Biochem Flashcards
what is alkaptonuria
congenital deficiency of homogentisate oxidase in the degradative pathway of tyrosine to fumarate–> pigment-forming homogentisic acid accumulates in tissues
autosomal recessive
usually benign
bluish-black connective tissue, ear cartilage, and sclerae
urine turns black on prolonged exposure to air
debilitating arthralgias (homogentisic acid toxic to cartilage)
WATER mnemonic for Wiskott-Aldrich syndrome for clinical findings
WATER: Wiskott-Aldrich: Thrombocytopenia, Eczema, and Recurrent (pyogenic) infection
defect of Wiskott-Aldrich syndrome
X-linked recessive
leukocytes and platelets unable to reorganize actin cytoskeleton–> defective antigen presentation
what to use to reverse methotrexate toxicity
folinic acid (leucovorin)
leucovorin potentiates the cytotoxic action of 5-FU
function of small nuclear RNA (snRNA)
essential component of spliceosomes, which remove introns from pre-mRNA to form mature mRNA by helping with athe removal of introns (noncoding regions)
how does PCR work?
amplify small fragments of DNA by repeated replication
1) denaturing: denatures the DNA template through heat
2) annealing: primers combine with denatured, single-stranded flanking ends of the target region
3) elongation: DNA polymerase forms new daughter DNA in 5’ to 3’ direction, starting from 3’ end of the each primer
what is western blot used for
used to detect target polypeptide or protein from within a mixed sample
what is Northern blot used for
identifies specific RNA sequences
sothern blot is used for
identifying specific DNA sequences
microarray analysis
genomic DNA or cDNA being analyzed is labeled with fluorescent tag and placed on gene chip containing complementary sequence for a large number of genes
degree of fluorescence corresponds to the mRNA expressed in the sample
where is the site of ribosomal subunit maturation and assembly
nucleolus
RNA polymerase I functions exclusively within the nucleolus to transcribe the 45S pre-rRNA gene, which codes for most of the ribosomal RNA components (18S, 5.8S, and 28S rRNAs)
metalloproteinases
zinc-containing enzymes that degrade components of the extracellular matrix and basement membrane (made up of mainly laminin and collagens IV and VII)
facilitate basement membrane penetration
angiogenesis (blodd vessel formaiton) is predominantly drive by which 2 substances
- vascular endothelial growth factor (VEGF)
- fibroblast growth factor
tumor necrosis factor-alpha: where is it produced and what does it do?
produced by macrophages in response to infection and to some neoplastic cells
produces fever (along with IL-1), mediates many of the symptoms of septic shock, and causes hepatic release of acute-phase reactants (C-reactive protein and fibrinogen)
