Which of the following statements are not true of the relationship of xylem and phloem?
A. Water exiting the phloem may enter the
xylem and be transported to leaves.
B. The volume of water moving through the
phloem is small compared to that in the
xylem.
C. The number and size of xylem conduits
greatly exceeds the number and volume of
sieve tubes.
D. In phloem, the plant actively generates the
force that drives transport, whereas
movement in xylem is largely driven by
transpiration.
E. Phloem cells are dead at maturity,
whereas xylem cells are alive at maturity.
E
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Which of the following is true of protein-based plant chemical defenses?
A. Plants and animals use the same 20 amino acids to construct proteins, but some plants have additional amino acids. B. Plants use the additional amino acids in their proteins, but animals that ingest them cannot. C. Insect herbivores that consume nonprotein amino acids grow more quickly and live longer. D. Plants can produce protease inhibitors, which bind to the active site of enzymes that break down proteins and enhance their activity. E. Insects that feed on plants with protease inhibitors have increased growth rates.
Its defoliant effects were first noticed when it leaked from gas lights; later found to be produced by plants themselves.
Choose the letter of the best match: A. abscisic acid B. auxin C. ethylene D. cytokinin E. gibberellin
If a person uses Percocet, a morphine relative, to which of these drugs might that person develop cross-tolerance?
A) ecstasy B) cocaine C) heroin D) marijuana
During what step of glycolysis are two ATP molecules required?
A. pyruvate formation B. cleavage and rearrangement C. oxidation D. acetyl-CoA formation E. glucose priming