Lecture 10: Transcription

Question 1

What is the Central dogma

Answer 1

DNA –> RNA –> Protein

Replication –> Transcription –> Translation

Question 2

Chromosomal DNa stores information in units called ________________

Answer 2

Genes

Question 3

What are some structural elements of a gene?

Answer 3

Regulatory sequence, promote, coding region of gene

Question 4

Does prokaryotic DNA have introns?

Answer 4

No
*introns are non coding regions

Question 5

____________ is a single mRNA that codes multiple proteins.

Which type of cell has this type of mRNA

Answer 5

Polycistronic

prokaryotic

Question 6

What is the first product of transcription

Answer 6

hnRNA it contains the introns
*The introns are then spliced out to form mRNA which is monocistronic

Question 7

What are the steps of transcription?

Answer 7

Initiation
Elongation
Termination

Question 8

What are the two major players in Prokaryotic cell initiation

Answer 8

-sigma factor
-RNA polymerase

Question 9

What are the steps of initiation in prokaryotic cells

Answer 9

1. After sliding on DNA, sigma factor recognizes the promotor and RNA polymerase forms a closed complex
2. An open complex is formed and a short RNA is made
3. Sigma factor is released and the core enzyme is able to proceed down the DNA

Question 10

What are the major players in eukaryotic initiation

Answer 10

TFIID
TFIIB
TFIIE
TFIIH

Question 11

What are the steps in initiation in eukaryotic cells

Answer 11

-TFIID binds to TATA box
-TFIIB binds to TFIID
-TFIIB binds to acts as a bridge to bind RNA polymerase II and TFIIF
-TFIIE and TFIIH bind to RNA polymerase II to form a preinitiation complex or a closed complex

-TFIIH acts as helices to form an open complex and it phosphorylates TFIIB

Question 12

What are the key enzymes in prokaryotic elongation

Answer 12

RNA pol holoenzyme

Question 13

What are the key enzymes in eukaryotic elongation

Answer 13

-RNA polymerase I, II, III

Question 14

What does prokaryotic termination require

Answer 14

protein RHO

Question 15

What does eukaryotic termination require

Answer 15

Poly(A) sequence is transcribed and Termination factors

Question 16

_____________ is sued to treated pulmonary tuberculosis. Explain its mechanism of action

Answer 16

Rifampin

*It binds to RNA polymerase and prevent chain growth beyond 3 nucleotides. Eukaryotic RNA polymerase will not bind to the drug

Question 17

W

Question 18

In alpha amanitin poisoning what is occurring

Answer 18

it inhibits eukaryotic RNA polymerase II

✓ Symptoms:
‣ gastrointestinal disturbances
‣ electrolyte imbalance
‣ fever
‣ liver and kidney dysfunction
✓ Leads to death within 10 days in 10% to
20% of patients
✓ No antidote

Question 19

What are the steps of mRNA processing in Eukaryotes

Answer 19

1. capping of mRNA
2. Addition of Poly A tail
3. Removal of intros

Question 20

What type of RNA is involved in processing and removal of introns

Answer 20

snRNA’s (Smurphs)