1. Cell Structure and Composition Prepared by: Ms. Bernabeth Jo T. Tendero

2. Major Parts of the Cell Nucleus Cytoplasm Cell Surface

3. Nucleus Region of the cell where the genetic material is located Generally oval-shaped or spherical shaped Most conspicuous part of the cell Regulates and coordinates all the activities of the cell Denser than surrounding cytoplasm

4. Parts of the Nucleus

5. Chromosomes - in form of chromatin - contains genetic information - Composed of DNA - Thicken for cellular division - Set number per species (i.e. 23 pairs for human)

6. Chromosomes

7. Chromatin

8. Nuclear Membrane Surrounds the nucleus Double membrane Has numerous opening called nuclear pores which serves as pathways for exchange of materials between the nucleus and the cytoplasm

9. Nuclear Membrane

10. Nucleolus Spherical shape Visible when cell is not dividing Contains RNA for protein manufacture

11. Nucleolus

12. Cytoplasm Protoplasm found outside the nucleus Collective term for cytosol and organelles Colloidal suspension Cytosol composed mainly of water with free floating molecules Viscosity constantly changes

13. Organelles Discrete structures of a cell having specialized functions

14. Centrioles: Helper in Cell Division Paired cylindrical organelles near nucleus Composed of nine tubes, each with three tubules Involved in cellular division Lie at right angles to each other

15. Centrioles

16. Cytoskeleton: Framework of the Cell Composed of microtubules Supports and provides shape Aids movement of materials in and out of cells Microtubules provide pathways for certain cellular molecules to move about

17. Cytoskeleton

18. Endoplasmic Reticulum: Manufacturers and Builders of the Cell Tubular network fused to nuclear membrane Goes through cytoplasm onto cell membrane Stores, separates and serves as cell’s transport system

19. Endoplasmic Reticulum

20. Endoplasmic Reticulum: Manufacturers and Builders of the Cell 2 types Rough Endoplasmic Reticulum (RER) - occurs as flattened sheets studded on its outer surface with small spherical bodies called ribosomes - aids in protein synthesis - prevalent in cells that specializes in secreting proteins

21. Rough Endoplasmic Reticulum

22. Endoplasmic Reticulum: Manufacturers and Builders of the Cell 2 types Smooth Endoplasmic Reticulum (SER) - occurs as tubes of membranes without ribosomes attached - site for fat metabolism and forms vesicles for transporting large molecules to other cell parts

23. Smooth Endoplasmic Reticulum

24. Golgi Apparatus: Packaging Counters of the Cell Discovered and named after Camillo Golgi in 1898 by observing nerve cells of an owl A system of membrane-bound sacs that look like a stack of pancakes Believe to be part of ER and where new membranes for the ER are manufactured Believe to prepare proteins for secretion after they are released from the ER

25. Golgi Apparatus

26. Lysosomes: Suicide Bags of the Cell “Lyso” – dissolving power and “some” – body Discovered in 1952 Contains hydrolytic/digestive enzymes for proteins, lipids and carbohydrates Transports undigested material to the cell membrane for removal Destroys cells when lysosomes burst

27. Lysosomes

29. Mitochondria: Powerhouses of the Cell 2 nd largest organelle with its own DNA (mtDNA) Double layered outer membrane with inner folds called cristae Energy-producing chemical reactions (produces ATP) takes place on cristae Controls level of water and other materials in cell Recycles and decomposes proteins, fats and carbohydrates, and forms urea

30. Mitochondria

31. Mitochondria

32. Ribosomes: Protein Factories of the Cell Composed of nucleic acids (RNA) and proteins Numerous in cells Manufacture proteins

33. Ribosomes

34. Ribosomes

37. Vacuoles: Storage Tanks of the Cell Membrane-bound sacs for storage, digestion and waste removal Contains water solution Contractile vacuoles for water removal

38. Vacoules

41. Peroxisome Contain enzymes that transfer hydrogen to various substrate of oxygen to produce hydrogen peroxide Use oxygen to break fats to use as fuel for cellular respiration Detoxify alcohol and other harmful compounds

42. Peroxisomes

43. Chloroplast: Site of Photosynthesis Plastid found in plant cells Contains green chlorophyll where photosynthesis takes place Has its own DNA and ribosomes Double membrane bound organelle Mobile and move around the cell through cytosleleton

44. Chloroplast

45. Cell Surface Protectively surrounds the cell Plasma membrane Cell wall Plasmodesmata

46. Plasma Membrane Double layer of phospholipid molecules Each phospholipid is composed of fats, phosphate and carbohydrates (oligosaccharide) Protein molecules are embedded in phospholipids Because of its structure the membrane has a semi-permeable property that allows only chosen substances to enter and leave the cell

47. Plasma Membrane

48. Cell Wall Lies outside the plasma membrane Compose of cellulose Protects the cells and provide rigid structure for cells Remains intact even after the rest of the cell has died

49. Cell Wall

52. Plasmodesmata small channels that directly connect the cytoplasm of neighboring plant cells to each other, establishing living bridges between cells allow certain molecules to pass directly from one cell to another and are important in cellular communication

53. Plasmodesmata

54. Plasmodesmata