1. Anne Tierney, University Teacher
Cells
Anne Tierney, University Teacher
Room 938, Boyd Orr Building
Available through the Centre for Bioscience

2. Intended learning outcomes
Know what constitutes a cell
Describe a typical cell
Prokaryote
Eukaryote
Calibrate a light microscope
Measure cells using a light microscope

3. What is a cell? Get into groups of two or three
You have five minutes to think of everything you can that defines what a cell is
Feed back to the class

4. Types of cell - prokaryote
Simple
1-2μm
No nucleus
No organelles
Single chromosome

5. The most common shapes of prokaryotes
Cocci – round
Bacilli – rod-shaped
Spiral

6. Types of cell - eukaryote
Complex
5-100μm
Membrane-bound nucleus
Several types of organelle
Several chromosomes
Single-celled organisms
Multi-cellular organisms

7. A eukaryotic cell - animal

8. A eukaryotic cell - plant

9. How do we measure cells?
Cells are (usually) too small to see with the naked eye
Visualised with a microscope
How can we measure with a microscope?
Done indirectly
Comparing a known scale with a scale that can be calibrated

10. Measuring cells
eyepiece graticule
stage micrometer

11. How do we do it?
We compare the known scale (stage micrometer) to the scale that is to be calibrated

12. Calibrating the eyepiece graticule
The eyepiece scale is UNKNOWN
The stage scale is KNOWN
100 stage divisions = 10mm
Calibration must be done for every magnification

13. Calibrating the eyepiece graticule
100 eyepiece divisions = ____ *stage divisions
We know that 100 stage divisions = 10mm
1 stage division = ____mm
____ *stage divisions = ____mm
100 eyepiece divisions = ____mm
1 eyepiece division = ____ mm or ____μm
Repeat this for each magnification