Protein formation

How do we make a protein such as haemoglobin?

Protein production starts inside the nucleus of a cell.

Note: Protein production takes place in all cells including plant cells.

Protein production takes place in all cell nuclei plants and animals

The genome in humans is comprised of 46 chromosomes. Each chromosome contains a long strand of DNA.

The genome in humans is comprised of 46 chromosomes each contains DNA

Within each of the DNA strands are segments or sections called genes.

Each strand of DNA contains Gene segments

Genes are the instructions for making proteins.

Graphic of haemoglobin gene segment of a DNA strand

The example below shows the process for constructing a haemoglobin protein which goes onto form part of the red blood cells

First the enzyme attaches to the DNA at the start of the gene sequence it wishes to read.

Enzymes attach to a DNA strand but at the start of the haemoglobin gene segment ready to read

Then the enzyme splits the DNA apart.

Before the Enzyme reads the gene segment it splits open the DNA so it can begin

This allows free floating nucleotides within the nucleus to join the DNA bases in the correct order.

As the enzyme reads the DNA, thousands of free floating nucleotides join the opened DNA only at the base

The nucleotides now joined together in the correct order create a new strand. This strand is called “messenger RNA” or mRNA. This messenger RNA (mRNA) starts to pull away from the DNA.

Joining nucleotides produces messenger RNA (mRNA)

The enzyme continues along the length of the DNA opening and closing it as it goes until it gets to the end of the gene segment.

The enzyme nearing the end of the gene produces a long mRNA and starts to close the DNA

Finally the messenger RNA (mRNA) is free to float away from the DNA. The enzyme also leaves the DNA.

At the end of the gene the enzyme closes the DNA and messenger RNA leaves the DNA