Question

Assertion:
Ribozymes are RNA molecules which catalyse the synthesis of certain specific RNAs and removal of introns from mRNA.
Reason:
Ribozymes are proteinaceous.
a. Both statement 1 and 2 are correct
b. Statement 1 is correct but statement 2 is incorrect
c. Statement 1 is incorrect but statement 2 is correct
d. Both statement 1 and 2 are incorrect

Answer 1

Hint: A ribozyme is a molecule with a well-defined tertiary structure that can act as protein enzymes to catalyse biochemical and metabolic reactions within cells. Cech (1982) found that when studying the mechanism of splicing of RNA molecules during the processing of hnRNA into mRNA the removal of individual protein enzymes from cell-free systems does not alter the ability of ribosomal RNA to bind.

Complete answer:
Let’s for answering the question study about ribozymes
• Like protein enzymes, some RNA molecules act as enzymes. Like protein enzymes, multiple RNA sequences form complex tertiary structures and act as biological catalysts. These RNA enzymes are known as ribozymes. Like enzymes, it has active sites, substrate binding sites, and cofactor binding sites such as metal ions.
• A ribozyme (ribonucleic enzyme) is an RNA molecule capable of catalysing certain biochemical reactions, including RNA splicing during gene expression, similar to the action of protein enzymes.
• They are also involved in a variety of RNA processing reactions, including RNA splicing, viral replication, and biosynthetic RNA delivery.
• The ribozyme has been extensively studied in the rRNA of the ciliated protozoan Tetrahymena thermophila and has also been found in the mitochondria of the fungi of the phage bacteria T4 and E. coli.
• So, from the above points it is clear that ribozymes are nucleic acids, not proteins and Ribozymes are RNA molecules which catalyse the synthesis of certain specific RNAs and removal of introns from mRNA.

Hence, the correct answer is option (B).

Note: Modern life, based primarily on the genetic material of DNA, is believed to originate from RNA-based organisms in the former RNA world. The lifespan of RNA depends on RNA-polymerase-dependent ribozymes, which copy functional RNA molecules, including the polymerase itself. However, this ribozyme could not replicate and its RNA product showed high mutation levels. However, progress is being made towards the goal of in vitro evolution - an accurate and efficient ribozyme that acquires replicating RNA polymerase for a better understanding of evolution at an early age.