transcription

Question 1

what is meant by ‘transcription’

Answer 1

the process of which a copy of DNA (base sequence of genes) is made in the nucleus to be transported to ribosomes for protein synthesis

Question 2

describe the properties of mRNA

Answer 2

• no H bonds
• 1 strand
• single helix
• ribose

Question 3

summarise the process of transcription

Answer 3

1. DNA helicase unwinds double strands and hydrolyses H bonds to form a sense and antisense strand
2. free RNA nucleotides pair with antisense strand using complementary base pairing, forms H bonds
3. RNA nucleotides join via phosphodiester bonds
4. the new strand is mRNA & leaves nucleus through a pore after detaching from antisense strand

Question 4

what is the sense strand?

Answer 4

strand which contains exact code needed for protein synthesis 5’-3’

Question 5

describe the antisense strand

Answer 5

complementary copy which acts as a template 3’-5’