1. 4.1 Cell Biology
Lesson 3

2. REQUIRED PRACTICAL 1
Microscope drawings
Learning objective: all students must measure the objective of 3 magnifications using a graticule, produce an accurate microscope drawing of an onion epithelial slide and calculate the magnification of their drawing.

4. Rules for microscope drawings:
Write a clear heading.
Use a sharp HB pencil.
Draw firm continuous lines and avoid using too much shading.
Include magnification of the lenses you have used
(Magnification of sample = eyepiece lens x objective lens).
Draw label lines horizontally with a ruler. These must touch the structure
you are labelling but not cross other lines.
Calculate the magnification of your drawing using the
magnification equation:
Magnification = image size ÷ actual size
(your drawing) (actual size of cell)