1. DNA AND GENETICS Chapter 12 Lesson 3

2. Essential Questions What is DNA? What is the role of RNA in protein production? How do changes in the sequence of DNA affect traits?

3. New Vocabulary DNA Nucleotide Replication RNA Transcription Translation Mutation

4. DNA Replication Replication – the process of copying a DNA molecule to make another DNA molecule Copy the steps!

5. Making Proteins The DNA of each cell carries the complete set of genes that provide instructions for making all the proteins in a cell.  Proteins are made with the help of RNA (ribonucleic acid) RNA – a type of nucleic acid that carries the code for making proteins from the nucleus to the cytoplasm  Made of nucleotide  One strand (DNA has 2 strands)  Nitrogen bases:  Uracil (U) (Instead of Thymine)  The rest are the same (A, G, C)

6. Making Proteins Transcription – the process of making mRNA from DNA (mRNA= messenger RNA)  First step of making a protein  Why do you think it needs to make RNA first? Remember DNA is found in the nucleus! Copy the steps! 

7. Making Proteins Translation – the process of making the protein from RNA (Copy the steps!) tRNA = transfer RNA rRNA = ribosomal RNA

8. Mutations Mutations – a change in the nucleotide sequence of a gene  Human chromosomes have 20,000-25,000 genes that are copied during replication. Sometimes mistakes happen!  Triggered by:  X-rays  UV light  Radioactive materials  Some chemicals The effect of mutations depend on what part of the DNA it affects  Some cause genetic disorders! (Like we will find out in your projects )

9. Types of Mutations Substitution – one nitrogen base is replaced by a different nitrogen base Insertion – one or more nitrogen bases are added to the DNA Deletion – one or more nitrogen bases are left out from the DNA (deleted)

10. Review What is created through transcription? A. DNA B. Mutations C. mRNA D. Protein

11. Review In DNA, which of the following is paired with guanine? A. Adenine B. Cytosine C. Thymine D. Uracil

12. Review Which of the following describes the mutation that occurs when three base pairs are added? A. Insertion B. Substitution C. Transgression D. Deletion