2. The Size Range of Cells

3. A Tour of the Cell Prokaryote No membrane bound nucleus or organelles DNA is concentrated in a region called the nucleoid 1 – 10 μm in diameter Include bacteria and archaea Eukaryote Membrane-bound organelles True nucleus (w/DNA) enclosed in a nuclear envelope 10 – 100 μm in diameter Include protists, plants, fungi and animal cells

4. A Tour of the Cell

5. Animal Cell

6. Plant Cell

7. Animal Cell Have: Mitochondria Nucleus Cell Membrane Rough & Smooth ER Ribosomes Golgi Apparatus Cytoplasm Cytoskeleton Peroxisomes Also: Lysosomes Centrioles Flagella and Cilia Plant Cell Have: Mitochondria Nucleus Cell Membrane Rough & Smooth ER Ribosomes Golgi Apparatus Cytoplasm Cytoskeleton Peroxisomes Also: Chloroplasts Vacuoles Cell Wall Plasmodesmata

8. Microscopes Transmission Electron Microscope (TEM) Scanning Electron Microscope (SEM)

9. The Compound Light Microscope Magnifies up to 1500x Living and non-living specimens 3-D image Image produced using 2 lenses Light must be able to pass through specimen

10. Parts of the Microscope Objectives Left- Scanning- 4x Middle-Low power-10x Right-High power-40x

11. Magnification - the ratio of an object’s image to its real size Total magnification = eyepiece x objective X

12. Resolving Power The ability of a microscope to distinguish clearly between objects close together under a microscope Low resolution High resolution

13. Field of Vision Amount of area visible under each objective

14. Measuring the field of vision 1 millimeter (mm) = 1000 micrometer (μm) How large is the field of vision pictured in mm? In μm? Suppose you estimate 13 microorganisms could fit across this field of vision? How large is one microorganism in μm?

15. Field of Vision Observe the next three slides. What is happening to the field of vision as the magnification increases?

16. Field of Vision

17. What happened to the field of vision as you change from scanning to low to high power objective? How would the object’s apparent size change?

18. The Stereoscope Also called dissecting microscope Can view large opaque objects Living and non-living specimens Magnifies up to 100x 3-D image

19. Electron Microscopes Electron Microscopes – Electron beam focused through the specimen or onto its surface (electron beams have wavelengths much shorter than visible light) Two types –Transmission Electron Microscope (TEM) – internal or ultrastructure –Scanning Electron Microscope (SEM) – surface of the specimen –Scanning Tunneling Microscope (STM) - views molecules at atom level

20. TEM Transmission Electron Microscope

21. TEM Beam of electrons pass through specimen Magnifies up to 500,000x 2-D image Non-living specimens only

22. TEM Collagen Fibrils in the cornea

23. TEM Plant Cell-22,500X C = Chloroplast ER = Endoplasmic Reticulum G = Granum M = Mitochondrion S = Starch Grain T = Thylakoids V = Vacuole W = Wall

24. SEM Scanning Electron Microscope Electrons bounce off surface Specimen placed in vacuum chamber

25. SEM Non-living specimens 3-D image Magnifies up to 60,000x

26. SEM Technician monitors image on screen

27. SEM Pollen Grain

28. Scanning Tunneling Microscope Developed in 1980’s Can view atoms on surface of objects Non-living 3-D image Magnifies up to 100 million x

29. STM Barium, Copper, and Oxygen atoms

30. STM Silica atoms A nanometer (nm) is one millionth of a millimeter