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Flashcards in Biochem High Yield Deck (80)
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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

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