True about RIBOZYME: (AllMS Nov 2013, Nov 2012)
**Core Concept**
Ribozymes are RNA molecules with catalytic activity, similar to enzymes in the protein world. They can perform specific chemical reactions, such as cleaving phosphodiester bonds, without the need for a protein catalyst. This property makes ribozymes useful tools in molecular biology and medicine.
**Why the Correct Answer is Right**
The correct answer is related to the mechanism of action of ribozymes. Specifically, ribozymes can catalyze the cleavage of RNA molecules by breaking phosphodiester bonds. This process involves the formation of a transition state, where the ribozyme binds to the target RNA sequence and facilitates the cleavage reaction. The most well-known example of a ribozyme is the hammerhead ribozyme, which is capable of self-cleavage.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because ribozymes are not directly involved in DNA replication. While they can affect RNA levels, they do not play a role in the replication of DNA.
* **Option B:** This option is incorrect because ribozymes do not have a direct role in the regulation of gene expression through epigenetic modifications. However, they can affect RNA levels, which can indirectly influence gene expression.
* **Option C:** This option is incorrect because ribozymes are not directly involved in the synthesis of proteins. While they can affect RNA levels, they do not participate in the translation process.
**Clinical Pearl / High-Yield Fact**
One important aspect of ribozymes is their potential use as therapeutic agents. For example, ribozymes can be designed to target specific disease-causing genes or proteins, and can be delivered to cells to modulate gene expression or to cleave specific RNA molecules.
**Correct Answer: C.**