Paper 1 RPAs Flashcards
What is the use of:
1. The objective lens
2. The stage
3. The lamp below the stage
What is the use of:
1. A mirror
2. The course focusing dial
3. The fine focusing dial
Complete a risk assessment for the microscope RPA.
- Don’t ingest the iodine or stain anything with it.
- Wear safety goggles so that the iodine does not get into your eye.
What is the aim of the microscope RPA?
The aim of the microscope RPA is to see the internal structures in animal or plant cells
Write a detailed method of the microscope RPA.
- Use a dripping pipette to put water on the microscope slide.
- Separate a thin layer of onion and peel off a thin layer of epidermal tissue. Put it on the microscope slide.
- Make sure the onion cells are laying flat on the microscope slide. Add 2 drops on iodine into the slide using a pipette. Then gently lower the coverslip onto the slide.
- Use filter paper to soak up excess water in the coverslip. Then put the slide on the microscope stage.
- Turn the nosepiece to the lowest power objective lens
- Look from the side and adjust the coarse adjustment knob. Then look through the eyepiece and stop when the cells focus.
- Make a clear drawing of the cells.
Why do we use a thin layer of onion skin?
We use a thin layer of onion skin so that light is able to pass through and make it more visible.
Why do we use iodine?
We use iodine to stain the cells to make the internal structures more visible
Why do we lower the coverslip gently?
We lower it gently to prevent trapping air bubbles.
What is the nosepiece in the microscope?
How do we find the total magnification of the microphone? (Write down the formula)
Magnification = magnification of eyepiece lens x magnification of objective lens.
What is the difference between low power and high power objective lens?
What is the difference between the eyepiece lens and the objective lens?
