Practice Exam 2

Question 1

Liposomes consists of what type of bilayer that encloses an aqueous compartment where drugs can be contained for delivery to specific tissues if target proteins are present

Answer 1

Phospholipid

Question 2

What is the role of cholesterol in animal cell membranes

Answer 2

Enhances membrane fluidity by disrupting intermolecular forces between fatty acid chains at low T and decrease fluidity at high Ts.

Question 3

Determination of the tertiary structure of a membrane protein finds that the outer surface is composed primarily of hydrophobic residues. Which conclusion is most likely from this observation

Answer 3

It is an integral protein

Question 4

Which does NOT apply to the diffusion of O2, CO2, and small hydrophobic molecules across a membrane

Answer 4

The transport is facilitated by the Na+/K+ pump

Question 5

Which of the following is the slowest movement of lipids in biological membranes

Answer 5

Transmembrane Diffusion
Flip-Flop

Question 6

Which of the following best describes what happens to entropy of a particular molecule as the number of resonance structures increases

Answer 6

Entropy is increased

Question 7

Which of the following types of proteins pass through both leaflets of the membrane

Answer 7

Integral membrane protein

Question 8

What kind of facilitated cotransport can move some substrate across a membrane against its concentration gradient

Answer 8

Active

Question 9

Is this true or false
Lipids and proteins move laterally at approximately the same rate within the membrane

Answer 9

False

Question 10

What enzyme is activated by association with an active G protein

Answer 10

Adenylate Cyclase

Question 11

A small molecule produced inside a cell in response to a hormone binding to its receptor is called what

Answer 11

secondary messenger

Question 12

When cyclic Amp is a second messenger what happens

Answer 12

The binding of hormone produces the desired effect in the cell by stimulating the production of cyclic AMP

Question 13

PFK catalyzes what and is inhibited by what and stimulated by what

Answer 13

F6P to FBP, ATP, AMP

Question 14

Metabolic steps are usually regulated at

Answer 14

A step where there is a large negative delta G for conversion of reactants to products

Question 15

In gluconeogensis, the net gain of ATP is what and the net gain of GTP is

Answer 15

-4, -2

Question 16

Hexokinase is an example of what kind of enzyme

Answer 16

Transferase

Question 17

Which of the following factors contributes to the highly exergonic nature of AcetylCoA hydrolysis

Answer 17

The high potential energy thioester bond

Question 18

A molecule that is considered a good fuel is one that is

Answer 18

In the most reduced state possible such as a saturated hydrocarbon

Question 19

Reasons for having high-phosphoryl-transfer potential

Answer 19

Reduction of charge repulsion
Increase in entropy
Increase in resonance stabilization.

Question 20

In general, catabolism is what

Answer 20

An oxidative process that releases energy

Question 21

Bile salts are derivatives of

Answer 21

Cholesterol

Question 22

Which substance is a product of glycolysis, a precursor of gluconeogeneis and a precursor of the citric acid cycle

Answer 22

Pyruvate

Question 23

Which of the following factors contribute to the highly exergonic nature of ATP hydrolysis

Answer 23

Decrease in negative-ion repulsion in ATP

Question 24

Which of the following enzymes requires ATP as a substrate

Answer 24

Phosphofructokinase

Question 25

Triose Phosphate Isomerase catalyzes a reaction that is most similar to

Answer 25

Phosphoglucose Isomerase

Question 26

The enzyme pyruvate carboxylase

Answer 26

Requires biotin for activity

Question 27

High concentrations of Fructose-2,6-Bisphosphate stimulate and inhibits what

Answer 27

Stimulate glycolysis
Inhibit gluconeogenesis

Question 28

Under anaerobic conditions in skeletal muscle, pyruvate is converted into

Answer 28

Lactate

Question 29

Spingomyelin contains a fatty acid linked by what bond and phosphocholine linked via teh C-3 hydroxyl group of sphingosine

Answer 29

Amide

Question 30

In an aqueous environment the hydrocarbon tails of lipids tend to associate by entropy-driven what effects and by Van der Waals interactions

Answer 30

Hydrophobic Effect

Question 31

Trans fatty acids have physical properties like those of

Answer 31

Saturated Fatty Acids

Question 32

Carriers of an Acyl Group

Answer 32

ATP: 3 Phosphate groups, 3 Rings
CoA: 2 Phosphate group, 3 Rings
FAD: 2 Phosphate group, 6 Rings
NAD+: 2 Phosphate group, 5 Rings