Explain the function of the helicases and why they are necessary
What will be an ideal response?
Answer: Helicase enzymes require energy from ATP to unwind double-stranded DNA into single-stranded (ss) DNA. Its function is necessary during the initiation of DNA synthesis, because the polymerase can operate only on ssDNA as the template.
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You are having lunch with an elderly friend when suddenly he begins to experience chest pain and tightness. He reaches into his pocket, gets out one of his nitroglycerin tablets and quickly takes it. After the episode passes, your friend asks you how the nitroglycerin helps his angina. You explain that nitroglycerin gets converted by cells to nitric oxide (NO) causing the smooth muscle cells of
the blood vessel to relax and increase blood flow to the heart. He pushes you for a more detailed explanation, so you explain further that: A. NO activates guanylyl cyclase, which catalyzes the synthesis of cGMP, which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation. B. NO activates a protein kinase which catalyzes the synthesis of cGMP, which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation. C. NO inhibits guanylyl cyclase, which allows the build up of cGMP, which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation. D. NO activates cGMP, which catalyzes the synthesis of guanylyl cyclase, which acts as an intracellular messenger in a pathway leading to smooth muscle relaxation.
What will be a consequence if current predictions of global warming are accurate?
A. Rates of natural selection will decrease. B. New continental land masses will appear. C. Freshwater will be more widely available. D. Organisms will need to migrate or adapt quickly in order to survive. E. Many plants and animals will become smaller.
Suppose that a mistake made during DNA replication in a cell is not corrected, but instead the
mutation remains in the single strand where it occurred. Then suppose that after the cell divides both daughter cells survive, and those cells then go on to have DNA replication and ultimately cell division. There are now four cells where there once was one cell. Assuming that the mistake was never corrected and that no new uncorrected mistakes occurred, how many of the four cells will have the mutation in their DNA?
a. none b. one c. two d. three e. four
What results would you expect if mitochondria are inherited biparentally?
A) Some, but not all, yeast colonies found on the plate without chloramphenicol will also grow on the plate with chloramphenicol. B) All of the yeast colonies on the plate without chloramphenicol will also grow on the plate with chloramphenicol. C) Many yeast colonies will grow on the plate without chloramphenicol and no colonies will grow on the plate with chloramphenicol. D) No colonies will grow on either plate.