Biology 3B

Biology 3B

1. Key Processes

   • There are only about 20 different naturally occurring amino acids. However, each protein molecule has hundreds, or even thousands, of them joined together in a unique sequence. This gives each protein its own individual properties
   • The long chains of amino acids fold to give each type of protein molecule a specific shape. Proteins act as:
     • Structural components of tissues (such as muscles)
     • Hormones (such as insulin)
     • Antibodies (part of the body's immune system)
     • Biological catalysts (enzymes)
   • The shape of an enzyme determines how it works. Enzymes have active sites that substrate molecules (the substances involved in the chemical reaction) fit into when a reaction happens
   • The shape of an enzyme determines how it works. Enzymes have active sites that substrate molecules (the substances involved in the chemical reaction) fit into when a reaction happens
   • Different enzymes work best at different pH values, their optimum pH. Many enzymes work fastest in neutral conditions. Making the solution more acidic or alkaline will slow the reaction down. At extremes of pH the reaction will stop altogether.
   • Changes in pH also alter an enzyme’s shape
   • As the temperature increases, so does the rate of reaction. But very high temperatures denature enzymes

2. Examples of proteins include: collagen, insulin and haemoglobin

3. Proteins are made of long chains of amino acids

4. Functions of proteins include: structural (collagen), hormones (insulin), carrier molecules (haemoglobin) and enzymes

5. Enzymes are biological catalysts that speed up chemical reactions in living cells: respiration, photosynthesis and proteins synthesis

6. Enzymes have active sites that substrate molecules fit into when a reaction takes place

7. Denaturing is an irreversible change that changes the shape of the active site and inhibits enzyme function

8. Q10 = rate at higher temperature / rate at lower temperature

9. Mutations are changes to genes that may lead to the production of different proteins

10. Mutations occur spontaneously but can be made to occur more often by radiation or chemicals

11. Mutations are often harmful but may be beneficial or have no effect

12. Some genes are switched off in any one cell; this determines the functions of a cell