lecture 6

Question 1

what must a cell do?

Answer 1

1. manufacture raw materials
2. remove wastes
3. obtain raw materials
4. generate the required energy
5. control all of the above

Question 2

purpose of organelles?

Answer 2

1. provides special conditions for the cell
2. keep incompatible processes apart
3. allow high concentrations of substances
4. form concentration gradients
5. package for transport or export (vesicles)

Question 3

cholesterol ________ membrane fluidity at moderate temperatures, and ___________ membrane fluidity at low temps

Answer 3

decreases

increases

Question 4

membranes are permeable to what?

Answer 4

lipid soluble hydrophobic molecules (steroid hormones and gases down concentration gradient

Question 5

membranes restrict what?

Answer 5

water soluble and charged molecules e.g glucose, ions and water

Question 6

roles of membrane proteins?

Answer 6

1. cell-cell recognition
2. intercellular joining
3. signal transduction
4. linking cytoskeleton to ECM

Question 7

examples of diseases from defects in transport proteins

Answer 7

epilepsy (K+ channel)
albinism (tyrosine transporter)
wilson’s disease (Cu2+ and Ag+)
cystic fibrosis (Cl-)