USABO Practice Questions with Verified Solutions

USABO Practice Questions with Verified Solutions What enzyme does HIV use to convert RNA to DNA? Reverse Transcriptase The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site for ______. 5'...RNA polymerase Which of the following is TRUE of prokaryotes? I. Simultaneous transcription and translation II. Presence of intron sequences III. Circular DNA 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? 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? 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? 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? schwann cell The cell bodies of afferent (sensory) nerves involved in somatic reflexes are located in the Dorsal root ganglion Rods and cones are associated with _____ and _____ vision, respectively. Light/dark...color Populations that are likely to be living at a density near the limit of their resources, are characterized as K-selected In many types of cancer, the function of the p53 gene is lost. Wild-type p53 is MOST likely to be a tumor suppressor What glycolytic product is shuttled to the mitochondria in aerobic respiration? Pyruvate During human development, which process leads to the formation of three germ layers? gastrulation Telomerase is responsible for _____ the size of telomeres, and its function is often ____ in carcinogenesis. maintaining ... increased Which of the following is NOT a mode of natural selection? sexual selection Protostomes have _____ and _____ types of cleavage. spiral ... determinate Which of the following is NOT a characteristic of all chordates? vertebrae In cardiac muscle, calcium ions can move freely between adjacent cells through which of the following? gap junctions