Structure and Function of the Cell pt II

1. Structure and Function of the Cell pt II

2. Objectives • Describe the function of the cell nucleus • Describe the function of the major cell organelles • Describe the function of the cell wall • Describe the theory of Endosymbiosis

3. Cytoskeleton • The cytoskeleton is a network of protein filaments that help the cell maintain its shape • This also is involved in movement • Principle protein filaments are: • Microfilaments • Microtubules

4. Microfilaments • Microfilaments: • Are made of the protein actin • Help the cell maintain its shape • Help cells move • Pseudopods are temporary projections of eukaryotic cells

5. Microtubules • Microtubules: • Important in cell division • Spindle fibers are bundles of microtubules that help move the chromosomes during cell division • In Animal cells centrioles located near the nucleus help in cell division

6. Cilia & Flagella Move cells Flagellum CILIA

7. Cytoskeleton is also used as a means of mobility. This unicellular algae have extensions of flagella that are anchored in the cell membrane.

9. Connection: How does cilia help with the surface area issue? What is the cilia used for here in the trachea? Cilia

10. Nucleus • Nuclear matrix helps it maintain its shape • Control center or brain of the cell • Nuclear envelope surrounds the nucleus • The chromatin inside the nucleus condenses prior to cell division to form chromosomes • Small openings called nuclear pores allow RNA to pass from the nucleus to the cytosol

11. Nucleus

12. Nucleolus • Where ribosomes are made Tour of an Animal Cell .mov

13. Plant Cells • Plant cells can have three structures that animal cells do not • Cell walls • Vacuoles • Plastids

14. Cell Wall • All cells are surrounded by a thin, flexible membrane • Plant cells also have a cell wall surrounding the membrane

15. Vacuoles Provide storage of and control water content Take up space! carbs, H2O, salts, proteins...

16. Plastids • Some store starch or fats, others contain pigments • Most common type is the chloroplast • Surrounded by two membranes and have their own DNA • Capture energy from the sun and convert it into chemical energy… Photosynthesis Tour of a Plant Cell .mov

17. Endosymbiosis • Endosymbiosisis a hypothesis that states mitochondria and chloroplast were originally prokaryotes and that a symbiotic relationship evolved

18. Comparing Animal Cells to Plant Cells

19. Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

20. Differences between plant cells and animal cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular Shape Regular shape No cell wall Cell wall present

21. Review • Describe the function of the cell nucleus • The nucleus contains most of the cells DNA and with it the codes instructions for making proteins and other important molecules • Describe the function of the major cell organelles • Nucleolus- where the assembly of ribosomes begins

22. Review… • Chloroplast- capture energy from the sun and convert it into chemical energy (food) • Cytoskeleton- helps the cell maintain its shape and is involved in movement • Vacuoles- take up space and provide storage

23. Review… • Describe the function of the cell wall • Provide support and protection for the cell • Describe the theory of Endosymbiosis • Endosymbiosis is a hypothesis that states mitochondria and chloroplast were originally prokaryotes and that a symbiotic relationship evolved