardly be captured as the average of the two pKa values.

For triprotic amino acids (i.e., those that have an acidic or basic side chain), the pI can be obtained by averaging the two acidic pKa values for acidic amino acids or the two basic pKa values for basic amino acids. Another way of saying this is that for acidic amino acids, the pI is the average of the two lowest pKa values; for basic amino acids, the pI is the average of the two highest pKa values. Be careful to avoid averaging all three values given; the pI is always the average of two, not three, pKa values.

Cholesterol returned to the liver may be processed into bile. In clinical contexts, LDL may be described as "bad cholesterol" and HDL as "good cholesterol."

From a strictly biochemical point of view, this is a misconception. LDL and HDL are transporters, not different types of cholesterol, as there is only one type of cholesterol. The reason for this description is that LDL levels are directly associated with an increased risk of developing cardiovascular disease, whereas HDL levels show an inverse association with cardiovascular risk.

Question 45 The intravenous solutions used to correct fluid imbalances in trauma patients are aqueous solutions of glucose. Approximately how much glucose is needed to make 1.0 L of a 100 mM solution? A. 18 mg Show Explanation B. 34 mg Show Explanation C. 18 g

From the molarity and the volume of the solution, we can calculate the number of moles and then the mass of glucose (C6H12O6, MW = 180 g/mol) needed to prepare the solution. 1.0 L x 0.10 mole/L x 180 g/mole = 18 g glucose. D. 34 g Show Explanation

Gender identity refers to how one experiences one's own gender personally, and gender expression describes the many different ways in which gender identity manifests behaviorally in a given cultural context.

Gender schema theory describes how cultural constructs of gender are shaped and transmitted.

Galvanic cells vs electric cells

In contrast to a galvanic cell, an electrolytic cell uses a connected power source to conduct a nonspontaneous redox reaction. While galvanic cells have positive Ecell values (indicating spontaneity), electrolytic cells are characterized by negative Ecell values.

negative control

Negative controls are treatments that are known to have no effect, and positive controls are treatments that are known to have a certain effect and can therefore be used to assess whether the experimental methodology was sound. In clinical contexts, experimental studies often use a double-blind design in which neither the subjects nor the researchers know who is receiving the treatment and who is receiving the control. In experimental design, it is important to account for confounding variables, which are external variables affecting both the independent and dependent variable. For instance, if a study analyzes the effects of stereotype bias on math performance by race, but fails to account for socioeconomic status (SES), its results may be suspect, because SES may predict math performance and be correlated with race. Moderating variables attenuate or strengthen a given relationship, and mediating variables provide an important logical link between an independent variable and a dependent variable, or outcome.

Missense A single nucleotide substitutions that codes for an altered protein product without also altering the length of the protein is likely a missense mutation. B. Frameshift This mutation type almost always results in a radically different protein product. Frameshift mutations are most often caused by single-nucleotide insertions or deletions. D. Silent Silent mutations do not alter the function of the protein produced because of the degeneracy of the genetic code. This answer cannot be correct because we know that while similar, there is a difference between the mutant and wild-type proteins.

Nonsense This mutation type almost always results in a radically different protein product. A nonsense mutation involves insertion of a premature stop codon. Such a change would almost certainly shorten the length of the translated protein.

A phenomenological research study focuses on subjective elements of an experience by trying to understand individuals' perceptions, perspectives and understanding of a particular situation or event.

Often, this is done by way of collecting narratives from multiple subjects regarding the same situation or experience, in order to make generalizations about the research topic.

In the 1973 words of the evolutionary biologist (and self-described creationist) Theodosius Dobzhansky, "nothing in biology makes sense except in the light of evolution." Natural selection is the mechanism through which evolution takes place. The concept of natural selection refers to the tendency of certain phenotypes to be favored in terms of reproduction. Natural selection is closely linked to the term fitness, which in the evolutionary context only refers to the chance of reproduction associated with a certain phenotype compared to baseline. Fitness must be defined in terms of specific environmental constraints. In the 20th century, the concept of group selection was proposed, arguing that natural selection could act on the level of the group, not the individual. The related concept of inclusive fitness expands the rigorous evolutionary definition of fitness (defined in terms of the differential reproduction of alleles) to account not just for individuals but also their relatives, who can be expected to share many of the same alleles. This idea helps to explain altruistic behavior. Additionally, multiple "types" of selection have been identified to describe the outcomes associated with different types of selective pressures on phenotypes that vary along a spectrum. Stabilizing selection occurs if both extremes are selected against, directional selection occurs if only one extreme phenotype is selected against and the other extreme is favored, and disruptive selection occurs when the median phenotype is selected against. The concept of Hardy-Weinberg equilibrium is often used to model stable gene pools that satisfy the following assumptions: (1) organisms must be diploid and reproduce sexually; (2) mating is random; (3) the population size is very large; (4) alleles are randomly distributed by sex; (5) no mutations occur; and (6) there is no migration into or out of the population. The Hardy-Weinberg equations allow us to use allele frequencies to predict the distribution of phenotypes in the population and vice versa. If p and q are the only two alleles of a gene present in the population, then p + q = 1. Squaring the equation yields: (p + q)2 = 12 = p2 + 2pq + q2 = 1. This second equation allows us to connect genotypes and phenotypes, because the p2 and q2 terms correspond to individuals homozygous for p and q, respectively, while the 2pq term gives the frequency of heterozygotes. Other mechanisms are associated with changes in the gene pool of a species, such as genetic drift and bottlenecks. Genetic drift refers to the role of chance, in the absence of strong selective pressures, in determining the reproductive fitness of various alleles. When no strong pressure exists for a certain allele, it may randomly happen to be reproduced more or less often. These random effects can add up over the course of evolution. A related, but more specific, concept is that of an evolutionary bottleneck. Bottlenecks occur when some external event dramatically reduces the size of a population in a way that is essentially random with regard to most, if not all, alleles. This dramatically reduces diversity in the gene pool.

Other mechanisms are associated with changes in the gene pool of a species, such as genetic drift and bottlenecks. Genetic drift refers to the role of chance, in the absence of strong selective pressures, in determining the reproductive fitness of various alleles. When no strong pressure exists for a certain allele, it may randomly happen to be reproduced more or less often. These random effects can add up over the course of evolution. A related, but more specific, concept is that of an evolutionary bottleneck. Bottlenecks occur when some external event dramatically reduces the size of a population in a way that is essentially random with regard to most, if not all, alleles. This dramatically reduces diversity in the gene pool.

Understanding the order of reactions

Physiologically, zero-order reactions are exemplified by enzyme-catalyzed reactions in which the enzyme is saturated—that is, when concentrations of the reactant far exceed the available active sites on enzymes. In such a situation, the catalysis is the rate-limiting step and the concentration of the reactant is irrelevant. First-order reactions are exemplified by radioactive decay and SN1 reactions that are dependent on carbocation formation. Second-order reactions physically involve collisions between two reactant molecules, as in SN2 reactions. In multi-step reactions, the step with the slowest rate determines the overall rate of the reaction, so it is known as the rate-limiting step.

kd is invese of affinity

Question 23 Based upon data presented in Table 1, which of the following ligands most unfavorably interacts with the residues in the binding pocket of the TPP riboswitch? A. TPP Show Explanation B. 4'-enol-OxyTPP Show Explanation C. 4'-keto-N1'H-OxyTPP Show Explanation D. 4'-keto-N3'H-OxyTPP The ligand that binds the TPP riboswitch with the largest Kd likely displays the least favorable interactions in the binding pocket of the TPP riboswitch. Table 1 shows that the Kd for the 4'-keto-N3'H-OxyTPP-TPP riboswitch complex is largest.

More moles=more entropy

Reactions that increase the number of moles of substances in the system (or produce more gas particles) typically increase the entropy of the system. Entropy generally increases when a solid or liquid is dissolved in a solvent. Entropy increases when the solubility of a gas decreases and it escapes from a solvent. Entropy generally increases as molecular complexity increases (KOH vs. Ca(OH)2) due to the increased movement of electrons.

Bacteriophages are viruses whose host cells are bacteria. Instead of entering the cell completely, they inject their genetic material into their host through a syringe-like structure known as a tail sheath.

Retroviruses are a distinct class of single-stranded RNA viruses, including HIV, that use an enzyme known as reverse transcriptase to synthesize DNA from their RNA genome.

Gender conditioning is a means by which, in part, gender roles are established.

This social conditioning stems from societal reinforcements and punishments of gender-related behaviors.

Self-actualization refers to the individual's striving to realize his or her potential and to develop inherent talents and capabilities. Self-concept is an individual's mental model of his or her abilities and attributes. Self-efficacy is the belief that one can perform adequately in a particular situation. Self-esteem, often analogized to self-image, is the attitude which influences moods and exerts a powerful effect on an individual's personal and social behaviors. Self-fulfilling prophecy is the phenomenon wherein an individual believes an event will occur and, consciously or unconsciously, behaves in such a way as to bring about this prediction. The prophecy can be positive or negative. Self-handicapping is the process of developing (anticipating failure) behavioral reactions and explanations that minimize personal responsibility for the failure. Self-perception theory posits that people observe themselves in order to figure out the reasons they act as they do. Self-serving bias is a set of biases in which people take credit for their successes and deny responsibility for failures.

Self-awareness is the "peak" level of consciousness, which signifies perception of the autobiographical character of a person's life experience.

Key differences between prokaryotes and eukaryotes

Since bacteria by definition do not have membrane-bound organelles, their structure is simpler than that of eukaryotes. However, they have some key structures, including a cell wall containing peptidoglycan that encloses the cell membrane, ribosomes that are differently sized from those of eukaryotes (30S and 50S subunits, instead of the 40S and 60S components in eukaryotes) , rotating flagella, and a single circular chromosome. Structural differences between eukaryotes and prokaryotes are often specifically targeted by antibiotics.

Scale of derivatives

Since carboxylic acid derivatives are closely interrelated molecules, they can be interconverted among each other. This process follows a scale of reactivity; more reactive carboxylic acid derivatives can be converted to less reactive carboxylic derivatives through nucleophilic substitution, but not vice versa. To "climb" the reactivity scale - or to go from a less to a more reactive derivative - requires converting a carboxylic acid derivative back to a carboxylic acid and then generating a new carboxylic acid derivative. Amides are the least reactive carboxylic acid derivative, while esters have intermediate reactivity and acid anhydrides are highly reactive.

DNA replication is semiconservative, which means that each strand of the original DNA molecule serves as the template for a complementary strand, with the new DNA molecule composed of an old strand and a new strand. This fact was discovered in 1958 in the Meselson-Stahl experiment, which used radiolabeling to distinguish semiconservative replication from alternate possibilities. DNA replication starts at the origin of replication and involves several important enzymes. Helicase unwinds the DNA helix and separates the two strands of DNA. Single-stranded DNA-binding proteins keep the separated strands from immediately re-annealing. Primase then synthesizes a short RNA primer with a free 3' OH group that is used as the starting point for the synthesis of a new strand. DNA polymerase reads the DNA template in a 3' to 5' direction and synthesizes the complementary strand in the 5' to 3' direction. DNA gyrase, also known as DNA topoisomerase II, alleviates the supercoiling that would otherwise be created as helicase works its way down the DNA molecule. Ligase links together Okazaki fragments, which are created from the lagging strand of DNA replication. The directionality of DNA polymerase may seem counterintuitive at first, but it is important to understand for the MCAT. It becomes clearer if we imagine DNA polymerase reading a template from left to right and generating complementary base pairs as it goes. Remembering that the new strand is antiparallel to the original strand, the synthesis must proceed from 5' to 3'.

Steps of DNA replication

Neurotransmitters must be cleared out of the synaptic cleft quickly. This allows the body to tightly regulate the strength and timing of the signals sent by nerves. Neurotransmitters can either be broken down by enzymes in the cleft (the classic example being acetylcholinesterase, which breaks down acetylcholine) or taken back up by the presynaptic axon for re-use later.

Synapses are small structures at the end of the axon of a neuron that allow the neuron to communicate with another nerve, a muscle cell, or a gland.

Amygdala The amygdala is part of the limbic system and is the brain's center for emotions and emotional behavior. The hippocampus is more closely involved with memory. Thalamus The thalamus is involved in relaying sensory and motor information to the rest of the brain.

Thalamus The thalamus is involved in relaying sensory and motor information to the rest of the brain. Anterior cingulate gyrus The anterior cingulate gyrus is involved in regulating autonomic processes in the body.

The electron transport chain (ETC) uses free oxygen as the final electron acceptor of the electrons removed from NADH and FADH2 formed in glycolysis and the Krebs cycle (also known as the citric acid cycle).

The ETC is composed of four large protein complexes (Complexes I-IV) embedded in the inner mitochondrial membrane and two small electron carriers shuttling electrons between them. Complex I is known as NADH dehydrogenase, II is known as succinate dehydrogenase, III is known as cytochrome bc or c, and IV is known as cytochrome c oxidase. Electrons are released from NADH and FADH2 through a series of reactions.

ETC ATP count

These reactions take place in specialized proteins where the energy from NADH and FADH2 is used up, molecular oxygen is reduced into water, and approximately 30-36 ATP are created from ADP and inorganic phosphate.

Somatic disorders are unified by somatic (bodily) symptoms that can cause stress and impairment to the sufferer.

These symptoms generally lack an identifiable physical cause. Alternatively, the individual may be impaired by irrational fears of developing or having a disease, as in illness anxiety disorder.

The elaboration likelihood model (ELM) is a theory that describes the ways in which persuasive information may be processed. The ELM proposes two major routes to persuasion: the central route and the peripheral route. Under the central route, persuasion will likely result from a person's careful consideration of the merits of persuasive information.

Under the peripheral route, persuasion results from a person's association with positive or negative cues such as the attractiveness of the message source and its related presentation. In this sense, if advertising images for a product are presented and prove persuasive, it will have occurred via peripheral route processing.Because the passage indicates that high self-monitors are "motivated to attain high social status," it can be assumed that they would react most positively to images associating a product with high status.

retrospective quantitative study

While a retrospective study does consider past events, it does not examine subjective elements of experiences. The study done wasn't quantitative, since it focused on the life story of a handful of women.

Social loafing describes how in larger groups, any given individual might work less because they count on the rest of the group. This is irrelevant here.

describes how in larger groups, any given individual might work less because they count on the rest of the group. This is irrelevant here.

Frequency of light

does not change through different mediums

false postive

error of recognition in which people think that they recognize some stimulus that is not actually in memory

Changing one's behavior can often be difficult, as behavior can be the result of prolonged conditioning or entrenched patterns. T here are five stages of behavioral change: precontemplation (before the individual is considering the change), contemplation (the individual's initial act of considering that they may want or need to change), preparation for action, action, and maintenance (the act of ensuring that the behavioral change "sticks"). When the behavioral change relates to addictive or harmful behaviors (as in an addict who decides to stop abusing drugs), maintenance often consists of relapse prevention, or methods designed to keep the individual from returning to that harmful set of actions.

preparation for action, action, and maintenance (the act of ensuring that the behavioral change "sticks"). When the behavioral change relates to addictive or harmful behaviors (as in an addict who decides to stop abusing drugs), maintenance often consists of relapse prevention, or methods designed to keep the individual from returning to that harmful set of actions.

altruism

unselfish regard for the welfare of others

Self-awareness is the "peak" level of consciousness,

which signifies perception of the autobiographical character of a person's life experience.

A stereotype is a prevalent but oversimplified idea or set of ideas about a certain group. This stereotyped group typically consists of people with similar characteristics (gender, race, sexual orientation, etc.). Stereotypes may sometimes be accurate, but since they are generalizations, even the most "harmless" stereotypes tend to obscure the nuances between individuals in the stereotyped group. In other instances, stereotypes are harmful outright, such as stereotypes that paint groups of people as unintelligent or lazy. =

. A stereotyped individual who is aware of the stereotype may intentionally try to avoid fulfilling it, which can lead to stress and anxiety. Ironically, this sometimes causes the individual to unintentionally fulfill the stereotype, making it an example of a self-fulfilling prophecy. In contrast, a prejudice is a preconceived notion about a person, group, or thing. Unlike stereotypes, prejudices specifically target people, groups, or things that the holder of the prejudice encounters. For example, if I believe that all people who wear red are loud and annoying, this constitutes a stereotype. If I actually see or hear about a person who is wearing red and form a negative opinion about that person, that is a prejudice. Importantly, prejudices are typically made with little to no experience with the prejudiced person or group, and they may be irrationally positive or negative.

Young's Modulus

A measure of the stiffness of an elastic material and defined by stress/strain. In solid-state physics, Young's modulus is a measure of the stiffness of an elastic solid material. The slope of the graph (stress/strain) is equal to the Young's modulus. The higher the Young's modulus, the stiffer the solid material is. Graph '1' has the highest slope and therefore is the stiffest.

dna primer

A small piece of single-stranded DNA. It acts a signal, binding to and marking the piece of DNA which is to be copied in the polymerase chain reaction (PCR).

A solid is a structure with a rigid, tightly-packed organization of atoms, such as ice, sodium chloride (table salt), and most metals, like iron. Solids are characterized by a fixed volume, meaning that they do not expand and are not compressible to any significant degree, as well as a fixed shape. Solids also do not flow, although their particles do vibrate in place. A solid may be either crystalline or amorphous in nature. Crystalline solids exhibit a regular arrangement of atoms. In solid sodium chloride (NaCl), for example, each Na+ ion is surrounded by six Cl- ions, and each Cl- ion is in turn surrounded by six Na+ ions. This structured arrangement is termed a lattice structure, and is extremely difficult to disrupt. However, it can be broken if the NaCl is dissolved in water, in which case polar H2O molecules will "solvate," or separate and surround, the individual ions. The lattice energy of an ionic solid refers to the amount of energy required to separate the solid into its component cations and anions. In contrast to crystalline solids, amorphous solids are solids that do not have a regular crystal structure. The classic example is glass, a solid typically composed of silica (SiO2).

An important property of solids (although it is not limited to solids) is the bulk modulus, which indicates the degree to which a material resists compression by measuring how much pressure is needed to compress a substance by a certain amount. Solids typically have very high values of this parameter, which is important for determining the speed of sound.

Ploidy refers to how many copies of each chromosome a cell has. In humans, the vast majority of cells are diploid (2n), meaning that they contain two copies of each chromosome (except for the sex chromosomes; females have two X chromosomes and males have an X and a Y chromosome). Such cells are known as somatic cells—that is, the cells of the body. In contrast, germ cells (i.e., ova and spermatozoa) are haploid (n), meaning that the only have a single copy of each chromosome. Aneuploidy results from having too many or too few copies of a given chromosome. This results from nondisjunction in anaphase during cell division. Having only one copy of a chromosome is known as monosomy, and having three copies is known as trisomy. Aneuploidy is commonly discussed as occurring in meiosis, and indeed, this is the only way for aneuploidy to be inheritable. For this reason, nondisjunction during meiosis is the cause of aneuploidies such as Down syndrome (trisomy 21) or Turner syndrome (monosomy X). However, nondisjunction during mitosis can also occur, and this is extremely common in cancer cells.

Aneuploidy results from having too many or too few copies of a given chromosome. This results from nondisjunction in anaphase during cell division. Having only one copy of a chromosome is known as monosomy, and having three copies is known as trisomy. Aneuploidy is commonly discussed as occurring in meiosis, and indeed, this is the only way for aneuploidy to be inheritable. For this reason, nondisjunction during meiosis is the cause of aneuploidies such as Down syndrome (trisomy 21) or Turner syndrome (monosomy X). However, nondisjunction during mitosis can also occur, and this is extremely common in cancer cells.

A continuous reinforcement schedule is defined as one reward per response.

Because the passage describes this as helping to constitute the experimental procedures, choice A is the correct answer.

tions: Types of Imaging For the most part, the intricacies of medical imaging can wait until medical school, but the MCAT does expect you to be familiar with some of the major imaging techniques, especially those applied to the brain. An EEG measures electrical impulses in the brain by covering the scalp with small sensors. Researchers can then present the subject with various stimuli and record which areas of the brain demonstrate increased electrical activity. Instead of measuring electrical activity, scientists can watch the level of blood flow in parts of the brain. By injecting a tracer molecule, scientists are able to image which parts of the brain are more active in response to certain stimuli. More active brain areas will see an increase in blood flow, and thus an increase in the tracer molecule. \

Brains can also be imaged using MRI, PET, and CT scans. MRI scans use magnetic fields and radio waves to image parts of the brain while avoiding the dangers of bombarding the body with ionizing radiation such as X-rays. Functional MRI, or fMRI, trades spatial resolution for temporal resolution and allows scientists to map active parts of the brain. It does so by analyzing the differences in oxyhemoglobin and deoxyhemoglobin concentration in parts of the brain. PET scans work by injecting the patient with a radioactive analogue of glucose, and then measuring the radioactive emissions from the body. Much like MRI and fMRI, PET scans work on the principle that more active areas of the brain will show increased metabolism, and thus increase their uptake of glucose. Such uptake can then be converted into a false-color "heat map" of the brain to show areas of increased or decreased activity. PET scans are also frequently used for imaging designed to detect cancer in any part of the body, due to the increased glucose flux through tumor cells. Finally, CT scans use X-rays, but unlike a typical single two-dimensional X-ray film, CT machines use computer processing to take many X-ray measurements from multiple different angles, generating images that can be used for diagnosis. CT scans can provide high-resolution images, but unlike fMRI, CT is not useful for imaging processes in progress.

Question 48 In which neuronal location will selective serotonin reuptake inhibitors (SSRIs) have the greatest effect? A. The axonal node of Ranvier SSRIs have no effect at the nodes of Ranvier. B. The dendrite Show Explanation C. The soma Show Explanation D. The synaptic cleft SSRIs inhibit the reuptake mechanism of serotonin from the synaptic cleft. This causes serotonin to remain in the cleft longer in order to facilitate the molecule's binding to dendritic neurotransmitter receptors. 1.5% A 3.67% B 1.5% C 93.33% D Your answer was incorrect. 93.33% of students answered this question correctly. Content Foundations: Synapses Synapses are small structures at the end of the axon of a neuron that allow the neuron to communicate with another nerve, a muscle cell, or a gland. Neurotransmitters are stored in vesicles in the axon terminal. When the action potential arrives, voltage-gated calcium channels are triggered, allowing Ca2+ to rush into the axon terminal. These calcium ions serve as the signal for the cell to use exocytosis to push the neurotransmitters into the synaptic cleft—the space that exists between the axon and the post-synaptic membrane. The space of the cleft is exceptionally small, such that simple diffusion is enough to very quickly carry the neurotransmitters across the cleft to the post-synaptic membrane. There, the neurotransmitters can act as ligands binding to their receptors. Neurotransmitters must be cleared out of the synaptic cleft quickly. This allows the body to tightly regulate the strength and timing of the signals sent by nerves. Neurotransmitters can either be broken down by enzymes in the cleft (the classic example being acetylcholinesterase, which breaks down acetylcholine) or taken back up by the presynaptic axon for re-use later.

Did not use common sense.

Nucleases are enzymes that cleave nucleic acids. There are two broad classes of nucleases that you should be aware of: exonucleases and endonucleases. Exonucleases cleave bases from the end of nucleic acid strands, and endonucleases cleave within a nucleic acid sequence. Additionally, ribonucleases in the cytosol degrade RNA. Exonucleases are most important in the context of genetic repair and proofreading. For example, DNA polymerase has a "proofreading" ability to excise mismatched base pairs and reinsert the correct base, a function that is referred to as 3'-5' exonuclease activity. RNA degradation also involves exonuclease activity. ]

Endonucleases are more commonly encountered on the MCAT, and often appear within the context of restriction endonucleases, or restriction enzymes, which are enzymes used extensively in recombinant DNA technologies. In nature, endonucleases occur in prokaryotes and archaea, where they act as a defense system against invading viruses by cleaving DNA in response to specific recognition sites, corresponding to sequences of 4 to 8 bases. These recognition sites usually involve some degree of symmetry, as reflected by palindromic sequences, which involve inverted repeats, in which the palindrome is reflected diagonally across the plane of symmetry created by drawing a vertical line through the middle of the recognition site. When a restriction enzyme cleaves a DNA sequence vertically across the recognition site, the resulting fragments have "blunt" ends, whereas "sticky" ends result from restriction enzymes that cleave a DNA sequence in a zig-zag fashion. Restriction enzymes can cleave DNA either within the recognition site or at some distance from it. This generates fragments that can be "tied" back together by DNA ligase without necessarily respecting the original location of the sequences. In other words, if you put a sequence of human DNA and a sequence of pig DNA in a Petri dish, digest the sequences with a restriction enzyme, and then treat the fragments with DNA ligase, you will get sequences of human + human DNA, pig + pig DNA, and human + pig DNA. This process is known as recombination.

Glutamate is an excitatory neurotransmitter and is the most common, as 90% of brain cells are responsive to glutamate. In contrast, GABA is the main inhibitory neurotransmitter of the CNS, and it hyperpolarizes cells to reduce action potential firing. Alcohol binds and activates GABA receptors (in other words, alcohol is a GABA agonist), so the effects of GABA are associated with alcohol intoxication. Glycine is another inhibitory neurotransmitter found in the spinal cord and brainstem that can work in conjunction with GABA. Dopamine is used in reward and motor pathways. It is particularly associated with Parkinson's disease and the loss of dopaminergic neurons in the substantia nigra.

Endorphins suppress pain and can produce euphoria. Serotonin regulates mood, appetite, and sleep in the brain, with low levels associated with depressive mood disorders. Neurotransmitters can also be active in the peripheral nervous system. Most notably, acetylcholine activates muscle contraction at the neuromuscular junction. It is used in all autonomic outputs from the brain to autonomic ganglia, and in the parasympathetic nervous system for post-ganglionic connections. Serotonin regulates intestinal movement in the gastrointestinal tract, in addition to its effects in the brain. Epinephrine stimulates the fight-or-flight response, and norepinephrine is used in post-ganglionic connections in the sympathetic division of the autonomic nervous system. It also increases arousal and alertness and focuses attention.

Unsaturated vs saturated fats

Fatty acids can either be saturated, if their aliphatic tail contains only C-C single bonds, or unsaturated, if at least one C=C bond is present. To remember which is which, it may be helpful to think of "saturated" as describing a situation in which the hydrocarbon tail has as many hydrogens as possible, meaning that only single bonds between carbon atoms are possible. The presence of one or more double bonds in a fatty acid has a significant effect on its physical properties. Naturally occurring unsaturated fatty acids generally have cis bonds, which introduce a degree of bending into the chain. This is especially true for polyunsaturated fatty acids with cis bonds. Such acids do not stack readily on top of each other, meaning that they tend to have lower melting and boiling points than the corresponding saturated fatty acids. In the context of plasma membranes, unsaturated fatty acids tend to make the membrane more fluid. Small amounts of trans fatty acids are produced in nature, but they are mostly present in the human diet as a result of the industrial processing of vegetable oils. Partial hydrogenation of unsaturated vegetable oils results in trans fats, which are more stackable than cis fatty acids and therefore are more likely to be solids at room temperature. Trans fats have been consistently linked to heart disease and have been banned in many countries. In the United States, they are expected to be phased out by 2018.

Phenols, an important class of organic molecules, are a subset of alcohols that contain one or more hydroxyl groups attached to an aromatic benzene ring. Phenols that contain two -OH groups are termed diols. For diols (as well as substituted benzene rings in general), the terms ortho(o), meta (m), and para (p) describe the orientation of the groups relative to each other. An ortho configuration involves two groups immediately adjacent to each other, while meta structures have two substituents separated by a single carbon. Finally, para diols include two -OH groups immediately across from each other on the ring. The oxidation of certain phenols is biologically relevant. P-benzenediol is alternatively known as hydroquinone, and when oxidized, it becomes quinone (2,5-cyclohexadiene-1,4-dione). Quinone contains two carbonyl groups formed via C=O bonds on carbons within its ring structure. Note that quinone itself is not an aromatic molecule, although it undergoes resonance stabilization when acting as an electrophile and its derivatives may contain aromatic rings. These quinone derivatives are known as quinones, a class of biologically important molecules that generally serve as electron acceptors. The addition of a single hydrogen atom to a quinone produces an unstable free radical species termed a semiquinone. Since the addition of bonds to hydrogen typically constitutes reduction, semiquinones are more reduced than quinones. Further reduction can produce a diol known as a hydroquinone.

For example, ubiquinone (shown in Figure 1 of this passage) is an electron carrier involved in complexes I, II, and III of the electron transport chain. Its amphipathic structure (polar head and long alkyl tail) allows it to be both lipid-soluble and a functional electron carrier. When carrying one electron, one of its carbonyl (C=O) groups is reduced to an alcohol, resulting in a molecule known as ubisemiquinone, and when carrying two electrons—as is commonly the case—both carbonyl (C=O) groups are reduced, and the molecule is termed ubiquinol. Similar reactions underpin the function of other biological electron carriers, such as NAD+/NADH and FAD/FADH/FADH2.

Churches are religious organizations that are thoroughly integrated into society and that are interested not only in the sacred and holy, but in day-to-day life as well. They are typically organized by a codified set of rules, and though many people are born into particular churches, they generally allow people to join later in life. Examples include the Presbyterian and Catholic churches. In contrast, sects are religious organizations that are notably not integrated into society, often formed after a split from a larger, more defined religious organization. Members are typically born into a sect or must convert. In more extreme cases, sects may withdraw from society at large to practice their beliefs in a more controlled setting. A state religion is a religious organization that includes most members of a society, is officially recognized, and may not tolerate other religions. A state religion is not necessarily a theocracy - that is, a government based on religious principles and run by religious figures. For example, the state religion of Sweden is Lutheranism: it is legally regarded as such, though the government is secular (not based on religious ideas). Iran, on the other hand, has a theocratic government: its state religion is Islam and its government is informed by principles of Islam. Finally, a cult is a relatively small religious organization that has beliefs and practices that are typically far outside of what a society regards as normal or even acceptable. A cult that survives and grows can become a major religion. From a functional sociological perspective, religion can give people meaning and purpose for their lives. It can bring people together (or inversely, pull them apart) and create a means for social change (or inversely, social control). In this way, religion is a powerful social institution that can have significant influence over people and society. Religiosity is a term that refers to the extent to which religion and religious ideas influence a particular society, group, or individual

From a functional sociological perspective, religion can give people meaning and purpose for their lives. It can bring people together (or inversely, pull them apart) and create a means for social change (or inversely, social control). In this way, religion is a powerful social institution that can have significant influence over people and society. Religiosity is a term that refers to the extent to which religion and religious ideas influence a particular society, group, or individual

The second response to stress is cognitive, initiating when the hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the pituitary gland to produce adrenocorticotropic hormone (ACTH), which in turn stimulates the release of cortisol from the adrenal glands. Cortisol helps the body to maintain the continuous supply of blood sugar needed to sustain a stress response by upregulating gluconeogenesis and mobilizing free fatty acids and amino acids from body stores to be metabolized. This makes more glucose available, which is necessary for proper brain function during times of stress because the brain's only energy source is glucose. If cortisol release continues for too long a period, the healthy functioning of white blood cells can be inhibited, making the immune system weaker and thus the body more susceptible to illness and infection. Irritability, moodiness, tenseness, and feelings of helplessness are some of the emotional responses that result from elevated stress. When paired with a perception that the stressor cannot be controlled, learned helplessness, an overwhelming sense that a goal cannot be accomplished, can develop.

Hypothalamus:>>>>> Corticotropin-Releasing Hormone>>>>Pituitary gland: ACTH which in turn stimulates the release of cortisol from adrenal glands. Cortisol upregulates gluconeogensis.

Continuous variables have an infinite number of categories. If the question was something like "how many full-time jobs have you had?" or "how many hours do you work each week?" there would be more than two categories for responses and would be a continuous variable. Since there were only two categories, choice A is incorrect. An ordinal variable Ordinal variables can be ranked to allow for comparisons. For example, if you were asked about highest level of education achieved, you could respond with high school degree, college degree, medical degree, etc. College degrees are at a higher level than high school degrees, and medical degrees are at a higher level than college degrees. The responses to the question can't be ranked in this case, so this choice is wrong. Independent variables are the variables in an experiment that are manipulated. There was no manipulation of employment in this study, so this choice is wrong.

Independent variables are the variables in an experiment that are manipulated. There was no manipulation of employment in this study, so this choice is wrong. A dichotomous variable Dichotomous variables only have two categories. Since the question was posed in a way that required one of two responses, it is a dichotomous variable.

An enzyme (a biological catalyst) may require another chemical compound to be present in order for it to carry out its biological functionality. In general, such "helper" molecules are known as cofactors. Cofactors can be either inorganic (with some common examples including metal ions such as Mg2+, Zn2+, and Cu+) or organic, and organic cofactors are sometimes known as coenzymes. Many coenzymes are vitamins or derivatives of vitamins, and they often contribute to the function of enzymes by carrying certain functional groups from one place to another in a reaction. Perhaps the most well-known example of this is coenzyme A, which transfers acyl groups from one place to another. Coenzymes that are tightly (or even covalently) bonded to their enzyme are known as prosthetic groups. A famous example of an organometallic prosthetic group is heme, which contains an iron ion in the center of a porphyrin ring, and is attached to oxygen-transport proteins such as hemoglobin and myoglobin. Vitamins are non-macronutrient compounds that are vital for healthy functioning and cannot be synthesized in adequate quantities by the body, meaning that they must be obtained from external sources. The B vitamins and vitamin C are coenzymes used for various important reactions, and are water-soluble. Vitamins A, D, E, and K are lipid-soluble. Vitamin A plays a key role in vision, vitamin D in calcium and phosphate absorption from the gastrointestinal tract, vitamin E is an antioxidant, and vitamin K promotes coagulation. Like vitamins, minerals contribute to essential roles in the body and must be obtained from the diet, but unlike vitamins, minerals are inorganic. The most important minerals in the body are calcium, phosphorus, magnesium, sodium, and potassium.

Many coenzymes are vitamins or derivatives of vitamins, and they often contribute to the function of enzymes by carrying certain functional groups from one place to another in a reaction. Perhaps the most well-known example of this is coenzyme A, which transfers acyl groups from one place to another. Coenzymes that are tightly (or even covalently) bonded to their enzyme are known as prosthetic groups. A famous example of an organometallic prosthetic group is heme, which contains an iron ion in the center of a porphyrin ring, and is attached to oxygen-transport proteins such as hemoglobin and myoglobin.

Reduction and oxidation (redox) reactions are often studied in the context of electrochemistry, generally focusing on reactions involving ionic compounds. However, reduction is defined as a decrease in the oxidation state of an atom, while oxidation is defined as an increase in the oxidation state of an atom, and these definitions can also be applied to reactions containing organic compounds. The following features are associated with reduction in organic chemistry: (1) gain of an electron, (2) decreased oxidation state, (3) formation of a C-H bond (e.g. alkene → alkane), and (4) loss of a C-O or C-N bond (or any bond between carbon and an electronegative atom). Conversely, oxidation is associated with (1) loss of an electron, (2) increased oxidation state, (3) loss of a C-H bond (e.g. alkane → alkene), and (4) gain of a C-O or C-N bond (or any bond between carbon and a highly electronegative atom). ]

Oxygen-containing organic compounds exist on a spectrum of oxidation from alcohols (most reduced/least oxidized) to aldehydes/ketones (intermediate reduction/oxidation) to carboxylic acids (least reduced/most oxidized). A primary alcohol can be oxidized to an aldehyde by a mild oxidizing agent (such as PCC) or to a carboxylic acid by a strong oxidizing agent like NaCr2O7. A secondary alcohol will be oxidized to a ketone by either a mild or a strong oxidizing agent. A strong oxidizing agent will likewise oxidize an aldehyde to a carboxylic acid. A strong reducing agent, such as LiAlH4, can reduce a carboxylic acid directly to an alcohol, while weak reducing agents such as NaBH4 will not reduce carboxylic acids at all. A special agent, DIBAL, can reduce a carboxylic acid to an aldehyde when applied at a precise 1:1 ratio. Both mild and strong reducing agents can reduce aldehydes and ketones to primary and secondary alcohols, respectively.

Important information

Subject Physics Topic Applications of Force, Energy Difficulty Tough AAMC Content Category 5B. Nature of molecules and intermolecular interactions Passage Relationship Pseudo-discrete Reasoning Skill Skill 2. Scientific Reasoning and Problem-solving Question 33 In the passage, the researchers attempted to model chemical bonds and intermolecular forces as springs. Suppose the chemical potential energy in a single disulfide bond was modeled as elastic potential energy stored in a stretched 10 Å spring, with a spring constant of 2 N/m. What would the length of the stretched spring be? (A disulfide bond has a bond dissociation enthalpy of 54 kJ/mol.) A. 3 x 10-13 m Show Explanation B. 3 x 10-10 m This answer choice results from a miscalculation. C. 1.3 x 10-9 m To tackle this question, we first need to figure out how much chemical potential energy is contained in a single disulfide bond. To do this, we have to divide the value of 54 kJ/mol by Avogadro's number. We will round Avogadro's number to 6 × 1023 to make the math a little easier: 54 kJ/mol / 6 × 1023 bonds/mol = 9 × 10-23 kJ/bond = 9 × 10-20 J/bond Recall that elastic potential energy has the following equation: PE (spring) = ½ kx2 where k is the spring constant and x is the displacement in the spring. We can rearrange this equation to isolate for the displacement: Now we'll substitute our values into this equation: But don't forget, we have to find the total stretched length of the spring. The passage tells us that 1 Å = 10-10 m, so our spring has a length of 10-9 m. Summing that value and the displacement of the spring gives us a grand total of 1.3 x 10-9 m for the length of the stretched spring. D. 2.3 x 102 m Show Explanation 9.54% A 35.62% B 38.42% C 16.41% D Your answer was incorrect. 38.42% of students answered this question correctly. Content Foundations: Springs Springs are devices made from elastic material that store energy when compressed. The most important thing to understand about springs for the MCAT is that the potential energy stored in a spring can be expressed as PEelastic = ½kx2,

In the ETC, the energy released from the series of electron transfers is used to pump H+ across the membrane. The unequal concentrations of H+ ions across the membrane establishes an electrochemical gradient, leading to chemiosmosis, or the passive diffusion of the protons down their concentration gradient, which is coupled to ATP synthase. This proton movement generates 90% of the ATP synthesized during oxidative phosphorylation.

The electrons passing through the electron transport chain gradually lose energy until eventually they are donated to O2, which accepts two H+ ions and is transformed into water. If the proton gradient is disrupted or destroyed, chemiosmosis can become uncoupled from the ETC, resulting in little to no ATP generation despite the transfer of electrons carrying on. Many poisons and toxins act by uncoupling the proton gradient from ATP synthase.

Eustress: Good stress; any stressor that motivates an individual toward an optimal level of performance or health. Neustress: Any kind of information or sensory stimulus that is perceived as unimportant or inconsequential. Distress: Eustress: Good stress; any stressor that motivates an individual toward an optimal level of performance or health. Neustress: Any kind of information or sensory stimulus that is perceived as unimportant or inconsequential.S

Types of stress

Paul Ekman described seven universal human emotions:

anger, contempt, disgust, fear, happiness, sadness, and surprise.

Question 44 If private social media posts, intended for friends, were used as evidence to create a negative image of an individual during the course of a criminal trial, this would represent an example of: B. front-stage communication becoming back-stage communication. This is the opposite of the correct answer. C. communication taking place in two front-stage regions. Show Explanation D. communication taking place in two back-stage regions. Show Explanation

back-stage communication becoming front-stage communication. The passage describes two regions: "the front stage, where performance can takes place, and [the] back stage, where the performer is out-of-character and comfortable." As it is defined by the passage, a defendant's private social media post, intended for friends, would constitute communication occurring on the back stage. Communication shared with a jury in a courtroom would constitute front-stage communication.

self monitoring

being attuned to the way one presents oneself in social situations and adjusting one's performance to create the desired impression

ldl

low density lipoprotein (bad cholesterol) Low-density lipoprotein (LDL) transports cholesterol to the tissues that need it. In contrast, high-density lipoprotein (HDL) transports cholesterol, as well as other lipids, away from the tissues, to the liver for processing and excretion. Cholesterol returned to the liver may be processed into bile. In clinical contexts, LDL may be described as "bad cholesterol" and HDL as "good cholesterol." From a strictly biochemical point of view, this is a misconception. LDL and HDL are transporters, not different types of cholesterol, as there is only one type of cholesterol. The reason for this description is that LDL levels are directly associated with an increased risk of developing cardiovascular disease, whereas HDL levels show an inverse association with cardiovascular risk.

continuous reinforcement

reinforcing the desired response every time it occurs

rna primer

short segment of RNA used to initiate synthesis of a new strand of DNA during replication