1. Regulating Gene Expression

2. Reviewing Vocab… GENE: a segment of DNA that codes for a particular protein/trait An expressed gene is one that is being transcribed (i.e. it is turned to the “on” position and is being used to make proteins!) A repressed gene is one that is not being transcribed (i.e. it is turned to the “off” position)

3. How do we turn genes on and off?

5. Demonstration Observe the two DNA models – can you identify the histones? What is different about the two models?

6. Video http://learn.genetics.utah.edu/content/epige netics/intro/ http://learn.genetics.utah.edu/content/epige netics/intro/

7. Vocabulary Epigenome Epigenetic Tags What do these do to the physical structure of DNA? What kinds of things shape your epigenome?

8. DNA structure and Regulation http://learn.genetics.utah.edu/content/epige netics/control/ http://learn.genetics.utah.edu/content/epige netics/control/ Watch what happens to the appearance of the DNA, the # of mRNA, # of proteins, and the appearance of the cell as you turn the knob.

9. TRUE OR FALSE? METHYL AND ACETYL GROUPS CONTROL GENE EXPRESSION BY CONTROLLING ACCESS TO DNA.

10. TRUE OR FALSE? THE PHYSICAL STRUCTURE OF DNA IS STATIC.

11. Lick your rats http://learn.genetics.utah.edu/content/epige netics/rats/ http://learn.genetics.utah.edu/content/epige netics/rats/

12. So what does this have to do with protein synthesis? http://www.teachersdomain.org/asset/biot09 _vid_epigenetics/ http://www.teachersdomain.org/asset/biot09 _vid_epigenetics/ http://www.pbs.org/wgbh/nova/teachers/bod y/epigenetics.html http://www.pbs.org/wgbh/nova/teachers/bod y/epigenetics.html http://www.pbs.org/wgbh/nova/body/epigen etics.html http://www.pbs.org/wgbh/nova/body/epigen etics.html

13. 30,000+ genes Does each cell need to be using all 30,000 genes? (hint: cell specialization!) Do you need to be using all 30,000 genes at all times? (hint: energy conservation!)

14. Regulation “Controls” over gene expression Variety of methods – One basic way is by modifying the structure of DNA

15. Epigenetics http://learn.genetics.utah.edu/content/epige netics/intro/ http://learn.genetics.utah.edu/content/epige netics/intro/

16. Epigenetics The development and maintenance of an organism is orchestrated by a set of chemical reactions that switch parts of the genome off and on at strategic times and locations. Epigenetics is the study of these reactions and the factors that influence them.

17. For example… Genes that control whether or not a cell gets to go through mitosis… – regularly turned on and off = cells only divide when needed. – Cancer cells = unregulated cell division = epigenetic profile looks different…

18. Epigenetic Tags Acetyl and methyl groups Chemicals that act as switches that determine gene expression without changing the underlying genetic code Turn genes on or off in response to cell signals Create a layer of control called the epigenome

19. Epigenome Reacts to factors throughout your lifetime. Can affect future generations too…

20. Regulation of Genes Genes can be turned on or off Off = not active, not making proteins – Tightly wound – DNA covered in methyl groups On = active, making proteins – Not tightly wound – Acetyl groups attached to histones

21. Other ways to control gene expression… Introns vs exons Activity -

22. http://www.youtube.com/watch?v=9k_oKK4T eco http://www.youtube.com/watch?v=9k_oKK4T eco