1. DNA and Genetics

2. The Structure of DNA Chromosomes are made of DNA. Each chromosome contains thousands of genes. The sequence of bases in a gene forms a code that tells the cell what protein to produce.

3. A Complex Molecule The shape of the molecule is like a twisted zipper. It is called a double helix. The scientist that discovered DNA and its shape realized that smaller molecules of DNA bond together and form this double helix shape.

4. The Genetic Code Genes and DNA: A gene is a section of DNA molecule that contains the information to code for one specific protein. Order of the Bases: The order of the nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced. Adenine (A) Cytosine (C) Thymine (T) Guanine (G)

5. How Cells Make Proteins Replication: the process of copying a DNA molecule to make another DNA molecule which produces identical strands of DNA. The Role of RNA: The genetic messenger, RNA, must first carry the genetic code from the DNA inside the nucleus into the cytoplasm. It is also made of nucleotides. Types of RNA: Messenger RNA, Transfer RNA, and ribosomal RNA. The process of making protein from RNA is called translation.

6. Translating the Code To make proteins, messenger RNA copies information from DNA in the nucleus. Messenger RNA and Transfer RNA then use this information to produce proteins.

7. Mutations A mutation is any change in a gene or chromosome. It can cause a cell to produce an incorrect protein during translation. As a result, the organism’s trait, or phenotype, may be different from what it normally would have been. The word comes from a Latin word that means “change.”

8. Types of Mutations During DNA Replication: -A cell can end up with too many or too few chromosomes -A cell can also end up with extra segments of chromosomes.

9. Effects of Mutations Good : can be a source of genetic variety. » Antibiotic resistance in bacteria Harmful: if it reduces its chance for survival and reproduction. Odd fur coloring that makes it stand out in its environment

10. Homework Read and add to notes pages 174-180. Test is on Friday, May 8. We will go over your notes in class tomorrow. Study!!!