Page 126 - Knowledge Organiser Yr9 24-25

Knowledge Base: Science B1: Cell Biology Year 9
5. Using a Light Microscope
5.1
Where should you place a prepared slide on a microscope?
On the stage.
5.2
What is the function of the nose piece on a microscope?
To select the objective lens.
5.3
Which objective lens should you begin with when using a microscope?
The lowest power objective lens.
5.4
How can you adjust the position of the stage on a microscope?
By turning the coarse adjustment knob.
5.5
When adjusting the position of the stage on a microscope, how can you avoid the lens coming into contact with the slide?
By looking from the side (not down the eyepiece).
5.6
How can you bring an image into focus on a microscope?
By looking down the eyepiece and turning the coarse adjustment knob and then
the fine adjustment knob.
5.7
How can you find the total magnification of an image produced by a microscope?
Objective lens magnification x eyepiece magnification.
4. Microscopy
4.1 Name two types of microscope. Light and electron.
4.2 What is magnification? Making something small look bigger.
4.3
What is resolution?
The ability of a microscope to distinguish detail.
4.4
Name two advantages of electron microscopes (compared to light microscopes).
Higher magnification, higher resolving power (resolution).
4.5
Name two disadvantages of electron microscopes (compared to light microscopes).
Much larger, more expensive, cannot view living specimens.
4.6
How have electron microscopes allowed biologists to see and understand many more subcellular structures?
High magnification and resolution allows scientists to study cells in much finer detail.
4.7
What is the equation for calculating the size of an image produced by a microscope?
Image size = actual size x magnification
4.8
If an image size of a cell is measured 4.5mm, how long is the cell in micrometres?
4.5mm x 1000 = 4500μm
4.9
A cell measured 1cm when it was magnified x250. Calculate the actual size in micrometres.
4.10
A cell measured 3.2mm when it was magnified x100. Calculate the actual size in micrometres.
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