Nitrogen Metabolism (L17-18)

Question 1

True or False: proteins (amino acids) are precursors for DNA/RNA

Answer 1

True

Question 2

Any protein consumed in excess will be ___ or used to make ____

Answer 2

degrade; carbohydrates/fats

Question 3

What are the essential amino acids?
(PVT TIM HALL)

Answer 3

Phenylalanine
Valine
Threonine

Tryptophan
Isoleucine
Methionine

Histidine
Arginine
Leucine/Lysine

Question 4

True or False: Arginine is usually a non-essential amino acid, except in pre-term infants who are unable to make it

Answer 4

True

Question 5

True or False: One may need more amino acids during stress or illness

Answer 5

True

Question 6

If sufficient amount of essential amino acids are not available, non-essential amino acids can become ___ in the diet

Answer 6

essential

Question 7

Biosynthesis of cysteine requires which essential amino acid?

Tyrosine requires which essential amino acid?

Answer 7

Cysteine requires Methionine

Tyrosine requires Phenylalanine

Question 8

True or False: Plant tissues have a higher biological value in protein

Answer 8

False - animal tissue does

Question 9

Where in the body are proteins denatured?

Answer 9

Stomach
- via: stomach acid

Question 10

In the acidic stomach, ___ is converted into ___, which allows for proteins to be degraded

Answer 10

pepsinogen, pepsin

Question 11

The movement of food into the intestine trigger the release of which two hormones?

Answer 11

1) CCK
2) Secretin

Question 12

True or False: In the basic conditions of the small intestine, zymogens (trypsinogen, chymotrypsinogen, procarboxypeptidase) are release in their INACTIVE form while proteases (enteropeptidase and aminopeptidase) are secrete in their ACTIVE form

Answer 12

True

Question 13

Where does absorption of amino acids occur?

Answer 13

Small intestine

-AA enter epithelial cells that line the gut and, ultimately, are released into the blood

Question 14

The presence of lipid or protein in feces, as in CF, suggests?

Answer 14

malabsorption syndrome

Question 15

What are two primary ways that non-essential amino acids are made?

Answer 15

1) Transamination of a-ketoacid
2) Modification of existing amino acids

Question 16

Oxaloacetate can be converted into ____
A-ketoglutarate can be converted into ____

Answer 16

Aspartic acid
Glutamic acid

Question 17

What three amino acids are made by modification of existing amino acids?

Answer 17

1) Asparagine (aspartic acid)
2) Glutamine (glutamic acid)
3) tyrosine (phenylalanine)

Question 18

Which two vitamins are important for making the non-essential amino acids?

Answer 18

1) Vit B6
2) Folic Acid

Question 19

_______Cycle describes the catabolism of amino acids

Answer 19

The Urea Cycle