cell communication

Question 1

what are the 2 forms of communication between cells?

Answer 1

electrical amd chemical

Question 2

describe electrical transmission between cells

Answer 2

direct contact via gap junctions which allow flow of current from cell to cell

Question 3

describe the stages in chemical transmission by synapse

Answer 3

. impulse arrives at terminal of presynaptic cells
. transmitters released from vesicles where they diffuse into synaptic cleft
. transmitters bind to receptors on post-synaptic cell altering that cell

Question 4

describe pancreatic communication

Answer 4

chemical sent to all parts of body via bloodstream, hormone only acts on cells with correct membrane receptor

Question 5

what is a second messenger?

Answer 5

intracelluar signalling molecule

Question 6

describe the action of steroid transmitters

Answer 6

lipids that can enter cell, act on receptors within the cell to form a steroid-receptor complex that acts on DNA in the nucleus to intiate protein synthses. Protein produced alters cell funtion

Question 7

describe the action of peptide transmitters

Answer 7

cannot enter cell so bind to receptor on plasma membrane of cell activating series of reactions controlled by g-proteins, which in turn activate cAMP and calcium ions

Question 8

describe the process by which a g-protein activates cAMP

Answer 8

. membrane receptor activates g-protein

. ATP converted to cAMP by adenyl cyclase which acyivates an enzyme which forms proteins

Question 9

what is autocrine?

Answer 9

when chemical acts on the cell releasing it

Question 10

what is paracrine?

Answer 10

hormones are released from cells and bind to receptor on nearby cells and affects their function

Question 11

give an example of when paracrine communication is used?

Answer 11

inflammation

Question 12

compare nerve communication to hormonal communication?

Answer 12

• nerve communication rapid but short lived

- hormonal communication slow but the action persists