Biochem High Yield Flashcards by Erin Allmer

What is the mechanism of leflunomide?

inhibits dihydrofolate dehydrogenase

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What is the mechanism for mycophenolate and ribavirin?

Inhibits IMP dehydrogenase

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What is the mechanism of hydroxyurea?

inhibits ribonucleotide reductase

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What is teh mecahnism of 6MP?

inhibits de novo purine synthesis

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What is the mechanism of 5- FU?

inhibits thymidylate synthase

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What is the mechanism of methotrexate and methoprim and pyrimethamine?

inhibits dehydrofolate reductase

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“defective purine salvage due to absent HGPRT”

Lesch- Nyhan syndrome

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What is the function of HGPRT?

Converts hypoxanthine to IMP and guanine to GMP

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What are teh 5 symptoms of Lesch- Nyhan syndrome?

Hyperuricemia
Gout
Aggression/ self mutilation
Retardation
Dystonia

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Enzyme that unwinds prokaryptic DNA for repliction?

Helicase

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What is the function of DNA topoisomerase?

creates single or double stranded break

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Synthesis and proofreading directions of bacterial DNA polymerase III?

Synthesis= 5–>3

Proofread= 3–>5

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What degrades RNA primer in DNA of bacteira?

DNA polymerase I

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What enzyme joins okazaki fragment?

DNA ligase

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“mutation that causes a changes amino acid”

missense

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“mutation that leads to early stop codon”

nonsense mutation

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What repair mechanism is defective in xeroderma pigmentosum?

Nucleotide excision repair (prevents repair of pyrimidine dimers from UV light exposure)

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What repair mechanism is defective in HNPCC?

mismatch repair

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What DNA repair mechanism is defective in ataxia telangiectasia?

Nonhomologous end joining

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Name 3 stop codons?

UGA
UAA
UAG

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What binds the promoter region in eukaryotes for gene expression?

RNA polymerase II

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What does Amanita phalloides (death cap mushroom) inhibit?

RNA polymerase II (eukaryotes)

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What post transcriptional alterations occur in the nucleus?

1- 5’ cap
2- Poly A tail
Splicing of introns

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What molecule is responsible for splicing of pre-mRNA?

snRNP complex

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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?

Methionine (AUG)

What does initiation need in order to occur?

GTP hydrolysis

What molecule catalyzes peptide bond formation in protein synthesis?

rRNA

What energy molecule is needed for translocation?

GTP

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?

N- linked!

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?

M-6-P

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?

Proteasome

What are each of the following a marker for? ``` Vimentin Desmin Cytokeratin GRAP Neurofilaments ```

Vimentin- CT Desmin- muscle Cytokeratin- epithelial cells GFAP- meuroglia Neurofilaments- Neurons

"infertility, dextrocardia, bronchiectasis/ recurrent sinusitus"

Kartagener syndrome

What type of collagen make sup bone, skin, tendon cornea, and late wound repair?

Type I

What type of collagen is basement membranes, basal lamina, and lens of the eye?

Type IV

What type of collagen is in skin, blood vessels, early scar formation?

Type III

What type of collagen is cartilage, vitreous body and nucleus populus?

Type II

Which type of collagen is affected in Ehlers- Danlos syndrome?

Type III

Which type of collagen is defective in Alport syndrome?

Type IV

Which type of collagen is targeted by autoantibodies in Good pasture syndrome?

Type IV

Collagen is 1/3 composed of....

glycine!

What is the form of collagen when it leaves the fibroblast?

Procollagen

What does hydroxulation of preprocollagen requires...

vitamin C

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"

Menkes disease

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?

Denaturing Annealing Elongating

Southern blot?

DNA

Northern blot?

RNA

Western blot?

Protein

Southwestern blot?

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?

Metaphase

"fluorescent DNA or RNA probe binds to specific gene site of interest on chromosomes"

FISH

What does cDNA not include?

introns

"both alleles contribute to the phenotype of the heterozygote"

codominance

"phenotype varies among individuals with the same genotype"

variable expressivity

"one gene contributes to mutiple different phenotypic effects"

Pleiotrophy

"mutations at differnt loci can produce a similar phenotype"

locus heterogeneity

"different mutations in the same locus produce the same phenotype"

Allelic heterogeneity

What chromosome is prader willi and angelman syndromes associated with?

Chromosome 15

Name the condition: "inappropriate laughter seizures, ataxia, and severe intellectual disability"

Angelman syndrome

Name the condition: "hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia"

Prader- willi syndrome

Which inheritance pattern skips generations?

X lined recessive

"ragged red fibers" that presents with myopathy, lactic acidosis and CNS disease

Mitochondrial myopathies