Exam 3: Protein metabolism and funciton

Question 1

describe metabolism of proteins

Answer 1

Dietary protein consists of long, complex chains of amino acids.
In the digestive process, enzymes (proteases) in the stomach and
small intestine break the complex protein down into polypep-
tides and then into individual amino acids. The amino acids are
absorbed through the wall of the small intestine, pass into the
blood, and then pass to the liver via the portal vein

Question 2

function

Answer 2

structural
transport
enzyme
hormone and neurotransmitter
immune
acid-base balance
fluid balance
energy
movement

Question 3

what happens to excess nitrogen?

Answer 3

Through
the process of deamination, the amino group (NH2) containing
the nitrogen is removed from the amino acid, leaving a carbon
substrate known as an alpha-ketoacid. The excess nitrogen must
be excreted from the body. In essence, the liver forms ammonia
(NH3) from the excess nitrogen; the ammonia is converted into
urea, which passes into the blood and is eventually eliminated by
the kidneys into the urine

Question 4

alpha-ketoacid is a substrate of AA after deamination. what are the fates?

Answer 4

• oxidation for energy
• accept amino group to make another amino acid
• form glucose or acetyl CoA or fat

Question 5

glucogenic amino acids,

Answer 5

glucose forming

Question 6

ketogenic amino acids

Answer 6

metabolized in the liver
to acetyl CoA, which may be used for energy production via the
Krebs cycle or converted to fat