Answer to Question 1
C
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After the effector cell has been stimulated by ACh, stimulation of the receptor site must be terminated and destruction of any ACh must occur. The destruction of ACh is carried out by the enzyme acetylcholinesteras e. This enzyme reacts with the ACh to form a chemically inactive compound. The breakdown of the released ACh is accomplished in 1/1,000 second, and the receptor is vacated, allowing the effector membrane to repolarize and be ready for the next stimulation. Dopa decarboxylase is an enzyme that converts dopa to dopamine. Norepinephrine is a catecholamine as are dopamine, serotonin, and epinephrine.
Answer to Question 2
D
Feedback:
Telbivudine is an antihepatitis B agent, and when given with adefovir (Hepsera) can result in severe hepatomegaly with steatosis, sometimes fatal. Cimetidine is a histamine-2 antagonist, diltiazem is a calcium channel blocker, and diphenhydramine is a first-generation antihistamine. These drugs are normally not considered nephrotoxic and could be used with adefovir.
The Cell Cycle
Activity of a Hippocampal Border Cell
The bacterial cell wall: (a) gram-positive bacterium; (b) gram-negative bacterium.
Three-cell model
The mitochondrion is the center of energy transformation in the cell
Major cell cycle checkpoints