1 / 28

What is the lac operon? How is it controlled?

What is the lac operon? How is it controlled?. QOD. Section 11-1. Control of Gene Expression. Gene Expression. Only some genes are expressed at any given time Cell specialization Two steps: Transcription – regulatory sites Translation. The Lac Operon. Jacob and Monod

carverl
Download Presentation

What is the lac operon? How is it controlled?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is the lac operon? How is it controlled? QOD

  2. Section 11-1 Control of Gene Expression

  3. Gene Expression • Only some genes are expressed at any given time • Cell specialization • Two steps: • Transcription – regulatory sites • Translation

  4. The Lac Operon • Jacob and Monod • Studied gene expression in lac operon of E. Coli • Structural genes • Promoter • Operator • Operon

  5. Controlling the Lac Operon • Repression • Repressor protein • Regulator gene • Activation • Inducer

  6. Gene Expression in Eukaryotes • Challenges: • Larger genome • Several chromosomes • Specialized cells • No operons

  7. How are genes controlled in eukaryotic organisms? QOD

  8. Structure of Eukaryotic Genes • Control before and after transcription • DNA is coiled – affects gene expression • Euchromatin • Heterochromatin • Introns-Exons • Options for producing different proteins • Role for introns?

  9. More on expression • Control after transcription • Locations • Pre-mRNA • Splicing mRNA exons – Spliceosomes • Alternative splicing • RNA as enzymes – ribozymes • Enhancer control • Enhancer region • Transcription factors

  10. Section 1 Control of Gene Expression Chapter 11 Removal of Introns After Transcription

  11. Section 1 Control of Gene Expression Chapter 11 Controlling Transcription in Eukaryotes

  12. How do complex multicellular organisms develop from an embryo? QOD

  13. Section 11-2 Gene Expression and Development

  14. Cell Differentiation • Morphogenesis • Homeotic (Hox) genes • Homeobox – 180 base pairs • Regulatory proteins – turn genes on/off • Similar sequences found in many eukaryotic organisms

  15. Cancer • Tumor • Benign tumor • Malignant tumor • Types • Carcinomas • Sarcomas • Lymphomas • Leukemia

  16. The Cell Cycle • Normal – Cell needs: • Adequate nutrition • Attached to other cells, membrane, fibers • Stop dividing when become crowded • Cancer-causing Agents • Growth factors and mutations • Carcinogens • Mutagens

  17. More Causes • Genetic factors • Environmental factors • Cigarette smoke • Air and water pollution • UV radiation • Viral infection • Prevention • Dietary methods • Behavior modification

  18. More on Causes: Genes • Oncogenes/Proto-oncogenes • Tumor-suppressor genes • See Fig. 11-10, p. 214 • Viruses

  19. Section 2 Gene Expression in Development and Cell Division Chapter 11 Effect of Mutation on Gene Expression

  20. Fig. 3.23

  21. Stem Cells - Properties • Undifferentiated (unspecialized) cells • Differentiate to any type of cell based on signals • Depending on potency • Self-renewing • Mitosis  differentiated cell + another stem cell

  22. Potency of Stem Cells • Totipotent • Zygote • Pluripotent • Embryonic • Multipotent • Adult

  23. Sources of stem cells • Embryonic • From blastula stage of developing embryo (within first approx. 2 weeks) • Pluripotent • Adult • Only in certain tissues (Brain, Bone marrow) • Multipotent • Induced Pluripotent Stem Cells (IPS) • Somatic cell  Pluripotent

  24. Uses and Hurdles • Potential Uses: • Cure diseases • Repair spinal injuries/brain injuries • Cloning organs • Hurdles: • Signals • Turning genes on/off is essential • Culturing • Maintaining lines • Moral/Ethical debate

More Related