Amino Acids

Question 1

What type of acid contains & produces the most energy?

Answer 1

fatty acids

Question 2

What are the sources of carbon?

Answer 2

• TCA cycle
• glycolysis
• PPP

Question 3

What is both an essential & nonessential amino acid?

Answer 3

arginine

Question 4

What is the difference between endopeptidase & exopeptidase?

Answer 4

• endo: cleaves internal peptide bonds
• exo: cleaves amino acids one at atime from the carboxyl or amino end

Question 5

What 2 amino acids are only ketogenic?

Answer 5

leucine & lysine

Question 6

What amino acid is considered a major ketogenic?

Answer 6

leucine

Question 7

How are proteins broken down into glucogenic amino acids?

Answer 7

Converted into intermediates used to make glucose

Question 8

How are proteins broken down into ketogenic amino acids?

Answer 8

Converted into intermediates used to make ketone bodies

Question 9

What are the 3 ways oxygen degradation can happen?

Answer 9

1. normal amino acid metabolism
2. excess dietary protein
3. starvation or diabetes

Question 10

What is th elocation of oxygen degradation of amino acids?

Answer 10

liver

Question 11

What is the function of oxidative degradation of amino acids?

Answer 11

amino groups are removed from amino acids

Question 12

What are the 2 metabolic fates of amino groups?

Answer 12

1. Ammonia can be used in the synthesis of other amino acids
2. Ammonia can be used in the urea cycle and excreted via urination

Question 13

Aminotransferases exist for all amino acids except for what?

Answer 13

Thr & Lys

Question 14

What is the key enzyme & cofactor for transamination?

Answer 14

• enzyme: aminotransferase
• co-factor: PLP

Question 15

What are the characteristics of glutamate dehydrogenase reaction?

Answer 15

• function: glutamate <-> alpha-ketoglutarate + NH4
• location: liver mitochondria
• enzyme: glutamate dehydrogenase

Question 16

How is the glutamate dehydrogenase reaction regulated?

Answer 16

• activated by ADP
• inhibited GTP
• flipped when alpha-keto -> glutamate

Question 18

What are the required co-factors for glutamate dehydrogenase reaction?

Answer 18

NAD or NADP
* flipped when alpha-keto -> glutamate

Question 19

What is the major transport form of ammonia & most abundant amino acid in the blood?

Answer 19

glutamine

Question 20

What are the characteristics of the glutamine synthetase reaction?

Answer 20

• function: glutamate + NH4 -> glutamine
• location: extra-hepatic tissues

Question 21

What si the key enzyme & required cofactor glutamine synthetase reactions?

Answer 21

• enzyme: glutamine synthetase
• cofactor: ATP

Question 22

What are the characteristics for the glutaminase reaction?

Answer 22

• function: glutamine -> glutamate + NH4
• location: liver mitochondria
• enzyme: glutaminase

Question 23

What are the links to the TCA cycle from the urea cycle?

Answer 23

• OAA
• alpha-keto
• fumarate

Question 24

What are the characteristics of the urea cycle?

Answer 24

• function: disposal of nitrogen
• location: mitochondria & cytosol in liver
• rate limiting enzyme: carbamoyl phosphate synthetase 1

Question 25

What are the 2 ways used to enter the urea cycle?

Answer 25

carbamoyl phosphate & aspartate

Question 26

How is the urea cycle regulated?

Answer 26

at rate limiting step -> N-acetylglutamate = allosteric activator of CPS 1

Question 27

What is marasmus?

Answer 27

• inadequate intake of both protein & caloric energy
• symptom: loss of fat reserves & muscle mass

Question 28

What is Kwashiorkor syndrome?

Answer 28

• inadequate intake of just protein
• symptom: Easy hair pluckability, Pitting edema, Skin breakdown, Delayed wound healing