Biochem Flashcards
1
Q
What is one of the main causes of Paresthesias?
A
- Parethesias is due to hypocalcemia
- CP: tickling/prickling from pressure/damage on peripheral nerves
- citrate (in stored blood) chelates calcium and magnesium and may decrease plasma levels
2
Q
Pyruvate kinase deficiency
A
causes hemolytic anemia because of failure of glycolysis and resultant failure to generate enough ATP to maintain erythrocyte structure
3
Q
What are the precursor proteins/peptides responsible for localized amyloidosis?
A
- cardiac atria-atrial natriuretic peptide (ANP)
- thyroid gland: calcitonin
- pancreatic islets: islet amyloid protein (aylin)
- cerebrum/cerebral blood vessels: beta-amyloid protein
- pituitary gland: prolactin
>>immune globulin light chain cuases multi-organ amyloid deposition in primary systemic amyloidosis
4
Q
What are the five cofactors needed by branched-chain alpha-ketoacid DH, pyruvated DH, and alpha-ketoglutarate DH?
A
(Tender Loving Care For Nancy)
- Thiamine pyrophosphate
- Lipoate
- Coenzyme A
- FAD
- NAD
5
Q
Kozak sequence
A
- plays a role in initiation of translation
- mut 3 bases upstream from start codon (AUG) in associated with thalassemia intermedia which leads to hypochromic, microcytic anemia
- mitochondria are needed for heme synthesis
6
Q
heterochromatin vs. euchromatin
A
- hetero:
- condensed chromatin made of heaviy methylated DNA in tight association with deacetylated histones
- LOW transcriptional activity
- [EU]chromatin:
- loosely arranges
- HIGH transciptional activity
7
Q
Maple Syrup Dz
A
- caused by defect in alpha-keto acid dehydrogenase
- leads to inability to degrade branched chain AA beyond their deaminated alpha-keto acid st
- results in dystonia, poor feeding, maple syrup scent of urine within first few days of life
- tx: dietary restrictions of branched-chain AA
8
Q
Vit B12
A
- only water-soluble vitamin that is NOT rapidly removed from body stores (without diet intake)
- b12 stores last for years
9
Q
Fabry disease
A
- (angiokeratoma corporis diffusum)
- cause: inherited deficiency of alpha-galactosidase A
- CP: globoside ceramide trihexoside accumulates in tissues
- early:
- angiokeratomas
- hypohidrosis
- acroparesthesis
- tx: enzyme replacement
- prognosis: progressive renal failure
10
Q
Chronic granulomatous disease (XL)
A
- cause: deficiency of NADPH oxidase
- NADPHox=enzyme responsible for formation of reactive oxygen species in phagosomes
- affected neutrophils can NOT kill catalase-producing organisms
- CP: recurrent bacterial and fungal infections
- involves: lungs, skin LN
11
Q
A1AT (alpha-1 anti-trypsin) and A1AT deficiency
A
- made mostly by liver
- serum protein that decreases tissue damage caused by inflammation through the inhibition of neutrophil elastase
- Histo: reddish-pink, periodic acid-schiff (PAS) positive granules of unsecreted, polymerized leads to liver disease
- A1AT in the peripheral hepatocytes
- A1AT deficiency-autosomal co-dominant
- affects the lungs and liver
- due to destruction of alveolar walls develop severe PANacinar emphysema
- smoking plays synergistic role with disease
12
Q
xeroderma pigmentosum
A
- enzymatic d/o (AR)
- CP: photosensitivity, poikiloderma, hyperpigmentation in sun-exposed
- risk: increased risk of skin cancer (all forms of cutaneous malignancy)..get it EARLY in life!
- defect: nucleotide excision repair
13
Q
Homocystinuria
A
- most commonly caused by a defect in cystathionine synthase
- causes: inability to form cysteine from homocysteine
14
Q
3 stop codons
A
UAA
UGA
UAG
15
Q
Homocystinuria
A
- AR-deficiency of cystathionine beta-synthase (co-factor=Vit B6 {pyridoxine})
- Tx: high dose pyridoxine and restriction of methionine
- most common inborn error of methionine metabolism
- CP1: 3-10 yo with ectopia lensis (dislocated lens)
- 50% pts have intellctual disability
- CP2: Marfanoid habitus
- elongated limbs
- arachnodactyly
- scoliosis
- High risk for: thromboembolic occlusion (large vessel and small vessels)..*brain, heart, kidney
