The Importance of Shapes Fitting Together in Cells and Organisms

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An example of shapes fitting together in biology is with enzymes and their substrates. Enzymes are very important for organisms, as they are biological catalysts, which can speed up the rate of reaction of a biological process. The enzyme does this by forming an enzyme substrate complex with the substrate. Each enzyme has a specific shape to one type of substrate and in order for the complex to form both the enzymes active site and the substrate need to be complementary. This is known as the lock and key model. There is also an induced fit model, which states that the model is not quite as rigid as the lock and key model states. In this model the enzyme may not have an active site that is perfectly complementary to the substrate, but when the substrate collides with the enzyme active site its shape is altered to fit the substrate and make a complex. Enzymes are proteins, the structure of the protein are very important as it give the protein a particular 3-D shape which gives the active site it’s specific shape. The protein structure consists of primary, secondary, tertiary and quaternary structure. The tertiary shape is the important 3-D shape formed as hydrogen bonds form between the polypeptide chain, which is the primary structure. The importance of the protein structure is shown when it is disrupted by mutation that results in non-functional enzymes. A mutation occurs in the primary structure by an addition of a base of deletion of a base, which results in the hydrogen bonds to be altered and the 3-D structure changed. An example of this is cystic fibrosis, which is caused by a deletion mutation as three adenine bases are missing this makes the protein unable to perform its role. A molecule of DNA codes for the sequence of amino acids and DNA relies on particular shapes fitting together. DNA is made up of two single strands, which are long chains of
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