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Proteins are considered macromolecules because of their size. Large molecules made up of repeating units are called polymers. The small units or monomers that make up proteins are called amino acids. There are 20 different amino acids. Since proteins are made up of many amino acids there can be an unlimited number of combinations (much like the many different words that can be made out of only 26 letters in the alphabet). Because of this the functions of different proteins can be as varied as their structures.
Proteins can be categorized as either structural or functional.
The jobs of structural proteins are to build or construct tissues of living organisms. For example, the protein myosin and actin are necessary for the building of muscle tissue. Other proteins are structural components of steroid hormones. In addition, proteins are structural components of antibodies whose job is to recognize foreign invaders and protect organisms against it.
Functional proteins do something other than "build". For example, enzymes are proteins whose job is to catalyze chemical reactions. They can do this by lowering the activation energy needed to start the chemical reaction. Hemoglobin is a protein in red blood cells to which oxygen binds and then gets transported to other cells. Embedded in the cell membrane of virtually all cells are proteins sometimes referred to transport proteins that help molecules move across the cell membrane.
The collection of proteins within a cell determines its health and function. Proteins are responsible for nearly every task of cellular life, including cell shape and inner organization, product manufacture and waste cleanup, and routine maintenance. Proteins also receive signals from outside the cell and mobilize intracellular response. They are the workhorse macromolecules of the cell and are as diverse as the functions they serve.
My biology teacher drilled into us the simplest way to describe a protein is that they do cellular work. They have a wide variety of functions in the cells. Here are some examples of proteins:
- Antibodies-help destroy pathogens
- Transport proteins-combine with and move substances from place to place
- Hemoglobin- transports oxygen
- Structural proteins-keratin in hair and myosin in muscles
- Enzymes-speed up chemical reactions
This is just a few examples, proteins are in everything! They do so much for us and are very important!
THANK YOU IAN!!!!!!
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