Small interfering RNA facts for kids
Small interfering RNA, or siRNA for short, is a tiny molecule found in living cells. Think of it as a special kind of instruction manual made of two strands of RNA twisted together. These tiny manuals are usually about 20 to 25 "letters" long.
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What is siRNA?
siRNA molecules are like tiny messengers in our bodies. They are a type of RNA, which is similar to DNA. But unlike DNA, which usually has two strands, siRNA is special because it's also made of two strands. These strands are built from small units called base pairs.
How siRNA Works
One of the most important jobs of siRNA is to help control what our genes do. This process is called RNA interference (RNAi). Imagine your genes are recipes for making different things in your body, like proteins. siRNA can stop certain recipes from being used.
It does this by looking for specific parts of a gene's message. If the siRNA finds a matching part, it can break down that message. This means the cell cannot read the recipe anymore. So, the protein that the gene was supposed to make will not be created.
Stopping Gene Messages
When a gene is active, it first makes a copy of itself called mRNA. This mRNA carries the instructions to build a protein. siRNA steps in after this mRNA copy is made. It finds the mRNA and helps to cut it into pieces.
By cutting the mRNA, siRNA prevents the cell from turning the gene's instructions into a protein. This is a way for the cell to turn off or quiet down certain genes.
Other Roles of siRNA
Besides stopping genes, siRNA also has other important jobs. For example, it can act like a tiny security guard against viruses. When a virus tries to infect a cell, siRNA can help to destroy the virus's genetic material. This stops the virus from making more copies of itself.
siRNA also plays a role in shaping the structure of chromatin. Chromatin is like the packaging material for our genome (all our DNA). siRNA can help to make sure this packaging is correct.
Images for kids
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siRNA Mechanism
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Dicer protein colored by protein domain.
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A simplified version of the Ping-Pong Method, involving proteins Aubergine (Aub) and Argonaute-3 (Ago3) cleaving the 3' and 5' ends of piRNA.
See also
In Spanish: SiRNA para niños
