MACRONUTRIENTS: PROTEIN

Question 1

how many amino acids are required by the body?

Answer 1

20

Question 2

how many essential amino acids are there for adults and children?

Answer 2

adults: 8
children: 9

Question 3

what are the major sources of body protein?

Answer 3

1. blood plasma
2. visceral tissue
3. muscle

Question 4

what is deamination

Answer 4

• nitrogen removal from aa
• occurs in liver and muscles
• enter citric acid cycle for oxidation

Question 5

how is protein metabolized?

Answer 5

1. deamination forms urea which leaves the body as urine
2. remaining carbon skeletons (aa after nitrogen removal) from deamination enter a metabolic pathway (aerobically):
   a) gluconeogenesis
   b) energy source
   c) fat synthesis

Question 6

what happens to aa in the gluconeogenesis pathway?

Answer 6

become a source for glucose synthesis

Question 7

what happens to aa in the energy source pathway?

Answer 7

form intermediates in the citric acid cycle

Question 8

what happens to aa in the fat synthesis pathway?

Answer 8

aa are a source of acetyl-CoA and can synthesize fatty acids

Question 9

what happens to glucogenic aa when deaminated?

Answer 9

yield intermediates for glucose synthesis via bluconeogenesis

Question 10

what happens to ketogenic aa when deaminated?

Answer 10

yield intermediates acetyl-CoA or acetoacetate

Question 11

why is the a continual need for new protein to replace degraded protein?

Answer 11

maintain nitrogen balance

Question 12

what is lipogenesis?

Answer 12

• glucose conversion to fat
• begins with C from glucose and skeletons from aa
• fatty acids are synthesized

Question 13

protein conversion to fat

Answer 13

• excess aa deamination
• converted to acetyl-CoA (energy storage)
• fatty acids are synthesized