Amino Acids (Part II)

Question 1

What are the conditionally indispensable amino acids?

Answer 1

• Tyrosine
• Cysteine
• Arginine
• Glutamine
• Glycine
• Proline

Question 2

What are the dispensable amino acids?

Answer 2

• Alanine
• Aspartate
• Asparagine
• Glutamate
• Serine

Question 3

In a strictly metabolic sense (i.e. with the appropriate precursors), which amino acids CANNOT be synthesized by providing precursors?

Answer 3

• Lysine
• Threonine
• Tryptophan

Question 4

What are the three cons of measuring amino acid requirement through direct oxidation?

Answer 4

1) Solely the branched-chain amino acids, lysine, and phenylalanine produce a labeled CO2 that may be utilized
2) Changing intake from a low amount to an excess of AA changes the AA pool, which may interfere with results
3) Analytical techniques are much more expensive than nitrogen balance

Question 5

Which amino acids are important and every day scenarios, and are likely to be limiting in diets?

Answer 5

• Lysine
• Tryptophan
• Threonine
• Cysteine
• Methionine

Question 6

Which indispensable amino acids compose the tripeptide glutathione?

Answer 6

Glycine, glutamate, and cysteine

Question 7

Describe the intestinal-renal axis for the synthesis of arginine.

Answer 7

• Intestine: glutamate and proline are synthesized into citrulline, which is released to the kidney
• Kidney: citrulline is converted to arginine

Question 8

Describe creatine synthesis.

Answer 8

1) Kidney: glycine and arginine combine to form an intermediate
2) Liver: methyl group is transferred from methionine to produce creatine