Basics of BiologyEnzymes—and Proteins—at Work |
What are proteins, and how do they work? |
Proteins do, in a word, everything. Proteins allow life to exist as we know it. They are the enzymes that are required for all metabolic reactions. They are also important to structures like muscles and act as both transporters and signal receptors. The following chart lists the types of functions of proteins:
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Type of protein |
Examples of functions |
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Defensive |
Antibodies that respond to invasion |
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Enzymatic |
Increase the rate of reactions, build and break down molecules |
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Hormonal |
Insulin and glucagon, which control blood sugar |
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Receptor |
Cell surface molecules that cause cells to respond to signals |
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Storage |
Store amino acids for use in metabolic processes |
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Structural |
Major components of muscles, skin, hair, horns, spider webs |
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Transport |
Hemoglobin carries oxygen from lungs to cells |