DNA 2

Question 1

How does transcription differ from DNA replication

Answer 1

1. Transcription begins at promoter while DNA replication begins at an origin of replication
2. DNA polymerase in DNA replication vs RNA polymerase in transcription
3. DNA replication requires RNA primer while transcription does not
4. Both DNA strands acts as a template during DNA replication while only one strand acts as a template during transcription
5. Transcription synthesises RNA while DNA replication synthesises DNA

Question 2

Explain how information to synthesise polypeptides is coded for by DNA

Answer 2

1. A specific sequence of nucleotides on a template DNA strand is transcribed by RNA
   polymerase to form mRNA by complementary base pairing
2. The mRNA contains codons. Each codon codes for aspecific amino acid
3. When the mRNA containing a specific sequence of codons which code for a specific amino acid sequence is translated at ribosomes, polypeptides are formed.

Question 3

How is transcription similar to DNA replication

Answer 3

1. Both occurs in the nucleus
2. Both involves breaking of hydrogen bonds between complementary bases
3. In both processes, products are synthesised from 5’ to 3’ direction