Question

9. Some diseases result from defective transport across the membrane. For example, cystic fibrosis results when a chloride ion transporter does not function. Which of the following is affected when this transporter does NOT function?
	the electrical gradient of the cell neither the chloride gradient nor the electrical gradient of the cell the chloride concentration gradient both the chloride concentration gradient and the electrical gradient of the cell

10.	Which way does the water move if the cell is in a hypotonic environment?
	out of the cell Water doesn't move across the hydrophobic core of cell membranes. into the cell

11.

Paramecium is a unicellular organism that lives in fresh water. Suppose you are studying two populations of this organism: one population lives in a pond in northern Ontario, Canada, and the other lives in a pond in southern Florida. If you examined the plasma membranes of both of these populations at the same time of year, what difference would you expect to find between the two populations' cell membranes?

The fatty acid side chains in the membrane phospholipids of the Florida Paramecia would generally be longer and would be less saturated compared to those in the membranes of the Canada Paramecia. The fatty acid side chains in the membrane phospholipids of the Florida Paramecia would generally be shorter and would be less saturated compared to those in the membranes of the Canada Paramecia. The fatty acid side chains in the membrane phospholipids of the Florida Paramecia would generally be shorter and would be more saturated compared to those in the membranes of the Canada Paramecia. The fatty acid side chains in the membrane phospholipids of the Florida Paramecia would generally be longer and would be more saturated compared to those in the membranes of the Canada Paramecia.

12.

Phospholipase is an enzyme that cleaves the phosphate head group off a phospholipid molecule. The plasma membrane is not, however, permeable to the enzyme. Imagine a cell where phospholipid A is present in the layer of phospholipids facing the exterior of the cell, and phospholipid B is present in the layer of phospholipids facing the interior of the cell. After adding phospholipase to the medium in which the cell is growing, what would you expect to find in the fluid surrounding the cell?

the phosphate head group from phospholipid B only phosphate head groups from neither phospholipids A nor B the phosphate head group from phospholipid A only phosphate head groups from both phospholipids A and B

13.	Which of the following represents the order that molecules cross a synthetic membrane composed of phospholipids but not proteins, from most easily (freely permeable) to least easily (not permeable)?
	water (H2O), glucose, sodium ions (Na+), O2 O2, water (H2O), glucose, sodium ions (Na+) sodium ions (Na+), glucose, water (H2O), O2 O2, sodium ions (Na+), water (H2O), glucose glucose, water (H2O), O2, sodium ions (Na+)

Answer 1

Q9) d. Both the chloride concentration gradient and the electrical gradient of the cell

Q10) c. Water will move inside the cell.

Q11) d .The fatty acid side chains in the membrane phospholipids of the Florida Paramecia would generally be longer and would be more saturated compared to those in the membranes of the Canada Paramecia.

Q12) c. phosphate head group from A only.

Q13) b. O2, water (H2O), glucose, sodium ions (Na+)