Flashcards in Biochem High Yield Deck (80)
What is the mechanism of leflunomide?
inhibits dihydrofolate dehydrogenase
What is the mechanism for mycophenolate and ribavirin?
Inhibits IMP dehydrogenase
What is the mechanism of hydroxyurea?
inhibits ribonucleotide reductase
What is teh mecahnism of 6MP?
inhibits de novo purine synthesis
What is the mechanism of 5- FU?
inhibits thymidylate synthase
What is the mechanism of methotrexate and methoprim and pyrimethamine?
inhibits dehydrofolate reductase
"defective purine salvage due to absent HGPRT"
Lesch- Nyhan syndrome
What is the function of HGPRT?
Converts hypoxanthine to IMP and guanine to GMP
What are teh 5 symptoms of Lesch- Nyhan syndrome?
Aggression/ self mutilation
Enzyme that unwinds prokaryptic DNA for repliction?
What is the function of DNA topoisomerase?
creates single or double stranded break
Synthesis and proofreading directions of bacterial DNA polymerase III?
What degrades RNA primer in DNA of bacteira?
DNA polymerase I
What enzyme joins okazaki fragment?
"mutation that causes a changes amino acid"
"mutation that leads to early stop codon"
What repair mechanism is defective in xeroderma pigmentosum?
Nucleotide excision repair (prevents repair of pyrimidine dimers from UV light exposure)
What repair mechanism is defective in HNPCC?
What DNA repair mechanism is defective in ataxia telangiectasia?
Nonhomologous end joining
Name 3 stop codons?
What binds the promoter region in eukaryotes for gene expression?
RNA polymerase II
What does Amanita phalloides (death cap mushroom) inhibit?
RNA polymerase II (eukaryotes)
What post transcriptional alterations occur in the nucleus?
1- 5' cap
2- Poly A tail
Splicing of introns
What molecule is responsible for splicing of pre-mRNA?
What is the T arm on tRNA necessary for?
tRNA ribosomal binding
What is the anti-codon loop needed for?
Binding the codon on the mRNA
Where does the AA bind tRNA?
3' end (ACC)
What is the D arm of tRNA needed for?
recognized by aminoacul- tRNA synthase
What is the initator tRNA?
What does initiation need in order to occur?
What molecule catalyzes peptide bond formation in protein synthesis?
What energy molecule is needed for translocation?
What are chaperone proteins needed for?
facilitate/ maintain protein folding
What phase transition of the cell cycle do p53 and hypophosphorylated Rb inhibit?
G1 to S progression
Where does RER add oligosaccharide?
What cell types are rich in RER?
mucus seccreting goblet cells of the small intestine and antibody secreting cells
What modifications and additions does the golgi make?
Modifies N oligosacharrides on asparagine
Adds O- oligosacchraides on serine and threonine
Adds mannose-6- phosphagte for trafficking to lysosomes
What signal is needed to traffic protein to lysosomes?
What is I cell disease?
inherited lysosomal storage disease
What is the defect in I cell disease?
N- acetylglycosaminyl-1 transferase fails to phosphorylate mannose residues... no trafficking to lysosomes
What trafficks proteins to the RER?
Signal recognition particle
What structure degrades damaged or ubiquitin tagged proteins?
What are each of the following a marker for?
Cytokeratin- epithelial cells
"infertility, dextrocardia, bronchiectasis/ recurrent sinusitus"
What type of collagen make sup bone, skin, tendon cornea, and late wound repair?
What type of collagen is basement membranes, basal lamina, and lens of the eye?
What type of collagen is in skin, blood vessels, early scar formation?
What type of collagen is cartilage, vitreous body and nucleus populus?
Which type of collagen is affected in Ehlers- Danlos syndrome?
Which type of collagen is defective in Alport syndrome?
Which type of collagen is targeted by autoantibodies in Good pasture syndrome?
Collagen is 1/3 composed of....
What is the form of collagen when it leaves the fibroblast?
What does hydroxulation of preprocollagen requires...
What is defective in osteogenesis imperfecta?
Decreased productino of otherwise formal type I collagen
Name 4 symptoms of osteogenesis imperfecta?
1- blue sclerae
2- multiple fratures
3- teeth problems
4- hearing loss
Inheritance pattern of ehlers danlos?
AD or AR
"X linked recessive CT disease caused by impaired copper absorption and transport due to defected menkes protein"
What residues is elastin rich in?
nonhydroxylated proline, glycine and lysine residues
What is defecctive in marfan syndrome?
Fibrillin (sheath around elastin)
3 steps of PCR?
DNA binding proteins
What is a direct ELISA?
Uses a test antibody to see if a specific antigen is present (antibody is directly coupled to a color- generating enzyme to defect antigen)
What is an indirect ELISA?
uses either a test antigen or antibody to see if a specific antibody or antigen
a secondary antibody is coupled to a color generating enzyme is added to detect the antbody antigen complex
What phase are chromosomes imaged in karyotyping?
"fluorescent DNA or RNA probe binds to specific gene site of interest on chromosomes"
What does cDNA not include?
"both alleles contribute to the phenotype of the heterozygote"
"phenotype varies among individuals with the same genotype"
"one gene contributes to mutiple different phenotypic effects"
"mutations at differnt loci can produce a similar phenotype"
"different mutations in the same locus produce the same phenotype"
What chromosome is prader willi and angelman syndromes associated with?
Name the condition:
"inappropriate laughter seizures, ataxia, and severe intellectual disability"
Name the condition:
"hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia"
Prader- willi syndrome
Which inheritance pattern skips generations?
X lined recessive