Biochemistry

Question 1

Pyruvate Dehyrdogenase Deficiency:-
Pyruvate can’t be metabolised to acetyl CoA and shunt towards lactate and cause lactic acidosis
Rx: KETOGENIC DIET( high fat low carbs moderate protein)
Two types of amino acids glucogenic and ketogenic
Ketogenic amino acids are Leucine and Lysine metabolized to ketone body precursor acetyl CoA

Question 2

Duchenne Muscular Dystrophy:-
X-linked recessive disorder in dystrophin gene most common mutation is deletion resulting in framshift and less common is non sense mutation result in premature stop codon
C/F include proximal muscle weakness, calf pseudohypertrophy and gower’s sign and increase CK level

Question 3

Fatty acid synthesis vs fatty acid oxidation:-
When ATP is abundant it inhibits isocitrate dehydrogenase
Citrate is accumulated in mitochondrial matrix and via citrate shuttle reach to the cytosol
ATP citrate lyase breakdown citrate into acetyl CoA
Acetyl CoA converts into malonyl CoA via acetyl CoA carboxylase rate limiting step
Malonyl CoA inhibits carnitine Acyl transferase which inhibits carnitine to shuttle acyl CoA from cytosol into the mitochondria

Question 4

Hartnup Disease:-
Defect in neutral amino acid transporter in small intestine and kidney
Clinical features are related to tryptophan deficiency
Tryptophan is precursor for niacin, serotonin, melatonin and deficiency of niacin cause pellagra-like symptoms
Treatment: high protein diet with nicotinamide supplements

Question 5

Dyskeratosis congenita:-
Telomere maintain chromosomal integrity and preserved in rapidly dividing cells (epithelial cells, lymphocytes, hematopoetic stem cells) by telomerase
Defect in telomerase leads to premature cell death in rapidly dividing cells cause mucocutaneous changes (oral leukoplakia and dystrophic nails) and pancytopenia and pul fibrosis due to alveolar epithelial cell death