Back to: MICROBIOLOGY 200 LEVEL
Welcome to class!
Welcome, my brilliant scholar! It’s always a pleasure to have you here, and today we’re taking another confident step into the fascinating world of genetics. This time, we’re focusing on something very essential — mRNA Synthesis and Processing. This topic is like the bridge between your genes and the proteins that make your body function. Let’s break it down together in the simplest and most relatable way possible!
mRNA Synthesis And Processing
Have you ever written a recipe you heard from your grandma before heading to the market? You first listen carefully, then jot it down (that’s transcription), and finally, you rewrite it clearly, maybe add headings or correct the spelling before giving it to someone else to cook. That final version is what the chef uses to prepare the meal.
That’s exactly how mRNA synthesis and processing work. The DNA gives instructions, mRNA is created through transcription, and then it’s processed and cleaned up before it’s used to make proteins. Without these steps, the message would be messy, confusing, or even useless!
mRNA Synthesis (Transcription)
This is the first step of gene expression, where RNA polymerase reads the DNA and creates a messenger RNA (mRNA) copy.
It occurs in the nucleus of eukaryotic cells.
Only one strand of the DNA (the template strand) is used.
The RNA polymerase builds the mRNA using complementary bases (A pairs with U instead of T, G with C).
Steps in mRNA synthesis:
Initiation – RNA polymerase binds to the promoter region of the gene.
Elongation – It moves along the DNA, adding RNA nucleotides.
Termination – It stops when it reaches a stop signal and releases the mRNA strand.
At this point, the mRNA is made, but it’s not ready yet — it needs to be processed.
mRNA Processing (in Eukaryotes)
Just like editing a school assignment before submission, mRNA must be polished before it’s useful.
5’ Cap Addition
A special cap is added to the beginning (5’ end) of the mRNA.
This protects the mRNA and helps it bind to ribosomes later for protein-making.
Poly-A Tail Addition
A long chain of adenine bases (A’s) is added to the end (3’ end).
This also protects the mRNA and controls how long it stays in the cell.
Splicing
The mRNA contains introns (non-coding regions) and exons (useful coding regions).
Splicing removes the introns and joins the exons together to make a clean, meaningful message.
It’s like removing the rough, unwanted parts from a recording before releasing the final track.
Let’s say you record a voice note for your cousin with steps for making jollof rice. First, you record (mRNA synthesis). But the voice note has background noise and repetition. So, before sending, you edit — remove noise, trim mistakes, and maybe add an intro and outro (processing). Now it’s clear and ready to be followed step by step. That’s exactly how mRNA is created and processed before it’s used in your body.
Summary
- mRNA synthesis is the process of making RNA from DNA, known as transcription.
- It involves initiation, elongation, and termination.
- mRNA must be processed before use: adding a 5’ cap, a 3’ poly-A tail, and splicing.
- Processing helps protect the mRNA and ensures only useful coding regions are kept.
- The final, mature mRNA is used to guide the building of proteins.
Evaluation
- What is mRNA, and what is its role in the cell?
- Describe the three steps of transcription.
- What is the function of the 5’ cap and poly-A tail?
- What happens during mRNA splicing?
- Why is mRNA processing necessary before translation?
You’ve just unlocked another powerful topic that brings you closer to understanding how your body and all living things work at the molecular level. Keep up the amazing energy, and remember — with Afrilearn, you’re never learning alone. Keep believing in your abilities, and get ready for the next exciting adventure in learning. See you soon!