Biochemistry and genetics Flashcards Preview

Z MD1 Respiratory block > Biochemistry and genetics > Flashcards

Flashcards in Biochemistry and genetics Deck (21):

what does increased phenylpyruvate cause?

damages the brain and inhibits tyrosinase (the melanin making enzyme)


what is alkaptonuria caused by?

error in an enzyme involved in the tyrosine catabolism


what does phenylketonuria cause?

within the first few weeks of life --> can cause mental retardation, seizures, tremors and behavioural disorders


where is the CFTR gene located

on chromosome 7


what does CF lead to?

a build up of mucous in the lungs --> repeated chest infections --> lung damage Mucous also blocks the digestive system Reproductive systems also affected


what is the multiple repeat sequence of collagen



what mutation causes sickle cell anaemia and why does it cause problems

mutation of glutamate to valine the hydrophobic vlaine binds to a hydrophobic pocket present in deoxy-Hb and forms an insoluble crystalline structure


What causes esch-Nyhan syndrome? And what does if do?

Lack HGPRT enzyme- recycles purine for DNA synthesis Causes self mutilation


How is red-green colour blindness inherited?

X linked recessive


what causes CF?

defective cystic fibrosis transmembrane conductance regular gene (CFTR) --> codes for a chloride channel active in membranes of the lungs, liver, pancreas, intestines, reproductive tract and skin


what causes osteogenesis imperfecta

glycine to cysteine mutation - side chain of cysteine disrupts the helix as it doesnt fit in the middle - causes a kink and interferes with strand alignment --> brittle bones


what causes marfan syndrome

mutation in fibrillin 1 gene --> decreased production of fibrillin-1, delayed transport of the protein out of the cell, or reduced amounts of the protein in the ECM


how is CF tested for as an infant

the guthrie heel prick blood test - look for elevated immunoreactive trypsin secreted by the panreas Diagnosis then confirmed by sweat test (excessive NaCl)


what kind of inheritance is blue-yellow colour blindness

autosomal dominant


what is the mutation in the CFTR gene causing CF

a phenylalaine amino acid is deleted


what causes phenylketonuria

a build up of Phenylalanine due to the lack of phenylalanine hydroxylase enzyme --> causes it to go through an alternative metabolism where it is converted into phenylpyruvate


what makes collagen so strong

hydrogen from glycine project into the middle - forms hydrogen bonds


Mendels first and second laws

first - parents have 2 copies of a gene for a character second - different characters are inherited independently


how is PKU tested for?

the guthrie test - a dried spot from a heel prick = tested for phenylpyruvate and other metabolites


what causes albinism

genetic lack of tyrosinase --> this would usually go on to catalyse the synthesis of melanin


what are examples of one gene mutations involving collagen

osteogenesis imperfecta Ehlers danlos marfans