BIOCHEM GP Flashcards
deficiency of transketolase causes a problem in the Pentose phosphate pathway to generate what products?
Ribose-5-phopshate
Fructose-6-phospahte
pt has a hx of skin infection which was tx with sulfonamide.
he presented two days later with pallor, malaise, jaundice. labs show abnormal erythrocytes and increased reticulocytes
What is dx?
Patient now has deficiency of G6DP
what drugs and food products cause G6PD deficiency?
Antibiotics:
1. Skin - sulfonamides
2. UTI - nitrofuratoin
anti-malarial
1. Primaquine
2. Chloroquine
Anti-TB
1. isoniazid
food
1. fava beans
ethnicity
1. african american.
Pt has been in fasting state (24hrs). But labs shows normal glucose level.
What reaction cycle has taken place so that the glucose levels remain untouched?
during fasting state, hepatic pyruvate is converted to form glucose by Acetyl-CoA. so she has normal levels of glucose in the body even though she has been in fasting state.
D-glucose trasnmembrane transport is much faster than any other type of glucose because?
D-glucose has affinity towards GLUT(Glucose transport protien). Therefore it has facilitated diffusion or carrier-mediated trasnport which is much faster.
during fasting state (>24hrs) how is glucose level maintained intracellular?
Cortisol initiates gluconeogenesis ( works intracellular)
G6PD is used for which all reactions?
fatty acid, cholesterol, glutathione biosynthesis
muscle strength increases post work out right after taking a carb rich diet. Why is this?
Crab rich diet increases gluconeogensis in skeletal muscle cells. this is becasue of the abundance of CA2+
symptoms:
hepatic fibrosis
abnromal polysacchrides in hepatocytes
hypotonia
hepatomegaly
hypoglycemia
ketoacidosis
what is dx? wha is pt deficient in?
Cori Disease (glycogen type 3)
deficient in glycogen debranching enzyme
symptoms:
poor excercise
muscle cramps
myoglobinuria
rise in ammonia levels during exercise
muscular blood flow increases rapidly during exercise
what is pt deficient in? what is dx?
deficient in myophosphorylase
dx is McArdle disease ( glycogen type 5)
cardiomyopathy
hypotonia
exercise intolerance
lysosomal dysfunction
hepatomegaly
dx? deficiency?
Pompe disease ( glycogen type 2)
deficient in alpha-glycosidase.
beta-oxydation of fatty acids is inhibited in a high carb high protein diet due to?
carbs increase Malonyl-CoA, which inhibits Carnitine Palmitoyltransferase which is an ezyme responsible for transporting fatty acid to mitochondria where Beta Oxidation takes place.
repeated copper reduction test is positive but urine glucose dipstic test is negative. this test shows defect in metabolism of ?
fructose metabolism.
pt has a sugar metabolism problem. but his diet includes fruits, vegetables and meat.deficiency in what enzyme leads to elevated fructose levels in blood and urine ?
what is dx?
fructokinase.
essential fructosuria
patient admitted to ER after eating a spoon of honey. test shows positive copper reduction test but negative urine gluocse test. patient exhibits, hypoglycemia, jaundice, vomiting, and cirrhosis.
what is imapired in this pt?
what is dx?
aldolase B deficiency
hereditary fructose intolerance.
in the absenceof fructokinase, what compound takes over ?
hexokinase.
fasting patient presents with seizure, muscle weakness, and low sugar levels. Further examination shows no ketone content in urine. she was vomiting, and is having faitgue. she feels better when she was given food.
What is the dx?
Medium Chain Acyl-CoA dehydrogenase deficiency.
How does hyperammonemia affect
1. TCA cycle?
2. CNS Functions?
hyperammonemia depletes
1. Alpha-ketoglutarate needed in TCA cycle
2. GABA which inhibits CNS over firing.
food rich in what nucleoside is recommended for a patient diagnosed with orotic aciduria?
uridine rich diet
ammonia tx for hyperammonemia due to urea cycle disorder?
sodium benzoate, sodium phenylacetate, soidum phenylbutyrate.
Patient has celiac disease. He has macrocytic megalobalstic anaemia. His Homocystein levels are elevated.
How can his homocystein levels be brought back to normal levels?
what is he deficient in?
He can be given folate. Vit B9. to produce tetrahydrofolic acid to decrease his homocystein levels and increase his methionine levels.
How does Arsenic poisoing affect Pyruvate dehydrogenase ?
Arsenic poisoning affect lipoic acid which help pyruvate dehydrogenase.
pyruvate dehydrogenase is responsible for converting pyruvate into acetyl-CoA which goes into the TCA cycle to produce glucose.
muscle strength increases post work out right after taking a carb rich diet. Why is this?
Crab rich diet increases gluconeogensis in skeletal muscle cells. this is becasue of the abundance of CA2+
patient has low carnitine content. Murmers, and hypotonia. Which end product is she deficient in?
What is dx?
acetoacetate.
she has primary carnitine deficiency.
pt has hemolytic anaemia and is unable to generate NADPH. but theres is coversion of Ribose-5-phopsahte and Fructose-6-phospahte.
What enzymes enables this formation?
Transketolase of Nonoxidative reaction in the HMP Shunt.
Orotic acid increase in urine, depleted BUN levels, asterixis, somnolence, cerebral oedema with megalobastic anoemia suugest?
orotic aciduria
KRAS gene will bind to what ?
KRAS mutation is common in what type of carcinomas?
Gproteins (GTP,GDP)
colorectal cancer, polyp, pancreatic malignancies.
GTP is the active compound which leads to tumor muttaions.
Gprotein coupled receptors such as TSH,LH,FSH has 3 domains.
1. extracellular domain
2.transmembrane domain
3.intracellular domain.
if the domain consists of hydrophobic amino acids such as Alanine, isoleucine, valine, leucine, tryptophan, phenylalanine, methionine, proline, glycine..
it also consist of multiple alpha helices. then what is that domain?
what is the function?
transmembrane domain.
function: anchoring to cell membrane.
symptoms:
hepatic fibrosis
abnromal polysacchrides in hepatocytes
hypotonia
hepatomegaly
hypoglycemia
ketoacidosis
normal lactate levels
limit dextrin structures found in cytosol
what is dx? wha is pt deficient in?
Cori Disease (glycogen type 3)
deficient in glycogen debranching enzyme
zinc ion aminod acid mastif links to what?
thyroid hormone, steroids, fat soluble vitamins.
Tx to decrease ammonia levels in GI due to ammonia bacteria ?
lactulose to acidify GI tract.
pt with ornithine deficiency or any urea cycle problems should have what kinda of nutritional restriction?
uridine
low protein diet.
what is the cofactor in transamination of alanine to alpha-ketopglutarate?
Vitamin B6 : PYRIDOXINE
Puryvate dehydrogenase complex is activated by which factors?
cA2+
ADP
NAD+/NADH ratio
Easy bruising+easy trauma+suturing difficutly on skin+hyperextensible skin+ecchymosis of forearms and pretibial region+umbilical hernia. Biopsy shows defective collagen synthesis.
This is collagen problem.
What is the dx? Which step is imapired in the collagen synthesis?
Ehlers-danlos syndrome.
Cleavage of N-terminal procollagen is impaired.
patient has liver failure with macrocytic megaloblastic anaemia. He has impaired tetrahydrofolic acid functioning.
Whta is he deficient in? hoe does this affect his methionine-homocystein levels?
He is deficient in Folate (VitB9).
low methionine and high homocystein.
Oxidative reaction in HMP shunt uses what to generate Ribose 6 phospahte and 2NADPH?
Glucose-6-phosphate dehydrogenase.
MI hx, Thrombolic events, arterial stenosis, cardiac events with elevated levels of homocystein.
What is dx? deficiency of what cofactors can cause this disorder?
dx: deficiency in either Vit B12, or methionine synthetase or Methyl tetrahydrofolate.
Elevated ammonia level in blood and elevated orotic acid in urine is suggestive of?
Ornithine transcarbamylase deficiency.
hemolytic anaemia
increased reticulocyte count
abnormal erthrocytes
heinz bodies
bite cells
jaundice
malaise
pallor
dark urine
What is the general dx?
Glucose-6-phospahte dehydrogenase deficiency
Patient has macrocytic megaloblastic anaemia. He eats only meet and rice. his diet does not have any leafy vegetables.
what is he deficient in?
how does this affect his methionine and homocystien levels?
patient has no leafy vegetable diet, shows he has folate deficieny. Vit B9 deficiency.
folate is needed for tetrahydrofolic acid used in methionine synthesis.
So his methionine levels are decreased and homocystein levels are elevated.
osteogensis imperfecta classic features?
BITE
and tx?
B-bone multiple fractures
I- eye blue sclera
T- teeth dentinogenesis imperfecta
E- ear hearing loss
tx- biphosphonates
ammonia tx for liver diease caused by colonic ammoniagenic bacteria?
antibiotics: rifaximin, neomycin.
Angular stomatitis, pins and needles sensation in legs, alocoholic use.
low urinary riboflavin output.
What enzyme is he deficient in?
what vitamin is it?
succinate dehydrogenase used in TCA cycle
vitamin B2
radiolabeled alanine experiment.
blood test detects traces of alanine first 3 hours but later traced only glucose.
Before alanine is coverted to glucose, its amino group is coverted to something else. ( transamination step).
what is it converted to?
alpha-ketoglutarate.
TCA CYCLE.
Neurological and developemntal delays, failure to thrive, decreased pyruvate dehydrogenase enzyme with elevated serum lactate levels.
What is the dx? What diet supply can be suggested to increase energy without further elevating lactate levels?
pyruvate dehydrogenase complex deficiency.
^ keto diet
^fatty food
^lysine and leucine levels in food.
chronic/binge alcoholic pt with no food intake presents with hypoglycemia. urine is strongly positive for ketones.
what is supressed in this patient that is responsible for the patient’s hypoglycemia?
gluconeogenesis is supressed.
glycogenolysis or insulin is not affected by ethanol.
patient has scurvy. what is she deficient in? which organelleis this compound made in?
vit c, collagen
found in Rough endoplasmic reticulum
patient has niacin deficieny and 20 year old history of alcohol abuse and is severly malnourished. waht are his symptoms?
what enzymes is he deficient in ?
pellagra symtoms: malar hyperpigmented rash on neck, collar bones, hands which worsen on sun exposure.
he is deficent in isocitrate dehydrogenase,
malate dehydrogenase, alpha-ketoglutarate dehydrogenase.
KRAS mutation is activated when coupled with what protein?
GTP
KRAS mutation is inactive when coupled with which protein?
GDP
KRAS mutation gene coupled with GTP predispose to which malignancies?
colorectal, GI, polyp
Pt presents with corneal clouding, hepatosplenomegaly and decreased joint mobility. She has problem in phosphorylation of mannose on glycoproteins. What is the dx?
what enzyme is she deficient in?
in an unaffected individual, glycoproteins are transported to which cellular region?
Pt has mannosidosis.
she has deficiency of Alpha-mannosidase which leads to accumulation of glycoproteins.
glycoproteins should be transported to lysosomes in an unaffected individual.
diet tx for propionic acidemia ?
low protein diet
pt has poor feeding, failure to thrive, lethargy, somnolence, dehydration and decreased muscle tone.
lab examination shows elevated propionic acid levels due to defective conversion of propinoyl-CoA to Methylamonyl-CoA.
What is dx? What proteins deficiency support this dx?
Pt has propionic acidaemia. characterised with deficiency of Valine, Isoleucine, threonine, Methionine
pt is diagnosed with defective conversion of propionyl-CoA to Methylamonyl-CoA. What should be the dietary restriction for this patient?
diet containing valine, isoleucine, threonine and methionine.
pt has progressive spastic diplegia, abnormal movements, growth delay. Ammonia levels are untouched.
serum test show elevated arginine levels. what enzyme is deficient in this patient? what cycle will be impaired due to deficiency of that enzyme?
pt has arginase deficiency. this affects urea cycle.
pt has microcephally, skin with diffuse hypo-pigmentation. deficiency of cofactor required for neurotransmitter formation predominantly in substantia nigra and locus caeruleus. What i sthe dx? what is the pt deficient in?
phenylketonuria is dx.
phenylalanine hydroxylase and BH4 deficiency.
pt has problems with heart, liver, spleen with a prominant forehead and broad nose. there is a diffuse haze over the corneas bilaterally.
what is accumulated more in this pt?
heparin sulfate.
pt has accumulation of heparin sulphate with hepatosplenomegaly and has an inability to breakdown complex carbohydrates. Pt also has gargolyilsm. What is the dx? what is the pt deficient in?
pt has hurler syndrome. with deficiency of alpha-L-iduronidase.
biochemical studies with accumulation of proteins or misfolded proteins always related to what pathway defect?
ubiquitine-proteasome pathway defect.
pt has prominent forrehead with depressed nasal bridge, epicanthal folds. analysis of lysosomal acid hydrolases shows an increased concentration within the serum and decreased within the cultured skin fibroblast cells. pt has defect in which step of protein synthesis?
post-translational modification .
I-cell disease and mannosidosis is both a lysosomal storage disorder.
T/F?
T
What acts as an effector in foreign antigen recognition at the cell surface by cytotoxic T lymphocytes which results in rapid cell apotosis?
caspases
in a pt with Aldolase-B deficiency what diet nutrient should be ceased?
sucrose.
pt has low carnitine content. what is she deficient in?
acetoacetate.ehl
ehlers danlos syndrome is associated with defect in what step of collagen synthesis?
N-terminal cleavage
pt has lactic acidosis and pyruvate dehydrogenase enzyme deficiency. What nutritional diet should be administered?
^lysine
^leucine
ketogenic diet
pt diagnosed with phenylketonuria is on restricted phenyl-alanine diet and takes tyrosine supplements. But pt later developed neurological findings such as axial hypotonia even thought the patient has normal phenylalanine levels with elevated prolactin levels. what is the dx?
what is the patient deficient in?
tetrahydrobiopterin syndrome.
deficiency of dihydropteridin reductase which leads to defective BH4 synthesis.
pt exhibits upward eye deviation, musty odour, fair-skinned, blue eyes. what is the dx? what nutritional treatment should be administered?
phenylketonuria
tyrosine nutrition should be added in the diet.
beta oxidation most important enzyme is?
acyl-CoA dehydrogenase
beta oxidation with acyl-CoA takes place in which cellular organelle?
mitochondria
menkes disease classic features
kinky hair,
impaired copper absorption
defective ATP7A
decreased activity of lysyl oxidase
menkes disease tx
copper chloride
L-Histidine injections.
primary carnitine deficiency is associated with the inability to break down what?
long chain fatty acid
