TRANSCRIPTION

Question 1

STEP 1

Answer 1

1. Hydrogen bonds (between DNA bases) break;
   Ignore DNA helicase.
   Reject hydrolysing hydrogen bonds.

Question 2

STEP 2

Answer 2

2. (Only) one DNA strand acts as a template;

Question 3

STEP 3

Answer 3

3. (Free) RNA nucleotides align by complementary base pairing;
   For ‘align by complementary base pairing’, accept ‘align to complementary bases’ or ‘align by base pairing’.

Question 4

STEP 4

Answer 4

4. (In RNA) Uracil base pairs with adenine (on DNA) OR
   (In RNA) Uracil is used in place of thymine;
   Do not credit use of letters alone for bases.

Question 5

STEP 5

Answer 5

5. RNA polymerase joins (adjacent RNA) nucleotides;
   Reject suggestions that RNA polymerase forms hydrogen bonds or joins complementary bases.

Question 6

STEP 6

Answer 6

6. (By) phosphodiester bonds (between adjacent nucleotides);