2. Introduction to Cells Topic 2:Investigating Cells Standard Grade Biology

3. Magnification Cells can be seen more clearly using Microscopes _________________________ the cells Microscopes may have two or three__________________________________________ and one ___________________________________________. microscopes objective lenses magnify eyepiece lens

4. Calculating Magnification To work out Total Magnification use the following formula TOTAL = x MAGNIFICATION magnification of eyepiece lens magnification of objective lens

5. Since microscopes magnify cells we have a new unit of measurement. These new units are called _________________________. 1mm=1000 µm 1 =1 µm 1000 microns

6. Measuring Cell Size We can use microscopes to estimate the size of cells we are looking at e.g.if we know the diameter of the field of our field of view we can then estimate the size of the cells

7. a)if the field of view = 1mm then onion cells are ______________ mm or ______________(µm) in length 1mm (1000 µm) Field of view Onion cell 0.5 500 microns

8. b)if the field of view = 0.5mm or 500µm then these cheek cells would be mm or ______________ µm in length 0.5 mm (500 µm) Human cheek cell 500 5 100

9. MagnificationField of View mmMicrons (µm) X404 X1501 X4000.5 4000 1000 500

10. Staining Cells Animal and plant cells can be _________________________ so that the ____________________________________ can be______________________________ stained structures within cells seen more clearly

11. _________________________ stains the _________________________ of onion cells and also its _________________________. cell wall nucleus Iodine

12. _________________________ is used to stain the _________________________ of __________________________. Methyl Blue nucleus human cheek cells

13. _________________________ is used to stain the _________________________ present in the nucleus of cells which are about to divide. Acetic orcein chromosomes

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