Transcription

Question 1

How does the flow of information work in cell replication

Answer 1

DNA (DNA replicated) -> RNA (transcription) -> Protein

Question 2

Central Dogma process

Answer 2

1) Transcription
DNA is transcribed into pre-mRNA by RNA polymerase
Copies genetic code into complementary RNA sequence
2) Processing
pre-mRNA splices introns out and exons join together
5’ cap and poly-A tail added to stabilise mRNA before it exits nucleus
3) Translation (protein synthesis)
Mature mRNA enters cytoplasm and attached to ribosome
tRNA brings specific amino acids to codons on mRNA sequence
RIbosome facilitated formation of polypeptide chain (links amino acids)

Question 3

how does RNA differ from DNA

Answer 3

1) RNA single stranded
2) RNA is ribose not deoxyribose
3) RNA has uracil not thymine

Question 4

what is the polarity of DNA

Answer 4

top: 5’ - to - 3’
Bottom: 3’ – to – 5’

5’-PO4 and 3’-OH groups

Question 5

Transcription has three phases

Answer 5

initiation
elongation
termination

Question 6

What does initiation do

Answer 6

RNA polymerase binds to promoter region
exposed template strand

Question 7

What does elongation do

Answer 7

RNA polymerase elongates RNA in 5’-to-3’ direction
adds RNA nucleotides to comp strand with template strands
ribonucleoside triphosphates hydrolysed, release energy for RNA synthesis

Question 8

What does termination do

Answer 8

transcription continues until RNA polymerase reaches termination sequence
pre-mRNA detaches and undergoes processing to form mRNA

Question 9

what happens to RNA after dna template

Answer 9

rna transcribed from DNA template, bases are exposed by unwinding double helix

Question 10

what changes about the DNA strand during elongation

Answer 10

One side os RNA the other is DNA
contains uracil