Lesson 35: RNA Processing

Question 1

rRNA Processing - do prokaryotes eukaryotes do it, what happens, draw

Answer 1

Prokaryotes = yes
Eukaryotes = yes

Pre-rRNA is cut into +2 different pieces - produce all rRNAs from a single gene

Slide 6

Question 2

tRNA Processing - do prokaryotes eukaryotes do it, what happens

Answer 2

Prokaryotes = yes
Eukaryotes = yes

Spcific A, C, G, U bases are modified - allow tRNA to fold into complex shapes

Question 3

mRNA Processing - do prokaryotes eukaryotes do it, what happens

Answer 3

Prokaryotes = no
Eukaryotes = yes

Three modifications perfromed to turn pre-RNA into mature mRNA

Proteins attach to RNA polymerase hop onto pre-mRNA

Question 4

What is added to 5’ and 3’ end of mRNA

Answer 4

5’: 5’ cap

3’: poly(A) tail

Question 5

Which enzyme adds to the poly(A) tail

Answer 5

Poly(A) polymerase

Question 6

3 reasons why 5’ cap and poly(A) tail added

Answer 6

Help mRNA exit nucleus

Help ribosome binding

Increase mRNA stability (protect from RNA eating enzymes)

Question 7

What are introns

Answer 7

Non-coding regions removed from the pre-mRNA

Question 8

What are exons

Answer 8

Coding regions that stay in mature mRNA

Question 9

Intron removal steps (3)

Answer 9

1. Splicing factors mark intron/exon boundaries
2. Spliceosomes remove introns after mRNA synthesis
3. Spliceosomes joins the exon together

Question 10

Spliceosomes - what are they made of, what do they do (2)

Answer 10

RNA and proteins

Cut the boundaries marked by splicing factors
Lights the exons together

Question 11

Prokaryotes & eukaryotes - which one have introns

Answer 11

Eukaryotes

Question 12

2 disadvantage of introns

Answer 12

Larger genes

Slower mRNA production

Question 13

Advantage of intron

Answer 13

Alternative splicing - multiple proteins from one gene

Question 14

Alternative splicing - what is it, how does it work, draw, why is it important

Answer 14

One gene makes multiple protein variants

RNA-binding proteins hide splice sites

Slide 34

Allow cell-specific protein production