gluconeogenesis

Question 1

What is gluconeogenesis? And why is it used?

Answer 1

The synthesis of glucose from other molecules.

In the absence of insulin, most of body uses FA for energy but brain and red blood cells use glucose for energy

Question 2

What does long term survival depend on?

Answer 2

Gluconeogenesis. DIAGRAM IN ON

Question 3

How to reverse glycolysis to make glucose from pyruvate if there are 3 irreversible steps? diagram in ON

Answer 3

Need two step processes on the irreversible steps.

1. Pyruvate > (carboxylase) OAA > (carboxykinase) phosphoenol pyruvate - 2 ATPS
2. F-1,6-P2 > (phosphatase) F-6-P chopping off a phosphate - 1 ATP
3. G-6-P > (phosphatase) Glucose chopping off phosphate in the endoplasmic reticulum.

Glucose is transported into cytoplasm VIA T3
have to do it twice because of that splitting step so overall costs 6 ATP’s

Question 4

Whats the cori cycle

Answer 4

Lactate travels to liver

Lactate turns into pyruvate then back to glucose.

This is a way to keep the glucose levels up.

Question 5

Why is Alanine the amino acid that’s the most used to turn into glucose?

Answer 5

When muscle breakdown, releases alanine into blood (e.g if u haven’t eaten for a few days).

Catabolism/Transamination in muscle of amino acids to alanine.

Alanine enters liver and liver uses alanine aminotransferase enzyme to turn it into pyruvate

DIAGRAM IN ON

Question 6

What are the other sugars in the diet that are similar to glucose?

Answer 6

Galactose, mannose, fructose.

Fructose just becomes F-6-P in non-liver tissues VIA hexokinase. In the lover, it becomes G-3-P. VIA

Galactose feeds into G-6-P - has a longer process tbf so it’s in ON

Mannose feeds into F-6-P VIA hexokinase to make M-6-P then phosphomannose isomerase to make F-6-P

They’re all sugars so they enter glycolysis where glucose is basically already there.