2. Cells & Cell Organelles

3. Cell Theory The cell theory is the unifying theme in biology because it emphasizes the similarity of all living things. –All organisms are composed of one or more cells. –Cells are the smallest living units of all living organisms. –Cells arise only by division of a previously existing cell.

4. Cell Characteristics Cells contain specialized structures to perform functions necessary for life. Cellular activities necessary for life include chemical reactions that facilitate: – acquiring energy – reproduction – adaptation –maintaining homeostasis

5. Cell Characteristics The basic processes necessary for living things to survive are the same for a single cell as they are for a more complex organism. A single-celled organism has to conduct all life processes by itself. A multi-cellular organism has groups of cells that specialize to perform specific functions.

6. Cell Characteristics All cells contain: Genetic material –single circular molecule of DNA in prokaryotes –double helix located in nucleus in eukaryotes Cytoplasm jelly-like substance that fills the cells interior Plasma membrane encloses the cell –– phospholipid bilayer Phospholipids Membrane proteins

7. Cell Types Cell structure is one of the ways in which organisms differ from each other. –2 Types of Cells Prokaryote Eukaryote

8. Prokaryotic Cells Earth ’ s first cells were prokaryotes. The simplest life forms are the prokaryotes. Prokaryotic cells exist in two major forms: eubacteria and archaebacteria.

9. Prokaryotic Cells Prokaryotes are cells that lack a nucleus and membrane bound organelles. Bacteria and related microorganisms are prokaryotes

10. Generalized Prokaryotic Cell

11. Eukaryote Eukaryotes arose from prokaryotes and developed into larger more complex organisms. Eukaryotes are cells that contain a nucleus and organelles surrounded by a membrane, such as mitochondria and chloroplasts.

12. Eukaryote Can be both unicellular or multi- cellular Examples of eukaryotes are: –All fungus, plant, and animal cells

13. Generalized Eukaryotic Cell

14. Cell size comparison Bacterial cell Animal cell  micron = micrometer = 1/1,000,000 meter  diameter of human hair = ~20 microns most bacteria  1-10 microns eukaryotic cells  10-100 microns

15. Visualizing Cells

16. Why study cells? Bodies  Cells –bodies are made up of cells –cells do all the work!

17. What jobs have to be performed for an organism to live… –breathe –eat –make energy –remove wastes –respond to environment –growth & development –reproduction The Work of Life these are the same jobs your cells have to do!

18. Cells gotta live! What jobs do cells have to do? –make energy for daily life for growth –build more cells growth reproduction repair –make proteins proteins control every cell function

19. Making Proteins

20. Proteins do all the work! cellsDNAproteins one of the major job of cells is to make proteins proteins do all the work!

21. Building Proteins Organelles involved –nucleus –ribosomes –endoplasmic reticulum (ER) –Golgi apparatus –vesicles nucleusribosomeER Golgi apparatus vesicles

22. Nucleus Stores genetic material Contains DNA site where RNA is made Nucleolus: Chromatin and ribosomal subunits Nuclear envelope: –Double membrane with pores Largest organelle BRAIN of the cell – controls protein synthesis

23. Nucleus

24. small subunit large subunit Ribosomes Function –protein factories: build proteins Structure –RNA & proteins –2 subunits

25. Ribosomes They can be found alone in the cytoplasm or attached to the endoplasmic reticulum. –Alone in cytoplasm- makes proteins for use within the cell –Attached to RER- makes proteins for export out of the cell

26. Endoplasmic Reticulum Function –duct work or hallways of cell –processing of proteins –membrane factory Structure –rough ER ribosomes attached –smooth ER

27. Endoplasmic reticulum –transports materials through the cell Rough ER - studded with ribosomes –Attached to nuclear membrane –site of protein synthesis and processing Smooth ER - lacks ribosomes –site of synthesis of phospholipids and the packaging of proteins into vesicles

28. rough ER –ribosomes attached smooth ER Types of Endoplasmic Reticulum

29. transport vesicles secretory vesicles Function –like UPS headquarters “ shipping & receiving department ” –finishes, sorts, tags & ships proteins –ships proteins in vesicles membrane sacs “ UPS trucks ” Golgi Apparatus

30. proteins transport vesicle Golgi apparatus vesicle smooth ER rough ER nuclear pore nucleus ribosome cell membrane protein secreted cytoplasm Making proteins

31. Making Energy ATP

32. Cells need power! Making energy –take in food & digest it –take in oxygen (O 2 ) –make ATP –remove waste ATP

33. Lysosomes Function –little “ stomach ” for cell digests food –“ clean up crew ” of the cell cleans up broken down organelles Structure –pockets of digestive enzymes

34. Lysosomes white blood cells attack & eat invading germs = digest them in lysosomes

35. Lysosome function Lysosomes fuse with food vacuoles –digest nutrients for the cell vacuole

36. When things go bad… Diseases of lysosomes are fatal –digestive enzyme not working in lysosome –picks up food, but can ’ t digest it lysosomes fill up with undigested material –grow larger & larger until disrupts cell & organ function example: Tay-Sachs disease build up undigested fat in brain cells

37. But sometimes cells need to die… Lysosomes can be used to kill cells when they are supposed to be destroyed –some cells have to die for proper development in an organism ex: tadpole tail gets re-absorbed when it turns into a frog ex: getting rid of webbing between your fingers during fetal development –“ auto-destruct ” process lysosomes break open and kill cell cell “ suicide ”

38. Making energy Mitochondria –make energy from sugar sugar (glucose)  ATP Chloroplasts –make energy & sugar from sunlight sunlight  ATP & sugar –ATP = active energy –sugar = stored energy ATP

39. Mitochondria "Powerhouse of the cell" - cellular metabolism Structure- outer and inner membranes, cristae Found in both plant and animal cells Very active cells have more mitochondria

40. Chloroplasts Chloroplasts are larger and more complex than mitochondria Contain green pigment called chlorophyll that absorbs sunlight in the first step of photosynthesis Found ONLY in PLANTS

41. The Great ENERGY Circle of Life sun ATP Photosynthesis Respiration O2O2 glucose sugar CO 2 H2OH2O + + plants animals & plants

42. Food & water storage plant cells central vacuole contractile vacuole food vacuoles animal cells

43. Major organelles Nucleus Ribosomes Endoplasmic reticulum Golgi apparatus Vacuoles & vesicles Lysosome Mitochondria Chloroplast

44. Cell Membrane controls what enters and leaves the cell Found in ALL cells Phospholipid bilayer with transport proteins, and cholesterol (for flexibility)

45. Cell Wall provides support Found in PLANT and BACTERIA cells Made from cellulose

46. Centrioles Cylindrical structures found near the nucleus Made of hollow, tubular structures arranged in bundles Important in cell division Found ONLY in ANIMAL cells

47. Plant vs. Animal Cells PLANT CELL ANIMAL CELL Cell membrane Mitochondria Golgi apparatus Nucleus Cytoskeleton Ribosomes Endoplasmic reticulum Lysosomes HAVE: Cell Wall LARGE vacuoles Chloroplasts DO NOT HAVE: Centrioles HAVE: Centrioles DO NOT HAVE: Cell Wall LARGE vacuoles Chloroplasts

50. Cell Differentiation Cell specialization occurs during the development of a multi-cellular organism. The genetic information necessary for all cellular functions remains in each cell but may not be used.