Ch 6: Proteins

Question 1

The ____ is the major site of amino acid metabolism

Answer 1

Liver

Question 2

After approximately _____ days of starvation, the brain switches its fuel source from glucose to ketone bodies

Answer 2

2 days; however, blood cells and the adrenal medulla continue to rely on glucose as the primary source of energy substrate

Question 3

1 gram of nitrogen = how many grams of protein?

Answer 3

1 g N = 6.25 g protein

Question 4

Which amino acid has demonstrated importance in immune function and wound healing?

Answer 4

Arginine

Question 5

Which amino acids are essential?

Answer 5

Threonine, Valine, Tryptophan, Isoleucine, Leucine, Lysine, Phenylalanine, Methionine, Histidine

Question 6

How many amino acids can humans produce?

Answer 6

Humans can produce 11 out of the 20 AA that are the building blocks of protein. Others must be supplied from the diet.

Question 7

Which amino acids are minimally extracted by the liver?

Answer 7

BCAAs (Leucine, Isoleucine, Valine) are minimally extracted by the liver, instead, they mostly enter the systemic circulation for metabolism largely by muscles.

Question 8

Which amino acids are conditionally essential?

Answer 8

Arginine, cysteine, glutamine, glycine, proline and tyrosine.

Question 9

Where does most protein digestion take place?

Answer 9

Small intestine

Question 10

What does nitrogen balance measure?

Answer 10

Nitrogen balance = nitrogen intake -nitrogen output

Question 11

What may be deficient in patients on long term PN?

Answer 11

Choline may be deficient in patients on long term PN (not a part of PN formulations). There are no IV forms of choline. Repletion, if necessary, needs to be via oral or enteral route

Question 12

What is the calculation for Nitrogen Balance?

Answer 12

Grams of protein consumed/6.25 - (24 hour UUN+4)

Question 13

When determining nitrogen balance, urea accounts for what percentage of total urine nitrogen losses?

Answer 13

80%