1. Cell Theory 2014-15

2. History Cells were unknown until the invention of light microscopes in the 1650’s two scientists working independently built the first microscopes –Anton von Leeuwenhoek in Holland –Robert Hooke in England

3. Anton von Leeuwenhoek Studied pondwater, sour milk, and semen named moving organisms “animalcules”

4. Anton von Leeuwenhoek People thought human sperm cells contained tiny human beings called a homunculus

5. Robert Hooke Studied cork - a kind of tree bark named the structures he saw “cells” because they reminded him of the small rooms monks slept in.

6. Matthias Schleiden (1804-1881) –German lawyer-turned-botanist –Studied plants, preferring to study plant structure under the microscope –Determined that all plants are made of cells

7. Theodor Schwann: 1810-1882 German physiologist Studied animal tissues, particularly nerve and muscle tissues Determined that all animals are made of cells

8. Rudolph Virchow (1821-1902) Omnis cellula e cellula ("All cells come from cells")

9. The Cell Theory The cell theory has three parts: –All living things contain at least one cell –Cells are the smallest living units of matter –Cells can only come from pre- existing cells

10. Modern light microscopes

11. Scanning electron microscopes 3-D images of outside of objects 25-50 million times magnification Pollen grains:

12. Transmitting electron microscope Looks at VERY thin slices of substances Sees the inner workings of the items

13. Disadvantages of electron microscopes Expensive Non-portable Can only look at dead things

14. All living things contain at least one cell Many scientists have observed many types of living things Each of them noted that no matter what they observed, ALL LIVING THINGS contain cells

15. Cells are the smallest living units of matter –scientists realized that when cells were dissected or broken open they died (still happens despite our fancy technology) –This meant that whatever “life” is, it is something that happens inside cells

16. Cells can only come from pre- existing cells –Except the first cell –has not been disproved yet- no scientist has ever built a living cell from nonliving molecules

17. Spontaneous Generation Until 1850, most people believed that living things could spontaneously appear from non-living material

18. Spontaneous generation People believed that mice could be “created” spontaneously by putting grain in dark, quiet place and leaving it for a few weeks. Scientists sought to disprove it

19. Francesco Redi First to challenge spontaneous generation Did not accept that flies appeared from rotting meat

20. Redi’s Experiment –IV= cover –DV= presence of flies –Hypothesis: If a jar containing rotting meat is covered, then it will produce no flies

21. Redi’s Conclusions –Flies lay eggs, grow into maggots, grow into flies –If flies can’t lay eggs, then no new flies

22. Objections to Redi –“sealing the jar closed kept a magical essence from entering the rotting meat and bringing it to life” –“Scientists seek only to challenge belief systems and stir things up”

23. Lazzaro Spallanzani microbes that spoil food come from the air and can be killed by boiling IV= air, DV= food spoilage Hypothesis: If air is allowed to reach food, then microbes will get in and cause it to spoil

24. Spallanzani’s Experiment Flask 1: boiled broth, open Flask 2: boiled broth, sealed shut Results –Flask 1 spoiled –Flask 2 did not spoil

25. Objections to Spallanzani Sealing the flask blocked the magical life force in the air from getting to the broth.

26. Louis Pasteur 1822. France Supported that spontaneous generation is a myth Invented pasteurization (sterilization by heat)

27. Pasteur’s Experiment Used special “swan-neck flasks” that allowed air in but kept bacteria out

28. Pasteur’s Experiment IV= bacteria, DV= spoiling broth Hypothesis; If boiled broth is kept free of bacteria, then it will not spoil even if air can reach it.

29. Spontaneous generation is dead! Redi didn’t believe in it, and did an experiment using flies Spallanzani didn’t believe in it, and experimented with broth Pasteur disproved it conclusively with his open-air yet spoilage free flasks.

30. Pasteur is the father of modern microbiology supported the last part of the cell theory: cells only come from pre-existing cells showed that heat can be used to sterilize foods and preserve them

31. As a result… in the late 1870’s, doctors start to wash their hands and instruments before operating...some even start wearing gloves

32. Organelles are membrane-bound cell parts Mini “organs” that have unique functions Located in cytoplasm (everything inside the cell membrane)

33. Cells have evolved two different architectures: Prokaryote Eukaryote

34. Prokaryote cells are smaller and simpler Commonly known as bacteria Single-celled (unicellular) or Filamentous (strings of single cells)

35. Prokaryote cells Very small These are prokaryote E. coli bacteria on the head of a steel pin.

36. Prokaryote Cells cytoplasm: inner liquid filling DNA in one big loop called the NUCLEOID

37. Prokaryote Cells ribosomes: for building proteins Reproduce using BINARY FISSION

38. Endosymbiont theory: a prokaryote ancestor “eats” a smaller prokaryote They join forces and become more complex

39. Eukaryotes Bigger and more complex Have membrane-bound organelles including NUCLEUS Have chromosomes can be multicellular include animal, plant, fungal, and protist cells

40. Cell membrane –delicate phospholipid and protein skin around cytoplasm –found in all cells Cell Structures

41. Nucleus –a membrane-bound sac evolved to store the cell’s chromosomes- DNA wrapped around histones –has nuclear pores: holes to let substances in and out

42. Parts of a nucleus: ribosomes

43. Nucleolus –inside nucleus –location of ribosome factory –made of RNA

44. nucleoplasm a highly viscous liquid that includes the chromosomes and nucleoli.

45. Chromatin Unraveled DNA (not involved in cell division, so not in our familiar chromosomes- looks like tangled yarn)

46. mitochondrion – makes the cell’s energy (ATP) via cellular respiration –the more energy the cell needs, the more mitochondria it has

47. Parts of a mitochondrion:

48. Ribosomes –Very small; build proteins from amino acids in cytoplasm –may be free-floating, or –may be attached to ER –made of rRNA

49. Endoplasmic reticulum –may be smooth: builds lipids and carbohydrates –may be rough: stores proteins made by attached ribosomes

50. Endoplasmic reticulum Part of intracellular transport system; always near nucleus

51. Golgi Complex –takes in sacs called vesicles of raw proteins from ER –sends out vesicles containing finished cell products –Smaller than ER and closer to cell membrane

52. Golgi Complex

53. Proteins in the Golgi Complex can be stored for later use, chemically changed, or exported to outside of cell

54. Lysosomes –sacs filled with digestive enzymes –digest worn out cell parts –digest food absorbed by cell

55. Lysosomes Can also be used to reabsorb body parts that are no longer needed –This is how you lost your tail <3

56. Centrioles –pair of bundled tubes (microtubules) –organize cell division

57. Centriole Also called centrosome Made of protein filaments Part of cytoskeleton

58. Cytoskeleton found throughout cytoplasm gives shape to cell & moves organelles around.

59. Structures found in plant cells Cell wall –very strong –made of cellulose (in plants) –protects cell from rupturing

60. Cell wall Also find cell walls in fungi (chitin), bacteria (peptidoglycans), and protists (cellulose)

61. Vacuole –huge water- filled sac –keeps cell pressurized –stores starch, signaling molecules, etc.

62. Chloroplasts (also in some protists) –filled with chlorophyll –turn solar energy into food energy

63. Chloroplasts:

64. Eukaryote cells can be multicellular The whole cell can be specialized for one job cells can work together as tissues Tissues can work together as organs

65. Label the cells