Which of the following does NOT require the
participation of a membrane protein?
a. active transport
b. exocytosis
c. facilitated diffusion
d. simple diffusion
e. all of these require a protein
Answer: d
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Plastoquinone (PQ), an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably _____
A) mobile in the thylakoid membrane B) lipid soluble C) a molecule that serves as a shuttle between the electron transport chain and ATP synthase D) both lipid soluble and a molecule that serves as a shuttle between the electron transport chain and ATP synthase
You ignore the garden the second summer. The sunflowers thrive but they are surrounded by grassy weeds. It is likely that the weeds are ___________ plant species
A. r-selected B. K-selected C. keystone D. All of the responses are correct. E. None of the responses is correct.
Phosphofructokinase (PFK) is an enzyme that converts fructose 6-phosphate to fructose 1,6-bisphosphate, by adding a phosphate group. This is the first committed step of the metabolic pathway of glycolysis, and thus it is very tightly regulated. AMP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and stimulates the formation of fructose 1,6-bisphosphate. ATP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and inhibits the formation of fructose 1,6-bisphosphate. There are other regulators of this enzyme as well. What is the role of AMP in this example?
A. Catalyst B. Noncompetitive inhibitor C. Allosteric inhibitor D. Competitive inhibitor E. Allosteric activator
Evaporation from the leaves of a tree will pull water up through the roots as an unbroken column throughout the entire height of the tree. This feat is possible because of which characteristic of water?
A) surface tension B) cohesion C) absorption D) kinetic energy E) vaporization