Translation

Question 0

Explain the process of translation

Answer 0

• the mRNA strand formed in the nucleus attaches to a ribosome in the cytoplasm, it is attached at the start codon (AUG) at the end of the 3’ strand
• transfer RNA (tRNA) molecules contain a sequence of 3 bases called an anticodon, the tRNA molecule will bond with a complementary codon on the mRNA strand
• as the ribosome moves along the mRNA another tRNA moves in carrying the corresponding amino acid
• the two amino acids are then joined together with a peptide bond by an enzyme
• another tRNA moves into the ribosome, adding another amino acid to the chain
• the first tRNA molecule is released and is free to collect another amino acid from the cytoplasm
• this process continues until a stop codon is reached on the mRNA strand, as there is not a corresponding tRNA for this sequence the polypeptide chain is released

Question 1

Explain how some proteins can be activated

Answer 1

• some proteins have to be activated by cyclic AMP

* its activates them by changing their 3D structure so that their shape is a better fit to their complementary molecules