2. Chromosomes and Genes Each chromosome has hundreds or thousands of genes. Each gene codes for a particular protein.

3. Changes in DNA Mutations: Any change in the genetic material of an organism. Can only be passed on if mutations happens in reproductive cells (sperm or egg). Caused by factors called mutagens Examples: radiation, chemicals and viruses.

4. Read sentence 1 and compare it to the others. 1. THE DOG BIT THE CAT 2. THE DOG BIT THE CAR. 3. THE DOG BII TTH ECA R. 4. THE DOB ITT HEC AR. a. What is wrong with sentence 2? b. How about # 3? # 4? c. Do #2, 3, 4 make sense? d. What would happen if these were mRNA codons? e. What is the term used for mistakes in DNA?

5. 2 Types of mutations Point mutations: A change in one base pair Wrong base is inserted -usually change only one amino acid in a protein. Frame shift mutations Addition or deletion of a base EVERY amino acid that follows the mutation is changed Produces damaged protein

6. Result: Gene mutations may cause a change in a gene which can change the shape of a protein. This will have an effect on the way the protein works (if it still works at all).

7. Example of a mutation: Sickle Cell Anemia inherited form of anemia — a condition in which there aren't enough healthy red blood cells to carry adequate oxygen throughout your body.