PPQ's

Question 1

What is the role of cholesterol in the membrane? (1)

Answer 1

Controls membrane fluidity.

Question 2

Tick the options that show movement down a concentration gradient? (1)
A. Simple diffusion
B. Facilitated diffusion
C. Active transport
D. Exocytosis

Answer 2

A and B, (diffusion).

Question 3

Endocytosis results in… (1)
A. a larger plasma membrane
B. a smaller plasma membrane

Answer 3

B - A smaller plasma membrane.

Question 4

Glucose enters the epithelial cells of the ileum from the gut lumen against a concentration gradient by facilitated diffusion. This is because… (1)
A. Glucose concentration is high in the cell
B. Sodium concentration is high in the cell
C. Glucose concentration is low in the cell
D. Sodium concentration is low in the cell

Answer 4

D - Sodium concentration is low in the cells.

Question 5

Below is a list of some proteases. Tick the options that are endopeptidases. (2)
A. pepsin
B. chymotrypsin
C. trypsin
D. aminopeptidase
E. carboxypeptidase

Answer 5

A, B and C.

1 mark for 1 and 2 marks for 3.

Question 6

What are the end products of endopeptidases? (1)
A. amino acids
B. dipeptides
C. short chain polypeptides

Answer 6

C - Short chain polypeptides.

Question 7

Cholomicrons are a stage in fat absorption. Which stage? (1)
A. Emulsification
B. lumen to epithelial cell
C. transport from microvilli to golgi
D. transport from golgi to lacteal

Answer 7

D - Transport from golgi to lacteal.

Question 8

Lactose is a dissacharide found in milk. Of which monomers is it formed? (1)
A. aplha glucose
B. beta glucose
C. fructose
D. galactose
E. ribose

Answer 8

A and D, alpha glucose and galactose.

Question 9

Lactose is digested by lactase. At adulthood most mammals stop producing lactase. If lactose subsequently enters the gut, it will not be digested by the animal’s enzymes. What will be the consequence to water potential in the colon? (1)
A. no difference
B. lowers
C. rises

Answer 9

B - Lowers.