Neurotransmitters that open K+ channels in receiving cells arecalled

QUESTION 10

		cross-linked
		inhibitory
		graded
		obligatory
		excitatory

QUESTION 14

The adaptive immune system can target and kill specificpathogens because

		stem cells determine which type of B and T cells to make.
		stem cells make different antigen receptors depending on theinvading microorganism.
		complement proteins are able to recognize specific antigens.
		the body contains an enormous diversity of lymphocytes, eachwith the ability to respond to a different antigen.
		lymphocytes are able to change their antigen specificity asrequired to fight infection.

QUESTION 17

What causes the signal that crosses a synapse to stop?

		The neurotransmitter is broken down or transported back to thesignaling cell.
		A second action potential traveling down the signaling cellsounds a sort of “retreat,” and the ions reverse direction.
		The responding cell runs out of sodium and is no longer able torespond to the stimulus.
		The responding cell runs out of potassium and is no longer ableto respond to the stimulus.
		The chemically-gated ion channels of the receiving cell’smembrane can only transport for a short period of time before theyinactivate (close).

QUESTION 22

Which of the following hormonal signals could act as a ligandfor a cytoplasmic receptor protein?

		An amino-acid derived hormone
		A protein kinase
		A peptide hormone
		A steroid
		A neurotransmitter

QUESTION 27

Which of the following might happen in individuals that had anonsense mutation in the middle of the gene for growth hormone (GH)?

		They would grow larger than normal
		Their liver would secrete high levels of somatomedins
		Their hypothalamus would secrete low levels of somatostatin
		Their anterior pituitary would secrete high levels of growthhormone (GH)
		Their hypothalamus would secrete low levels growthhormone-releasing hormone (GH-RH)