USABO Practice Exam With 100% Correct Answers 2024, Exams of Advanced Education

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USABO Practice Exam With 100%

Correct Answers 2024

What enzyme does HIV use to convert RNA to DNA? - Correct Answer-Reverse Transcriptase The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site for ______. - Correct Answer-5'...RNA polymerase Which of the following is TRUE of prokaryotes? I. Simultaneous transcription and translation II. Presence of intron sequences III. Circular DNA - Correct Answer-I and III only Integral transmembrane proteins are proteins imbedded in the cell membrane. Which of the following amino acids would you MOST expect to find in the transmembrane region of such proteins? - Correct Answer-Tryptophan When the base composition of DNA from bacterium Mycobacterium tuberculosis was determined, 18% of the

bases were found to be adenine. What is the G + C content in M. tuberculosis? - Correct Answer-64% The frequency of individuals affected with an autosomally recessive inherited disorder is 1 in 4. Assuming that the population affected by this disease is in Hardy-Weinberg equilibrium, what is the proportion of carrier individuals in this population? - Correct Answer-50% The velocity of action potential conduction across a nerve axon is increased by the presence of the myelin sheath. In the peripheral nervous system, what cell myelinates the axon? - Correct Answer-schwann cell The cell bodies of afferent (sensory) nerves involved in somatic reflexes are located in the - Correct Answer-Dorsal root ganglion Rods and cones are associated with _____ and _____ vision, respectively. - Correct Answer-Light/dark...color

Which of the following is NOT a characteristic of all chordates?

• Correct Answer-vertebrae In cardiac muscle, calcium ions can move freely between adjacent cells through which of the following? - Correct Answer-gap junctions Unlike most polypeptide hormones, steroid hormones are unique in that they - Correct Answer-Diffuse across cell membranes In superoxide dismutase 1, an enzyme implicated in amyotrophic lateral sclerosis (Lou Gehrig's disease), a copper ion is bound to the active site and is important for enzyme activity. In this enzyme, copper most likely functions as a(n) - Correct Answer-cofactor The order of normal blood flow through the human heart is - Correct Answer-right atrium, right ventricle, lungs, left atrium, left ventricle, body

Allopatric speciation refers to species formed after which type of separation: - Correct Answer-geographic Which two functional groups are always found in amino acids?

• Correct Answer-Carboxyl and amine Movement of ions across the membrane from higher to lower concentrations through a channel protein is an example of - Correct Answer-Facilitated diffusion Which group of plants has vascular tissue but does not produce seeds? I. Mosses II. Ferns III. Gymnosperms - Correct Answer-II Which of the following is true for transport in xylem? - Correct Answer-Movement through xylem depends mainly on transpiration

III. Earth's magnetic field - Correct Answer-I,II, and III Generally, there are more species per square kilometer in which of the following types of ecosystem? - Correct Answer- Coral reef RUBP is used and PGA is formed in: - Correct Answer-dark reaction (Calvin cycle) of photosynthesis Which is TRUE of the dark reaction (Calvin cycle) of photosynthesis? - Correct Answer-It uses carbon dioxide In the fern life cycle, the dominant generation is the: - Correct Answer-diploid sporophyte Assume a person is placed on cortisol medication, a glucocorticoid. How would you expect the rates of ACTH and CRF hormone production to change in the person? - Correct Answer-ACTH production would decrease, CRF production would increase

Carbon particles were injected into the blood of mice. In which of the following places would you most likely find the particles? - Correct Answer-In monocytes of the spleen Kidneys provide osmoregulation for the body. Consumption of which nutrient creates the greatest need for osmoregulation?

• Correct Answer-Protein During translation in prokaryotes, the ribosome binds to: - Correct Answer-the Shine-Dalgarno sequence The quaternary structure of a protein is determined by: - Correct Answer-.interactions between amino acids of different polypeptide chains. Which of the following is not a function of the parasympathetic division of the nervous system? - Correct Answer-. Stimulation of the adrenal medulla You place a growing seedling in an east-facing window. On which side of the plant will active auxin accumulate? - Correct Answer-West side

Tobacco mosaic virus has RNA rather than DNA as its genetic material. If the RNA genome from a tobacco mosaic virus is mixed with proteins from a human rhinovirus, the result is a mixed virus. If that virus could infect a cell and reproduce, what would you expect the resulting viruses to be like? - Correct Answer-Tobacco Mosaic Virus An amphipathic molecule is a molecule that is characterized by: - Correct Answer-A hydrophilic end and a hydrophobic end The function of a molecular chaperone is to - Correct Answer- bind to specific structures on the polypeptide in order to assist the folding of a protein into its correct three dimensional shape. Ethidium Bromide is used in electrophoresis of DNA fragments because it: - Correct Answer-makes the fragments visible under UV light. The species Homo sapiens first appeared in which geologic epoch? - Correct Answer-Pleistocene

Which of the following marine communities would be LEAST affected by a volcanic eruption or meteor impact that injected enough debris into the atmosphere to reduce sunlight by 50% for two years? - Correct Answer-Deep sea vent community A unique feature of fertilization in angiosperms is that: - Correct Answer-it is a double fusion event; one sperm fertilizes the egg, the other sperm combines with the polar or fusion nucleus. Which statement describing plant structure is appropriate? - Correct Answer-Sclerenchyma cells provide support for the plant body The Hardy-Weinberg equilibrium principle assumes all of the following statements EXCEPT: - Correct Answer-. for a given trait the frequency of dominant alleles is greater than that of recessive alleles. Professor Jones is running an experiment with his graduate students in his physiology lab. One group of students drinks a liter of water, another group drinks a liter of coffee, and a third group drinks a liter of concentrated salt solution. The volume of urine produced by all individuals in the three

A toxin exists that inhibits the enzyme succinate dehydrogenase. If this were used in an experiment to stop respiration, how many net NADH and ATP molecules would be generated from each pyruvate molecule during pyruvate oxidation and the citric acid cycle up to that stage? - Correct Answer-3, 1 Which of the following characteristics is an adaptation of temperate climatic zone plants? - Correct Answer-Dormant buds Which of the following statements is acceptable? - Correct Answer-A long day plant will flower if it has over a half day of darkness interrupted by a short flash of light Which of the following is NOT a second messenger? - Correct Answer-Magnesium ion The reduction phase of the Calvin cycle is equivalent to which of the following processes in reverse? - Correct Answer-Energy payoff phase of glycolysis

Which of the choices below correctly ranks [from least to greatest] the contribution of the various ecosystems as to their "Average Net Primary Production per unit area (kcal/m2/yr)"? - Correct Answer-Open ocean, savanna, temperate forest, tropical rain forest In most terrestrial mammalian species, parental investment is greater for female parents than for male parents. This is because: - Correct Answer-females are typically 'K-selected', whereas males are more often 'r-selected'. Which of the following is part of the egg-producing structure in plants? - Correct Answer-The megagametophyte of angiosperms A booster dose of a vaccination helps to: - Correct Answer- increase the blood antibody level by increasing the number of effector cells. In mice, one gene regulates color. Homozygous recessive organisms are white, homozygous dominant organisms are black, and some organisms exhibit incomplete dominance (gray fur). A gray male and a gray female produce an offspring

Plant systematicists have found that monocots were not the first flowering plants to evolve. This would suggest that: - Correct Answer-evolution does not always proceed from simple to complex. In a certain population of 100 deer, 34 births and 25 deaths were recorded in one year. Assuming no immigration or emigration occurred, what is r for that population? - Correct Answer-0. A patient is suffering from kidney failure. Which of the following symptoms will most likely be present in this patient? - Correct Answer-A higher salt concentration in the blood An investigator found 150 different diatom species in one mile of a stream. None of the species comprised more than 5% of the total population. In a second observation twenty-five miles downstream, there were only 20 different diatom species, with 2 species representing 80% of the total population. What is the best explanation of these two observations? - Correct Answer-Organic wastes high in nitrates and phosphates entered the stream somewhere between the two sampling stations

Which of the following statements is an acceptable statement about growth in plants? - Correct Answer-Some plants lack secondary growth ATP is an important molecule in metabolism because it: - Correct Answer-has high-energy phosphate bonds. Crossing over contributes to the genetic variation of a species by exchanging chromosomal segments between nonsister chromatids of homologous chromosomes. In the production of which type of cell does the crossing over occur? - Correct Answer-Gametes In a population of 15 AA, 25 Aa, and 10 aa individuals, the frequency of the a allele is: - Correct Answer-0. Use the cladogram below to answer the following question. Which group(s) represent(s) a monophyletic taxon? (number 47 on 2004 exam) - Correct Answer-A, B, C, D, E, F, and G A ribozyme is a(an): - Correct Answer-RNA molecule that functions as a enzyme.

indistinguishable from homozygous dominants. What percentage of this population is probably heterozygous for the fur color trait assuming the rats are following Hardy-Weinberg population genetics? - Correct Answer-42% In Pompe's disease, the liver is damaged due to the accumulation of glycogen. What organelle is most likely malfunctioning? - Correct Answer-lysosome Transport of which nutrient across the intestinal epithelium is by passive diffusion? - Correct Answer-fructose Which two brain centers control mammalian respiration? - Correct Answer-medulla oblongata and pons The presence of a vertebral column is with respect to all vertebrates [first term], but is with respect to all chordates [second term]. - Correct Answer-primitive; derived The main explanation for the lack of a continuing abiotic origin of life on Earth today is that: - Correct Answer-our oxidizing atmosphere is not conducive to spontaneous formation of complex molecules

Scientists have determined that three classes of genes (named A, B, and C) control development of the four flower parts: Sepals, Petals, Stamen, and Carpels. Genes A and C mutually repress each other. Gene B is not regulated by either Genes A or C. The expression pattern of these genes in wild-type flowers is shown below, where +++ indicates gene activity. A mutation in Gene C, which prevents its expression, will result in which of the following floral patterns? (question 8 of 2005 exam) - Correct Answer-Sepals-Petals-Petals-Sepals An inbred strain of plants has a mean height of 24 cm. A second strain of the same species also has a mean height of 24 cm. When these plants are crossed, the F1 are also 24 cm. However, when the F1 plants are crossed, the F2 plants show a wide range of heights; the majority of F2 are like P1 and F1, but approximately 4 of 1000 are only 12 cm tall and 4 of 1000 are 36 cm tall. What fraction of the F2 plants will be 27 cm in height? [Assume that for the genes involved in determining plant height, each allele contributes the same amount.] - Correct Answer-56/ To be functional, a linear chromosome most often contains at least: - Correct Answer-two telomeres, one centromere, and a large number of origins of replication