What happens in cells (and what do cells need)? - OCR GatewayProtein synthesis - Higher

The genetic code of all life on Earth is made from DNA. Proteins like enzymes and hormones are made during protein synthesis. Enzymes are biological catalysts which speed up chemical reactions.

Part ofBiology (Single Science)Cell level systems

Protein synthesis - Higher

Greg Foot explains how the structure of DNA affects the proteins made in DNA synthesis

consists of two stages – transcription and translation. In transcription the DNA code is read, and in translation the code is used to build up molecules.

DNA is a triplet code. Each triplet, a group of three bases, codes for a specific amino acid.

Diagram showing how protein is synthesised in a DNA structure
Figure caption,
An overview of the process of protein synthesis

Transcription and translation

DNA is often called the genetic code. It is the code to make proteins.

DNA remains in the but during transcription a copy is made from mRNA. This moves from the to a in the .

Diagram illustrating the process of transcription - when a gene is converted to protein
Figure caption,
A detailed view of the process of transcription - making an mRNA copy of a gene’s worth of DNA in the nucleus

During translation, proteins are synthesised in ribosomes. During this process, carrier molecules, called tRNA, bring specific amino acids to add in the correct order to the growing protein. There are only about 20 different naturally-occuring amino acids. Each protein molecule has hundreds, or even thousands, of amino acids joined together in a unique sequence. It is then folded into a unique shape. This is very important, as it allows the protein to do its job. Enzymes and hormones are proteins and their correct shapes are crucial to their functions.

The protein produced depends on the DNA code used, and if this sequence changes a different protein could be made.

Image gallerySkip image gallerySlide1 of 2, Amino acid sequence 1 showing acid chain folding into precise shape, Different amino acid sequences result in proteins folding into different shapes, with protein one functioning as an enzyme
A molecular model of haemoglobin which is a protein found in red blood cells
Image caption,
A molecular model of haemoglobin which is a protein found in red blood cells

Learn more about protein synthesis with Dr Alex Lathbridge.

Learn about how proteins are made during the processes of transcription and translation.