mcat practice question mix
The elastic potential energy of the compressed spring, (1/2)kx^2, is converted to the kinetic energy,
(1/2)mv2, of the bullet. Setting (1/2)kx2 equal to (1/2)mv2, we find that k = mv^2/x^2.
protic solvent examples
- carboxylic acids - ammonia/amines - water/alcohols
Transduction in bacteria
...type of bacterial recombination (create genetic diversity) in which there is an exchange of bacterial DNA through bacteriophages - viruses that infect bacteria. There are two types of transduction: generalized and specialized transduction.
What is the configuration of the electrons in the valence shell of a chloride anion?
3s23p6
Stearic acid (or octadecanoic acid) is a saturated fatty acid with the formula CH3(CH2)16COOH After undergoing β-oxidation, it will generate:
9 acetyl-CoA, 8 NADH and 8 FADH2. Stearic acid has 18 carbons and so will undergo 8 rounds of β-oxidation. This will generate 9 molecules of acetyl-CoA molecules of NADH and 8 molecules of FADH2
Cell membrane (plasma membrane)
A cell structure that controls which substances can enter or leave the cell. Small and nonpolar (hydrophobic) molecules can freely pass through the membrane, but charged ions and large molecules such as proteins and sugars are barred passage. The plasma membrane is selectively permeable; hydrophobic molecules and small polar molecules can diffuse through the lipid layer, but ions and large polar molecules cannot. Integral membrane proteins enable ions and large polar molecules to pass through the membrane by passive or active transport.
If a neutralization similar to Trial 2 were performed with the same molar values of NaOH and acetic acid, which of the following results is the most likely to occur?
A lower temperature due to a smaller |ΔH|
A researcher obtains a sample of recombinant mutant isocitrate dehydrogenase and wants to confirm its activity in vitro. To do this, she could:
Add a-ketoglutarate as the substrate and analyze reaction completion via 1H NMR
Which of the following statements best supports why two equivalents of hydroxide are used in the basic hydrolysis of dichorine monoxide in Reaction 1?
Adding only one equivalent will lead to the formation of a buffer solution of hypochlorous acid and its conjugate base, and therefore an incomplete reaction.
Which of the following describes the most likely mechanism by which gemcitabine inhibits DNA synthesis?
After addition to the growing DNA strand, gemcitabine's atypical structure inhibits DNA polymerase's recognition of the growing strand. according to the passage, gemcitabine is a nucleoside analog, with 2 fluorine atoms at the 2' position. Because the 5' end of gemcitabine is unaltered, it can be added onto the growing DNA strand. The presence of the abnormal fluorine atoms, however, will prevent DNA polymerase from adding additional nucleotides
Based on the TTSP results described in the passage, how might the researchers explain a given participant's high number of total errors?
Atrophy of the frontal lobe As described in the passage, the TTSP, or Test of Task-Switching Proficiency, measures task-switching ability. The passage states that TTSP performance was negatively correlated with the number of total errors, which means that, as TTSP performance decreased, the number of total errors increased. researchers might attribute a high number of errors to atrophy, or deterioration, of the frontal lobe
What trends should be expected for the deviations from ideal gas behavior when comparing F2(g) to Cl2(g) to Br2(g)?
Both negative and positive deviations of the curves will increase at low and high pressures, respectively. As stated in the passage, positive deviations from ideal behavior are caused by increasing molecular volume, while negative deviations are caused by increasing intermolecular forces. As you go down the halogen family atomic size increases, so we'd expect a greater deviation from ideal behavior in the positive direction on the graph from F to Cl to
Most biological unsaturated fatty acids are cis and contain non-conjugated double bonds. Because of this, additional steps are required in β-oxidation. These most likely include:
Combining two double bonds via a reductase enzyme (which uses NADPH as a reducing agent), then changing the resultant cis double bond to trans via an isomerase enzyme
If one woman in a small and isolated Korean village fell ill with shin-byung, and then her close friend also began experiencing similar symptoms, claiming that she too was being pursued by spirits, which of the following might explain this occurrence regarding the friend?
Conformity followed by private acceptance Conformity, obedience, and compliance are related but distinct terms. Private acceptance is an attitude change that can occur in a person due to the social influence of others. Thus, it is most likely that the friend first conformed to the behavior of the woman initially affected by shin-byung symptoms, then privately accepted the possibility of spirit possession after modifying her behavior
aprotic solvent examples
DMF, DMSO, acetone
A mutation in the thyroid hormone receptor which blocks hormone binding would cause which of the following?
Elevated secretion of TRH thyroid hormone causes feedback inhibition of TRH and TSH secretion. Thyroid hormone receptor is responsible for hormone signaling, including feedback inhibition by thyroid hormone. If thyroid hormone receptor is defective, this will prevent feedback inhibition, causing TRH and TSH levels to become elevated
occur at the placenta
Exchange of CO2 and O2 between fetal and maternal blood
Which of the following statements best explains why fiber-optic cables are used instead of copper wiring in real-time data transmission networks?
Fiber-optic cables transmit data at or near the speed of light, whereas copper wiring does not.
In a facultative anaerobe, which of the following processes occurs under both aerobic and anaerobic conditions?
Glycolysis
Which of the following equilibria could be present in a buffered solution?
H 2 CO 3 ( aq ) Equilibrium arrow H + ( aq ) + HCO 3 - ( aq )
The standard potential for the reaction K+ + e- Equilibrium arrow K(s) equals -2.93 V, as referenced against 2H+ + 2e- Equilibrium arrow H2(set to 0.0 V by definition). If solid potassium is placed into an aqueous solution of HCl, then:
H2(g) and KCl(aq) are produced.
Which of the following methods should be used to purify the mesylate mixture produced from Reaction 1 from any remaining starting material?
HPLC best choice as this form of chromatography would easily quantitatively purify a mesylate from its parent alcohol based on the difference in polarities of these functional groups.
Adiponectin can bind one of three receptors (ADIPOR1, ADIPOR2 or CDH13) at a target cell and this causes activation of AMP-activated protein kinase (AMPK). Which of the following is most likely true?
High adiponectin levels activate AMPK, which stimulates hepatic fatty acid oxidation and ketogenesis The passage says that adiponectin up-regulates catabolic processes (such as fatty acid oxidation), which means it also likely downregulates anabolic processes (such as lipogenesis, cholesterol synthesis and triglyceride synthesis)
After a patient undergoes a bilateral vagotomy for a perforated duodenal ulcer, which of the following recommendations should be made regarding follow-up treatment with omeprazole or another drug in the same class?
It should be prescribed because there are multiple ways of activating second messenger proteins involved in Hal production While bilateral vagotomy decreases vagal (parasympathetic) input to parietal cells and decreases acid secretion, there are at least two other mechanisms by which the H+/K+-ATPase may be stimulated Gastrin and histamine both bind to receptors on parietal cells and activate second messenger cascades that lead to acid secretion
PDC deficiency is a rare genetic disease. Which of the following conditions would be expected in patients with the disease?
Lactic acidosis in PDC deficiency, the pyruvate cannot be converted to acetyl-CoA and therefore, the cells can only undergo glycolysis and anaerobic respiration. The end product of anaerobic respiration in humans is lactic acid. Thus, patients with PDC deficiency have lactic acidosis
HPLC (high performance liquid chromatography)
Most widely used liquid chromatography Fractionation of drugs, hormones, lipids, carbohydrates, and proteins
If the shin-byung syndrome is seen to occur across several generations of families who tend to live very close to one another, often in the same house, which of the following would be the best non-genetic reason for the generational repetition?
Observational learning
Muscle fibers are composed of small contractile units called sarcomeres. During contraction, which of the following occurs within a sarcomere?
Overlap between actin and myosin filaments increases.
characteristic of the Krebs cycle?
Oxaloacetate is combined with acetyl-coA to produce citrate. Most of the energy is produced indirectly through high-energy electron carriers. 6 NADH, 2 FADH2, and 2 GTP are produced per glucose. Only two of the 20 ATP made from the Krebs cycle are from substrate-level phosphorylation.
Trivalent arsenite prevents the regeneration of S-S form of lipoamide. This would immediately block which of the following processes?
Oxidation of lipoamide Reduction of FAD The reduction of FAD is linked to oxidation of lipoamide, thus, it will be blocked.
Barth syndrome is a rare X-linked recessive genetic disorder and is caused by a mutation in the gene coding for tafazzin, an enzyme involved in remodeling of cardiolipin acyl chains. Which of the following is true?
Patients with Barth syndrome commonly suffer from cardiomyopathy and general weakness.
Which of the following is the most likely sequence of events in the infection of E. coli by phage T1?
Production of viral DNA polymerase, replication of viral genome, assembly of infectious virus, translation of viral lysozyme The production of viral DNA polymerase must occur prior to replication of the viral genome since the polymerase is needed to do this (choice A is wrong). The last step must be production of lysozyme since this will lyse the cell, bursting it open and stopping any further activities required to produce infectious virus
Which of the following would be the most effective method to determine if transcription of a gene had been silenced?
RT-PCR RT-PCR uses reverse transcriptase to make cDNA from mRNA. The cDNA can then amplified, and then tested for. This is the only method listed that can be used to test for the presence of mRNA and determine if transcription of the gene is occurring or not
In humans, the fusion of the plasma membranes of a sperm and an ovum is followed first by which of the follo
Release of the second polar body from the fertilized ovum
In which of the following are the acrosomal enzymes synthesized?
Rough endoplasmic reticulum Acrosomal enzymes are located inside a membrane-bound vesicle and are going to be secreted. It is likely that they are processed through the secretory pathway, and to do so they must be synthesized in the rough ER
1-Methylcyclohexanol reacts with HBr to form 1-bromo-1-methylcyclohexane. The mechanism for this reaction is likely to be an:
SN1 reaction Since no double bonds are formed or broken, this must be a substitution reaction.\ The protonated OH group (under acidic conditions) will leave as water to yield a tertiary carbocation, which will be attacked by the bromide ion to give the produc
Object permanence allows human beings to realize that an object continues to exist outside of their perception of it. During which of Jean Piaget's stages does this ability develop?
Sensorimotor Object permanence develops during Piaget's first stage, the sensorimotor stage. During all of the subsequent stages, according to Piaget's theory of cognitive development, children are using the object permanence skill that they previously developed. During the preoperational stage, children think more symbolically as they develop memory and imagination . Next is the concrete operational stage, when children begin to exhibit logical reasoning. This is followed by Piaget's final stage, that of formal operations, when children are able to consider abstract relationships and concepts
Which of the following best describes how the brain determines the location of a sound?
Sound waves reach the ear closest to the source of the sound first, and this difference in timing allows the brain to determine the location of the sound.
The friction present in the ratchet system will have what effect on the experimental results?
The calculated muzzle velocity will be less than the actual muzzle velocity
A person is presented with four unlabeled boxes that are 8, 9, 11, and 12 pounds each and one 10-pound box that is labeled. He first picks up the 10-pound box, followed by the 9-pound box, and says that they are the same weight. He then picks up the 10-pound box, followed by the 11-pound box, and says that they are the same weight as well. However, when he compares the 8 and 10-pound boxes, he notices that the 8-pound box is lighter, and when he compares the 12 and 10-pound boxes, he notices that the 12-pound box is heavier. Which of the following is true in this scenario?
The difference threshold is 2 pounds
Measurements of which of the following would be sufficient to calculate the usable work performed by a mechanical engine?
The power output of the engine and the amount of time the engine was running P = W / t. W = Pt.
Which of the following inhibitors would have no effect on the slope of a Lineweaver-Burk plot?
Uncompetitive Inhibitor An uncompetitive inhibitor leads to an equal decrease in the both the Km and Vmax, leading to a series of parallel lines on a Lineweaver-Burk plo
Which of the following is LEAST likely to lead to social loafing?
Working in cohesive groups
Can glucogenic amino acids be converted into glucose?
Yes: pyruvate and Krebs cycle intermediates can be converted into oxaloacetate, then phosphoenolpyruvate, which can enter gluconeogenesis.
The vitelline layer in sea urchins is analogous to which of the following layers in the human ovum?
Zona pellucida The vitelline layer is analogous to the zona pellucida in human ova, since both are protective acellular layers located just outside the plasma membrane The corona radiata is a region of surrounding supportive cells
An ectopic TSH-secreting tumor is suspected in a hyperthyroidic (high thyroid-hormone concentration) patient with goiter. Administration of a high dose of thyroid hormone confirms this, due to the fact that:
[TSH] in the systemic circulation remains high. in a normal individual, high levels of thyroid hormone would suppress the release of TRH by the hypothalamus and TSH by the anterior pituitary. Injection of even more thyroid hormone should suppress the release of TRH and TSH even further. If this does not occur, and TRH and/or TSH levels remain high, it is likely that something outside the normal axis is involved. The passage states that ectopic tumors do not respond to normal feedback inhibition pathways; so, if an ectopic TSH-secreting tumor were present, the injection of thyroid hormone would not reduce the level of TSH in the system
Fetal circulation differs from adult circulation in many ways. One of the main differences is that in the former:
a pathway exists for blood to circumvent the lungs
A confounding variable is
a variable that cannot be directly measured
Sensitization
an increase in behavioral response after exposure to a stimulus
in Graves disease, thyroid-stimulating immunoglobulins (TSI) contain an active site that can mimic the active site of TSH to stimulate thyroid hormone production. One would expect TSI to cause:
an increase in thyroid gland size because of the trophic effect of TSH. goiter is caused by overstimulation of the thyroid gland by TSH. If TSI mimics TSH, then it would produce the same response: enlargement of the thyroid gland
During the exponential phase of bacterial growth, bacteria are reproducing by:
binary fission
statements regarding enzymes are true
can be stereospecific in substrate recognition are often regulated by feedback inhibition. reduce the activation energy of reactions.
Compliance involves
changing one's behavior in response to a request from another person who is of equal or lower status (thus differing from obedience).
Obedience involves
changing one's behavior in response to the direct command or order of a person who is in authority or is of higher social status.
Hypocalcemia
deficient calcium in the blood
Tautomers are
different forms of an organic molecule, such as a base in DNA.
T3 and T4 most likely exert their effect on target cells by:
diffusing across the cell membrane and binding to a nuclear receptor. the passage states that T3 and T4 are lipid soluble; in fact, although they are peptide hormones, T3 and T4 have the same mechanism of action as the steroid hormone, diffusing through the plasma membrane to bind to an intracellular receptor that goes into the nucleus to regulate transcription
The oocytes used in the research study in passage were:
diploid cells arrested in prophase I. Primary oocytes are arrested in prophase I metaphase I does not occur until a primary oocyte reenters the meiotic cycle after dictyate.
Networks built of copper wiring experience signal degradation. This occurs because copper wires:
dissipate some of the electrical energy that flows through them as heat. Resistivity of a current-carrying component immediately implies dissipation of heat
In Structure 1, the R group is shown in one stereospecific position. However, the carbon bearing the R group is α to a carbonyl. This implies that:
during the synthesis the natural sterics of the ring force a defined stereochemistry All α-hydrogens to carbonyls or acid derivatives are weakly acidic. The enolate formed from deprotonation of an α-hydrogen is trigonal planar, but upon reprotonation the hydrogen can generally approach from either the top or bottom of the π bond, causing racemization at the α-carbon. Therefore all stereochemistry is lost when the neutral carbonyl reforms. However, there is no mention or depiction of a mixture of diastereomers due to racemization at the α-carbon in the passage.
According to self-determination theory, which proposes that people will seek autonomy, competence, and relatedness throughout their lifespans, the oldest participants in the study would most likely:
emphasize that any decisions to limit their respective driving privileges are self-endorsed. Self-determination theory maintains that, throughout the lifespan and especially in older age, people seek autonomy, competence, and relatedness. Autonomy refers to viewing one's circumstances as self-endorsed, while competence refers to the expression of one's talents. Finally, relatedness refers to a sense of being cared about by other people. Therefore, according to this theory, one of the oldest participants in this study would emphasize that a decision to limit his or her driving is self-endorsed
ELISA
enzyme-linked immunosorbent assay (test to detect anti-HIV antibodies)
Hypercalcemia
excessive calcium in the blood
In one case study, the acrosomal process does not extend following fusion of the acrosomal vesicle with the sperm plasma membrane. This could best be explained by the:
failure of intracellular H + concentration to decrease. Following fusion of the acrosomal vesicle, calcium and sodium enter the sperm while potassium and protons exit the sperm. The decrease in H + concentration allows actin to polymerize and the acrosomal process to extend. Failure of the H + concentration to decrease would prevent the acrosomal process from extending
The amphoteric character of amino acids best explains their ability to:
form dipolar ions. the amphoteric character of amino acids describes their ability to do two things: accept a proton or donate a proton. In other words, amino acids can act as either an acid or a base. When the amino portion of an amino acid deprotonates its own carboxylic acid, a dipolar ion (or zwitterion) forms.
(+)-Ginkgolide B is a diterpenoid trilactone with six five-membered rings, and is extracted from the root bark and leaves of the Ginkgo biloba tree. This molecule has blood-brain barrier permeability, the molecular formula C20H24O10 and a molecular weight of 424.4 g/mol. This molecule must contain:
four isoprene units, additional functional groups and is able to perform simple diffusion through endothelial cells connected by tight junctions. Diterpenoids contain four isoprene units The blood-brain barrier is a highly selective permeability barrier that separates the circulating blood from the central nervous system. It is formed by endothelial cells , which are connected by tight junctions
A semipermeable membrane separates an aqueous solution of 0.003 MNaCl from an aqueous solution of 0.0025 MBaF2. With this apparatus, one would observe that water crosses the membrane:
from the NaCl solution to dilute the BaF 2 solution.
contribute to speciation
geographic isolation of populations genetic diversity. natural selection.
total internal reflection occurs when the angle of incidence is
greater than the critical angle
A therapist uses a white noise machine in her office for privacy; the therapist has been using the machine for years and doesn't even notice the sound it makes when it is on. One of her patients finds that noise produced by the white noise machine very irritating; every time he hears it he becomes more and more agitated. The therapist:
has become habituated to the white noise while the patient has become sensitized to it.
Goiter development resulting from iodine deficiency is most likely due to:
high levels of TSH Iodine is required for thyroid hormone production, so in the absence of sufficient iodine, thyroid hormone levels will fall, and feedback inhibition will not occur. TSH and TRH levels will increase, causing goiter
A possible contributor to Alzheimer's disease is the clumping of amyloid proteins formed from the degradation of larger proteins in the fatty tissues surrounding nerve cells. This degradation could be a result of:
hydrolysis of some of the amide peptide linkages, creating smaller polypeptide units.
Decreased secretion of aldosterone has all of the following effects
increased loss of Na + in urine. decrease in extracellular fluid volume. increase in urine volume.
A patient with elevated parietal cell secretions but restricted mucus secretions will most likely exhibit:
increased protein catabolism, a gastric ulcer and a gastric pH that is lower than normal. Parietal cells are found in the stomach and are responsible for producing HCl, which causes the stomach contents to have a low pH. HCl also non-specifically digests proteins by cleaving peptide bonds, and activates pepsinogen. Elevated parietal cell secretions would mean more acid, and a lower gastric pH
Intercalator1 causes mutations in DNA by:
inserting itself between base pairs. Intercalator1 is an intercalating agent; this means it inserts itself between base pairs in DNA
hooke law constant k =
k = YA/I0
Increased intermolecular attractions cause the ratio PV/(RT) to decline because individual molecules:
lose kinetic energy to potential energy and strike the side of the container with less force. intermolecular attractions increase the potential energy between molecules, decreasing their kinetic energy
Children who bully or otherwise harass gender atypical peers likely view them as:
members of an out-group
TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) is a method for detecting DNA fragmentation by labeling the terminal end of nucleic acids. BrdU (5-bromo-2'-deoxyuridine) can also be used in staining protocols, as this synthetic nucleoside can be incorporated into nucleic acids during replication instead of thymidine. Tumor cells have:
minimal TUNEL staining due to their low apoptotic rate, but strong BrdU staining due to active genome replication. Genome fragmentation is one of the hallmarks of apoptosis and tumor cells generally evade apoptosis. This means tumor cells will have minimal TUNEL staining.. Tumor cells have high proliferation rates and so will be actively replicating the genome. This means they will likely display strong BrdU staining
β-oxidation occurs in the
mitochondrial matrix and fatty acid biosynthesis occurs in the cytoplasm. both β-oxidation and fatty acid biosynthesis occur in four steps; fatty acid biosynthesis involves elongation, two redox reactions and a dehydration. β-oxidation involves the reduction of both FAD and NAD+; fatty acid biosynthesis oxidizes two NADPH (generated by the pentose phosphate pathway) to two NADP+ β-oxidation generates acetyl CoA, while fatty acid biosynthesis uses malonyl CoA, which is made from acetyl CoA by acetyl CoA carboxylase.
Conjugation in bacteria
one bacterium transfers genetic material to another through direct contact. During conjugation, one bacterium serves as the donor of the genetic material, and the other serves as the recipient. The donor bacterium carries a DNA sequence called the fertility factor, or F-factor.
Conformity involves
one's behavior in order to fit in with the norms of a particular social group, most typically a group that has a certain level of social importance.
If Trial 2 were performed with 25.0 mL of NaOH instead of 50.0 mL, the resulting solution would have:
pH < 1 Only 0.05 mol of NaOH is added (instead of 0.1 mol). Therefore, only half of the HCl will be neutralized (so [H3O+] > [OH-], less heat is liberated , and the temperature will not increase as much.
The serotonin transporter (or SERT) removes serotonin from the synaptic cleft and recycles it back into the presynaptic cell. It thus terminates the effects of serotonin and this mechanism has been targeted in treatments for alcoholism, clinical depression, obsessive-compulsive disorder, and hypertension. SERT spans the plasma membrane 12 times and is also a
protein with twelve transmembrane domains, each of which is an Alpha-helix with no proline and external hydrophobic residues, stabilized by hydrogen bonds. Membrane transport is mediated by proteins, not phospholipids
Systolic blood pressure approaches 0 mm Hg when it reaches the:
right atrium. Blood from the systemic circulation at the end of its circuit through the body enters the heart through the right atrium, and at this point its pressure is near 0 mm Hg Blood leaves the heart through the aorta on its way to the systemic circulation and is at its highest pressure at that point from the aorta the blood travels through many arteries, and the pressure in these vessels is still high
Which of the following accurately lists the composition of the endoplasmic reticulum, phosphofructokinase and alanine, respectively?
single membrane surrounding a lumen, amino acids linked together by covalent peptide bonds, four different groups on a chiral Alpha carbon the endoplasmic reticulum is an organelle with a single membrane surrounding a lumen Phosphofructokinase is an enzyme of glycolysis, and so is a protein made of amino acids linked together by covalent peptide bonds. Alanine is a chiral amino acid, and so has four different groups on a chiral alpha carbon (
SN2 reaction
solvent aprotic ex DMSO, acetone -bimolecular nucleophilic substitution reactions - only 1 step (concerted reaction) -nucleophile attacks the compound at the same time as the leaving group leaves -Nucleophile actively displaces the leaving group in a backside attack for this to occur, nucleophile must be strong & substrate can't be sterically hindered -concentrations of substrate & nucleophile have role in determining the rate --> rate = k[Nu][R-L] -Position of the substituents around the substrate carbon is inverted
SN1 reaction
solvent polar ex alcohols *unimolecular nucleophilic substitution reactions: 2 steps 1. Leaving group leaves forming a positively charged carbocation (rate limiting step) *The rate of rxn depends only on the concentration of the substrate rate = k [R-L] R-L is the alkyl group containing the leaving group *Anything that accelerates the formation of the carbocation increase the rate of rxn 2. Nucleophile attacks the carbocation (unstable) *results in substitution product
Y= stress/ strain
strain = street/Y
Anti-bullying campaigns, which promote awareness and teach students how to intervene if they witness bullying, have been launched by many educational institutions. These sorts of interventions, which attempt to empower onlookers to stop bullying, work best by undermining:
the bystander effect.
DNA sequencing
the process of determining the precise order of nucleotides within a DNA molecule
The Ka for the first ionization of sulfurous acid (1.7 × 10-2) is significantly larger than the Ka for the second ionization (6.4 × 10-8). A likely explanation for this is that:
the remaining hydrogen atom experiences greater electrostatic attraction after the loss of the first hydrogen ion. After loss of the first proton, the remaining hydrogen is bound to a negatively-charged molecule. Electrostatic attraction between this remaining hydrogen and the negatively-charged molecule would disfavor loss of the second proton, resulting in a smaller K. Therefore, K2 << K1.
In the normal circulation,
the right ventricle pumps blood through the pulmonary artery to the lungs. Blood returns from the lungs to the left atrium and is pumped by the left ventricle through the aorta to the rest of the body. If blood from the left ventricle passes to the pulmonary artery instead of the aorta and is then returned to the left atrium, oxygenated blood will loop around through the pulmonary system without passing to the rest of the body. At the same time, the deoxygenated blood from the systemic circulation will pass to the right atrium, then back out to the systemic circulation through the aorta rather than the pulmonary artery, causing deoxygenated blood to loop through this system
DNA from resistant bacteria in Dish 6 is extracted and placed on agar with phage-sensitive E. coli. After incubation it is determined that these E. coli are now insensitive to phage T1 infection. The most likely mechanism for their acquisition of resistance is:
transformation. The definition of transformation is the process in which naked DNA, not a virus, is taken into a cell and changes the genetic characteristics of that cell.
amino acids that are both ketogenic and glucogenic
tryptophan, threonine, tyrosine, isoleucine and phenylalanine
At physiological pH, the amino acid with the formula C4H7NO4 has:
two deprotonated carboxylic acid groups and is glucogenic
The blood vessel that carries the most highly oxygenated blood in the fetus is the:
umbilical vein. The most highly oxygenated blood would be the blood returning from the point of oxygenation to the systemic circulation. In the adult this would be the pulmonary vein, but the point of oxygenation in the fetus is the placenta, not the lungs. The ductus arteriosus does carry oxygenated blood but is found after the umbilical vein, so it does not carry the most highly oxygenated blood. The umbilical artery carries deoxygenated blood from the fetus to the placenta
Social loafing is a phenomenon
whereby individuals exert less effort on a task when working in a group than they would if working alone.
pancreatic enzymes
• Amylase • Lipase • Prothrombin time digestive proteins found in pancreatic secretions that breakdown all organic nutrients