This deep dive covers Required Practical 2: Observing Mitosis within Cell Biology Practical Investigations for GCSE Biology. Comprehensive practical skills, experimental design, data analysis, microscopy techniques, and scientific methodology in cell biology It is section 4 of 18 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Required Practical 2: Observing Mitosis
Equipment
- Garlic or onion root tips
- 1M hydrochloric acid
- Toluidine blue stain
- Glass slides and coverslips
- Mounted needles
- Water bath at 60°C
Method
- Cut 5mm from growing root tips
- Place in 1M HCl at 60°C for 5 minutes
- Wash root tips in cold water
- Place on slide with toluidine blue stain
- Cover with coverslip and tap gently to spread cells
- Observe under microscope at x400 magnification
- Identify different stages of mitosis
Safety Considerations
- Wear safety goggles when using HCl
- Use water bath safely - avoid burns
- Handle glass slides carefully
- Dispose of biological material appropriately
Expected Observations
- Interphase cells (most common) - nucleus visible
- Prophase - chromosomes condensing
- Metaphase - chromosomes aligned at equator
- Anaphase - chromosomes moving to poles
- Telophase - new nuclei forming
Practice questions for Cell Biology Practical Investigations
When using a light microscope to observe cells, which objective lens should be used first?
Describe how to focus a light microscope on a specimen.
Quick recall flashcards
What is the formula for percentage change in mass?
Percentage change = ((Final mass - Initial mass) ÷ Initial mass) × 100
What is the formula for magnification?
Magnification = Image Size ÷ Actual Size