Transcription and mRNA Processing

Question 1

What is the role of RNA polymerase?

Answer 1

Catalyze RNA synthesis; pries DNA strands apart and joins together RNA nucleotides

Question 2

What is a promoter?

Answer 2

Area where factors bind to DNA

Question 3

What is the upstream sequence?

Answer 3

Anything before the start codon

Question 4

What is the terminator?

Answer 4

Area after the stop codon telling RNA polymerase to stop coding

Question 5

What is the transcription termination site?

Answer 5

Area where the RNA polymerase releases from the strand

Question 6

What is the transcription initiation site?

Answer 6

Area where the RNA polymerase starts coding

Question 7

What are the stages of transcription?

Answer 7

1. Initiation- start of transcription
2. Elongation- growth or elongation (actual synthesis)
3. Termination- ending transcription

Question 8

Does initiation require ATP?

Answer 8

YES

Question 9

Does the initiation process have 3’ to 5’ exonuclease activities?

Answer 9

NO

Question 10

Where does transcription being in eukaryotic promoters?

Answer 10

TATA Box

Question 11

What is the name of the complete complex one the transcription factors bind to the DNA?

Answer 11

Transcription initiation complex

Question 12

What direction does elongation take place?

Answer 12

5’ to 3’

Question 13

Does transcription need a primer to help process occur?

Answer 13

NO

Question 14

What type of cell has pre-mRNA?

Answer 14

Eukaryotes

Question 15

How does RNA polymerase know when to release from DNA strand?

Answer 15

The transcription will force the RNA to change shape and stop the process

Question 16

What is the polyadenylation signal sequence?

Answer 16

AAUAAA sequence after the stop codon that makes the RNA stop and release from DNA strand in eukaryotes

Question 17

Why does a eukaryotic cell add a 5’ cap and 3’ Poly-A tail?

Answer 17

Mediate mRNA to reach the cytoplasm

Question 18

What is the reason for the caps at the ends of pre-mRNA?

Answer 18

1. Facilitate mRNA export to cytoplasm
2. Protect mRNA from hydrolytic enzymes
3. Helps ribosomes attach to 5’ end

Question 19

What is found in the 5’ cap?

Answer 19

Modified guanine nucleotide with 3 phosphates

Question 20

The polyadenylation signal tells the RNA to make what?

Answer 20

3’ Poly-A (adenine) tail

Question 21

What will the caps do to the pre-mRNA?

Answer 21

Bond together and form a closed-loop structure for protection, transport, and ribosome binding

Question 22

What is RNA splicing?

Answer 22

Removal of intron sequences which leave exons only

Question 23

Are exons or introns expressed?

Answer 23

Exons are expressed

Question 24

Introns are indentified by consensus sequences: _ _ at the start and _ _ at the other end.

Answer 24

GT

AG

Question 25

What is the spliceosome?

Answer 25

Area that identifies the beginning and end of transcription

Question 26

What is the job the small RNA in the splicosome?

Answer 26

Removal of introns

Question 27

What is the role of ribozymes?

Answer 27

Catalytic RNA molecules that function as enzymes

Question 28

How do ribozymes act as a catalyst? (3)

Answer 28

1. Can form 3D structures- complementary base pairing
2. Some bases in RNA contain functional groups that may participate in catalysis
3. RNA may H-bond with other nucleic acid molecules

Question 29

Why do we have introns?

Answer 29

Ribozymes and some introns contain sequencing that may regulate gene expression

Question 30

What is alternative RNA splicing?

Answer 30

Not all exons are expressed, a cell can splice out introns and exons to form different types of proteins