Glycolysis, Anaerobic Respiration, Cori cycle, Gluconeogenesis

Where does glycolysis occur?

Cytosol

Outline the whole process of “Glycolysis”

What is the net result of glycolysis?

• 4x ATP

• 2x NADH

Does glycolysis occur in anaerobic respiration?

Yes

Glycolysis requires 2x NAD⁺ to work. In anaerobic respiration, how is NAD⁺ regenerated?

Pyruvate is reduced to S-lactate and NADH is oxidised to NAD+

What happens to S-lactate when oxygen is available again?

When oxygen is available again, S-lactate is reoxidized to pyruvate using NAD+

What is the Cori cycle?

The Cori cycle is the process where S-lactate produced in muscles during anaerobic respiration is transported to the liver, converted back into glucose, and then returned to the muscles for reuse.

Outline the Cori cycle

1. S-lactate is transported in the blood, from muscle to the liver

2. In the liver, lactate dehydrogenase converts S-lactate to pyruvate

3. Pyruvate is converted to glucose via gluconeogenesis

How much ATP is required in the Cori cycle?

6x ATP per glucose molecule

What does gluconeogenesis mean?

Forming a glucose

Where does gluconeogenesis mainly occur?

Liver

How many pyruvates are needed to form a glucose molecule in gluconeogenesis?

2x pyruvates

What is the process of gluconeogenesis?

1. Pyruvate is converted to oxaloacetate in the mitochondria using ATP and CO₂

2. Oxaloacetate is transported to the cytosol and converted into phosphoenolpyruvate

3. Phosphoenolpyruvate is converted to glyceraldehyde-3-phosphate using 2x ATP and 1x NADH

4. Glyceraldehyde-3-phosphate → Fructose-1,6-bisphosphate

5. Fructose-1,6-bisphosphate is converted to glucose using the enzyme phosphatase