B1

Question 1

Microscopes allow us to/have a role of magnifying.

What’s the definition of magnification?

Answer 1

How many times larger the image appears, compared the real object

Question 2

Define resolution

Answer 2

The smallest distance between two objects that can be distinguished. Basically, how much detail you can see in the image.

Question 3

Advantages of Electron microscopes.

Answer 3

ADVANTAGES:
•Greater magnification and use electrons instead of light therefore a greater resolution. (2000x L.M)
•Greater res allows detail In the nucleas that we could never see with a light microscopes e.g study subcellular structures.

Question 4

Advantages and Disadvantages of Light microscopes.

Answer 4

Advantages: Easy to use, Relatively cheap, produce images in colour. Can magnify living specimens

Disadvantages:
Rely on light,
Limited resolution to 0.2um - any details less than this blurry (making E-microscope 2000× greater res). Can’t study subcellular structures in detail.

Question 5

How can we calculate the magnification of a microscope

Answer 5

Magnification = Size of image ÷
size of real object

Question 6

Why do electronic microscopes have greater magnification and resolution than light microscopes

Answer 6

They use a beam of electrons rather than light waves, and the electrons have a shorter wavelength than light waves allowing them to resolve smaller details

Question 7

What are 4 disadvantages of Electron Microscopes.

Answer 7

DISADVANTAGES
•Expensive
•Hard to set up and use - heavy to transport.
•Require specialist training
• Cannot observe living cells
•Can only see images in Black and White.

Question 8

How can you make the image you see through a microscope look better

Answer 8

Multiply the magnification of the eye peice and the high and low powerd objective lens piece being used, And refocus.

Question 9

How do we measure the length of cells under a microscope RPA

Answer 9

• Peel one cell layer of skin from an onion using a scalpel and tweezers.
• Place this on the microscope slide. Add a drop of iodine to stain the cells. Place a cover slip on top and clip the slide onto the microscope stage.
• turn on the light or position mirror so light reflects through the condensor to the slide.
• Use the lowest magnification objective lens. Use the coarse adjustment knob and fine adjustment knob to focus. Increase magnification and refocus if needed.

A gratiticule on the slide can allow you to measure the lengths of cells in in micrometer e.g. 2.5×10‐⁶