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Flashcards in Gene Expression Deck (23):
1

What enzyme do you need to make DNA?

DNA polymerase

2

What activated substrates do you need to make DNA?

Deoxynucleotides triphosphates

3

What template is used to make DNA?

DNA

4

What enzyme is needed to make RNA?

RNA polymerase

5

What activated substrate is needed to make RNA?

Ribonucleotides triphosphates

6

What template is used for making RNA?

DNA

7

What enzyme is needed to make a polypeptide?

Ribosomes

8

What activated substrate is needed to make a polypeptide?

Amino acids

9

What template is needed to make a polypeptide?

mRNA

10

What happens in the initiation stage of transcription?

TATA box sets the direction of transcription
Transcription begins at the promoter region as acts as a recognition site for RNA polymerase
DNA helix unwinds and opens

11

What happens in the elongation stage of transcription?

RNA polymerase slides along the template strand
Complementary bases pair up
RNA polymerase link nucleotides from the 3' end

12

What happens in the termination stage of transcription?

Once the RNA polymerase reaches the end section the mRNA is complete and so dissociates

13

What is capping in RNA processing?

At 5' end a linage is created which provides protection against degradation

14

What is polyadenylation in RNA processing?

A polyA tail is added at the 3' end
Protects against degradation
E.g. AAAAAAA

15

What is splicing in RNA processing?

Removal of introns

16

What is the name for many ribosomes?

Polyribosome or polysome

17

How do prokaryotes and eukaryotes ribosomes differ?

Eukaryotes ribosomes are bigger

18

What are the different types of RNA?

Ribosomal- few kinds, most of RNA 80%
Messenger- 100,000 of kinds, least of RNA 2%
Transfer- 100 kinds, some RNA 15%

19

What are the properties of the genetic code?

4 letter DNA language to 20 letter protein language
Triplet code
Degenerate
Non overlapping
Comma less
5' to 3' becomes N to C

20

What is a wobble base?

A single tRNA species can recognise more than one codon
G and U can bind at the wobble base

21

What happens at the initiation stage of translation?

mRNA binds to small ribosomal subunit upstream form start codon
Complementary base pairing occurs between codon and anticodon
Large ribosomal subunit will bind

22

What happens at the elongation stage of translation?

tRNA binds to the A site of the ribosome and forms a peptide bond with the amino acid in the P site
The tRNA in the E site will then leave

23

What happens in the termination stage of translation?

Stop codon is reached
Release factor binds to the A site at a stop codon and the polypeptide is released