Informal Class Evaluation

1. Informal Class Evaluation What do you like about the class? What works well for you? What should we do more of? What do you not like about the class? What doesn’t work for you? What should we do less of? What are your thoughts on the labs so far (good / bad / indifferent)? How could the class be improved for the rest of the term? What about for next term?

2. Lab Debriefing Why did the potato extract turn brown as it sat out on the desk? What would you observe if the reaction was proceeding quickly? slowly? Was the potato the enzyme? What was the substrate?

3. Enzyme Concentration Color Intensity (from chart) Time (min)

4. Substrate Concentration Color Intensity (from chart) Time (min)

5. Salt Concentration Color Intensity (from chart) Time (min)

6. Cell Structure and Compartments

7. The Cell Is the Basic Unit of Life All living things are made of cell(s) (characteristic of life)

8. Cells • An organism can be unicellular or multicellular • Range from one to billions of cells • Humans have over 200 types of cells

9. Cells • An organism can be unicellular or multicellular • Range from one to billions of cells • Humans have over 200 types of cells

10. History of Cell Discoveries 1590’s: Hans and Zacharias Janssen • Lens grinders • First compound microscope

11. History of Cell Discoveries 1665: Robert Hooke • Observed thin slice of cork through microscope • Tiny, hollow, roomlike structures = “cells” (what monks live in) • Only saw outer walls because cork is dead

12. History of Cell Discoveries 1680’s: Anton van Leeuwenhoek • Blood, rainwater, scrapings from teeth, etc • “Animalcules” = unicellular organisms, bacteria?

13. History of Cell Discoveries 1838-9: Schleiden and Schwann • Schleiden - plant parts are made of cells • Schwann - animal parts are made of cells

14. CELL THEORY • Cells are the basic units of structure and function in all living things • All living things are made of cells • All cells come from pre-existing cells

15. How do we study cells? Light Microscope Electron Microscope

16. Light Microscopes (LM) • Passes visible light through a specimen • Can study living cells • Can magnify only about 1,000 times • Can resolve objects as small as 2 m

17. Light Microscope Pictures

18. Electron Microscope (EM) • Greater magnification than LM • Uses a beam of electrons rather than light • Has much greater resolution than LM (2 nm) • Can magnify up to 100,000 times • Cannot be used with living specimens

19. Scanning Electron Microscope (SEM) • Studies detailed architecture of cell surfaces

20. POLLEN SEM Pictures FISH GILLS BLOOD CELLS

21. Transmission Electron Microscope (TEM) • Details of internal cell structure

22. TEM Pictures NEURON MELANOCYTE

23. BACTERIA BACTERIA E. coli 400X 2m = 0.002 mm

24. BACTERIA BACTERIA E. coli Electron microscope

25. ANIMAL CELL HUMAN CHEEK CELL Homo sapiens 400X 60m = 0.06 mm

26. ANIMAL CELL HUMAN CHEEK CELL Homo sapiens 600X

27. PLANT CELL Estimate size? 50 - 150 m = 0.05 - 0.15 mm ELODEA LEAF CELLS Elodea canadensis 400X

28. PLANT CELL ELODEA LEAF CELLS Elodea canadensis 600X

29. Cell Types Which two types of cells are more similar? Which type is more different?

30. Prokaryotes and Eukaryotes • Prokaryotes • Little internal organization • Much smaller than eukaryotes

31. Prokaryotes and Eukaryotes • Eukaryotes • DNA contained in nucleus • Membrane bound organelles - internal compartments for special functions Figure 5.2

32. Origin of Eukaryotes ENDOSYMBIOSIS • Large cells engulfed smaller cells, but didn’t digest them Animation: Cain Ch 5 09 - Endosymbiosis

33. Origin of Eukaryotes ENDOSYMBIOSIS • Large cells engulfed smaller cells, but didn’t digest them MEMBRANE INFOLDING • Cells folded membrane in from outside of cell to increase surface area

34. Cell Size How big is a cell?

35. Cell Size • Most cells are microscopic • Some aren’t.

36. Cells Vary in Size • Minimum size = total size of all the molecules required for cellular activity

37. Cell Size • Minimum size = total size of all the molecules required for cellular activity • Maximum is limited by the need for sufficient surface area to carry out functions

38. Surface area to Volume Ratio • A small cell has a greater ratio of surface area to volume than a large cell of the same shape

39. Surface area to Volume Ratio • The microscopic size of most cells ensures a sufficient surface area across which nutrients and wastes can move to service the cell

40. Surface area to Volume Ratio • Microvilli in the small intestine

41. Prokaryotes and Eukaryotes

42. Functions performed by an organism Growth / development MAKING ENERGY OBTAINING FOOD GETTING RID OF WASTE REPRODUCING MOVING

43. Functions performed by an organism Growth / development MAKING ENERGY OBTAINING FOOD GETTING RID OF WASTE REPRODUCING MOVING

44. Prokaryotes • Unicellular • The cell must perform ALL functions • Unspecialized

45. Eukaryotes • Unicellular • Multicellular • Cells can be specialized to perform one function • Cells interact together

46. Biological Hierarchy • Molecule • Cell • Tissue • Organ • Organ System • Organism

47. Parts of the Cell • Cell ORGANELLES: Parts of the cell that perform a specialized function just like an organ in the body

49. Function #1: Keeping your insides inside CELL MEMBRANE • PROKARYOTES • EUKARYOTES

50. Function 1b: Food, Waste, Gas Exchange CELL MEMBRANE • Controls what enters and leaves the cell