How is glucose involved in catabolite repression of the lac operon?
A) Glucose causes cAMP levels to increase, which leads to increased CRP binding and the lac operon is activated even when lactose is present.
B) Glucose causes cAMP levels to decrease, which leads to decreased CRP binding and the lac operon is repressed even when lactose is present.
C) Glucose is also a substrate for ?-galactosidase and thus competes with lactose for this enzyme.
D) Glucose activates transcription of the lacI gene to increase the amount of Lac repressor in the cell.
B) Glucose causes cAMP levels to decrease, which leads to decreased CRP binding and the lac operon is repressed even when lactose is present.
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Knockout experiments involving __________ genes in fruit flies (Drosophila melanogaster) revealed local controls
over gene expression. Fill in the blank(s) with the appropriate word(s).
Alligators excavate holes in the bottom of bodies of water. During times of severe drought these holes act as refugia for various aquatic organisms that might perish if there were no water available. Thus, alligators in this system can be classified as a(n)
A. keystone species. B. symbiotic species. C. sympatric species. D. allopatric species. E. refugistic species.
When glass fractures, the first lines that appear on the side opposite the impact are the _________.
Fill in the blank(s) with the appropriate word(s).
The energy transformation pathways of cellular respiration and photosynthesis are related in which of the following ways?
a) Photosynthesis is the energy-releasing stage and cellular respiration is the energy-acquiring stage. b) Photosynthesis is the energy-acquiring stage and cellular respiration is the energy-releasing stage. c) Photosynthesis produces glucose and oxygen while cellular respiration produces carbon dioxide and water. d) Photosynthesis requires carbon dioxide and water while cellular respiration requires oxygen and glucose. e) b), c), and d) are correct.