Describe the sequence of events in DNA transcription
An enzyme called DNA helicase breaks the hydrogen bonds holding the complimentary base pairs together in a double stranded DNA molecule. This causes the DNA helix to unwind, exposing the unpaired bases. Another enzyme called RNA polymerase binds to a 'promotor' region on the exposed DNA strand and moves downstream, attaching free complementary mRNA nucleotides to the exposed DNA bases. This strand of mRNA is released to form a strand of pre-mRNA. The non-coding regions called introns are removed via RNA 'splicing', resulting in a strand of coding mRNA.
EM
Related Biology A Level answers
All answers ▸Explain how two populations of organisms may develop into two separate species.
Describe two ways in which genetic diversity is achieved during meiosis?
Describe how the cardiac cycle is coordinated with reference to the sinoatrial node (SAN), the atrioventricular node (AVN), and Purkinje tissue.
State 3 organelles found in a Eukaryotic cell and the functions of each organelle.