1. Bell ringer L3
Compare your calculations with your neighbor, discuss any differences.

2. Bellringer L4
Set up your microscopes and calibrate the x10 and x40 objective lenses
Discuss with your partner:
Which cell measurement would be more accurate and why?
Measure at x10 and calculate cell size using x4 calibration and factoring in the magnification difference
Measure at x10 and use the calibration for the x10 objective to calculate the cell size

3. Bell ringer 5 Look at the drawings and compare the quality of work.
Identify good practice and necessary improvements

4. HW: Exam style question (10 marks)
In this questions, one mark is available for the quality of written communication.
Plant/animal cells* are also eukaryotic. Outline the functions(s) of each part of a plant/animal* cell.

5. Light microscopy

6. Specimens for Light Microscopes
Sectioning:
Some material distorts when you try & cut it into thin sections
Specimens are embedded in wax
Thin sections are cut without changing the structure of it.
Staining:
A lot of biological material is not coloured
Chemicals that bind to the specimen allowing it to be seen
Some stains are specific to cell structures
e.g. Acetic orcein stains DNA dark red.

7. Object name: Onion cells
Stain: Methylene Blue
Magnification: x400
Name, Date:
Cell wall
Cell membrane
Nucleus
Cytoplasm
Tonoplast
Vacuole

8. Biological Drawings White paper + sharp pencil
Safely carry out the practical as described. Take care to follow safety precautions indicated (especially using stains!)
Biological Drawings
White paper + sharp pencil
Title, date and the magnification power
Low power drawings - only the outline of the structures or tissues
High power drawings - Individual cells are required.
Draw large (~ 1/2 page), neat and tidy
Draw what you see – don’t copy textbooks
Draw with bold, dark, smooth lines.  Shading and the use of crayons are not encouraged.
Draw freehand but use a ruler for underlining and labels. Never cross lines
Include a scale bar that shows the actual size.
Draw overview x4
Draw 3-4 connected cells with detail x10

10. Plant cells

11. Animal cells