What is gene expression?
Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are proteins. Gene expression is the process of making proteins - when a protein has been made, the gene has been expressed!
What have proteins got to do with anything?
Proteins give us our characteristics. They enable us to carry out MRSCGREN to stay alive! Proteins can function as:
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To put it simply, we can't function without proteins. We need them, we need to make them. The code on our DNA tells our bodies how to make them. We eat protein (fish, veggies, protein shakes, etc.) and our body breaks them down into their simplest form - amino acids. This is the only way we can get protein into our system. Our cells (actually, ribosomes in our cells) read our DNA which tells them what order to assemble the amino acids in, to make proteins that we need, to allow us to display traits and keep carrying out MRSCGREN. |
A protein can't function unless its been folded into a specific shape.
Each protein folds into its own special shape - for example keratin will fold one way whereas haemoglobin will fold in a completely different way. Neither will function unless its been folded correctly.
Primary structure
Amino acids connected by peptide bonds to form a 'polypeptide chain'. The primary structure of a protein is the order of amino acids in the polypeptide chain.
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Secondary structure
Polypeptide chain folds into a helical shape (think of DNA - double helix), This shape is held in place by hydrogen bonds between the polypeptide backbones.
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Tertiary structure
Helical shape (alpha-helix) folded back onto itself in a way that makes a specific 3D shape. Don't worry about R groups.
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Quaternary structure
These structures contain 2+ tertiary units. For example. haemoglobin consists of two alpha chains and two beta chains.
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