Summary B13 Notes, GSCE AQA higher

TRANSCRIPTION
• the process of taking a single gene
HOW IS mRNA FORMED? TRA
of DNA and copying it into • the pr
structure called mRNA mRNA
WHY?
——> gene we want to copy
produ
• nucleus contains all genetic material of
that cell in the form of DNA For both
• DNA contains thousands of genes, bases
which are all small sections of the DNA
that have a specific sequence of bases
(TRIPLET
so are able to code for a specific amino a
sequence of amino acids, which when
1. Enzyme called RNA
combined will form a particular protein polymerase binds to the
DNA just before where the
1. DNA is too big to leave the nucleus gene starts
itself
2. To use a gene, you have to make a
copy of that gene first 2. Just ahead of the RNA
3. Copying a single gene rather than polymerase, the two strands of the
the entire DNA strand, it will be DNA seperate apart so that all of
small enough to leave the nucleus
4. Therefore the ribosome can read it their bases are exposed


3. RNA polymerase moves along
the DNA strand (template strand)
and read the bases one by one and
use them to make an mRNA strand