Background

Question 1

Name the 8 major metabolic pathways

Answer 1

Glycolysis, gluconeogenesis, glycongenesis, glyconeolysis, lipogenesis, beta-oxidation, Ketogenesis, Proteolysis

Question 2

Metabolism = _________ + __________

Answer 2

Catabolism (breakdown of nutrients for energy)

Anabolism (Production of macromolecules from precursors)

Question 3

Give some examples of anabolism of precursor molecules.

Answer 3

Amino acids -> Proteins
Sugars -> polysaccharides
Fatty Acids -> Lipids
Nitrogenous bases -> Nucleic acids

Question 4

What are some examples of energy depleted end products of catabolism?

Answer 4

CO2
H20
NH3

Question 5

Give some intermediates of carbohydrate metabolism..

Answer 5

Glucose 6-phosphate -> Glycogen / Ribose 5-phosphate

Glycose 6-phosphate -> Pyruvate -> Acetyl-CoA (-> citric acid cycle)

Question 6

Give some intermediates and products of protein/amino acid metabolism.,

Answer 6

Amino acids -> Liver proteins / Nucleotides+hormones / NH3 -> Urea
Amino acids -> Pyruvate -> Acetyl-CoA(->Citric acid cycle)
Pyruvate -> Glucose -> Glycogen

Question 7

Give some intermediates and products of lipid/fatty acid metabolism..

Answer 7

Fatty acids -> Liver lipids / plasma lipoproteins / free fatty acids
Fatty acids -> Acetyl-CoA -> Citric acid cycle or Cholesterol or ketone bodies

Question 8

Name 3 irreversible ‘one-way’ enzymes of glycolysis

Answer 8

Glucokinase, Phosphofructokinase, Pyruvate Kinase

Question 9

Malonyl-coA acts as an _____ inhibitor of fatty acid oxidation.

Answer 9

allosteric

Question 10

_________ is the principle site of insulin regulation. This is the _______ step in fatty acid synthesis. The reaction product is ________ which inhibits _______ oxidation.

Answer 10

Acetyl coenzyme A carboxylase
committed step
malonyl-coA
fatty acid

Question 11

What is fatty acid oxidation and what are the competing pathways of synthesis and oxidation partly controlled by?

Answer 11

Conversion of fatty acids into long chain acyl-coA molecules.
Compartmentalisation - synthesis in the cytosol and oxidation in them mitochondria

Question 12

What are the ways in which amino acids can be metabolised?

Answer 12

Converted to acetyl-coA for fatty acid synthesis or ketone bodies
Converted to TCA or glycolytic intermediates
Converted by transamination - removal of the amino group to transfer to other intermediate
e.g. glutamate -> alpha ketoglutarate
Eventually Urea