Gluconeogenesis

Question 1

Why are there only three different steps in glyconeogenesis compared to glycolysis?

Answer 1

The three different steps are those that are irreversible in glycolysis and require different pathways to go backward. All other steps are reversible, with the enzymes catalysing the forwards and backward reactions.

Question 2

What pathway is used to convert Pyruvate to Phosphoenolpyruvate?

Answer 2

This pathway requires two steps, with the first being converting pyruvate to oxaloacetate in the mitochondria, using the enzyme pyruvate carboxylase and the cofactor biotin. This step also requires ATP to proceed. From here, oxaloacetate is converted to PEP using the enzyme PEP carboxylase and GTP, releasing GDP and CO2

Question 3

What pathway is used to convert Fructose -1,6-phosphate to Fructose-6-phosphate?

Answer 3

Using the enzyme Fructose-1,6-Bisphosphatase-1 and the cofactor of H2O will also release Pi

Question 4

What pathway is used to convert Glucose-6-phosphate to Glucose?

Answer 4

1) Glucose -6- phosphate uses a G-6-P transporter protein to cross the membrane from to cytosol to outside the cell.
2) Once outside the cell, glucose -6-phosphatase dephosphorylates the glucose -6- phosphate to create glucose.
3) The glucose is then transported back into the cytosol through a glucose transporter, and then GLUT2 transports the glucose into the blood stream.

Question 5

Where does G-6-P to Glucose occur in the cell?

Answer 5

In the Hepatocytes of the liver and the cortex of the kidney cells