Nutrition & metabolism

Question 1

Define fuel metabolism, anabolism and catabolism.

Answer 1

Reactions involving degradation, synthesis and transformation of organic molecules for energy. Anabolism - synthesis of larger macromolecules, catabolism - degradation of macromolecules (by hydrolysis, oxidation)

Question 2

Define the various reactions of fuel metabolism.

Answer 2

Glycogen → glycogenolysis → glucose → glycolysis
Protein → proteolysis → amino acids → glycolysis
Triglyceride → lipolysis → fatty acids → Krebs cycle

Question 3

Explain the importance of cellular ATP as an energy carrier.

Answer 3

High energy phosphate bond

Question 4

Describe the fate of metabolic fuels during the absorptive FED and post absorptive FASTED state.

Answer 4

Absorptive / fed -
Glucose from diet → glycolysis → pyruvate → energy
Excess citrate + fatty acids from diet → acetyl CoA + bicarbonate → + insulin activation → triglycerides to adipose tissue

Post-absorptive state / fasted -
Glucose from glycogen → pyruvate
Oxaloacetate → gluconeogenesis → glucose + ketones
Fatty acids from adipose tissue → gets carnitine added → transported into mitochondria for beta-oxidation → acetyl CoA