How do bacteria make proteins?

DNA sequence

DNA sequence, top line ATGCAAATCCTTGCTTGA, bottom line complimentary TACGTTTAGGAACGAACT

 In bacteria the DNA is on a circular chromosome. It is a double stranded helix.

Cartoon drawing of DNA double helix with bases in certain colours

DNA double helix

On Zooniverse, we look at one strand of DNA, the one that encodes the gene of interest. The other strand is "complimentary" to it and pairs it.  

A (orange) pairs with T (purple) and C (red) pairs with G (green).

This is complimentary base pairing and is a very important feature of DNA. 

It enables DNA to be transcribed (below) and replicated. 

Arrow with description: "Transcription makes a copy of the coding strand"

mRNA Sequence 

mRNA is single stranded. It has Us instead of Ts.

mRNA sequence AUGCAAAUCCUUGCUUGA
Cartoon drawing of mRNA sequence
Arrow with description: "Translation makes a protein dependent on the mRNA sequence"

Protein

Cartoon drawing of generic blue protein

 Proteins are made of amino acids. The ribosome reads mRNA to get the sequence.

Proteins have lots of different roles:

Some are ENZYMES, for example ones that break down food - we have these!

Another human example is haemoglobin. This protein is found in a blood cells and is responsible for carrying oxygen.

25 January 2023
Sophie MacKay