Describe how mRNA is formed by transcription in eukaryotes.
- AQA - A-Level Biology - Question 10 - 2020 - Paper 1
Question 10
Describe how mRNA is formed by transcription in eukaryotes.
Worked Solution & Example Answer:Describe how mRNA is formed by transcription in eukaryotes.
- AQA - A-Level Biology - Question 10 - 2020 - Paper 1
Step 1
Hydrogen bonds between DNA bases break
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Answer
The process of transcription begins when hydrogen bonds between the bases of the DNA strands break, allowing the DNA to unwind and expose the gene that is to be transcribed.
Step 2
DNA strand acts as a template
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Only one strand of the DNA serves as the template for mRNA synthesis. This strand directs the synthesis of the corresponding mRNA.
Step 3
RNA nucleotides align by complementary base pairing
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Free RNA nucleotides then align along the DNA template strand by complementary base pairing with the DNA bases (A pairs with U in RNA, and C pairs with G).
Step 4
RNA polymerase binds and forms mRNA
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RNA polymerase attaches to the DNA and catalyzes the formation of the mRNA strand by joining together the RNA nucleotides.
Step 5
Pre-mRNA processing
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Once synthesized, pre-mRNA is processed to remove introns and splice together the exons. The final mature mRNA is then transported out of the nucleus for translation.
