Exam 4

Question 1

Which of the following statements it true about lipoproteins?

Answer 1

HDL is considered “good” cholesterol because it transports cholesterol to the liver for elimination from the body

Question 2

Which of the following is most likely to be a liquid at room temp?

Answer 2

a 16 carbon polyunsaturated fatty acid

Question 3

What method of membrane transport involved ions moving against their concentration gradients?

Answer 3

active transport

Question 4

What is false about the lipid bilayer in animal cells?
A. proteins can span the lipid bilayer to form ion channels
B. The area between the layers of the bilayer is very hydrophobic
C. an animal cell membrane is semipermeable so that nutrients can enter and waste products can leave
D. The lipid bilayer is a rigid, foxed structure without much flexibility
E. phospholipids are arranged with their polar heads on the inner and outer surfaces of the cell membrane

Answer 4

E. phospholipids are arranged with their polar heads on the inner and outer surfaces of the cell membrane

Question 5

What is true of glycerophospholipids?

Answer 5

Glycerophospholipids contain two fatty acids attached by ester golipicbonds to a glycerol backbone

Question 6

In the polypeptide shown above, the C-terminal amino acid is _________

Answer 6

polar, neutral

Question 7

Which part of the amino acid determines whether it is polar or non polar?

Answer 7

Side chain (R group)

Question 8

Which level of protein structure has a beta-sheet as a component?

Answer 8

Secondary

Question 9

In ant reaction catalyzed by an enzyme, the reacting molecule is called the _________

Answer 9

substrate

Question 10

What is true about enzymes?

Answer 10

They catalyze a specific reaction by lowering the activation energy of the reaction

Question 11

Maltase exhibits its highest activity at a pH of 6.5. What is expected for maltase at a pH of 7.1?

Answer 11

It will have slightly lower activity than at pH 6.5

Question 12

Sucrase exhibits its highest activity at a temperature of 37C. At a temperature of 85C sucrase would be expected to __________

Answer 12

have a complete loss of activity because of denaturation

Question 13

Glutamine synthetase binds a regulator molecule at a site separate from the active site. This is an example of a(n) _____ enzyme

Answer 13

allosteric

Question 14

The induced fit model states that enzymes are ________ so that their shape ________ as substrate binds.

Answer 14

flexible; changes

Question 15

Metal ions are often required in the active site for oxidoreductases to catalyze a reaction. In this scenario, the metal ion is a ________

Answer 15

cofactor