1. A Tour of the Cell, cont… Last Time: The Nucleus and the Endomembrane System Today: Other Organelles and the Cytoskeleton

2. Cells need energy to work

3. Figure 6.8 The structure and hydrolysis of ATP

4. Chloroplasts in plant cells convert sunlight into chemical energy that will be used to make ATP

5. ATP is manufactured through cellular respiration that takes place in the mitochondria

6. Peroxisomes

7. The cytoskeleton

8. Microfilaments Actin Two intertwined strands maintain cell shape by resisting tension Actin subunit Protein subunits Structure Functions motility via pseudopodia muscle contraction cell division in animals 7 nm Intermediate filaments Keratin, others Fibers wound into thick cables anchor nucleus and some other organelles Microtubules  -tubulin and  - tubulin dimers Hollow tube Keratin subunitsTubulin dimer maintain cell shape by resisting compression motility via flagella/cilia move chromosomes during cell division move organelles 10 nm 25 nm 3 types of cytoskeletal structures

9. Structure of kinesin Tail Stalk Head Motor molecules like kinesin, myosin, and dynein work with the cytoskeleton to produce movement

10. Transport vesicle Kinesin Microtubule ATPADP+P i Kinesin "walks" along a microtubule track ATPADP+P i

11. Microfilaments and Intermediate Filaments Networks of filaments near the plasma membrane help to maintain a cell’s shape

12. Microfilaments aid in motility

13. Centrosome containing a pair of centrioles Microtubules often grow out from the region called the centrosome

14. CiliaFlagella Cilia and Flagella move the entire cell

15. TEM of flagella Microtu bule doublet Cell membrane Central pair Outer doublet Dynein Spoke Cilia and Flagella have a “9 +2” arrangement of microtubule doublets

16. Bend The motor protein Dynein “walks” along the microtubules within the flagella on one side, causing bending

17. Figure 7.23 A comparison of the beating of flagella and cilia

18. Plant cells are surrounded by cell walls made of cellulose Plasmodesmata connect adjacent plant cells

19. Animal cells are connected through Intercellular junctions

20. Review of an animal cell (centrioles)

21. Review of a plant cell