cell communication

Question 1

purpose of cell communication

Answer 1

• communication for development
• communication for homeostasis
• however communication breaks down in old age

Question 2

characteristics of signals

Answer 2

• duration
• speed
• mechanism
• range
• specificity
• form of signal

Question 3

contact-dependent communication

Answer 3

cell-to-cell direct communication
very short range

Question 4

synaptic communication

Answer 4

communication via neurotransmitters along an axon
short-medium transport

Question 5

paracrine communication

Answer 5

local transmission to surrounding cells via a local mediator

Question 6

endocrine communication

Answer 6

hormones through bloodstream

Question 7

types of response to signals

Answer 7

• be in form of gradient = morphogen gradient
• cells can react in different ways on the basis of the strength of the signal

Question 8

possible downstream effects of receptor stimulation

Answer 8

metabolism for enzyme
gene expression
changes in cell shape/movement

Question 9

factors affecting speed of response

Answer 9

• changing the structure of an existing protein eg. ion channel (very fast)
• changing the post translational modification eg phosphorylation (quite fast)
• changing protein levels via gene expression (slow)

Question 10

how does signal regulation occur?

Answer 10

regulation of enzymes such as kinases and phosphatases which take part in mechanisms
- positive and negative feedback