1. GENES, DNA, AND PROTEINS CHAPTER 5 SECTION 4

2. THE GENETIC CODE Review Question: What do you remember about DNA?

3. THE GENETIC CODE Gene:  Is a portion of DNA that codes for a particular protein.  Can contain several hundred to several million nitrogen bases.  The order of nitrogen bases forms the Genetic Code.

4. MAKING PROTEINS  DNA carries all the instructions for the cell.  It is RNA that makes the proteins.  Unlike DNA, RNA has only 1 strand

5. MAKING PROTEINS DNA NITROGEN BASES Guanine (G) Cytosine (C) Adenine (A) Thymine (T) RNA NITROGEN BASES Guanine (G) Cytosine (C) Adenine (A) Uracil (U)

6. MAKING PROTEINS Messenger RNA (mRNA) – Copies coded messages from the DNA  The “messenger” must carry the code for DNA from the Nucleus to the Cytoplasm.  In order to build a protein you need to connect many amino acids. Transfer RNA (tRNA) – Carries amino acids to the ribosome, making a protein. http://www.phschool.com/atschool/phsciexp/active_art/protein_synthesis/index.html

7. MUTATIONS Mutations can cause a cell to produce an incorrect protein. As a result the traits may be different from what it normally would have been it normally would have been.

8. MUTATIONS Types of Mutations: Substitution – One base pair is substituted for another. Deletion – One base pair is removed Addition – One base pair is added.

9. MUTATIONS Effects of Mutations: Mutations can be Helpful, Harmful, or Neutral. A mutation is harmful if it reduces the organisms chances for survival or reproduction. A mutation is helpful if it increases the organisms chances for survival or reproduction.

10. WARM-UP Describe,in detail, how you can tell the difference between DNA and RNA. (Make sure you answer in complete sentences. Try your best to complete a well written response)