Carbohydrate Metabolism I: Overall Regulation of Glucose Metabolism

Question 1

After ingesting a high carbohydrate meal, what happens to glucagon and insulin levels?

Answer 1

only insulin levels increase

glucagon: increases blood sugar level to prevent low blood sugar
insulin: decreases blood sugar

Question 2

The signal that indicates to muscle that protein degredation needs to be iniated is which of the following?
A. cortisol
B. epinephrine
C. glucagon
D. glucose
E. insulin

Answer 2

A. cortisol

Question 3

Durnig active growth periods such as childhood and pregnancy, catabolic pathways are still active because…
A. catalytic pathways generally have positive deltaGs such that they result in net weight gain
B. energy extracted from these pathways is needed to fuel anabolic pathways
C. enzymes for catalytic pathways have infinite half lives
D. substrates for catalytic pathways generally have a positive feedback mechanism
E. synthetic pathways are always catabolic

Answer 3

B. energy extracted from these pathways is needed to fuel anabolic pathways

Question 4

Catabolism and anabolism

Answer 4

Anabolism requires energy to grow and build. Catabolism uses energy to break down

Question 5

Is glucagon anabolic or catabolic?

Answer 5

Glucagon is a catabolic hormome.

it promotes the breakdown of large storage molecules like glycogen inside the cells of the liver and fat in adipose tissue, into small energy molecules in the blood - like glucose and fatty acids.

The major target of glucagon is the liver, where it promotes the breakdown of glycogen stores into glucose through glycogenolysis

Question 6

True or False:

Glucagon promotes glycogenolysis by stimulating glycogen phosphorylase.

Answer 6

TRUE

Question 7

Glucagon, a hormone produced during a period of fasting, is made by pancreatic α-cells, which are adjacent to the insulin-producing β-cells. Which of the following best describes the action of glucagon?
A. stimulates glycogen synthesis
B. inhibites the activity of glycogen phosphorylase
C. increases the rate of glycolysis
D. inhibits gluconeogenesis
E. stimulates fatty acid oxidation

Answer 7

E. stimulates fatty acid oxidation

Question 8

Glucagon is the hormone of fasting produced by pancreatic α-cells. It primarily acts on the liver and adipose tissue in humans. It stimulates what 3 processes?

Answer 8

• glycogenolysis
• gluconeogenesis
• fatty acid oxidation

Glucagon also stimulates the release of insulin, thereby allowing insulin-sensitive cells to take up the released glucose. Glucagon secretion is also inhibited by insulin, amylin, and somatostatin.

Question 9

Which of the following statements best describes glucagon?
- it acts as an anabolic hormone
- it acts on skeletal muscle, liver, and adipose tissue
- it acts primarily on the liver and adipose tissue
- its concentration in teh blood increases after a high carbohydrate meal
- its concentration increases n the blood when insulin levels increase

Answer 9

• it acts primarily on the liver and adipose tissue

Question 10

Which of the following compounds is slowest in bringing about changes in blood glucose concentration?
A. 8 oz of orange juice taken by mouth
B. cortisol
C. epinephrine
D. glucagon
E. insulin

Answer 10

B. cortisol

Question 11

Pyruvate is a key intersection in the network of metabolic pathways. Pyruvate can be…
1. decarboxylated to
2. carboxylated to
3. transaminated to
4. reduced to

Answer 11

1. pyruvate can be decarboxylated to acetyl CoA
2. pyruvate can be carboxylated to oxaloacetate
3. pyruvate can be transaminated to alanine
4. pyruvate can be reduced to lactate with anaerobic glycolysis

Question 12

Which of the following hormones requires cyclic AMP in the signaling mechanism?
A. cortisol
B. glucagon
C. growth hormone
D. insulin
E. thyroxine

Answer 12

B. glucagon

Question 13

When blood sugar concentration is increased what happens to levels of insulin and glucagon?

Answer 13

insulin will increase and glucagon will fall

Question 14

Patients with diabetes are often treated with certain drugs that can predispose htem to develop hypoglycemia. Hypoglycemia may cause uncomfortable symptoms like sweating and palpatation that the patient recognizes. What counter regulatory hormone is responsible for these responses to hypoglycemia?
A. acetylcholine
B. cortisol
C. epinephrine
D. glucagon
E. growth hormone

Answer 14

C. epinephrine

Question 15

Whato do kinases and phosphatases do?

Answer 15

Kinases are enzymes that transfer a phosphate group to a protein while phosphatases remove a phosphate group from protein

Question 16

Which of the following kinases helps tranduce insulin signaling to stimulate glycogen synthesis?
A. Janus kinase (JAK kinase)
B. MAP kinase
C. Protein kinase A
D. Phosphatidylinositol 3 kinase (PI-3K)
E. Receptor tyrosine kinase

Answer 16

D. Phosphatidylinositol 3 kinase (PI-3K)