What does a gene do?You should understand that genes are the units that make up the genome, but do you know what a gene does? We have discussed the genome as a book of instructions to make an organism, but how are instructions translated into a living thing? That is what we will discuss in this section.
What does a gene do?With some exceptions, each gene is the instructions for making a single protein. Proteins are the machines and major building blocks of living organisms. Each gene stores the information about how and when to make its protein. How does it do this?
Let’s look at the parts of a gene again. The promoter contains the information about when the gene should be “turned on”. So what happens when the gene is turned on? Protein is made. First a “message” is sent from the DNA gene to the ribosome, which “translates” the message into a protein.
What does a gene do?The message sent from the DNA is in the form of RNA, a closely related molecule to DNA. The message is in essence an RNA copy of the DNA coding region. RNA has several functions in a cell, so depending on the function it gets a special name. The RNA that carries a message from DNA to the ribosome is called “messenger RNA” or mRNA for short.
Ribosomes then take the message and holds it just right presenting one codon at a time, so that another type of RNA, “transfer RNA” or tRNA can see if it fits with the codon being presented. Each tRNA carries a specific amino acid (the building blocks of proteins). When a tRNA that matches the presented codon binds to the mRNA the amino acid is transferred from the tRNA to the newly forming protein that is attached to the ribosome. When the end of the message is reached, the “stop codon”, the newly formed protein is released from the ribosome and the ribosome lets go of the mRNA.
About the site:
I developed geneticsalive.com as a companion website to cellsalive.com.
Everything a cell does is a direct result of the genetics of that cell,
whether it is a single-cell organism or part of a much larger organism.
Thus, understanding the cells requires an understanding of the basis of
all of their behaviors.
About the author:
I am a microbiologist studying microbial pathogenesis and the host
immune response. My studies have included work in many pathogens
including Rabies and Influenza viruses, Mycobacterium tuberculosis,
Francisella tularensis, and Salmonella enterica. I currently live just
outside of Philadelphia, PA, where I work as a postdoctoral fellow
researching antigen processing and presentation during rabies
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