Cells and Life

Science — First Preparatory

Applications and examples from life

Comparison aspect	Main idea	Keywords
Onion skin experiment	we peel a thin layer from the inner surface of an onion scale place it on a slide with a drop of water and observe it under the microscope. We see rectangular cells packed closely together with clear walls and without green chloroplasts in this layer	peelthinlayerinner
Cheek cell experiment	we gently scrape the inside of the cheek with a clean cotton swab spread it on a slide add a drop of methylene blue stain and observe. We see small animal cells with no cell wall and with a clear nucleus	gentlyscrapeinsideclean
Calculating magnification	if the eyepiece lens is 10× and the objective lens is 40× the total magnification = 10 × 40 = 400 times. If the objective is replaced by a 100× lens the magnification becomes 10 × 100 = 1000 times	eyepiecelensobjectivetotal

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