- A protein is a polymer constructed from a set of just 20 kinds of monomers called amino acids.
- Each amino acid monomer consists of a central carbon atom bonded to four partners.
- Three of the central carbon's partners are the same in all amino acids. One partner is a hydrogen atom and two others are a carboyl group and an amino group.
- Cells create proteins by linking amino acids together into a chain called a polypeptide.
- Proteins are composed of one or more polypeptide chains.
- Most polypeptide chains are at least 100 amino acids in length.
- A protein in the simple form of amino acids linked together cannot function properly.
- Denaturation is loss of normal shape of an protein due to heat or other factor.
- Hot molecules collide with enough force to overcome these weak attractions.
Concept Check 5.4
1. Give at least two examples of proteins you can "see" in the world around you. What are their funtions?
Cheese and beef.
2. Relate amino acids, polypeptides, and proteins.
Polypeptide and protein are made up of amino acids.
3. Explain how heat can destroy a protein.
The process called denaturation of the protein. Heating unfolds protein because most of the forces that maintain folding are weak attractions between pairs of side groups. Hot molecules collide with enough force to overcome these week attractions.
4. Which parts of an amino acid's structure are the same in all amino acids? Which part is unique?
A protein in the simple form of amino acids linked together cannot function properly. A functional protein consists of one or more polypeptides precisely twisted, folded, and coiled into unique shape.
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