Question

Neurotransmitters that open K+ channels in receiving cells are called

QUESTION 10

		cross-linked
		inhibitory
		graded
		obligatory
		excitatory

QUESTION 14

The adaptive immune system can target and kill specific pathogens because

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

QUESTION 17

What causes the signal that crosses a synapse to stop?

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

QUESTION 22

Which of the following hormonal signals could act as a ligand for 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 a nonsense 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 growth hormone (GH)
		Their hypothalamus would secrete low levels growth hormone-releasing hormone (GH-RH)

Answer 1

10. Inhibitory, a neurotrasmitter can usually bind to and activate multiple receptor proteins.whether it is excitatory or inhibitory at a synapse depends on which of its receptor is present in postsynaptic cell.

14. The body contain enormous diversity of lymphocytes each with ability to respond to a different antigen. adaptive immune system is also known as acquired immunity which is attained by body after exposure to foreign or pathogenic particles.

17. The chemically gated ion channel of recieving cell membrane can only transport for a short period of time before they inactivate(close). Since it is for a very short period of time, a milisecond after that it degrades.

22. A peptide harmone, Since they are know to bind and activate cell surface receptors. these activated receptors can interact and modulate the activity of cell surface enzymes,etc.

27. Their hypothalamus would secrete low level of growth harmone-releasing harmone(GH-RH) as it causes growth failure leading to dwarfism and metabolic dysfunction according to research conducted on mice.