Cells can increase their responsiveness to an external chemical regulator by
A. increasing the number of their transmembrane receptors by exocytosis.
B. decreasing the number of their transmembrane receptors by endocytosis.
C. uncoupling their receptors from the second message generator.
D. increasing the number of their transmembrane receptors by endocytosis.
E. mutating their extracellular receptors so that the affinity for the chemical regulator is reduced.
A
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What will be an ideal response?
Why does running downhill tend to increase running speed?
A. increased stride length B. increased stride frequency C. both A and B D. none of the above
Answer the following statements true (T) or false (F)
1. Capillary blood pressure and plasma protein concentration have the opposite effects on interstitial fluid. 2. If plasma volume drops drastically, adequate circulation cannot be maintained. 3. Dehydration and overhydration occur in about equal frequency. 4. Prolonged vomiting can result in dehydration. 5. Middle-aged adults are at the greatest risk for dehydration caused by diarrhea.
All of the following are true concerning enzymes except that they
A) are proteins.
B) function as biological catalysts.
C) lower the activation energy required for a reaction.
D) affect only the rate of a chemical reaction.
E) are consumed during the reaction.