Tuesday, 3 February 2015

HIGH YIELD POINT FOR BIOCHEMISTRY 2015



HIGH YIELD POINT FOR BIOCHEMISTRY 2015


http://www.doctorsquiz.com important topics for DNB-CET, AIPGMEE, FMGE, DNB-PDCET, UPSC-CMS online medical examination .



Glycine: • smallest amino acid. inhibitory neurotransmitter in spinal cord (blocked by toxm in tetanus), synthesis of heme and collagen and bile salts and acids

Alanine: • alanine cycle during fasting. major substrate for gluconeogenesis (transarninated mto pyruvate)

Valine: • essential A..A.. • branched-chain amino acid.> not degraded in liver. • utilized by muscle.

• increased in maple syrup urine disease

Leucine: • essential A.A... • branched-chain amino acid. • not degraded in liver. • kerogenic, •

utilized by muscle, • increased in maple syrup urine disease

Isoleucine: • essential .A.../\.• • branched-chain amino acid, • not degraded in liver. • utilized by

muscle, • increased in maple S)'TUp urine disease

Methionine: • essential A.A. • polypeptide chain initiation, • methyl donor (as S·adenosyl methionine)

Proline: • helix breaker. • only amino acid with side chain attached to a-amino group. • hydroxylation in collagen aided by ascorbic acid, • binding site for cross-bridges in collagen Phenylalanine: • essential A.A. • increased in phenylketonuria (PKC). • aromatic side chains: increased in hepatic coma

Trypropban: •essential AA, • serotonin. niacin, and melatonin precursor. • aromatic side chains:

increased in hepatic coma

Cvsteiue: • forms disulfide bonds,• component of glutathione, an important antioxidant in RBCs

(deficient in G6PD deficiency}

Serine: • single-carbon donor: converted into glycine when carbon removed. • phosphorylatcd by

k.nases

Threonine: • essential A..A. • phosphorylated by kinases

Tyrosine: • precursor of catecholamines, melanin, thyroid hormones. • phosphory lated by

kinases: important in second messengers. • aromatic side chains: increase in hepatic coma. • must be supplied in diet in phenylketonuria

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