Cambridge (CIE) AS Your notes
Biology
The Microscope in Cell Studies
Contents
The Microscope in Cell Studies
Magnification Calculations
Eyepiece Graticules & Stage Micrometers
Resolution & Magnification
Calculating Actual Size
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, The Microscope in Cell Studies
Your notes
Microscope Slide Preparation
Preparing a microscope slide
Specimens can be viewed under a light microscope; this allows some details of cellular
material to be observed
Pre-prepared permanent slides can be viewed
Such slides are produced by cutting very thin layers of tissue which are stained and
permanently mounted on a glass slide for repeated use
Different methods will be used to view different types of specimen, e.g. temporary
slide preparations can be produced in the school laboratory as described below
Preparing a slide using a liquid specimen
1. Add a few drops containing the liquid sample to a clean slide using a pipette
2. Lower a coverslip over the specimen and gently press down to remove air bubbles
Coverslips protect the microscope lens from liquids and help to prevent drying out
Preparing a microscope slide using a solid specimen
1. Use scissors or a scalpel to cut a small sample of tissue, and peel away or cut a very thin
layer of cells from the tissue sample
The preparation method always needs to ensure that samples are thin enough to
allow light to pass through
2. Place the sample onto a slide
A drop of water may be added at this point
3. Apply iodine stain
4. Gently lower a coverslip over the specimen and press down to remove any air bubbles
Preparing a microscope slide using onion cells diagram
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, Your notes
Tissue from an onion is as a solid specimen, and can be prepared here using iodine stain
Preparing a slide using human cells
1. Brush teeth thoroughly with normal toothbrush and toothpaste
This removes bacteria from teeth so they don't obscure the view of the cheek cells
2. Take a sterile cotton swab and gently scrape the inside cheek surface of the mouth for
5-10 seconds
3. Smear the cotton swab on the centre of the microscope slide for 2-3 seconds
4. Add a drop of methylene blue solution
Methylene blue stains negatively charged molecules in the cell, including DNA and
RNA
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Biology
The Microscope in Cell Studies
Contents
The Microscope in Cell Studies
Magnification Calculations
Eyepiece Graticules & Stage Micrometers
Resolution & Magnification
Calculating Actual Size
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 1
, The Microscope in Cell Studies
Your notes
Microscope Slide Preparation
Preparing a microscope slide
Specimens can be viewed under a light microscope; this allows some details of cellular
material to be observed
Pre-prepared permanent slides can be viewed
Such slides are produced by cutting very thin layers of tissue which are stained and
permanently mounted on a glass slide for repeated use
Different methods will be used to view different types of specimen, e.g. temporary
slide preparations can be produced in the school laboratory as described below
Preparing a slide using a liquid specimen
1. Add a few drops containing the liquid sample to a clean slide using a pipette
2. Lower a coverslip over the specimen and gently press down to remove air bubbles
Coverslips protect the microscope lens from liquids and help to prevent drying out
Preparing a microscope slide using a solid specimen
1. Use scissors or a scalpel to cut a small sample of tissue, and peel away or cut a very thin
layer of cells from the tissue sample
The preparation method always needs to ensure that samples are thin enough to
allow light to pass through
2. Place the sample onto a slide
A drop of water may be added at this point
3. Apply iodine stain
4. Gently lower a coverslip over the specimen and press down to remove any air bubbles
Preparing a microscope slide using onion cells diagram
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 2
, Your notes
Tissue from an onion is as a solid specimen, and can be prepared here using iodine stain
Preparing a slide using human cells
1. Brush teeth thoroughly with normal toothbrush and toothpaste
This removes bacteria from teeth so they don't obscure the view of the cheek cells
2. Take a sterile cotton swab and gently scrape the inside cheek surface of the mouth for
5-10 seconds
3. Smear the cotton swab on the centre of the microscope slide for 2-3 seconds
4. Add a drop of methylene blue solution
Methylene blue stains negatively charged molecules in the cell, including DNA and
RNA
© 2025 Save My Exams, Ltd. Get more and ace your exams at savemyexams.com 3
