B5-061 AA Metabolism

Question 1

calculate nitrogen intake from protein in diet

Answer 1

daily protein (g)/6.25

Question 2

conditions that necessitate a positive nitrogen balance

3

Answer 2

• pregnancy
• body builder
• a growing child

Question 3

consuming the correct amount of protein should result in a

Answer 3

zero nitrogen balance

Question 4

released from muscle due to protein breakdown

Answer 4

alanine

Question 5

• transports nitrogen
• transfers carbons to the liver for GNG

Answer 5

alanine

Question 6

the brain can use […] as an alternative to glucose

Answer 6

ketone

Question 7

what lab values would be elevated as a result of ketone body metabolism due to a low calorie diet?

2

Answer 7

acetoacetate
B hydroxybutyrate

Question 8

elevated BUN indicates increased […] catabolism

Answer 8

amino acid

Question 9

9-4-4 rule of thumb for calculating calories from diet

Answer 9

9 fatty acid
4 carbohydrate
4 protein

calories/gram

Question 10

proteins have [..] calories/gram

Answer 10

4

Question 11

in fed states, excess AA are converted to

2

Answer 11

glucose
FA

stored in liver

Question 12

where does the urea cycle occur?

Answer 12

liver

Question 13

where does AA catabolism occur?

Answer 13

peripheral tissues

Question 14

what vitamin acts as a coenzyme in transaminase reactions?

Answer 14

B6 (pyridoxal phosphate)

Question 15

chemical reaction that transfers and amino group to a ketoacid to form new amino acids

Answer 15

transamination

Question 16

transamination reactions

3

Answer 16

• alanine -> pyruvate
• aspartate -> oxaloacetate
• glutamate -> a-ketogluterate

Question 17

deamidation + transamination reaction

Answer 17

Asn -> Asp -> oxaloacetate

Question 18

dehydratase reactions

2

Answer 18

serine -> pyruvate
cysteine -> pyruvate

Question 19

a-ketogluterate
oxaloacetate
pyruvate

glucogenic or ketogenic?

Answer 19

glucogenic

Question 20

anthing with Acetyl-CoA cannot be used to make

Answer 20

glucose

Question 21

carbons that can be used to generate ketone bodies and fat, but not glucose

Answer 21

ketogenic

Question 22

the two inputs into the urea cycle

Answer 22

glutamate
aspartate

Question 23

how do we get glutamate for the urea cycle in the starved state?

Answer 23

a-ketoglutarate + alanine –> glutamate

transaminase reaction

Question 24

a ketoglutarate can be generated from

Answer 24

alanine via pyruvate

Question 25

how do we get aspartate for the urea cycle in a starved state?

Answer 25

Question 26

what AA can the liver make, even in a starved state? | 3

Answer 26

alanine aspartate glutamate

Question 27

AA that is main focus in the liver during starvation

Answer 27

alanine

Question 28

AA that is main focus in the kidney during starvation

Answer 28

glutamine

Question 29

byproduct of glutamine to glucose production found in urine

Answer 29

ammonia

Question 30

tyrosine is not typically considered an essential amino acid, but is for patients with [...]

Answer 30

phenylketouria | cannot make Tyr from Phe

Question 31

essential amino acids | PVT TIM HALL

Answer 31

Phenylalanine Valine Tryptophan Threonine Isoleucine Methionine Histadine Arginine Lysine Leucine | PVT TIM HALL

Question 32

excess protein is

Answer 32

catabolized

Question 33

fat cannot be converted to

Answer 33

sugar

Question 34

excess fatty acids are stored as

Answer 34

fat

Question 35

there is [...] of carbon from Acetyl CoA to PEP

Answer 35

no net flux

Question 36

any disruption in the urea cycle will cause

Answer 36

hyperammonia | reduced urea formation

Question 37

the urea cycle involves enzymes in the | where in the cell

Answer 37

cytosol and mitchondia

Question 38

BUN and urinary urea nitrogen indicate protein catabolism [...] the urea cycle | before or after

Answer 38

after

Question 39

during starvation, do we expect an increase in BUN or Urinary Urea Nitrogen?

Answer 39

both

Question 40

nitrogen balance is a simple consideration of nitrogen [...] vs nitrogen [...]

Answer 40

in out

Question 41

a negative nitrogen balance indicates a need to [...] protein in the diet

Answer 41

increase

Question 42

if the nitrogen is removed from alanine the remaining carbon backbone is a

Answer 42

pyruvate

Question 43

AA made in the urea cycle but still considered essential in the diet

Answer 43

arginine

Question 44

someone with PKU lacks what enzyme?

Answer 44

phenylalanine hydroxylase | converts Phe to Tyr

Question 45

a primary site for amino acid catabolism in the well fed state is in the

Answer 45

liver

Question 46

a [....] amino acid can be catabolized into metabolites used to make lipids

Answer 46

ketogenic

Question 47

in the starved state, there are high levels of catabolism in the [...] that lead to increased levels of [...] in the blood

Answer 47

muscle alanine

Question 48

transaminase use the [...] form of vitamin B6 as a cofactor

Answer 48

pyridoxal phosphate

Question 49

after a transmaminase removes a nitrogen from an amino acid....

Answer 49

it remains bound to the enzyme until transferred to a different carbon skeleton | modified enzyme state

Question 50

urea is a product of cleaving the end of

Answer 50

arginine

Question 51

the two nitrogens of urea are derived from

Answer 51

aspartate and ammonia

Question 52

blood urea decreases in what disorders? | 3 examples

Answer 52

* liver failure * pregnancy * urea cycle disorders