Principles of BiologySlide 2Slide 3The MicroscopeFocusing the MicroscopeSlide 6CellsSlide 8Onion Skin CellsSlide 10Slide 11Slide 12DrawingsFinally, you become an expert.The EndPrinciples of BiologyByFrank H. Osborne, Ph. D.Lab 2 - Microscope and CellsA. The microscope is used to magnify objects.B. The object on the slide is magnified by the objective lens. 1. The shortest scanning lens (4X) is used to search for objects on the slide. 2. The low power (10X) lens is used for general magnification. 3. The high power (40X) objective lens is used for close-up work. Do not use the high power lens to observe thick preparations.C. The image produced by the objective lens is magnified by the ocular lens (10X). 1. The scanning lens gives a total magnification of 40X. 2. The low power lens gives a total magnification of 100X. 3. The high power lens gives a total magnification of 400 X.The MicroscopeOcular LensObjective LensesCoarse AdjustmentFine AdjustmentStageFocusing the Microscope1. Use the lowest power.2. Look at the slide, not through the ocular lens.3. Bring the lens and slide as close together as possible.4. Now, look through the ocular lens and focus upward slowly until you see something. 5. Put the object in the exact center of the field of view.Focusing the Microscope6. Turn to the next higher power7. Find the object.8. Focus slowly.CellsA. Animal cells1. Animal cells do not have a cell wall.2. With our microscope, you can see the nucleus and the cytoplasm.3. Methylene blue dye is used to see the nucleus and cytoplasm better.CellsB. Plant cells 1. Plant cells have a cell wall. 2. You can see more parts. a. Onion skin cells i. nucleus ii. nucleolus iii. cytoplasm in strands iv. vacuole v. cell wallOnion Skin CellsNucleolusCell wallCytoplasm in StrandsNucleusVacuoleB. Plant cells b. Elodea cells i. nucleus ii. chloroplasts iii. cytoplasm iv. vacuole v. cell wall3. Some cells have cytoplasmic streaming (cyclosis).Elodea leaf Elodea leaf magnified 100XElodea spicule (pointy cell) magnified 400XCell wallChloroplastNucleusCytoplasmVacuoleDrawingsA. Draw one cell or several cells.B. Label each of the parts you saw. Do not label parts that cannot be seen, like the cell membrane.C. Do not include air bubbles.D. Label the magnification that you used.Finally, you become an expert.The EndLab 2Microscope and
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