1. The Living Cell Chapter 21 Great Idea: Life is based on chemistry, and chemistry takes place in cells

2. Chapter Outline The Nature and Variety of Cells How Does a Cell Work? Metabolism: Energy and Life Cell Division

3. The Nature and Variety of Cells

4. The Cell Theory All living things are composed of cells The cell is the fundamental unit of life All cells arise from previous cells

5. Observing Cells: The Microscope

6. How Does a Cell Work?

7. Cell Membranes –Isolate cell –Separates cell parts Transport –Individual molecules –Specific materials channels Receptors –Bind molecules Cell Wall –Plants

8. Plant Cell

9. The Nucleus Nucleus –Contains genetic material Prokaryotes –No nucleus Eukaryotes –Nucleus Double Membrane

10. The Energy Organelles: Chloroplasts and Mitochondria Organelle –Specialized structure in cell Chloroplasts –Energy transformation chlorophyll –Plant cells only –Double membrane Mitochondria –Produces cells energy –Double membrane –Own DNA

13. Cytoskeleton –Gives cell shape –Anchors –Allows movement –Transport system Within cell Structure –Strong filaments –Complex web

14. Metabolism: Energy and Life

15. The Cell’s Energy Currency Adenosine triphosphate (ATP) –Provides energy Structure –3 phosphate groups –Sugar molecule: ribose –adenine Function –Removal of phosphate group provides energy

16. Photosynthesis –Convert sunlight to energy Process –Energy + CO 2 + H 2 O  carbohydrate + O 2 Colors

17. Glycolysis: The First Step in Energy Generation in the Cell Respiration –Oxidation of carbohydrate –Retrieves energy in glucose –Aerobic Process –Glycolysis Split glucose Result –Pyruvic acid –2 ATP –2 energy carriers Convert energy carriers to 2-3 ATP –1 molecule glucose = 6-8 ATP

18. Fermentation: A Way to Keep Glycolysis Going Fermentation –Anaerobic –Inefficient Yeast –alcohol Animal cells –Lactic acid

19. The Final Stages of Respiration Krebs cycle –Glucose broken down –CO 2 produced –ATP –Energy-carrying molecules Result –36-38 ATP

20. Cell Division

21. Mitosis –Cell division –Not for sexual reproduction Chromosomes Process –Copy chromosomes –Spindle fibers –Migration of chromosomes –Nuclear membrane reforms

23. Meiosis –Sexual reproduction –1 cell forms 4 gametes Gametes are genetically unique Process –Copy chromosomes –Crossing over –Segregation –Segregation again Result –4 daughter cells –½ normal chromosomes

24. Meiosis