N: PROTEIN: metabolism

Question 0

define endogenous amino acid:

Answer 0

from within the body

Question 1

define exogenous amino acid:

Answer 1

from food

Question 2

what does a protein molecule consist of?

Answer 2

amino acid
C-H
side group
carboxylic acid

Question 3

what must first happen to proteins before entering catabolic pathways?

Answer 3

they must first have their nitrogen containing groups removed
via deamination OR transamination

Question 4

outline process of deamination:

Answer 4

deamination = straight stripping off of amino group off the amino acid

this occurs in the liver
amino acid group -> keto acid producing NH3(toxic converted to urea)
non-essential amino acids can reverse the process using NH3 to go back to amino acid group

Question 5

outline process of transamination:

Answer 5

pass amino group onto another molecule to make a new amino acid

Question 6

where do amino acids feed into metabolism cycle?

Answer 6

depend on side group, they can feed into:

• > pyruvate => can generate glucose when carb not available
• > acetyl-CoA
• > enter TCA via another intermediate
• • some AA can feed into more than one point!

Question 7

basic steps in protein metabolism?

Answer 7

protein

• > amino acids
• > pyruvate, acetyl-CoA(lots of energy can make fatty acids from acetyl-CoA), TCA cycle
• > ETC

Question 8

what is the nitrogen balance?

Answer 8

when nitrogen intake from protein in food = nitrogen excretion in urine, sweat and faeces

Question 9

describe negative nitrogen status:

Answer 9

muscle(protein mass) loss eg. starvation, sickness

Question 10

describe positive nitrogen status:

Answer 10

muscle(protein mass) gain eg. children, pregnant women