Cell structures and functions

1. Cell Structures and Functions Presented by: Joevani S. Peñol

2. 1. Plasma Membrane Outermost component of the cell. Encloses the cytoplasm and forms the boundary between material inside and materials outside the cell.

3. Structure of the Plasma Membrane The plasma membrane is a double layer (bilayer) of proteins and phospholipids and is fluid rather than solid. This can be interpreted by the fluid mosaic model developed by Jonathan Singer and Garth Nicolson in 1972.

4. Function of the Plasma Membrane Regulate material moving into and out of the cell. Separate the internal and external part of the cell. Provide a large surface area on which specific chemical reactions can occur.

5. Functions of the Plasma Membrane Separate cells from one another. Site for the receptors containing specific cell identification markers that differentiate one cell type from the other.

6. 2. Cytoplasm Semifluid enclosed within plasma membranes and are consist of organelles, cytosol and other structures.

7. Animal Cell

8. Function of the Cytoplas m Dissolves substances and houses organelles and vesicles.

9. 3. Nucleus Control center of the cell. Contains nucleolus and DNA.

10. 4. Endoplasmic Reticulum an extensive membranous network continuous with the outer nuclear membrane . Contains series of channels and is storage unit for enzymes and other proteins.

11. Endoplasmic Reticulum

12. 2 Types of ER Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum

13. Rough Endoplasmic Reticulum Attached to it is the ribosomes.

14. Microscopic view of Rough ER

15. Smooth Endoplasmic Reticulum Site for lipid production, detoxification of a wide variety of organic molecules and storage of calcium ions in muscle cells. Don’t have ribosomes attached on it.

16. Microscopic View of the Smooth ER

17. 5. Golgi Apparatus Collection of membranes associated physically and functionally with the ER in the cytoplasm. Named after Camillio Golgi, 1998.

18. Structure Composed of flattened stacks of membrane bound cisternae

19. Function Sorts, packages, and secretes proteins and lipids.

20. Golgi Apparatus/Golgi Bodies

21. 6. Mitochondrion Double-membrane bound organelles that are spherical to elongate in shape. Powerhouse of the cell. Contains its own DNA.

22. 7. Lysosomes Membrane bound spherical organelles that contain enzymes called acid hydrolases, which are capable of digesting organic molecules under acidic conditions.

23. Microscopic view of the Lysosome

24. 8. Centrioles Located within microtubule-organizing center . Contains nine triplet microtubules Forms basal body of cilia and flagella. Function in mitotic spindle fiber formation.

25. Microscopic view of the Centriole

26. 9. Chloroplast Found only in plant cells Site of photosynthesis. Contains its own DNA.

27. Chloroplast

28. 10. Ribosomes Site of protein synthesis.

29. 11. Cilia/Flagella Threadlike processes. Move small particles past fixed cells and are a major form of locomotion in some cells.

30. Cilia and Flagella

31. 12. Vacuoles Membrane surrounded, often large sac in the cytoplasm. Storage site of food and other compounds, also pump water out of a cell.

32. 13. Cytoskeleton Interconnecting microfilament and microtubules; flexible cellular framework. Assist in cell movement; provides support; site for binding of specific enzymes.

33. Cytoskeleton

34. 14. Peroxisomes Small membrane bound vesicles containing enzymes that break down fatty acids, amino acids, and hydrogen peroxide (H 2 O 2 ).

35. 15. Cell Wall Rigid (up to many micrometers in thickness) and gives plant cells a very defined shape. Composed of cellulose fiber, polysaccharides, and proteins.

36. Function Cell stability Determines its shape, Influences its development, protects the cell against pathogens Counterbalances the osmotic pressure.

37. Structure Composed of primary and secondary cell walls.

38. References http://www.phschool.com/science/biology_place/biocoach/cells/intro.html http://people.eku.edu/ritchisong/301notes1.htm http://www.uic.edu/classes/bios/bios100/summer2002/lect05.htm