Cell membrane - Fluidity

Question 1

why is a fluid membrane essential? 3 points

Answer 1

1. allows diffusion of substances across the membrane
2. needed for membranes to fuse
3. allows cells to change shape

Question 2

what are the three factors that affect fluidity?

Answer 2

temperature, cholesterol and lipids

Question 3

How does a low temperature affect the fluidity of cm?

Answer 3

the phospholipids have less kinetic energy = more packed together = less fluid

Question 4

How does a high temperature affect the fluidity of cm?

Answer 4

the phospholipids have more kinetic energy = less packed together = increasing fluidity

Question 5

At temperatures below Zero, what happens to the membrane?

Answer 5

ice crystals form and pierce the membrane = highly fluid

Question 6

at a high temperature - above 45 degrees - what happens?

Answer 6

the bilayer melts = more permeable = water starts to expand and put pressure on the membrane - carrier/channel proteins deform and can’t function = decrease in fluidity

Question 7

How does long/saturated lipids affect fluidity?

Answer 7

they decrease fluidity = unkinked and fatty acids are packed closely together

Question 8

how does short/unsaturated lipids affect fluidity?

Answer 8

increase fluidity = double bonds create kinks = packed more loosely together.