Nitrogen

Question 1

Where does nitrogen come from in the body

Answer 1

From diet

Question 2

What are the nitrogen containing molecules of the body

Answer 2

Proteins
Nucleic acids
nucleotides
Haem containing molecules

Question 3

What enzyme cuts protein in the ‘stomach’, ‘small intestine’

Answer 3

Pepsin cuts protein into peptides in stomach
Trypsin and chymotrepsin cut proteins into smaller peptides small intestine
Aminopeptidase and carboxypeptidases A and B degrade peptides into amino acids

Question 4

What happens to amino acids from digested proteins

Answer 4

In the liver,
Converted to NH4+(ammonium), urea or uric acid
Or converted to carbon skeletons for CAC

Question 5

What is the urea cycle

Answer 5

Urea is formed in the urea cycle
Excess glutamate is metabolised in the mitochondria of hepatocytes
Ammonia is re-captured via synthesis of carbamoyl phosphate
Nitrogen from carbamoyl phosphate enters the urea cycle
Urea is formed through a hydrolysis reaction of arginine