USABO Open Exam Study Guide Questions And Answers Verified 100% Correct

USABO Open Exam Study Guide Questions And Answers Verified 100% Correct During migrations, some birds use which of the following as reference frameworks? I. The sun II. Constellations III. Earth's magnetic field [ ] A. I only [ ] B. I and II only [ ] C. I and III only [ ] D. I, II, and III - ANSWER -D Generally, there are more species per square kilometer in which of the following types of ecosystem? [ ] A. Temperate grassland [ ] B. Arctic tundra [ ] C. Boreal forest [ ] D. Coral reef - ANSWER -D RUBP is used and PGA is formed in: [ ] A. glycolysis [ ] B. the Kreb's cycle [ ] C. light reaction of photosynthesis [ ] D. dark reaction (Calvin cycle) of photosynthesis - ANSWER -D Which is TRUE of the dark reaction (Calvin cycle) of photosynthesis? [ ] A. It uses oxygen [ ] B. It uses carbon dioxide [ ] C. It produces sucrose [ ] D. Both b and c are correct - ANSWER -B In the fern life cycle, the dominant generation is the: [ ] A. haploid gametophyte [ ] B. diploid gametophyte [ ] C. haploid sporophyte [ ] D. diploid sporophyte - ANSWER –D What enzyme does HIV use to convert RNA to DNA? [ ] A. DNA gyrase [ ] B. RNA polymerase [ ] C. Reverse transcriptase [ ] D. DNA helicase - ANSWER -C Which of the following is TRUE of prokaryotes? I. Simultaneous transcription and translation II. Presence of intron sequences III. Circular DNA [ ] A. I and II only [ ] B. I and III only [ ] C. II and III only [ ] D. I, II, and III - ANSWER -B The promoter region of a prokaryotic gene is located ______ to the gene and is the binding site for ______. [ ] A. 3'...DNA polymerase [ ] B. 3'...RNA polymerase [ ] C. 5'...DNA polymerase [ ] D. 5'...RNA polymerase - ANSWER -D . 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? [ ] A. Lysine [ ] B. Serine [ ] C. Tryptophan [ ] D. Arginine - ANSWER -C Tryptophan (it is non polar and does not have a charge) 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? [ ] A. 12.5% [ ] B. 25% [ ] C. 50% [ ] D. 100% - ANSWER -C 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? [ ] A. Oligodendocyte [ ] B. Astrocyte [ ] C. Schwann cell [ ] D. Microglial cell - ANSWER -Schwann cell Rods and cones are associated with _____ and _____ vision, respectively. [ ] A. Light/dark...color [ ] B. Color...light/dark [ ] C. Near...far [ ] D. Far...near - ANSWER -A In many types of cancer, the function of the p53 gene is lost. Wild-type p53 is MOST likely to be a [ ] A. proto-oncogene [ ] B. tumor suppressor [ ] C. positive regulator of cell cycle progression [ ] D. gene required for DNA replication - ANSWER -B What glycolytic product is shuttled to the mitochondria in aerobic respiration? [ ] A. Acetyl-CoA [ ] B. Fumarate [ ] C. Succinyl-CoA [ ] D. Pyruvate - ANSWER -D Telomerase is responsible for _____ the size of telomeres, and its function is often ____ in carcinogenesis. [ ] A. maintaining ... decreased [ ] B. maintaining ... increased [ ] C. decreasing ... decreased [ ] D. decreasing ... increased - ANSWER -B Which of the following is NOT a mode of natural selection? [ ] A. stabilizing selection [ ] B. sexual selection [ ] C. directional selection [ ] D. diversifying selection - ANSWER -B