Amino acid metabolism

Question 1

what do amino acids make?

Answer 1

protein

Question 2

amino acid general structure

Answer 2

amine group, carboxylic acid group, unique side chain

Question 3

essential amino acids

Answer 3

obtained from dietary sources of protein

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Question 4

non-essential amino acids

Answer 4

made in our body

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Question 5

after a large meal

Answer 5

protein broken into amino acids

amino acids used as building blocks in protein synthesis

Question 6

why do cells need to make use of amino acids?

Answer 6

ammonia (amine group) can become toxic if it is freed and builds up

Question 7

how do we get rid of ammonia?

Answer 7

ammonia must be removed, sent to liver to be metabolized into a less toxic molec: urea

Question 8

what enzyme transfer amino group from amino acids to keto acids

Answer 8

transaminases/aminotransferases

Question 9

transamination reactions

Answer 9

reversible

can go in either direction using the same enzyme

Question 10

what do transamination reactions require?

Answer 10

pyridoxine (Vitamin B6) as a cofactor

Question 11

alanine transamination

Answer 11

in a muscle cell
alanine transaminase (ALT) switches amino group on alanine with oxygen on alpha-ketoglutarate
results in pyruvate (with oxygen group) and glutamate (with amino group)

Question 12

what do we do with pyruvate? (option 1)

Answer 12

pyruvate dehydrogenase converts pyruvate to acetyl-CoA

acetyl-CoA can enter citric acid cycle

Question 13

what do we do with pyruvate? (option 2)

Answer 13

1) lactate dehydrogenase converts pyruvate to lactate which then travels to the liver
gluconeogenesis or glycolysis
make acetyl-CoA and ATP

Question 14

why is glutamate unique?

Answer 14

it is the only amino acid that doesn’t have to transfer its amine group to another molecule

Question 15

how does glutamate get away with not transferring its amine group to another molecule?

Answer 15

it undergoes oxidative deamination

Question 16

oxidative deamination

Answer 16

process that removes hydrogens and an amino group

Question 17

oxidative deamination where does it occur

Answer 17

glutamate travels to liver mitochondria bc free ammonia in cytoplasm is harmful

Question 18

oxidative deamination step 1

Answer 18

glutamate dehydrogenase takes glutamate to alpha-ketoglutarate
H2O is used
NAD+ goes to NADH
releases free ammonia

Question 19

where does free ammonia go?

Answer 19

to urea cycle

Question 20

when would these reactions run in reverse?

Answer 20

if we needed amino acids, such as alanine

Question 21

what does the cell have to do after the amine group is gone?

Answer 21

metabolize the rest of the amino acid

Question 22

glucogenic amino acids

Answer 22

serve as substrates to make new glucose

EX: alanine, glycine

Question 23

ketogenic amino acids

Answer 23

form ketone bodies

EX: leucine, lysine

Question 24

amino acids that feed into citric acid cycle

Answer 24

used to make ATP in CAC

EX: valine, aspartate

Question 25

what amino acid is glucogenic, ketogenic, and feeds into citric acid cycle?

Answer 25

phenylalanine

Question 26

glucogenic amino acids become?

Answer 26

pyruvate or CAC intermediate

can produce glucose under low glucose conditions

Question 27

ketogenic amino acids become?

Answer 27

ketone bodies when energy is low

Question 28

when do we degrade proteins/amino acids?

Answer 28

when energy sources are low

Question 29

higher protein diet requires more…

Answer 29

Vitamin B6 (bc it processes amino groups from proteins)