| what is transcription | the process of copying the sequence of bases in the DNA |
| what is translation | at the ribosome, mRNA is used to produce a polypeptide chain |
| transcription part 1 | process of making a molecule of RNA, the primary transcript (initial RNA copy), using one strand of the section of DNA as a template, known as the transcribed strand or the template strand |
| what is a non transcribed strand | the DNA strand that is not copied and not play a part in transcription |
| initiation part 1 | initiation - RNA polymerase enzyme attatches to a region of the DNA called the promotor, near the section of DNA that is to be transcribed |
| initiation part 2 | the DNA molecule in the region of attatchment of RNA polymerase unwinds and hydrogen bonds between the 2 strands are broken |
| elongation part 1 | the strands continue to seperate as RNA polymerase moves along the DNA, as hydrogen bonds between complementary base pairing are broken, the nucleotides on the template strands get exposed |
| elongation part 2 | the nucleotide bases on the DNA template strand pair with the complementary RNA nucleotides from the pool that is present in the nucleus |
| elongation part 3 | as RNA polymerase moves along the strand the correct RNA nucleotide is alligned opposite its complementary DNA base and is joined to its neighboring nucleotide by a phosphodiester bond. |
| elongation part 4 | in this way, an exposed guanine base on the dna is temporarily linked by hydrogen bonds to the cytosine base of a free activated RNA nucleotide. simarlily adenine links to uracil |
| elongation part 5 | as the RNA polymerase adds the nucleotides one at a time to build a strand of primary transcript RNA. the DNA strands rejoin behind it |
| elongation part 6 | the rejoining allows the newly synthesised sections of the RNA molecule to be released from the DNA template strand . As a result only 12 base pairs of the DNA are exposed at one time |
| termination part 1 | when the RNA polymerase reaches a particular sequence of bases known as a termination sequence, it detatches and the production of the primary RNA transcript is then complete |
| termination part 2 | rna molecule is formed as the same length as the gene |
