Test 1-3: Biochemistry Flashcards
Synchronization of glycogen degradation with skeletal muscles contraction occurs due to what
release of sarcoplasmic calcium following neuromuscular stimulation
Increased intracellular calcium in skeletal muscles activates what
phosphorylase kinase: stimulating glycogen phosphorylase to increase glycogenolysis
Glycogen is broken down by what enzyme
glycogen phosphorylase
What enzyme is responsible for phosphorylation of glycogen phosphorylase
Phosphorylase kinase
what catalyzes dephosophrylation of glycogen phosphorylase
phosphoprotein phosphatase
How is phosphorylase kinase activated in the liver?
- Epinephrine and glucagon
2. increases [cAMP]
What are 2 ways skeletal muscles activates phosphorylase kinase
- Epinephrine-induced increase in cAMP
2. Increase intracellular calcium
Release of sarcoplasmic calcium allows for the synchronization of what?
- skeletal muscle contraction
2. glycogen breakdown
What can be beneficial in the treatment of measles infections by reducing comorbidites, recovery time, and length of hospital stays?
Vitamin A
Pyridoxine
B6
Cobalamin
Vitamin B12
Most common urea cycle disorder
Ornithine transcarbamylase deficiency
how is ornithine transcarbamylase deficiency inherited
X-linked recessive
What is found in the the system of an ornithine transcarbamylase deficiency patient? they have symptoms of what?
- increased orotic acid in blood and urine
- decrease BUN
- hyperammonemia
Why is there increased orotic acid in blood and urine for ornithine transcarbamylase
excess carbamoyl phosphate is converted to orotic acid
what is the rate limiting enzyme in the urea cycle
Carbamoyl phosphate synthetase I
- convertes bicarb, ammonia and ATP to carbamoyl phosphate
What acts as the regulator of the urea cycle through activation of carbamoyl phosphate synthetase I
N-acetylglutamate
What are some symptoms for hyperammonemia
episodes of vomiting, and confusion/coma
tachypnea
rapid breathing
What is the problem in orotic aciduria
uridine monophosphate synthetase deficiency
Which one has megaloblastic anemia: ornithine transcarbamylase deficiency or orotic aciduria
orotic aciduria
Which one has hyper ammonia: ornithine transcarbamylase deficiency or orotic aciduira
ornithine transcarbamylase deficiency
Bloom syndrome: what is the problem
mutations in BLM gene encoding DNA helicase
How do Bloom syndrome patients present
- growth retardation
- facial anomalies
- photosenstive skin rash
- immunodeficiency
Thiamine is a cofactor for what 3 things
- pyruvate dehydrogenase
- alpha-ketoglutarate dehydrogenase
- transketolase
Administration of glucose to thiamine deficient patients can results in
Wernicke encephalopathy due to increased thiamine demand
Metabolism of alcohol increases what ratio
NADH/NAD+
In setting of Wernicke encephalopathy, thiamine-dependent enzymes are especially affected due to the fact of what factors
- NAD+ ( required for TCA)
2. thiamine
In addition to lowering blood glucose, insulin increases glycogen synthesis in hepatocytes by activating what enzyme
Protein phosphatase
What receptor can activates protein phosphatase
Tyrosine kinase dimer receptor, with insulin
Southern blotting is used to detect
DNA mutations
Familial hypercholesterolemia is defective in what
Absent or defective LDL receptors
Familial hypercholesterolemia is inherited how
autosomal dominant
What is telomerase? What does it to
- Reverse transcriptase ( RNA-dependent DNA polymerase)
- lengthens telomeres by adding TTAGGG repeats to 3’ of chromosomes
What type of cells have long telomeres
Stem cells
- high telomerase activity
What serves as a source of glucose during fasting and as an energy store that can be mobilized quickly during strenuous muscle
glycogen
What are the glycogen storage disease
Very Poor Carbohydrate Metabolism
- Von Gierke
- Pompe
- Cori
- McArdle
Who is someone with muscle cramps, myoglobinuria ( red urine) with strenuous exercise, and arrhythmia form electrolyte abnormalities
McArdle disease
What enzyme is deficient in McArdle disease
- skeletal muscle glycogen phosphorylase
- Myophosphorylase
Increased frequency in patients with activating mutations involving Phosphoribosyl pyrophosphate syntheses leads to what
gout
What is the first line therapy for treating acute gouty arthritis
NSAIDS
- inhibits neutrophils
What is the second lune of therapy for acute gout
Colchicine
MOA for Colchicine
- binds ands stabilizes tubulin to inhibit microtubule polymerization
- impairing neutrophil chemotaxis and degranulation
What are symptoms for dry Beriber
- symmetrical peripheral neuropathy
- polyneuritis
What are symptoms for wet beriberi
- high output cardiac failure (cardiomyopathy)
- edema
hemorrhage and necrosis in the mammillary bodies and periaqueductal gray matter are found in what problem
Wernicke-Korsakaff syndrome
Activity of what can diagnosed thiamine deficiency
- baseline erythrocyte transketolase activity is low
- but then increases after addition of thiamine pyrophosphate
Protoporphyrin is a precursor for what
heme
What is the rate-limiting step in pentose phosphate pathway
Erythrocyte glucose-6-phosphate dehydrogenase
When do you see methylmalonic acid levels increased
Vitamin B12 deficiency
55-year old farmer: pupils are symmetric, 2mm, and reactive to light. Eyes are tearing considerably. Scattered wheezes bilaterally on lung auscultation . Skin is clammy and he is sweating profusely? toxicity ?
Organophosphates
- used in pesticides in agriculture
MOA for organophosphates
- inhibit breakdown of acetylcholine
