1. 1 GENE EXPRESSION: Individuality and Expression HOW DOES DNA KNOW WHEN TO MAKE A PROTEIN?

2. 2 Genes: The Video Clip

3. 3 DNA and Individuality Are all genes turned on in all cells?

4. 4 The answer is NO! Every body cell contains all DNA Cells “use” only genes specific for function –EX. Red blood cells use only genes that make it carry oxygen –Can you list more examples? Enzymes, insulin, cell membrane, hair, muscles **THEREFORE, NOT ALL DNA IS EXPRESSED (MADE INTO PROTEIN) IN EVERY CELL!**

5. 5 MUTATIONS When DNA goes bad  Mutations to control genes can transform one body part into another. Scientists have studied flies carrying Hox mutations that sprout legs on their foreheads instead of antennae!

6. 6 Mutation: The Video Clip

7. 7 IMPORTANT FACT! MUTATIONS MUST OCCUR IN SEX CELLS IN ORDER FOR THEM TO BE PASSED ON TO NEXT GENERATION!!!!!!!!!!

8. 8 Gene Mutations 1. Change in DNA sequence which effect genetic information and traits –one nitrogen base is affected 2. When do mutations occur? During replication (meiosis / mitosis) and protein synthesis **Review** What does DNA ultimately code for? Proteins 3. Is construction of protein based on original DNA strand? Yes! (b/c it is what codes for mRNA)

9. 9 Gene Mutations con’t… 4. What would happen to protein made if DNA sequence was changed? –Wrong protein made –Wrong shape of protein This would make protein unusable Normal red blood cells (top) and sickle cells (bottom)

10. 10 DNA fails to copy accurately

11. 11 D. Types of Gene Mutations 1.POINT MUTATION: CHANGE : Base is switched from one point to another EXAMPLE : CTC on DNA makes GAG mRNA EXAMPLE : CTC on DNA makes GAG for mRNA –GAG codes for GLU »If T changed to G, would have GUG on mRNA »This codes for VAL RESULT: Wrong AMINO ACID is coded for which means, wrong PROTEIN is made which means, wrong PROTEIN is made

12. 12 2. FRAME-SHIFT Mutation: CHANGE: base is either deleted or added EXAMPLE: TCA TTT on DNA; AGU-AAA on mRNA codes for Ser + LysAGU-AAA on mRNA codes for Ser + Lys If the T is deleted in the DNA, the mRNA would now read GUA AAIf the T is deleted in the DNA, the mRNA would now read GUA AA tRNA will read “GUA” first which codes for ValtRNA will read “GUA” first which codes for Val Similar results if a base is addedSimilar results if a base is added RESULT: Wrong AMINO ACID is coded for = wrong PROTEIN is made OR Translation will abruptly RESULT: Wrong AMINO ACID is coded for = wrong PROTEIN is made OR Translation will abruptly STOP

13. 13 Deletion Duplication Inversion Translocation E. Chromosomal Mutations Match the terms with the diagrams : Inversion, Translocation, Duplication, Deletion

14. 14 Mutation Problems Affecting Humans: A.Non-Disjunction- _____________________________________________ 1. causes this: ______________________________________________ 2. chromosome # in a normal cell: _____ chromosome # in a non-disjunction cell: ______ 3. common name of disorder in human: ___________________________ results in: ________________________________________________ An extra chromosome at location # ____ chromosome pairs don’t separate an extra chromosome in the cell 46 47 Down Syndrome mental retardation and distinguishing facial features 21

15. 15 DOWN SYNDROME MALE DOWN SYNDROME MALE

16. 16 B. PKU : _______________________________________________ 1. cause: _______________________________________________ 2. problem: _____________________________________________ 3. symptoms: ____________________________________________ 4. controlled by: __________________________________________ Phenylketonuria gene which controls the breakdown of phenylalanine is missing Phenylalanine builds up to toxic levels Mental retardation or death Eliminating phenylalanine from your diet

17. 17 C. Sickle Cell Anemia ________________________________________ 1. cause: ________________________________________________ 2. problem : ______________________________________________ 3. symptoms: ________________________________________ Red blood cells become sickle shaped A mutated hemoglobin gene red blood cells can’t carry oxygen; stick into blood vessels Lack of oxygen, weakness, pain Normal Cell Sickle Cell

18. 18 Human Chromosomes (46 in a normal human cell!)Human Chromosomes (46 in a normal human cell!) Two types:Two types: a) Normal chromosomes: 44 in each BODY CELL; 22 in each GAMETE (sex cell) b) Sex chromosomes: 2 in each BODY CELL; 1 in each GAMETE (sex cell) 1 in each GAMETE (sex cell) MALE: X and YMALE: X and Y FEMALE: X and XFEMALE: X and X G. Determining Sex

19. 19 Chances for having a boy or girl? 50% OF COURSE…LET’S SEE! X Y X XXX XXXX X XX XX XYXYXYXY XYXYXYXY

20. 20 Human Karyotype Arrangement human male

21. 21 H. Environmental Expression Some genes are “turned on” under certain environmental conditions EX. Himalayan Rabbit: Fur changes color due to TEMPERATURE changeEX. Himalayan Rabbit: Fur changes color due to TEMPERATURE change –WARM = White fur (no pigment produced) –COLD = Black fur Why does this make sense? Because black absorbs the heat, helping little bunny rabbit to stay warm

22. 22 I. Summary of Mutations Must occur in sex cells to be passed onMust occur in sex cells to be passed on Not all mutations are bad (depends on environment)Not all mutations are bad (depends on environment) Ultimate source of variation within a species!!!!!!Ultimate source of variation within a species!!!!!! –Take humans for instance….do we all look the same????????? NO!!!!!! Caused by:Caused by: –Exposure to radiation (ex. UV Rays) –Exposure to certain chemicals (in cigarettes, emitted from factories)

23. 23 How do we know that traits and diseases are genetically related? The Human Genome Project 1) What is it? _______________________________________________ 2) Why do it? _______________________________________________ 3) How far along are we? _____________________________________ Project to identify the location of 30,000 genes To identify the locations of genetic diseases and possibly control/eliminate them the map was completed in 2004 III. The Human Genome

24. 24 The Code of Life video Getting the Letters Out (5:52) One Wrong Letter (8:57) Finding Cures is Hard (8:07) Finding Disease Genes (4:06) DNA Databases (4:14) A Family Disease (8:05) Genetic Modification (4:27) NOVA Online | Cracking the Code of Life | Watch the ProgramNOVA Online | Cracking the Code of Life | Watch the Program Let’s watch: Genetic Modification http://NOVA Online | Cracking the Code of Life | Watch the ProgramNOVA Online | Cracking the Code of Life | Watch the Program