Question

Observe the given figure and answer the questions given below.

Which fraction would you expect to produce most radioactively-labelled protein if labelled amino acids were added? Give a reason for your answer.

Answer 1

The fraction E was centrifuged at the speed of 300,000 g. The ribosomes are separated free from the other organelles when the fraction is centrifuged at the speed of 150,000 - 300,000 g for 60 minutes. The ribosomes are formed by the assembly of many rRNA proteins. These are the site of protein synthesis. The tRNA and the mRNA play an important role in protein synthesis. The ribosome move along the mRNA molecule. The ribosome catalyze the assembly of the amino acids to form the protein molecules. These ribosomes also attach to the tRNA and other proteins which are involved in protein synthesis. So, the radio-labelled amino acids will be transformed to radio-labelled proteins in the fraction E.