Chapter 17 - Transcription, RNA Processing, Translation

Question 1

Sigma

Answer 1

Part of Initiation Phase - A Protein that binds to DNA before RNA polymerase. Can only bind in one orientation!

Question 2

Holoenzyme

Answer 2

Combination of Sigma and RNA Polymerase

Question 3

Where does Sigma bind?

Answer 3

Promoters

Question 4

What is a Promoter?

Answer 4

A section of DNA that Sigma binds to.

Question 5

In what direction are RNTPs added?

Answer 5

5’ to 3’ direction just like NTPs!

Question 6

When does Transcription end?

Answer 6

When a transcription termination signal region of DNA is read. When this area is read, the RNA forms a hairpin loop.

Question 7

-10 Element

Answer 7

Part of Prokaryotic Promoter. Contains TATAAT box. Essential for Transcription

Question 8

-35 Element

Answer 8

Part of Prokaryotic Promoter. Causes high transcription rate.

Question 9

What is one of the Eukaryotic Promoters?

Answer 9

TATA box

Question 10

RNA Processing - RNA Cap

Answer 10

Guanosine cap @ 5’ end

Question 11

RNA Processing - RNA Tail

Answer 11

PolyA tail at 3’ end. Where prokaryotic would have a hairpin. Increases rna’s longevity.

Question 12

What type of cell uses RNA caps and tails?

Answer 12

Eukaryotes

Question 13

What is the first letter of the transcription template called?

Answer 13

+1 site

Question 14

How many RNA polymerases do Eukaryotes have?

Answer 14

Three

Question 15

What do Eukaryotes use instead of Sigma?

Answer 15

Basal Transcription Factors

Question 16

Which part of the RNA is discarded in RNA processing?

Answer 16

Introns because exons (exit) the nucleus

Question 17

What is the wobble hypothesis?

Answer 17

Many amino acids are specified by more than one codon and the codons have the same nucleotides at the first and second positions but a different nucleotide at the third position.

Question 18

Spliceosome

Answer 18

snRNPs form spliceosomes. Act as ribozyme

Question 19

What is an example of a ribozyme?

Answer 19

Spliceosome

Question 20

What does a mature RNA transcript contain?

Answer 20

Untranslated regions, coding region, 5’ cap, PolyA tail

Question 21

A site

Answer 21

Holds the aminoacyl tRNA

Question 22

P Site

Answer 22

Holds tRNA with growing polypeptide attached

Question 23

E site

Answer 23

Holds a tRNA that will exit soon

Question 24

aminoacyl tRNA synthetases

Answer 24

Adds amino acids to tRNA. Specific synthetases for each amino acid.

Question 25

What does it mean to charge tRNA?

Answer 25

This happens when amino acids bind to the right tRNA. This process requires energy. Aminoacyl tRNA synthetases charges the tRNA

Question 26

How are tRNA joined to amino acids?

Answer 26

Covalent bonding

Question 27

What is the binding site for amino acids on tRNA?

Answer 27

A CCA sequence at the 3’ end of each tRNA

Question 28

What is the final shape of tRNA?

Answer 28

L-shape tertiary form

Question 29

Where is the anti-codon located?

Answer 29

At the opposite end of the tRNA from the amino acid.

Question 30

What makes up a ribosome?

Answer 30

Protein and rRNA

Question 31

What does the small ribosome subunit do?

Answer 31

Holds mRNA in place

Question 32

What does the large ribosome subunit do?

Answer 32

This is where the peptide bond forms

Question 33

What are the three steps of prokaryotic translation initiation?

Answer 33

1. mRNA binds to small ribosome subunit
2. Initiator f-met binds to start codon at the P site
3. Large ribosome subunit binds

Question 34

How does Prokaryotic translation terminate?

Answer 34

A site recognizes stop codon and release factor enters the site.

Question 35

Molecular Chaperones

Answer 35

Speed up protein processing folding into higher structural forms