Under what circumstances does membrane transport require energy?
A) wherever large molecules are moved within a cell
B) whenever a solute is moved against its electrochemical gradient
C) whenever an ion moves through a phospholipid bilayer membrane
D) whenever oxygen moves through a phospholipid bilayer membrane
Answer: B
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Radioisotopes are useful when
A) very high sensitivity is required. B) turnover rates need to be determined. C) the fate of portions of particular molecules need to be followed. D) very high sensitivity is required, turnover rates need to be determined, and the fate of portions of particular molecules need to be followed.
Inflammation is a nonspecific defensive reaction to a tissue injury.
Answer the following statement true (T) or false (F)
Amphibians have
a. a two-chambered heart. b. a three-chambered heart. c. a four-chambered heart. d. none of the above.
Independent ______ occurs because each pair of homologous chromosomes separate independently of the others.
a. conjugation b. linkage c. assortment d. differentiation e. segregation