Shapes Fitting Together Essay

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The Importance of Shapes Fitting Together in Cells and Organisms Lots of molecules in cells and organisms fit together with other molecules that have complimentary shapes in order to work and serve their purpose. An example of a type of molecule that does this is enzymes. Enzymes are proteins that speed up metabolic reactions, from the digestion of food to the synthesis of DNA, and so are very important. One of two models that demonstrate how enzymes work is the ‘lock and key’ model, in which the active site of an enzyme has a complimentary shape to a specific substrate and they fit together perfectly (like a key in a lock, hence the name) to form an enzyme-substrate complex. The other model is the ‘induced fit’ model, which describes the formation of an enzyme-substrate complex as a result of the enzyme’s active site adapting its shape to fit with the substrate (almost like a glove) to allow for…show more content…
These shapes fitting together to form enzyme-substrate complexes is very important in many processes. For example, in the process of DNA replication, DNA helicase must have the correct shape in order to separate the DNA strands and DNA polymerase must have the correct shape so that free nucleotides can join to their complimentary base pair on sugar phosphate backbone to create new strands of DNA. It is also important for the nucleotides to join together with their complimentary base pair, which is more shapes fitting together to form DNA. It is also important that antigens and antibodies fit together. When a bacteria enters the body it has antigens on its surface that are recognised by the white blood cells. B-Lymphocytes then produce antibodies with complimentary shapes to the antigens, which bind to them. This is important our immune system to work and fight off
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