Transcription

Why does transcription need to happen?

Protein synthesis occurs in the cytoplasm at ribosomes, but a chromosomal DNA molecule is too large to leave the nucleus to supply the coding information needed to determine the protein’s amino acid sequence- base sequences of genes are copied and transported to ribosomes

What does RNA polymerase do?

Unzips DNA and adds RNA nucleotides which pair wth complementary bases exposed on the antisense strand when the DNA unzips

What is the sense strand?

Contains the code for the protein to be synthesised, it runs from 5’ to 3’

What is the antisense strand?

Complementary copy of the sense strand and does not code for a protein, it acts as the template strand during transcription so complementary RNA strand formed carries same sequence as the sense strand

How does transcription stop?

RNA polymerase moves along the DNA until it reaches a terminator sequence. RNA polymerase releases the new mRNA strand

How does mRNA leave the nucleus?

Via nuclear pores in nuclear membrane to reach the cytoplasm