The Functions of Proteins
- A protein is a polymer constructed by 20 kinfd of monomers called amino acids.
- Proteins are responsible for the functioning of organisms.
Amino Acids
- An amino acid consists of carbon atoms which are bonded to four pairs.
- The side group of amino acid serine contains a hydroxyl group that attracts water.
Building a Protein
- Cells create proteins by linking amino acids together into a chain called a polypeptide.
- And each link is created by a dehydration reaction between the amino group and the carboxyl group.
- Proteins are composed of one or more polypeptide chains.
- Our body can make a variety of proteins by arranging different amino acids in different orders.
- Most polypettide chains are at least 100 amino acids in length.
Protein Shape
- A protein in the simple form or amino acids connected together cannot function properly.
- A Proteins shape is influenced by the surrounding enviroment.
- Water attracts hydrophilic side groups and rejects hydropobhic ones.
- A change in pH, tempreture and other quality of the enviroment can cause a protein to unravel and lose it normal shape. This process is called denaturation of proteins.
Concept Checks
1.)Give at least two examples of proteins you can "see" in the world around you. What are their functions?
Animal muscle and hair are two examples of proteins. Muscles allows animals to move freely, and hairs protect their skin.
2.)Relate amino acids, polypeptides and proteins.
Proteins are created by the combination of amino acids, forming a chain called polypeptide.
3.)Explain how heat can destroy a protein
Heat can destroy a protein because the heat causes the weak attractions of molecules to collide, causing it to lose its shape.
4.)Which parts of an amino acids's structure are the same in all amino acids? Which part is unique?
An amino group, carboxyl group and a hydrogen atom are similar. The fourth bond is unique because it is reponsible for the chemical properties of each amino acid.
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