2.5.2 factors affecting membrane structure

Question 1

what happens to a membrane when it’s below 0°C?

Answer 1

the phospholipids have very little energy so they can’t move much because they’re rigid
water solidifies which may pierce the cell membrane and make it permeable
proteins denature

Question 2

what happens to a membrane when at 0°C - 45°C?

Answer 2

the membrane isn’t packed as tightly together and has some kinetic energy to allow the phospholipids to move around - this makes it partially permeable

Question 3

what happens to a membrane above 45°C?

Answer 3

the phospholipids have more kinetic energy and are able to move more
this makes the membrane more fluid and begin to lose its structure which makes it permeable
water will expand and put pressure on the membrane
channel/carrier proteins will de-nature which will affect the transport of substances across the membrane and make it even more permeable

Question 4

why are alcohols used in antiseptic wipes?

Answer 4

because alcohols are less polar or non-polar and dissolve the membranes of bacteria in a wound which kills them and reduces the risk of infection

Question 5

what do less concentrated solutions of organic solvents do to membranes?

Answer 5

it won’t dissolve the membrane but the non-polar molecules enter the membrane which disrupts it and makes it more permeable