This document provides information on cell theory and types of cells. It begins by outlining cell theory, including that living organisms are composed of cells, cells are the smallest unit of life, and cells come from pre-existing cells. It then discusses unicellular organisms like Euglena and Paramecium that carry out all life functions. The document continues by looking at evidence for cell theory, sizes of cells and organelles, the importance of surface area to volume ratio for cell size, differences between prokaryotic and eukaryotic cells, plant and animal cells, cell membranes and transport, and cell division.

1. TOPIC 2: CELLS.

2. 2.1: CELL THEORY

3. 2.1.1. and 2.1.2. Cell Theory Robert Hooke Living organisms are composed of cells Cells are the smallest unit of life Cells come from pre-existing cells

4. 2.1.3: Unicellular Organisms Euglena. sp Paramecium. sp STATE: Unicellular organisms carry out all the functions of life metabolism e.g. cellular respiration response homeostasis growth reproduction nutrition

5. Evidence for the Cell Theory Can’t be proven “true” Require us to examine every single cell….which is impossible! Evidence comes form observations and experimentation.

6. When Separated cells’ individual parts can not sustain life. “The whole is greater than the sum of the parts.” The first cells are believed to come from self-replicating molecules. Inorganic Organic

7. Onion Cell Onion Cell Stained with Iodine x40 Magnification How big is an onion cell?

8. Size Matters! Size Matters! Size Matters!

9. Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells, using the appropriate SI unit. A molecule 1nm http://mendosa.com/glucose_molecule.jpg

10. Glucose (1nm) A molecule 10nm http://www.biolibogy.com/images/structure_of_plasma_membrane.JPG

11. A virus – the T bacteriophage 100nm 10nm http://oceanworld.tamu.edu/resources/oceanography-book/Images/BacteriophageCartoon.jpg

12. E.coli (bacteria cell) Bacteriophage (virus) 100nm 0.1µm 1000nm1µm http://bio1903.nicerweb.com/doc/class/bio1903/Locked/media/ch18/18_01T4PhageEColi_LP.jpg

13. Bacteria (1µm) Organelle (10µm) Eukaryote Cell (100µm) http://www.cic-caracas.org/departments/science/images/08eukaryote.jpg

14. 2.1.4: Relative sizes

15. In the last sequence of slides every thing increased by a magnitude of 10x each time. The IB requires you to remember the sizes. Make up a mnemonic to help you to remember the order! My Mom Visits BieberOutside Concerts. My Money Vanishes Beautifully On Cars. My Most Valued subject is Bio, Obviously! Cool!

16. 1mm = 1,000 µm 1 µm = 1,000 nm 1 nm molecules 10 nm membrane thickness 100 nm virus 1 µm bacteria (up to) 10 µm organelles (up to) 100 µm cells http://learn.genetics.utah.edu/content/begin/cells/scale/

18. Cheek Cell

19. Magnification of Your Drawing How Much Bigger is it? Drawing Size / Real Size Drawing size 10 cm Real Size 100 µm (work out from field of view) Convert units 100 µm = 0.01 cm 10cm/0.01cm= 1,000 Magnification

20. 2.1.5: Scale bar 15 µm

21. Why are cells so small? Nutrients and wastes move across a cell surface by diffusion. The chemical reactions that take place is known as the cell’s metabolism

23. Rate materials enter and leave the cell depends on surface area

25. The volume relates to how much material is needed at a time. The bigger the volume is the more material is needed to maintain it for an amount of time.

26. Lets look at Surface areas and volumes……… Fill in the table below: a a a

27. What trend did you notice? What happened to the area as side size increased? The area increased much faster than the side size. What happened to the volume? The volume increased much faster than the side size Which one (area or volume) increased the fastest?

29. If the cell gets too large and the ratio of Surface Area to Volume decreases it can’t take in the essential materials or excrete the waste fast enough….. So it must divide.

30. The same idea is relevant for heat and waste needing to be given out by an organism.

31. Can you think of some organisms that have to deal with this problem? Elephant – a very big organism produces lots of heat. How does it get rid of all the heat with a relatively low SA : Vol ratio? Find out about elephant ears. The Shrew – A very small organism with a relatively large SA : Vol ratio. How does it manage to stay warm in winter? Find out about changes in metabolism.

32. 2.1.6: Surface area : volume

33. 2.1.6: Surface area:volume

34. 2.1.7: Multicellular Organisms STATE: Multi-cellular organisms show emergent properties

35. 2.1.8: Multicellular Organisms All cells in an individual contain the same genetic information At an early stage of embryonic development, cells differentiate and become specialized to perform specific function. Some genes are turned on while others are not turned on to produce specific cells e.g. in muscle cells, muscle genes get turned on while liver genes get turned off.

36. 2.1.9: Stem cells STATE: Stem cells retain the capacity to divide and have the ability to differentiate along different pathways

37. 2.1.10: Therapeutic stem cells

38. For more than 30 years, bone marrow stem cells have been used to treat cancer patients with conditions like leukemia and lymphoma. During chemotherapy, most of the leukemia cells are killed as are the bone marrow stem cells needed as a patient recovers. However, if stem cells are removed before chemotherapy, and then re-injected after treatment is completed, the stem cells in the bone marrow are able to produce large amounts of red and white blood cells, to keep the body healthy and to help fight infections.

39. 2.2: PROKARYOTIC CELLS

40. 2.2.1, 2.2.2: Ultrastructure of E.coli Plasmid Mesosome

41. 2.2.3: Electron micrograph of E.coli

42. 2.2.4: Binary fission

43. 2.3: EUKARYOTIC CELLS

44. 2.3.1, 2.3.2: Liver cell

45. 2.3.3: Electron micrograph of liver cell (rat) Glycogen

46. 2.3.4: Prokaryotic VS Eukaryotic cell

47. 2.3.5: Plant VS Animal cell Plant cells have large vacuoles and animal cells do not have large vacuoles. Plant cells have a cell wall and animal cells do not have a cell wall. Plant cells (may) have chloroplasts and animals do not have chloroplasts. Plant cells store excess glucose as starch and animal cells store excess glucose as glycogen.

48. 2.3.6: Extracellular components The plant cell wall maintains cell shape, prevents excessive water uptake, and hold the whole plant up against the force of gravity. Animal cells secrete glycoproteins that form the extracellular matrix. This functions in support, adhesion and movement. Glycoproteins

49. 2.4: MEMBRANES

50. 2.4.1: Membrane Structure

51. 2.4.2: Hydrophobic/hydrophilic

53. 2.4.3: Membrane Proteins Hormone binding sites Immobilized enzymes Cell adhesion Cell to cell communication Channels for passive transport Pumps for active transport

54. Simple diffusion

55. 2.4.4: Diffusion

56. 2.4.4: Osmosis

57. 2.4.5: Passive Transport

58. 2.4.5: Passive Transport

59. 2.4.6: Active Transport

60. 2.4.7: Vesicle Transport

62. 2.4.8: Endo/Exocytosis

63. 2.5: CELL DIVISION

64. 2.5.1: Cell Cycle Cytokinesis starting

65. 2.5.2: STATE: Tumours (cancer) cells are the result of uncontrolled cell division and these can occur in any organ or tissue

66. 2.5.3: STATE: Interphase is an active period in the life of a cell when many metabolic reactions occur, including protein synthesis, DNA replication and an increase in the number of mitochondria and / or chloroplasts

67. Mitosis is division of the nucleus in which one parent nucleus divides into two daughter nuclei each having the same number of chromosomes as the parent nucleus.

69. 2.5.4 and 2.5.5: Mitosis Supercoiling of chromosomes Nuclear membrane breaks down Spindle microtubles extend from pole to equator Microtubules attach to centromere Chromosomes line along equator of cell Centromere splits and sister Chromatids (now chromosomes) move to opposite poles Reformation of nuclear membrane around chromosomes Chromosomes uncoil

70. STATE: Growth, embyonic development, tissue repair and asexual reproduction involve mitosis