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Transcription and Translation: From DNA to Protein
The nucleotides of DNA contain information known as genes. By itself,
this information is not useful to the body. This information must be
translated and made into a protein so the body can use it.
What is RNA?
RNA is ribonucleic acid. Its job is to take information from
DNA and make it into a protein. RNA is different from DNA
in a few ways. It is a single strand, has ribose sugar as
part of its backbone and it contains Uracil as one of its 4
nitrogen bases instead of Thymine.
Remember it this way: U R single (You are Single).
Uracil, Ribose and a Single strand.
How does the information on DNA in the nucleus end up as
a protein made by ribosomes in the cytoplasm? It happens
in two main steps.
1. Transcription— The DNA unzips and RNA polymerase
makes a single strand RNA copy of the information.
The copy will match bases as C-G and A-U (not A-T like
in DNA). This copy is called messenger RNA (mRNA).
2. Translation— The mRNA moves out of the nucleus and
goes to a ribosome in the cytoplasm of the cell. The
bases on the mRNA strand are read in groups of three
called a codon. A different molecule called transfer RNA
(tRNA) reads each codon. tRNA carries an amino acid
for each codon. The amino acids are put together in a
chain following the same order as the codons on mRNA
and a protein is formed.
Analogies
In a factory, there are people who have jobs similar to RNA
to help make products correctly.
1. DNA is like blueprints.
The blueprints are kept safe in an office so they don’t
become damaged. The machines are out in the shop.
Most factory workers can’t read blueprints, and they aren’t
allowed in the office. The information needs to be brought
out to the workers and explained.
2. A blueprint reader is like mRNA.
The blueprint reader doesn’t know how to work the
machines. That is the job of the machine operators.
3. The machine operator is like tRNA.
Machine operators use the information the blueprint reader
tells them, and programs the machine to make the
product.
4. The machine is like a ribosome.
5. The product is like a protein.