Describe the process of translation in prokaryotes Highlight the role of ribosomes in the process.

OR

Describe Hershey and Chase’s experiment. Write the conclusion they arrived at.

Translation is the process of polymerisation of amino acids to form a chain and thereby formation of protein. In this process the mRNA is decoded and amino acids are produced which are attached to each other by peptide for formation of protein.

The cellular factory responsible for protein production is ribosome. Ribosome consists of a small and a large subunit. Whenever the smaller unit of ribosome encounters an mRNA then it binds to it and the larger unit starts the process of translation. The process of translation initiates from the start codon AUG and ends at the stop codon. There are various non translated sequences known as Untranslated Regions (UTR). They increase the efficiency of translation.

The initiator tRNA recognises the start codon and then starts translating the codons further on and then the amino acids produced are attached with peptide bond thus forming a long chain until stop codon is recognised.

At the end the release factor binds to it and releases the polypeptide chain from the ribosome.

OR

Hershey and Chase in their experiment grew viruses some in medium containing radioactive phosphorous and some in medium containing radioactive sulphur. The viruses with radioactive phosphorous had radioactive DNA and one with radioactive sulphur had radioactive protein.

These viruses were then allowed to infect bacteria and the infected bacteria were found to have radioactive DNA.

Thus with their experiment Hershey and Chase concluded that DNA was the genetic material.