Biochem 1

Question 1

What must be bound for transcription to take place?

Answer 1

Transcription factors must be bound to promotoer region

Question 2

What are specific promoter regions?

Answer 2

(-25 Hogness/Pribnow/TATA box and -75 CAAT box from start seq.

Question 3

Where is the operator region?

Answer 3

Between promoter region and start site

Question 4

2 things that operator region can do?

Answer 4

1. Binds repressor-> stop transcrption. 2. Bind inducer-> start transcription

Question 5

What can the enhancer region do?

Answer 5

Inc or dec the rate of transcription when bound by protein factors

Question 6

What is an operon?

Answer 6

Structural genes that are transcribed + promotor region + all regulatory regions

Question 7

What are the mRNA stop codons?

Answer 7

UAA, UGA, UAG

Question 8

How many RNA pol do eukaryotes have and what do they do?

Answer 8

3. RNA I-makes rRNA (most abundant). RNA II-makes mRNA (longest). RNA III-makes tRNA( smallest)

Question 9

What can a-amanitin do?

Answer 9

Found in mushrooms, can inhibit RNA Pol II

Question 10

How many RNA pol do prokaryotes have?

Answer 10

1 that makes all 3 kinds of RNA

Question 11

What are 4 ways that protein can interact w/ DNA?

Answer 11

1. Helix-Loop-Helix. 2. Helix-Turn-Helix. 3. Zing Finger Motif. 4. Leucine Zipper Protein

Question 12

What does hnRNA need to become mRNA?

Answer 12

1. capping of 5’ end (ie. add 7 methylguanosine cap via S-adenosyl methionine). 2. Polyadenylation of 3’ end (via Poly-A polymerase-AAUAA-does not need template). 3. Splicing out of introns in spliceosomes.

Question 13

2 methods for terminating transcription?

Answer 13

1. Rho factor dependent (an RNA dependent ATPase). 2. Rho-factor independent: GC (strong bc 3 H bonds) rich DNA -> GC same strand binding forms stem-loop RNA (hairpin loop) -> loop places pressure on RNA pol -> RNA pol pauses -> subsequent weak RNA bonds (uracil region-2H bonds) -> separation of RNA pol and rel.

Question 14

Lac operon

Answer 14

SG 189