Question

Read the following statement and inferences, and select the correct option.

Statement: The core of the larger ribosomal subunit, where the catalysis of the peptidyl bond happens between one amino acid and the next, is made up entirely of rRNA.

Inference:

A. rRNA is smaller than proteins and hence can fit in the smallest of crevices

B. rRNA has catalytic capability and hence confers the name ribozyme to ribosome

C. The proteins which make up ribosome do not have a significant role to play in its catalytic activity

Which of the inferences are true?

• A. A only
• B. B and C only
• C. D only
• D. All of the above

Answer 1

The correct option is C D only

Ribosomes are made up of rRNA and proteins. The proteins present in ribosomes act only as structural scaffolding. The real player behind the scenes is rRNA especially in the larger subunit. rRNA is quite smaller than proteins and since it also has more affinity toward each other, they bind closely together and form the structural core. Due to the inherent ability of RNA to catalyse reactions of itself and other molecules, the rRNA core forms the catalytic core too where it catalyses the formation of peptidyl bonds between the last amino acid of the growing peptide chain and the incoming amino acid.