Page 181 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

Types of RNA

Messenger RNA (mRNA)

Short-lived type of RNA that serves as the intermediary between DNA and

the synthesis of protein products
• The mRNA carries the message from the DNA, which controls all of the

cellular activities in a cell. If a cell requires a certain protein to be synthesized,

the gene for this product is “turned on” and the mRNA is synthesized through

the process of transcription

• The mRNA then carries genetic codes from the DNA in the nucleus to

ribosomes

• mRNA is relatively unstable and short-lived in the cell, especially in

prokaryotic cells, ensuring that proteins are only made when needed.

Ribosomal RNA (rRNA)

A stable RNA that is a major constituent of ribosomes, ensuring proper
Ribosomes are composed of
alignment of the mRNA and the ribosomes as well as catalyzing the formation

of the peptide bonds between two aligned amino acids during protein synthesis

General Microbiology & Immunology (PM 401) theoretical handbook Page 170