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) |
