RNA Synthesis- Lecture 8/19/21

Question 1

Sugars and bases in mRNA

Answer 1

Ribose, has 2’ OH and uracil instead of thymine

Question 2

RNA polymerase

Answer 2

Synthesizes RNA strands from DNA

Question 3

Transcription factors

Answer 3

Likely ~1600 TFS, regulate transcription with the recruitment of cofactors (activation or repression)

Question 4

Pol I

Answer 4

Synthesizes rRNA

Question 5

Pol II

Answer 5

Synthesized pre-mRNA (RNA that has yet to be processed

Question 6

Pol III

Answer 6

Synthesizes tRNA, 5s rRNA and other small RNA genes

Question 7

A-amanitin

Answer 7

Pol I is resistant, Pol II is sensitive, how we distinguished

Question 8

Ribosomal RNA

Answer 8

Components of eukaryotic ribosomes, synthesizes 5.8 S and 28 S in large subunit and 18 S in small

Question 9

rRNA transcription unit

Answer 9

located in tandem throughout the genome, transcribes a long strand then cleaved into pieces by enzymes

Question 10

RRNA transcription regulation

Answer 10

S and B factors binds to promoter and recruiters PolI to transcribe prerRNA

Question 11

RNA pol III

Answer 11

Transcribes many small RNAs, promoters often lie within the genes

Question 12

Transcription factors of RNA pol 3

Answer 12

Binding of TFIIIA and TFIIIC to the promoter recruits TFIIIB and finally Pol III

Question 13

Promoters (Pol II)

Answer 13

Usually located immediately upstream, crucial to the accuracy and rate of transcription

Question 14

Enhancers

Answer 14

Sequences that up-regulate gene transcription, can be located anywhere on the genome and function in either orientation

Question 15

TATA box

Answer 15

Preserved element which various TFII proteins recognize to initiate transcription

Question 16

Processing events of pre-mRNA

Answer 16

1. Capping
2. Polyadenylation
3. Splicing

Question 17

Capping

Answer 17

Placing of a 7-ethyl-guanisine to the 5’ end with three phosphates, acts as a shield and signals this will be a protein

Question 18

Polyadenylation

Answer 18

Addition of polyA sequence that is signaled by an intra-RNA signal, cleaved after that

Question 19

CPSF

Answer 19

Responsible for the cleavage of the mRNA after poly A site

Question 20

PolyA polymerase

Answer 20

Adds the poly A tail

Question 21

Sliceosomes

Answer 21

Enzymes responsible for cleavage at the start of an intron, facilitates nucleophilic attack to next exon, creates lariat

Question 22

Introns

Answer 22

Parts of the primary transcript not found in mature mRNA

Question 23

Exons

Answer 23

Will ultimately be spliced into functional mRNA

Question 24

Splicing mechanism

Answer 24

Introns have a conserved GU and AG region at either end, with an A residue that acts as an intermediate in the middle

Question 25

Thalassemias

Answer 25

Diseases of a-globulin or b-globulin that prevent correct splicing

Question 26

Alternative splicing

Answer 26

Using different exons in a complete mRNA for specified protein function