1: Microscopy

Question 1

Equipment (8p)

Answer 1

Forceps
Onion
Microscope slide
Iodine
Mounted needle
Cover slip
Microscope
Scalpel

Question 2

Method (5p)

Answer 2

1) Cut a small piece of onion
2) Peel thin membrane away from inner side of layer using forceps
3) Lay the skin flat on slide and add a few drops of iodine
4) Lower cover slip onto slide using mounted needle- make sure there are no trapped air bubbles
5) Put the slide on the microscope stage and focus the microscope until there is a clear image

Question 3

Risks (2p)

Answer 3

• Scalpel is sharp
• Iodine is corrosive

Question 4

Purpose of iodine

Answer 4

To make the onion visible under the microscope