Lec 35: RNA Processing

Question 1

What kind of organisms have rRNA processing?

Answer 1

Prok. and Euk.

Question 2

What happens during rRNA processing?

Answer 2

Pre-rRNA is cut into two or more different pieces to produce all rRNAS from a single gene

Question 3

What happens during tRNA processing?

Answer 3

A, C, G or U bases are modified

Question 4

Why does during tRNA processing some of the bases are modified?

Answer 4

Modified bases allow tRNAs to fold into complex shapes

Question 5

What kind of cell does tRNA processing?

Answer 5

Both Prok. and Euk.

Question 6

Which kind of cells do mRNA processing?

Answer 6

Prok= no
Euk= Yes

Question 7

What is pre-RNA?

Answer 7

Pre-RNA (precursor RNA) is the initial, unprocessed RNA molecule transcribed from DNA, containing both coding (exons) and non-coding (introns) segments, needing modifications like splicing, capping, and tailing in eukaryotes to become mature, functional mRNA, rRNA, or tRNA, which then carries out its job in the cell, such as making proteins or forming ribosomes.

Question 8

What are the three steps for converting pre-RNA to mature mRNA?

Answer 8

1. Add a protective cap onto the 5’ end
2. Non-coding regions are cut out and coding regions are joined together
3. An enzyme adds a tail of 50-250 nucleotides to the 3’ of the mRNA

Question 9

How does the three steps for converting pre-RNA to mature mRNA?

Answer 9

The proteins that do the three steps all rid the RNA Pol and then hop onto the pre-mRNA

Question 10

True or False: Capping Factors aren’t polymerases so don’t follow my nucleic acid rules

Answer 10

True

Question 11

How can Poly (A) polymerase not be made using a ssDNA template?

Answer 11

Doesn’t need a template because it is only using A base

Question 12

Why do we make so many modifications to make this RNA?

Answer 12

-Helps export from nucleus
-Helps ribosomes bind
-It also extends the lifespan of mRNA as it is harder to degrade

Question 13

Why does these modification extend the lifespan of mRNA?

Answer 13

RNA digestion enzymes are blocked from both sides due to the 5’ cap and the Poly (A) tail on the 3’ end

Question 14

True or False: Euk. mRNAs have introns removed

Answer 14

True, introns are cut out and exons are spliced together

Question 15

What do Introns (Intervening regions) do?

Answer 15

Idk but they are removed from pre-mRNAS

Question 16

What is the only thing that remains in mature mRNAS?

Answer 16

Exons (Expressed regions) not introns

Question 17

How do we remove the introns from the mRNA?

Answer 17

1. Splicing factors mark location of introns during mRNA synthesis

Question 18

What do splicing Factors mark?

Answer 18

-Exon/intron boundaries
-Introns/Exon Boundaries

Question 19

True or False: There are specific sequences that tell use when the intron begins and ends

Answer 19

True

Question 20

What are spliceosomes made of?

Answer 20

Spliceosomes are made of proteins + RNAs

Question 21

What do Spliceosomes do?

Answer 21

They remove introns after mRNA synthesis by cutting the boundaries and ligating the exons together

Question 22

What is the difference between spliceosomes and ribosomes?

Answer 22

Both made of RNAS and proteins
Splice: Cuts introns out (Processes mRNAS in the nucleus)
Ribosomes: Reads mRNAS in the cytosol

Question 23

True or False: Eukaryotic mRNAS have introns

Answer 23

True, which is werid because prok. dont

Question 24

What are the disadvantages of having introns?

Answer 24

-Genes are larger
-mRNAS take more time to make

Question 25

What are the advantages of having introns?

Answer 25

Alternative splicing: 1 gene (1 section of DNA) can make 2+ different proteins

Question 26

True or False: You can hide a exon

Answer 26

True, a part of Euk. alternative splicing of pre-RNA to make mRNA

Question 27

Why is Alternative Splicing important?

Answer 27

It allows multicellular Euk. to make cell-specific versions of proteins