When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as
a. facilitated diffusion
b. osmosis
c. active transport
d. pinocytosis
e. the work of an ion pump
Answer: a. facilitated diffusion
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Which of the following distinguishes bacterial
flagella from those of eukaryotes? a. number per cell and structure b. structure and mechanism of movement c. function and mechanism of movement d. number per cell and mechanism of movement e. number per cell and function
Which neurotransmitter may function to regulate emotions and is involved in pathways that control complex movements?
A) dopamine B) serotonin C) norepinephrine D) synapse
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. noncompetitive inhibitor B. allosteric inhibitor C. catalyst D. competitive inhibitor E. allosteric activator
The fluid that covers the brain and spinal cord is ____.
A. part of the meninges B. part of a rapid type of nerve conduction C. involved in reflex actions D. involved in the "jumping" of impulses E. called cerebrospinal fluid