Cell Communication

Question 1

How can cells communicate BETWEEN cells?

Answer 1

• Electrical signalling

- Chemical signalling

Question 2

How does electrical transmission occur between cells?

Answer 2

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

Question 3

How does chemical transmission occur between cells?

Answer 3

Cell -> cell (chemical synapse & neurotransmitter)
Cell -> several cells (paracrine)
Many cells -> many cells (endocrine)

Question 4

What are the steps in cell to cell chemical transmission?

Answer 4

• Impulse arrives at presynaptic cell terminal
• (neuro)transmitter released from storage vesicle which diffuses into synaptic cleft
• (neuro)transmitter binds to postsynaptic receptor
• Alters postsynaptic cell

Question 5

What’s the advantages and disadvantages between nervous transmission and hormonal transmission?

Answer 5

Nerves:

• Very fast response
• Actions very specific/localised

Hormonal:

• Can affect many cells in different parts of body
• Slow to act, but effect persists
• Coordinated, body-wide actions

Question 6

What are intracellular signalling molecules called?

Answer 6

Second messengers

Question 7

What’s the main difference between First and second messengers?

Answer 7

First messenger acts on receptors on cell membrane - extracellular factors (CANT PASS THROUGH MEMBRANE)

Second messengers are used for signalling within the cell and are released as a result of a primary messenger receptor being activated

Question 8

What is special about steroid transmitters?

Answer 8

Steroids are lipids that CAN pass through the outer cell membrane to act on receptors inside target cells, results in initiated protein synthesis