USABO Practice Questions with Complete Solutions (Latest 2025) What enzyme does HIV use to convert RNA to DNA? - Correct Answers ✅Reverse Transcriptase The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site for ______. - Correct Answers ✅5'...RNA polymerase Which of the following is TRUE of prokaryotes?
- Simultaneous transcription and translation
- tuberculosis? - Correct Answers ✅64%
II. Presence of intron sequences III. Circular DNA - Correct Answers ✅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 Answers ✅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
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 1 / 4
USABO Practice Questions with Complete Solutions (Latest 2025) equilibrium, what is the proportion of carrier individuals in this population? - Correct Answers ✅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 Answers ✅schwann cell The cell bodies of afferent (sensory) nerves involved in somatic reflexes are located in the - Correct Answers ✅Dorsal root ganglion Rods and cones are associated with _____ and _____ vision, respectively. - Correct Answers ✅Light/dark...color Populations that are likely to be living at a density near the limit of their resources, are characterized as - Correct Answers ✅K-selected In many types of cancer, the function of the p53 gene is lost.Wild-type p53 is MOST likely to be a - Correct Answers ✅tumor suppressor What glycolytic product is shuttled to the mitochondria in aerobic respiration? - Correct Answers ✅Pyruvate 2 / 4
USABO Practice Questions with Complete Solutions (Latest 2025) During human development, which process leads to the formation of three germ layers? - Correct Answers ✅gastrulation Telomerase is responsible for _____ the size of telomeres, and its function is often ____ in carcinogenesis. - Correct Answers ✅maintaining ... increased Which of the following is NOT a mode of natural selection? - Correct Answers ✅sexual selection Protostomes have _____ and _____ types of cleavage. - Correct Answers ✅spiral ... determinate Which of the following is NOT a characteristic of all chordates? - Correct Answers ✅vertebrae In cardiac muscle, calcium ions can move freely between adjacent cells through which of the following? - Correct Answers ✅gap junctions Unlike most polypeptide hormones, steroid hormones are unique in that they - Correct Answers ✅Diffuse across cell membranes 3 / 4
USABO Practice Questions with Complete Solutions (Latest 2025) 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 Answers ✅cofactor The order of normal blood flow through the human heart is - Correct Answers ✅right atrium, right ventricle, lungs, left atrium, left ventricle, body Allopatric speciation refers to species formed after which type
of separation: - Correct Answers ✅geographic
Which two functional groups are always found in amino acids? - Correct Answers ✅Carboxyl and amine Movement of ions across the membrane from higher to lower concentrations through a channel protein is an example of - Correct Answers ✅Facilitated diffusion Which group of plants has vascular tissue but does not produce seeds?
- Mosses
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II. Ferns III. Gymnosperms - Correct Answers ✅II