CP2-Light Microscope

Question 1

Objectives- Use a light microscope to observe and measure biological samples

Answer 1

Objectives:

• know how to record observations using appropriate biological drawings
• understand importance of staining specimens
• know how to use an eyepiece graticule

Question 2

Risks?

Answer 2

• toluidine O is harmful if swallowed
• razor blades/broken slides can cut through skin
• wash touluidine O off skin if in contact
• do not leaver razors/slides on desk
• dispose of broken glass slides immediately
• cut away from fingers not towards

Question 3

Method?

Answer 3

• calibrate microscope and eyepiece graticule on low power, then medium, then high power
• use razor to cut thin transverse sections of plant stem
• mount one section on slide using mounting needle, add one drop of water and close the coverslip, make sure there are no air bubbles
• remove excess water from other section and add 2 drops of toluidine O dye and close the coverslip, wipe away any excess dye
• examine stained and unstained slides on low power, and draw and annotate simple tissue plan
• examine again on medium and high power

Question 4

What is Magnification?

Answer 4

Magnification= image size/actual size

Question 5

Importance of staining?

Answer 5

Cells are usually translucent so staining allows the different organelles to absorb the stain and show up in a different colour, making them easier to identify