Which of the following observations provides the strongest evidence against root pressure being the principal mechanism of water transport in the xylem?
A) Not all soils have high concentrations of ions.
B) Root pressure requires movement of water into the xylem from surrounding cells in the roots.
C) Over long distances, the force of root pressure is not enough to overcome the force of gravity.
D) There is no water potential gradient between roots and shoots.
C
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Bioluminescence is catalyzed by luciferase, which creates light by
A) shunting electrons from FMNH2 to O2, which releases energy in the form of light. B) reversing photosynthesis. C) hydrolyzing ATP. D) reducing LuxR.
Which of the molecules listed in question 5 are involved in transcription?
A. DNA, B. mRNA, C. tRNA, D. Amino Acids
Which of the following describes the events of apoptosis?
A) The cell dies, it is lysed, its organelles are phagocytized, and its contents are recycled. B) The cell's DNA and organelles become fragmented, the cell dies, and it is phagocytized. C) The cell's DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell's parts are packaged in vesicles that are digested by specialized cells. D) The cell's nucleus and organelles are lysed, then the cell enlarges and bursts.
What are NOD proteins?
A) cytoplasmic receptors of microbial molecules B) cellular signals triggering inflammation C) receptors of microbial molecules in phagocyte cell membranes D) activators of complement E) chemotactic factors