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Question 1

What bases are methylated in DNA replication?

Answer 1

CYTOSINE and ADENINE

this allows MMR enzymes to distinguish bt old + new strands

Question 2

How does histone acetylation activate transcription?

Answer 2

Relaxes DNA coiling. (Acetylation makes dna Active)

(-) acetylation binds (+) histones. This weakens bond bt (+) histones and (-) DNA –> Histones less adherent to DNA

Question 3

What group does thymine have?

Answer 3

THYmine has meTHYl (CH3)

Question 4

What happens when cytosine is deaminated?

Answer 4

Uracil!

Question 5

What AA needed for purine synthesis?

Pyrimidine syn?

Answer 5

GAG
Glycine
Aspartate (only AA needed for pyrimidine syn)
Glutamine

Question 6

DNA Pol III function?

DNA synthesis 5–>3

Answer 6

PROKARYOTIC ONLY !

1) elongates leading (5’-3’)
2) Proofreads/removes damaged DNA seq (3’-5’)

Question 7

DNA Pol I function?

DNA syn 5–>3

Answer 7

PROKARYOTIC ONLY

1) degrades RNA primer and replaces it w DNA (**5–3 exonuclease activity unique!!)
- also does what dNA polIII does:
1) elongates leading (5’-3’)
2) Proofreads/removes damaged DNA seq (3’-5’)

Question 8

What is telomerase & what does it do?

Answer 8

RNA- dependent DNA polymerase.

- adds DNA to 3’ ends of chrome to avoid loss of genetic material after each cycle of DNA replication

Question 9

What makes the phosphodiester bond?

Answer 9

dna LIGASE (joins okazaki fragments)

Question 10

1) what repairs bulky helix distorting lesions (thymine dimers)
2) repairs deamination (1 base)
3) DS breaks. no req for homology?

Answer 10

1) bulky helix distorting lesions (thymine dimers)=NUCLEOTIDE EXCISION repair XP
2) repairs deamination (1 base)-BASE EXCISION REPAIR
3) DS breaks. no req for homology?-NONHOMOLOGOUS END JOINING.AT

Question 11

What are the STOP codons (3)?

Answer 11

UGA, UAA, UAG

Question 12

What does Promoter bind to (2) and where is it located?

Answer 12

RNA Pol + TFs bind

AT-rich sequence (TATA) 25bp upstream

Question 13

What happens if mutation in promoter region?

Answer 13

decrease level of transcroption

Question 14

Out in field day. eat mushrooms. What is inhibited? Symptoms?

Answer 14

a-amanatin:inhibits RNA Pol II (no mRNA made–>apoptosis)

sx: CHOLERA-LIKE DIARRHEA + HEPATOTOXOCITY. renal failure (PT), GI

Question 15

RNA Pol I
RNA Pol II
RNA Pol III

Answer 15

RNA Pol I - rRNA, assembles ribosome subunits (NUCLEOLUS). anaplastic cancer will have large nucleolus bc lots ribosome sun.
RNA Pol II - mRNA, sNRNA (splicing), microRNA
RNA Pol III: tRNA
** NO PROOFREADING FX (unlike DNAPol in prokaryotes)

Question 16

What is polyadenylation signal (3’)?

Answer 16

AAUAA

Question 17

Eu and Pro rib?

Answer 17

Eu: 40S + 60S = 80S (Even)
PrO: 30S + 50S = 70S (Odd)
30S=16S rRNA–>binds Shine Delgarno

Question 18

Pro ribsome. What are parts composed of?

Answer 18

PrO: 30S + 50S = 70S (Odd)
30S=16S rRNA–>binds Shine Delgarno on mRNA so translation can start

50S=23S –> peptide bond formation