Transciption Flashcards
1
Q
What are the 2 strands in DNA?
A
Sense and antisense strand
2
Q
What is the sense strand?
A
The strand which carries the code
3
Q
What is the antisense strand?
A
It is the strand which acts as template for the synthesis of mRNA
4
Q
What is the enzyme involved in the breaking of hydrogen bonds?
A
RNA polymerase
5
Q
What are the steps of transcription?
A
- The sequence of bases in the gene coding for a protein is exposed by unwinding the helix and unzipping the DNA by breaking the hydrogen bonds by enzyme.
- RNA polymerase binds to the promoter region of the gene.
- As the DNA unwinds and ‘free; mRNA nucleotides hydrogen bond to the exposed bases of the antisense strand of the DNA by base pairing rule.
- A complementary strand of mRNA is formed by the RNA polymerase joining the mRNA nucleotides together to form the sugar-phosphate backbone
- RNA polymerase also seals up the DNA up again as it travels along the gene and the DNA double helix reforms behind the growing mRNA.
- RNA polymerase travels along the gene until it reaches the stop codon
- The mRNA carries a copy of the base sequence on the gene to the ribosome.
- mRNA peels away from the DNA and mRNA leaves the nucleus via a nuclear pore
6
Q
What enzyme joins together the sugar-phosphate backbone in mRNA?
A
RNA polymerase
7
Q
What are the stop codons?
A
TAA, TAG or TGA
