Nucleotide Metabolism

Question 1

What are the three major junction points?

Answer 1

1. Glucose 6 Phosphate: used in gluconeogenesis to make glucose via Fru-1,6-Bisphosphatase, Glycogenesis to make glycogen via GK, Glycolysis for pyruvate via PFK-1, PPP to make Ribose 5 Phosphate via G6PDH.
2. Pyruvate: made from glycolysis can be converted into Acetyl CoA via Pyruvate DH in TCA cycle, Also Lactate via lactate DH in exercising muscle. Pyruvate can go to Alanine through ALT in a transamination. Also Pyruvate can go to OAA via Pyruvate Carboxylase to enter TCA.
3. Acetyl CoA can go into TCA producing CO2. Fatty acids are used to make TAG’s, Finally Ketone Bodies are synthesized from this in the liver.

Question 2

What energy source does the liver rely on?

Answer 2

Beta Oxidation of fatty acids

Question 3

What energy source does adipose use?

Answer 3

Adipose can use glucose to make TAG’s and degrades TAGs and releaes fatty acids and glycerol for other tissues

Question 4

Describe the brains use of energy?

Answer 4

Highly dependent on glucose, can use ketone bodies during starvation. Has no store of glycogen although astrocytes store glycogen and can release glucose