Gene expression

Question 1

DNA characteristics

Answer 1

Double stranded thus very stable.

Contains heritable information to be transfered to RNA

Question 2

RNA

Answer 2

Single stranded thus less stable.

Acts as a messenger of DNA information to be used in protien production

Question 3

Protien purpose

Answer 3

Carry out cellular functions

Question 4

Promotor region

Answer 4

Where molecules bind to initate transcription

Question 5

Transcription

Answer 5

Transfer of DNA information into RNA

Question 6

Three steps of transcription

Answer 6

1. Initiation
2. Elongation
3. Termination

Question 7

Transcription - Initiation process

Answer 7

Trasncription factors assemble at TATA site and bind to DNA to cause a kink enabling substances to reach eachother

Question 8

RNA polymerase role in transcription

Answer 8

Unwinds DNA strands to bring along more transcription factors

Question 9

Transcription - Elongation process

Answer 9

RNA nucleotides added to template strand from 3 prime

Question 10

Transcription - Termination process

Answer 10

Once the polyadenylation signal (End signal) is reached, Pre mrna and RNA polymerase is released

Question 11

Three steps of mrna processing

Answer 11

1. Capping
2. Tailing
3. Splicing

Question 12

Mrna processing - capping process

Answer 12

Guanine nucleotide is added to 5 prime end of mrna

Question 13

mrna processing - Tailing

Answer 13

adenine nucelotides are added to 3 prime end of mrna

Question 14

Purpose of capping and tailing

Answer 14

Facilitate export, stabilise and facilitate ribosome binding in cytoplasm

Question 15

mrna processing - Splicing

Answer 15

Introns are removed from transcript so exons can join together - occurs in nucleus splicesomes

Question 16

Exon

Answer 16

Coding region

Question 17

Intron

Answer 17

Non coding regions in between exons

Question 18

UTR

Answer 18

Untranslated regions at 5 prime and 3 prime

Question 19

Splicesomes

Answer 19

Complex of protiens and RNA

Question 20

Alternate splicing

Answer 20

Different combination of exon joining to form multiple forms of mRNA

Question 21

Ribosome function and components

Answer 21

Holds tRNA and mRNA to form polypeptides

1. Large and small subunit
2. E site
3. P site
4. A site
5. Exit tunnel
6. mRNA binding site

Question 22

Transfer RNA

Answer 22

Bring in amino acids via anticodons that bind to codons of mRNA

Question 23

Translation

Answer 23

mrna exits nucleus into cytoplasm to form polypeptide chains

Question 24

Translation - Initiation

Answer 24

Small subunit ribosome binds to start site AUG of mrna and binds initiator tRNA via hydrogen bonds followed by bond of Large subunit

Question 25

Translation - Elongation - Codon recognition

Answer 25

codons are paired with anticodons

Question 26

Translation - Elongation - Peptide bond formation

Answer 26

Large subunit catalyses peptide bond formations between two adjacent amino acids

Question 27

Translation - Elongation - Translocation

Answer 27

trna with now lost amino acid sequence is removed from A to P to E site

Question 28

Translation - Termination

Answer 28

Ribosome reaches stop codon and hydrolosis of P site and trna releases polypeptide

Question 29

Regulatory protiens

Answer 29

Block translation

Question 30

Gene expression control

Answer 30

Temporal and spatial control - Protiens are continously produced and cell signalling activates trasncription

Question 31

Protiens to function in cytoskeleton..

Answer 31

Complete translation on free ribosomes

Question 32

Protiens that go to endomembrane system...

Answer 32

Complete translation on fixed ribosomes on RER