Control of gene expression in eukaryotes part 4 Flashcards Preview

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Flashcards in Control of gene expression in eukaryotes part 4 Deck (15)
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1

Define RNAi

A mechanism by which very selective degradation of mRNA takes place

2

Define the role of Dicer

cuts dsRNA into 22 nt pieces

3

Define siRNA

22bp of target mRNA

4

Define RISC

RNA-induced silencing complex
A complex of proteins that takes the siRNA and matches it to the target RNA, and then cleaves the RNA

5

Define Argonaut

Protein in RISC that cleaves the dsRNA

6

Define microRNAs

- A way of attacking mRNA from an intrinsic source
-

7

What are the two ways microRNA can work?

1. perfect match: degradation of mRNA immediately
2. Imperfect match: transportation to p bodies for degradation

8

Define RITS?

RNA-induced transcriptional silencing complex.

9

How does RITS work?

RITS interacts with mRNA exiting RNA pol. The presence of RITS near the gene attracts CRCs, to create heterochromatin

10

There will probably be a question of comparing the different types of RNA.

Ok

11

What are four modes of negative control in eukaryotes

1. Protein inhibits stat or stop codon
2. Cold temperatures cause hairpin, hiding start codon
3. Small molecule creates hairpin that hides start codon
4. antisense RNA covers the start codon

12

Define ferritin

Protein that binds iron when it is in excess

13

Define transferrin receptor

Protein that transports iron through the plasma membrane

14

What is eIF-2?

A factor needed for assembly of the 40S unit of the ribosome

15

What is the role of eIF2B?

It is responsible for exchanging GDP for GTP on EiF-2