Which of the following statements best describes the effects of caffeine on the body?
A. Caffeine is only water-soluble, not fat-soluble, so it is less likely to be absorbed into the bloodstream.
B. Caffeine is considered a psychoactive drug because it changes brain function.
C. Caffeine cannot readily cross the plasma membrane into body cells, so all effects are short-lived.
D. Caffeine is a diuretic and can cause extreme water loss.
E. In the brain, caffeine activates receptors for adenosine and blocks the action adrenaline.
Answer: B
You might also like to view...
The extracellular matrix of an animal cell is composed of:
A. collagen. B. cadherin. C. cellulose. D. All of the above are correct.
The kidneys are important homeostatic organs, contributing to maintenance of all of the following EXCEPT
A. ion concentration of extracellular fluids. B. blood pressure. C. destruction of worn-out red blood cells. D. blood volume. E. blood pH.
Mutations in a normal growth-stimulating gene are most likely to have no effect or to cause
A) the loss of responsiveness to growth stimulation in the cell with the mutant gene. B) the cell with the mutant gene to become cancerous. C) excessive growth in the cells surrounding the one with the mutant gene. D) a mutator effect in the cell with the mutant gene. E) apoptosis of the cell with the mutant gene.
A fearsome predator lurks in the dark corners of human dwellings. It has many similar body segments, with a single pair of long legs on each, and a pair of poison claws. This animal would be a _____
Fill in the blank(s) with the appropriate word(s).