1. Two main types of cells §Prokaryotic – no nucleus, no membrane- bound organelles §Eukaryotic – has a nucleus, has membrane- bound organelles

2. An Overview of Cell Structure §All cells have three components l Cell/plasma membrane l Genetic material l Cytoplasm/cytosol

3. The Plasma Membrane

4. The Plasma Membrane Surrounds the Cell § Phospholipid bilayer contains embedded proteins

5. The Plasma Membrane Surrounds the Cell §Proteins enable cell to interact with environment §Transport proteins facilitate passage across membrane §Receptors induce cell changes with contact by molecules §Markers provide cell identity

6. The Central Portion of the Cell Contains the Genetic Material

7. Genetic material in prokaryotes §Single, circular molecule of DNA §Is concentrated in the center, not membrane bound

8. Genetic material in eukaryotes §Contained within the nucleus §Surrounded by two membranes

9. The Cytoplasm Comprises the Rest of the Cell's Interior §Cytoplasm is a semifluid matrix §Contains chemicals to carry out growth and reproduction

10. The Cell Theory

11. Robert Hooke § First cells seen with invention of microscope in 1665 § Observed honeycomb of empty compartments in cork

12. Antonie Van Leeuwenhoek § First to observe living cells

13. Matthias Schleiden §Observed plant tissues

14. Theodor Schwann §Observed animal tissues

15. Modern principles of cell theory §All organisms composed of one or more cells §Cell is smallest living functional unit §Cells arise only from the division of other cells

16. The Structure of Simple Cells: Bacteria (Prokaryotic)

17. A. Simplest Cellular Organisms §Great diversity §Similar organization, small size §May adhere in masses, but are fundamentally separate from one another

18. B. Strong Cell Walls §Carbohydrate matrix cross linked with peptide units §Gram positive, thick cell wall, retains stain, purple §Gram negative, thinner cell wall, releases stain, red or pink

19. The Prokaryotic Cell

20. C. Simple Interior Organization §1. Lack internal compartmentalization l a. Cell strength due to cell wall l b. Reactions not separated, single metabolic unit §2. Lack membrane-bound organelles l less efficient metabolic functions

21. The Structure of Eukaryotic Cells: An Overview §Plants, animals, fungi and protists are all eukaryotic §Eukaryotes are more complex than Prokaryotes

22. Eukaryotes Are More Complex Than Prokaryotes §Hallmark is compartmentalization l Organelles are separated from one another by membranes

23. The Animal Cell

24. Eukaryotes possess internal membrane-bound organelles §Golgi complex and lysosomes created by folding endoplasmic reticulum §Mitochondria and chloroplasts associated with cellular energy

25. Eukaryotes possess internal membrane-bound organelles (cont). §Central vacuole in plants stores protein and wastes §Vesicles in animals store and transport many materials §Nucleus contains chromosomes made of DNA

26. The Plant Cell

27. Plant Cells §Cytoskeleton-An internal scaffold of proteins §Cell walls-Cellulose fibers embedded with polysaccharides and proteins

28. The Endoplasmic Reticulum §Thin membranes not visible in light microscope §Divide interior into compartments §Lipid bilayer with embedded proteins §Abbreviated ER

29. Endoplasmic Reticulum (ER) Rough ER Smooth ER

30. Rough ER: Manufacturer of Proteins for Export §Ribosomes assist in the manufacturing of proteins l They contain groups of proteins and RNA l Translation of RNA into proteins

31. Smooth ER: Organizer of Internal Activities §Lack ribosomes §Contain embedded enzymes §Associated with detoxification, carbohydrate and lipid synthesis

32. The Nucleus: Information Center for the Cell §Spherical appearance in most cells §It is the largest organelle, readily visible §Centrally located, positioned by filaments

33. The Nucleus

34. The Nuclear Envelope §Double layer of membranes, outer membrane continuous with ER §Membranes pinched together at nuclear pores l Embedded with proteins, serve as molecular channels l Restrict passage of molecules to proteins and RNA

35. Proteins are made on the Ribosomes §On the ribosome, RNA is made into proteins §Proteins are necessary for the function of life l Ribosomes are the worker bees of the cell

36. The Golgi Complex: The Delivery System of the Cell §Golgi Bodies l Individual, flattened stacks of membranes l Collectively called the Golgi complex l Function in Molecule Collection, Packaging, Distribution l The FedEx of the cell

37. The Golgi Complex

38. Lysosomes: §Producers of digestive enzymes for the cell §Membrane bound organelles containing digestive enzymes l Digest worn-out cell components and recycle material into new structures §Digest pathogens engulfed by white blood cells l The garbage truck of the cell §Participate in selective cell annihilation

39. Lysosomes

40. Centrioles: Microtubular Assembly Plants §Present in animal and protist cells §Occur in pairs at right angles near nuclear envelope, forms the centrosome §Associated with assembly and organization of microtubules l Help move DNA during Mitosis

41. Centrioles

42. Mitochondria: The Cell's Chemical Power Plant §Occur in all organisms §Bounded by double membrane l a. Outer membrane is smooth l b. Inner membrane is folded into contiguous layers called cristae §Mitochondria possesses own DNA §Mitochondria are capable of replication

43. Mitochondria

44. Chloroplasts: Where Photosynthesis Takes Place §Occur in photosynthetic organisms, plants and algae §Bounded by double membrane §Internal membranes form disk-shaped thylakoids (look like pancakes) §Photosynthetic pigments on thylakoid surface §Possess own DNA, can reproduce

45. Chloroplast

46. The Cytoskeleton §Interior Framework of the Cell

47. Flagella and Cilia §Motility for the Cell

48. Flagella vs. Cilia

49. Cilia § Have functions other than locomotion §Pass fluids over tissue surface §Bend in response to sound waves l In your aural canal

50. ENDOSYMBIONT HYPOTHESIS §Mitochondria and chloroplasts originally were independent prokaryotic cells (with their own DNA). §Were engulfed by larger cells, eventually became symbiotic with each other.