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Flashcards in Biochem High Yield Deck (80):
1

What is the mechanism of leflunomide?

inhibits dihydrofolate dehydrogenase

2

What is the mechanism for mycophenolate and ribavirin?

Inhibits IMP dehydrogenase

3

What is the mechanism of hydroxyurea?

inhibits ribonucleotide reductase

4

What is teh mecahnism of 6MP?

inhibits de novo purine synthesis

5

What is the mechanism of 5- FU?

inhibits thymidylate synthase

6

What is the mechanism of methotrexate and methoprim and pyrimethamine?

inhibits dehydrofolate reductase

7

"defective purine salvage due to absent HGPRT"

Lesch- Nyhan syndrome

8

What is the function of HGPRT?

Converts hypoxanthine to IMP and guanine to GMP

9

What are teh 5 symptoms of Lesch- Nyhan syndrome?

Hyperuricemia
Gout
Aggression/ self mutilation
Retardation
Dystonia

10

Enzyme that unwinds prokaryptic DNA for repliction?

Helicase

11

What is the function of DNA topoisomerase?

creates single or double stranded break

12

Synthesis and proofreading directions of bacterial DNA polymerase III?

Synthesis= 5-->3

Proofread= 3-->5

13

What degrades RNA primer in DNA of bacteira?

DNA polymerase I

14

What enzyme joins okazaki fragment?

DNA ligase

15

"mutation that causes a changes amino acid"

missense

16

"mutation that leads to early stop codon"

nonsense mutation

17

What repair mechanism is defective in xeroderma pigmentosum?

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

18

What repair mechanism is defective in HNPCC?

mismatch repair

19

What DNA repair mechanism is defective in ataxia telangiectasia?

Nonhomologous end joining

20

Name 3 stop codons?

UGA
UAA
UAG

21

What binds the promoter region in eukaryotes for gene expression?

RNA polymerase II

22

What does Amanita phalloides (death cap mushroom) inhibit?

RNA polymerase II (eukaryotes)

23

What post transcriptional alterations occur in the nucleus?

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

24

What molecule is responsible for splicing of pre-mRNA?

snRNP complex

25

What is the T arm on tRNA necessary for?

tRNA ribosomal binding

26

What is the anti-codon loop needed for?

Binding the codon on the mRNA

27

Where does the AA bind tRNA?

3' end (ACC)

28

What is the D arm of tRNA needed for?

recognized by aminoacul- tRNA synthase

29

What is the initator tRNA?

Methionine (AUG)

30

What does initiation need in order to occur?

GTP hydrolysis

31

What molecule catalyzes peptide bond formation in protein synthesis?

rRNA

32

What energy molecule is needed for translocation?

GTP

33

What are chaperone proteins needed for?

facilitate/ maintain protein folding

34

What phase transition of the cell cycle do p53 and hypophosphorylated Rb inhibit?

G1 to S progression

35

Where does RER add oligosaccharide?

N- linked!

36

What cell types are rich in RER?

mucus seccreting goblet cells of the small intestine and antibody secreting cells

37

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

38

What signal is needed to traffic protein to lysosomes?

M-6-P

39

What is I cell disease?

inherited lysosomal storage disease

40

What is the defect in I cell disease?

N- acetylglycosaminyl-1 transferase fails to phosphorylate mannose residues... no trafficking to lysosomes

41

What trafficks proteins to the RER?

Signal recognition particle

42

What structure degrades damaged or ubiquitin tagged proteins?

Proteasome

43

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

44

"infertility, dextrocardia, bronchiectasis/ recurrent sinusitus"

Kartagener syndrome

45

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

Type I

46

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

Type IV

47

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

Type III

48

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

Type II

49

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

Type III

50

Which type of collagen is defective in Alport syndrome?

Type IV

51

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

Type IV

52

Collagen is 1/3 composed of....

glycine!

53

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

Procollagen

54

What does hydroxulation of preprocollagen requires...

vitamin C

55

What is defective in osteogenesis imperfecta?

Decreased productino of otherwise formal type I collagen

56

Name 4 symptoms of osteogenesis imperfecta?

1- blue sclerae
2- multiple fratures
3- teeth problems
4- hearing loss

57

Inheritance pattern of ehlers danlos?

AD or AR

58

"X linked recessive CT disease caused by impaired copper absorption and transport due to defected menkes protein"

Menkes disease

59

What residues is elastin rich in?

nonhydroxylated proline, glycine and lysine residues

60

What is defecctive in marfan syndrome?

Fibrillin (sheath around elastin)

61

3 steps of PCR?

Denaturing
Annealing
Elongating

62

Southern blot?

DNA

63

Northern blot?

RNA

64

Western blot?

Protein

65

Southwestern blot?

DNA binding proteins

66

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)

67

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

68

What phase are chromosomes imaged in karyotyping?

Metaphase

69

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

FISH

70

What does cDNA not include?

introns

71

"both alleles contribute to the phenotype of the heterozygote"

codominance

72

"phenotype varies among individuals with the same genotype"

variable expressivity

73

"one gene contributes to mutiple different phenotypic effects"

Pleiotrophy

74

"mutations at differnt loci can produce a similar phenotype"

locus heterogeneity

75

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

Allelic heterogeneity

76

What chromosome is prader willi and angelman syndromes associated with?

Chromosome 15

77

Name the condition:

"inappropriate laughter seizures, ataxia, and severe intellectual disability"

Angelman syndrome

78

Name the condition:

"hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia"

Prader- willi syndrome

79

Which inheritance pattern skips generations?

X lined recessive

80

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

Mitochondrial myopathies

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