Central dogma of molecular biology facts for kids
The central dogma of molecular biology is a big idea in science that helps us understand how living things work. It was first explained by a scientist named Francis Crick in 1958. He's famous for helping discover the shape of DNA, which looks like a twisted ladder called a double helix.
The central dogma explains how important information flows inside our cells. It says that information usually goes from DNA to RNA, and then from RNA to proteins. But, this information almost never goes backward from proteins to DNA. Think of it like a one-way street for genetic instructions!
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What is the Central Dogma?
This idea helps scientists understand how genetic information is used to build and operate living things. It focuses on three main types of important molecules in our bodies:
These molecules work together to carry out all the jobs inside our cells.
How Information Moves
Scientists have identified different ways information can move between DNA, RNA, and proteins. These are grouped into three types:
Normal Information Flow
These are the most common ways information moves in almost all living cells:
- DNA to DNA (Replication): DNA can make copies of itself. This happens every time a cell divides, so new cells get a full set of genetic instructions.
- DNA to RNA (Transcription): The information in DNA can be copied into a special type of RNA called messenger RNA (mRNA). Think of mRNA as a temporary message carrying instructions from the DNA.
- RNA to Protein (Translation): The information in mRNA is used to build proteins. Proteins are like tiny machines that do most of the work in cells.
Special Information Flow
These transfers happen, but only in certain situations, like in some viruses or in a science lab:
- RNA to DNA (Reverse Transcription): Some viruses, like HIV, can copy their RNA information back into DNA. This is unusual for most living things.
- RNA to RNA (RNA Replication): Some viruses can make copies of their RNA directly from an RNA template.
- DNA to Protein (Direct Translation): This is very rare and only happens in a lab under special conditions.
Unknown Information Flow
These transfers are believed to never happen naturally:
- Protein to DNA: Information from proteins is not copied back into DNA.
- Protein to RNA: Information from proteins is not copied into RNA.
- Protein to Protein: Proteins do not directly copy information from other proteins.
Weismann's Barrier
The central dogma is a modern version of an older idea called the Weismann barrier. This idea, from scientist August Weismann, said that information from our body cells cannot be passed back to our genes. It means that changes you make to your body during your life (like getting stronger muscles) cannot be passed down to your children through your genes. Genetic information only flows from the special cells that make babies (called germline cells) to the rest of the body's cells (somatic cells).
Images for kids
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Unusual flows of information highlighted in green
See also
In Spanish: Dogma central de la biología molecular para niños
