Describe the roles of DNA and RNA in determining the sequence of amino acids in proteins.
The sequence of bases (a gene) on DNA determines the order of amino acids that come together to form a polypeptide (protein) chain.
The DNA is 'unzipped' by enzymes called Helicases. This allows a single strand of DNA to be copied (transcription) to form a molecule of messenger RNA (mRNA).
The mRNA then leaves the nucleus through the nuclear pores and enters the cytoplasm.
In the cytoplasm the mRNA associates with a ribosome.
Free amino acids within the cytoplasm are brought together in the correct order (determined by the sequence of the mRNA) to form a polypeptide chain (protein).
AH
Related Human Biology A Level answers
All answers ▸What is the mechanism which leads to an increase in heart rate during exercise?
What are the major parts of a neuron? What are the three types of nerve cells?
What are the 4 main valves in the heart, and where are each of them located?
What makes the structure of Haemoglobin good for the transport of oxygen to tissues? (3 marks)