During neuronal signaling, a change in membrane potential will cause sodium channels to open and let Na+ ions diffuse down their concentration gradient into the cell. Which of the following helps establish the concentration gradient necessary for this process to occur?
A. voltage-gated Na+ channel
B. Na+/K+ channel
C. Na+ symporter
D. Na+/K+ pump
Answer: D
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Which of the following does not occur when antidiuretic hormone is present?
A. Water diffuses into the collecting duct from the interstitial fluid. B. The collecting duct walls become permeable to water. C. Aquaporins insert in the membrane of the collecting duct cells. D. The urine in the collecting duct becomes more concentrated. E. All of these events occur when antidiuretic hormone is present.
Lysosomal storage diseases are the result of deficiencies in lysosomal proteins. An example of one such disorder is
A) adult-onset diabetes. B) tuberculosis. C) Huntington's disease. D) chronic fatigue syndrome. E) Tay-Sachs disease.
Which portion of the stomach is connected to the duodenum?
a. esophagus b. body c. gall bladder d. pyloric sphincter e. gastroesophageal sphincter
When a root is placed on its side, what happens to the amyloplasts in the root cap cells?
a. They move away from the direction of gravity. b. They settle in the direction of gravity c. They are digested by amylase. d. They move into the root apical meristem. e. They move into a root hair.