1. IB Topic 2 Cells

14. Example of stem cell differentiation

17. Comparing microscopes Light microscopes Electron microscopes Focus beams Lenses electromagnets Resolving power 200 nm 0.2 nm Color No staining required/can see color Requires metal dyes/black and white only Object Alive or dead Dead only Expense High school range/cheap Universities/high cost

30. How Big Is A Cell? OBJECT SIZE Eukaryotic 10-100 μ m Prokaryotic 1-5 μ m Nucleus 10-20 μ m Chloroplast 2-10 μ m Mitochondrion 0.5-5 μ m Large virus (HIV) 100 nm Ribosome 25 nm Cell membrane 7.5 nm DNA dbl. helix 2 nm H atom 0.1 nm

31. Prokaryotic Cells E. coli

32. Diagram of a typical prokaryote

35. An electron micrographs of E. coli ** For IB you must be able to identify the structures on a micrograph. http:// www.cellsalive.com/index.htm

36. Another diagram of a prokaryote

38. Eukaryote Cells Animal cell

42. Diagram of a plant cell

45. Homework: Outline the roles of extracellular components in plants (cell wall) and animals (extracellular matrix).

46. Summary of differences between eukaryotes and prokaryotes! Prokaryotic Cells Eukaryotic cells small cells (< 5 mm) larger cells (> 10 mm) always unicellular often multicellular no nucleus or any membrane-bound organelles always have nucleus and other membrane-bound organelles DNA is circular, without proteins (naked) DNA is linear and associated with proteins to form chromatin (not naked) ribosomes are small (70S) ribosomes are large (80S) no cytoskeleton always has a cytoskeleton cell division is by binary fission cell division is by mitosis or meiosis reproduction is always asexual reproduction is asexual or sexual

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