Explain why myosin II in a sarcomere can produced force only for that sarcomere contraction and not for that sarcomere extension
What will be an ideal response?
Answer: In each half sarcomere, myosin heads on each end of a bipolar filament can step only toward the actin thin filament plus end, which is anchored to the Z line on that end of the sarcomere. This causes contraction of the sarcomere. To generate force for sarcomere extension, myosin II heads would need to produce force by stepping toward the minus end of the actin filament, which only myosin VI (of the myosins described in the text) is capable of.
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In nature, what is the order of events in processing the product of the gene for insulin?
A) cleavage of 35 amino acids from the middle of the polypeptide to make two chains that are then joined by disulfide bonds B) cleavage of 24 amino acids from the N terminus to form proinsulin that is subsequently cleaved to make A and B chains C) removal of 5? leader sequence from the mRNA, and splicing out of a large central intron to produce the mRNA that codes for the final form of polypeptide D) removal of large mRNA sequences by RNA editing, followed by splicing of the products of the two insulin genes E) transcription of the two insulin genes A and B, translation, and posttranslational joining of the two polypeptides
Compare and contrast the processes of photosynthesis and aerobic respiration. How are they similar and how do they
differ? What will be an ideal response?
Which of the following lipids is the primary component in cell membranes?
A) glycerol B) triglycerides C) steroids D) phospholipids
During which of the phases of cellular respiration is the majority of ATP formed?
A. Krebs cycle B. processing of pyruvic acid for the Krebs cycle C. glycolysis D. electron transport E. All phases produce the same number of ATP molecules.