chapter summary qs

Question 1

explain why a bilayer arrangement is formed in cells (3)

Answer 1

• phosphate heads are hydrophilic
• fatty acid tails are hydrophobic
• fatty acid tails face inwards and phosphate heads face outwards

Question 2

state 3 roles of membranes within cells and the component which coordinates this (3)

Answer 2

• partially permeable barrier to polar substances; phospholipid
• site of reactions; enzymes
• site of cell signalling; glycoproteins

Question 3

a student placed beetroot in water. the water turned red. explain why (2)

Answer 3

• the beetroot particles diffused out
• from a high to low concentration

Question 4

define active transport (3)

Answer 4

• net movement of molecules from a low to high concentration
• against a concentration gradient
• using ATP and carrier proteins

Question 5

state which mechanism of transport moves H+ into inter membrane space from matrix (2)

Answer 5

active transport
- movement from a low to high concentration gradient

Question 6

state which mechanism of transport moves H+ into matrix from IM space (3)

Answer 6

facilitated diffusion
- moves from a high to low concentration gradient
- using intrinsic proteins

Question 7

describe the mechanism of how catalase breaks down H2O2 (3)

Answer 7

• H2O2 binds to active site of catalase
• via random collisions
• forming an enzyme substrate complex