Carbohydrate metabolism: gluconeogenesis and hormonal control

Question 1

What is gluconeogenesis?

Answer 1

Synthesise glucose from non-carbohydrate sources

Helps maintain normal blood glucose levels in times of inadequate dietary carb intake

Question 2

Input and output for gluconeogenesis

Answer 2

INPUT: Pyruvate from a non-carbohydrate source

OUTPUT: Glucose

Question 3

Which metabolic processes are required to create a lot of ATP during strenuous exercise?

Answer 3

1. Glycolysis
   (glucose into energy and pyruvate for CAC)
2. Glycogenolysis
   (breaks down glycogen into free glucose)
3. Common metabolic pathway
   (acetyl CoA enters the common metabolic pathway to generate a lot a lot of ATP. CAC > ETC/OP)
4. Anaerobic respiration

Question 4

Which hormone assists in obtaining energy from glycogen during strenuous exercise?

Answer 4

Glucagon activates the glycogen breakdown process, glycogenolysis.

After the glycogen is broken down into glucose, the glucose is taken out of the cell and moves into the blood. Once in the blood, the glucose can move to the organ that requires the glucose to produce ATP e.g. muscle or brain.

Question 5

Which metabolic reaction that uses glucose takes preference to the other reactions?

Answer 5

Glycolysis

Question 6

After glycolysis, which metabolic reaction that uses glucose occurs next (after the cell’s energy needs have been met)?

Answer 6

Glycogenesis (storing excess glucose as glycogen in liver and muscles)

Question 7

Once the energy needs of the cells have been met and the glycogen stores of the individual are full, what would
excess glucose be used for?

Answer 7

Fatty acids (via lipogenesis) will be created. TAGs are stored as fat in the adipose tissue

Question 8

Where does gluconeogenesis take place?

Answer 8

Cytosol

Question 9

Which steps of glycolysis can not be reversed by using the identical enzymes in gluconeogenesis?

Answer 9

1, 3 and 10

Question 10

What types of metabolic reactions does insulin activate?

Answer 10

Insulin activates processes that use glucose to derive energy (glycolysis) or for storage as
glycogen (glycogenesis)

Question 11

What types of metabolic reactions does glucagon activate?

Answer 11

Glucagon activates processes that make glucose.

> Gluconeogenesis (makes glucose from a non-carbohydrate source of pyruvate)
Glycogenolysis (breaks down glycogen into glucose)