Biochemistry 2.0 Flashcards
deficient enzyme in Von gierke’s disease
glucose-6-phosphate
deficient enzyme in Corri’s disease
alpha-1,2, glucosidase
deficient enzyme in pompe’s disease
lysosomal alpha-1,4, glucosidase
deficient enzyme in McArdle’s disease
glucogen phosphorylase
(myophosphorylase)
features of Von Gierk’s disease
hypoglycaemia
hepatomegaly
lactic acidosis
features of Corri’s disease
hypotonia
wasting
hepatomegaly
elevated CK
features of pompe’s disease
cardiomegaly
(pompe is huge)
macroglossia, hepatomegaly, hypotonia
features of McArdle’s disease
myoglobinuria during exercise
myalgia
(jumping over Mc Hurddles)
deficient enzyme in Gauchers
beta-glucocerebrosidase
(gaucho’s food causes energy to getsto your head)
what type of mutation is associated with gauchers
splice site mutation
defective enzyme in Tay Sach’s disease
hexosaminidase A
(tay bridge is huge)
defective enzyme in nielmann-pick disease
sphingomelinase
defective enzyme in Fabry’s disease
alpha-galactoside
defective enzyme in krabbe’s disease
galactocerebrosidase
(krabs gallop)
features of gauchers disease
hepatosplenomegaly
bone pain
aseptic necrosis of femur
thrombocytopenia
anaemia
features of tay sachs disease
cherry red spots on macula
normal liver size
developmental delay
features of neilmann pick disease
hepatomegaly
cherry red spots on macula
lipid-laden macrophages
features of Krabbe’s disease
peripheral neuropathy, optic atrophy, globoid cells
G6PD deficiency mode of inheritance
X linked recessive
lab findings on blood smear in G6PD deficiency
heinz bodies
bite cells
(bite into some heinz ketchup)
enzyme affected in PKU
phenylalanine hydroxylase
2 types of PKU
BH4 deficiency - usually die in infancy
phenylalanine enteropathy - increased phenylalnine levels in pregnant women with untreated PKU
when is PKU tested in babies
2-3 days after birth
(not at birth due to normal levels with maternal enzyme)
treatment for PKU
increased tyrosine and decreased phenylalanine in diet
pathophysiology of maple syrup disease
reduced degradation of branched amino acids (I, S, V) due to a decreased branched-chain alpha-ketoacid dehydrogenase
= increased keto-acids in blood
deficient enzyme in maple syrup disease
alpha keto-acid dehydrogenase
a rise in what amino acids occur in maple syrup disease
branched amino acids;
Isoleucine
Leucine
valine
condition which causes urine to turn black in prolonged exosure to air
alkaptonuria
alkaptonuria mode of inheritance
autosomal recessive
pathway affected in alkaptonuria
defect in homogentisate 1,2, dioxygenase
metabolism of phenylalanine and tyrosine (tyrosine to fumarate)
results in a build up to toxic homogentisic acid
Ddifference in marfan habitus in homocystinuria compared to marfans
marfans - lens subluxes up and out
homocystinuria - lens subluxes down and in
(marFAN - fans out)
cystinuria diagnostic test
urinary Na cyanide nitroprusside test
cystinuria is caused by defective reabsorption of what amino acids
COLA causes stones
Cystine
Ornithine
Lysine
Arginine
mode of inheritance of familial hypercholesterolaemia
autosomal dominant
pathogenesis of familial hypercholesterolaemia
defective/absent LDL receptors or defective apo B100
mode of inheritance of hyperchylomicronaemia
autosomal recessive
pathogenesis of hyperchylomicronaemia
lipoprotein lipase or apo CII deficiency
mode of inheritance of dysbeta-lipoproteinaemia
autosomal recessive
pathogenesis of familial dysbeta-lipoproteinaemia
APO E deficiency
mode of inheritance of hypertriglyceridaemia
autosomal dominant
pathogenesis of hypertriglyceridaemia
hepatic overproduction of VLDL
familial dyslipidaemias - I, II, III, IV
Can Cholesterol DysBeliefs Tri again)
I - hyperchylomicronaemia (AR)
II - hypercholesterolaemia (AD)
III - dysbeta-lipoproteinaemia (AR)
IV - hypertriglyceridaemia (AD)
D lactic acid is increased in what conditions
short gut syndrome
propylene glycol toxicity
increased levels of what result in oxidative stress in G6P deficiency
oxidized glutathione (due to low levels of NADPH)
what condition causes pearly papules on the skin, aggressive behaviour, frontal bossing, enlarged tongue
hunter syndrome
what condition causes hepatosplenomegaly, clouded cornea, hirutism, developmental delay and skelatal anomalies
hurler syndrome
deficient enzyme in hurler syndrome
alpha-L-iduronisase
deficient enzyme in hunter syndrome
iduronidate-2-sulfatase
alkaptonuria is due to what defective enzyme
homogentisic dioxygenase
treatment for alkaptonuria
high vitamin C
reduce phenylalanine and tyrosine
vitamin B6 features
(pyridoxine)
sideroblastic anaemia, peripheral neuropathy, seizures
vitamin B7 features
(biotin)
alopecia, dermatitis
caherins role and what ion they require to function
cell-cell adhesion
Calcium (‘calcium-dependant adhesion’)
i.e. desmoglein is caused by Ab against desmoglein 3 which is a type of cadherin
drugs that affect folate metabolsim
TMP
Trimethoprim
methotrexate
pyrimethamine
phenytoin (affects absorption)
hereditary fructose intolerance is caused by what defective enzyme
aldolase B
neonatal diabetes is caused by what defective enzyme
glucokinase
rate limiting step in urea cycle
carbomyl phosphate synthetase I
vit B12 deficiency causes elevated levels of what
methylmalonyle mutase
(this is normal in folate deficiency)
ezyme that catalyses conversion of phospholipids to arachidonic acid
phospholipase A2
enzyme that catalyses conversion arachidonic acid to leukotrienes
lipoxagenase
enzyme that converts glutamate to GABA
glutamate decarboxylase
function of proteosomes
breakdown of proteins
function of peroxisomes
catabolism of long chain fatty acids
function of lysosomes
catabolism of polysaccharides and proteins
whats the main mechainsm by which vit D supplements increase Ca levels
increases Ca reabsorption in the gut
mode of inheritence of hunter syndrome
x-linked recessive
mode of inheritance of hurler syndrome
autosomal recessive
what is low in PKU
dopamine
melatonin
(due to decreased tyrosine which is the precursor to dopamine and melanin)
what enzymes are inhibited by lead toxicity
ferrochelatase
alpha-aminolevulinic acid dehydrogenase
features of lead toxicity
neurological
gatsroentrointestinal
microcytic anaemia
features of galactosaemia
infantile cataracts
vomiting
jaundice
intellectual disability
enzyme affected in galactosaemia
galactose-1-phosphate uridyltransferase
in allergic reactions, what enzyme within the cytoplasm will increase
phsopholipase C (increase permability and cause vasodilatation)
what is the mechanism by which vitamin C deficiency causes bleeding and poor wound healing
defective hydroxylation of collagen residues
a defect in what mechanism occurs in folate deficiency
transfer of methyl groups
mechanism in cyanide poisoning
inhibition of electron transport
features of cyanide poisoning
often seen in house fires
nausea/vomiting
respiratory
bright red venules on ophthalmoscopy
almond odour like breath
features of cyanide poisoning vs C0
similar but cyanide causes distinct almon odour to breath
usually when removed from the causative agent, symptoms resolve in C0 poisoning
defective enzyme in malignant PKU
DHPR
the rate of what enzymatic reaction is increased in patients taking steroids resulting in hyperglycaemia
oxaloacetate to phosphenolpyruvate by the enzyme PEP carboxykinase
(irreversible step in gluconeogenesis)
what amino acid is a precursor to thyroid hormone
phenylalanine (which is a precursor to tyrosine)
thyroid hormone is made of tyrosine
describe the effects of defect dopamine-beta-hydroxylase
causes high dopamine and low epinephrine = hypotension
DBH catalyses (with the use of co-enzyme vitamine C) dopamine to epinephrine so when defective = low epinephrine
dopamine-beta-hydroxylase requires what co-factor to convert dopamine to epinephrine
vitamin C
catecholamine synthesis / tyrosine catabolism
Pure True Love Does Not Exist
phenylalanine
tyrosine
L-dopa
dopamine
norepinephrine
epinephrine
what pathway does salbutamol activate
B2 agonists stimulate Gs pathway
where in the cell is insulin synthesised
rough endoplamsic reticulum
what does acetyl CoA catalyse the rate limiting step of
fatty acid synthesis
acetyl-CoA to Malonyl coenzyme A
what compound is used in steroid synthesis
NADPH
features of porphyria cutanea tarda
sun exposed skin blisters
tea coloured urine
midly elevated transaminases
enzyme affected in prophyria cutanea tarda
UROD enzyme
what mechanism will be inhibited in vitamin K deficiency
carboxylation of glutamic acid
(carboKylation - vitamin K)
vitamin K deficiency features
bleeding
prolonged PT and PPT
can occur after prolonged abx i.e. cephalosporins
features of galactosaemia
e.coli infections
vomiting
diarrhoea
jaundice
hepatomegaly
cataract
Deficient enzyme in classic galactosaemia
GALT
Galactose-phosphate uridyltransferase
Classic galactosaemia causes elevated levels of what
Galactitol (due to upregulation of galactose which is reduced to galactitol by aldose reductase)
Galactose-1-phosphate (GALT is required to convert galactose-1-phosphate to glucose-1-phosphate)
What does a positive urine reducing substrate assay indicate
Inborn error of carbohydrate metabolism
What is the main enzyme in gluconeogenesis and its role
Fructose-1,6-biphosphatase
fructose-1,6- biphosphate is converted to fructose-6-phosphate which can then be converted to glucose-6-phosphate
Lead poisoning will cause a rise in what substance in the blood
aminovuelinate
Erythrocyte protoporphyrin
Treatment for organophosphate poisoning and its mechanism
Atropine (muscarinic antagonist)
Pralidoxime (promotes acetylcholinesterase)
Pathophysiology of organophosphate poisoning
Irreversibly inhibits acetylcholinesterase
Pathophysiology of cyanide poisoning
Affects electron transport chain by inhibiting cytochrome C oxidase
drugs that affect folate absorption and how
affect metabolism by inhibiting dihydrofolate reductase - trimethroprim, methotrexate, pyrimethamine
affect intestinal absorption of folate - phenytoin
features of inclusion cell disease
coarse facial features
restricted movement
recurrent infections
clouding cornea
hepatosplenomegaly
pathophysiology of inclusion cell disease
defect in N-acetylglucosamine-1-phosphate transferase resulting in failure of the golgi apparatus to transfer phosphate to mannose residues on specific proteins
defective enzyme in inclusion cell disease (I-cell)
N-acetylglucosmine-1-phosphate transferase
where in the cell is the defect in I-cell disease
golgi apparatus
(defect enzyme N-acetylglucosamine phosphate transferase = unable to transfer phosphate to mannose residues on specific proteins in golgi apparatus)
structure of collagen
triple helix
