2.5 Coding and Non-coding RNA

Question 1

What was the nature of the defect that caused hemophilia in the family of Tsar Nicholas?

Answer 1

Defect in splice site caused inactivation of hemophilia gene. Point mutation.

Question 2

What is the concept of collinearity and noncollinerity.

Answer 2

Suggests that a continuous sequence of nucleotides in DNA encodes a continuous sequence of amino acids in a protein.

Question 3

What are euk genes? noncolinearity or colinearity?

Answer 3

Noncolinearity

Question 4

How did we find out that euk genes were noncolinear?

Answer 4

By hybridizing DNA and mRNA

Question 5

How did we find out that euk genes were noncolinear?

Answer 5

By hybridizing DNA and mRNA

Question 6

Why are euk genes noncolinear?

Answer 6

The coding sequences (exons) of most euk genes are disrupted by noncoding introns.

Question 7

What is the splicing mechanism for Group I introns?

Answer 7

self splicing

Question 8

What is the splicing mechanism for Group II introns?

Answer 8

Self splicing

Question 9

What is the splicing mechanism for Nuclear pre-mRNA introns?

Answer 9

Spliceosomal

Question 10

What is the splicing mechanism for tRNA introns?

Answer 10

Enzymatic

Question 11

What does a gene include?

Answer 11

1. DNA seq that code for exons and introns. 2. Seq at the beginning and end of RNA that are not translated into a protein, including the entire transcription unit (promoter, RNA coding seq, terminator)

Question 12

What is the structure of mRNA?

Answer 12

5’ UTR (where 5’ cap is), Protein coding region and 3’ untranslated region which is site if microRNA binding. (poly a tail)

Question 13

The splicesome must know what in order to splice?

Answer 13

The consensus sequences on the 5’ and 3’

Question 14

What does the addition of 5’ cap do?

Answer 14

Helps binding of ribosome to 5’ end of mRNA, increases mRNA

Question 15

What does the addition of polyA tail do?

Answer 15

Increases stability of mRNA, helps binding of ribosome to mRNA.

Question 16

What is the seq of events for splicing? 5 steps

Answer 16

1. 5’ site recognized and brings proteins in to do cutting. 2. 5’ bent around and attache to A. 3. 3’ end cut. 4. intron released. 5. Exons spliced together.

Question 17

Where does RNA splicing take place?

Answer 17

Within the spliceosome

Question 18

What is nuclear organization?

Answer 18

intron removal, mRNA processing, and transcription take place at the same site in the nucleus.

Question 19

Pertaining to alternative splicing, what does it depend on?

Answer 19

Where the 3’ cleavage site is

Question 20

What is RNA editing?

Answer 20

Coding seq altered after transcription

Question 21

What are guide RNAs?

Answer 21

Responsible for RNA editing. They change seq of a message POST transcriptionally, so that it is slightly modified . Thus making significant changes in amino acids.

Question 22

When is mature euk mRNA produced?

Answer 22

When pre-mRNA is transcribed and undergoes sever types of processing

Question 23

What two things do siRNAs and microRNAs have?

Answer 23

Dicer and RISC.

Question 24

What does Dicer do?

Answer 24

Dicer cleaves dsRNA and pre-miRNA into short ds RNA fragments (siRNA and microRNA)

Question 25

What is RISC?

Answer 25

RNA-induced silencing complex

Question 26

What do siRNAs do?

Answer 26

Interfere with the expression of specific genes with complementary nucleotide sequenced by degrading mRNA after transcription. Preventing translation.

Question 27

Which is more common? siRNA or microRNA?

Answer 27

siRNA

Question 28

What is the origin of siRNA?

Answer 28

mRNA, transposon, or virus

Question 29

What is the origin of miRNAs?

Answer 29

RNA transcribed from distinct gene

Question 30

What is siRNA cleaved from?

Answer 30

RNA duplex or ssRNA that forms long hairpins

Question 31

What is miRNA cleaved from?

Answer 31

ssRNA that forms short hairpins of dsRNA

Question 32

What is the size of siRNA and miRNA?

Answer 32

same size, 21-25 nucleotides

Question 33

What does siRNA inhibit through action?

Answer 33

Transcription

Question 34

What does miRNA inhibit through action?

Answer 34

Translation

Question 35

What is the target of siRNA?

Answer 35

genes from which they were transcribed

Question 36

What is the target of miRNA?

Answer 36

Genes from other than those from which there were transcribed.

Question 37

What are snoRNAs?

Answer 37

purpose is to modify other noncoding RNAs like the ribosome. Add mythel groups, not inhibiting but slightly changing

Question 38

What regulatory role do snoRNAs play in?

Answer 38

Development

Question 39

What is the structure of tRNA?

Answer 39

Rare modified RNA nucleotide bases (ribothymine and pseudouridine), the cloverleaf structure (2ndary structure), and anticodon

Question 40

What do all tRNAs posses?

Answer 40

a common 2ndary structure, the cloverleaf structure.

Question 41

What is the anticodon on tRNA?

Answer 41

Has 3 bases and interacts with a codon in mRNA. Determines which amino acid is attached to the acceptor arm

Question 42

What is the acceptor arm in tRNA?

Answer 42

the site of attachment of amino acids to tRNA

Question 43

What are tRNAs capable of?

Answer 43

self splicing

Question 44

When is ribosomal RNA processed?

Answer 44

After transcription

Question 45

What is CRISPR?

Answer 45

Prokaryotic noncoding RNA, function in defense against invasion of foreign DNAs and chops it up.