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Question 1

How does a light microscope work?

Answer 1

the objective lens magnifies the image, which is then magnified again by the eyepiece lens. the light is shone through to make the specimen visible.

Question 2

What is magnification?

Answer 2

how many times larger an image is than the actual specimen.

Question 3

what is resolution?

Answer 3

the ability to see individual objects as separate entities and distinguish between them ( how clear an image is)

Question 4

how can resolution be increased?

Answer 4

by using beams of electrons, which have far shorter wavelengths than light.

Question 5

What is the magnification calculation triangle?

Answer 5

mag= size of image/ actual size of object

Question 6

what are the 2 types of electron microscopes?

Answer 6

Transmission electron microscopes and scanning electron microscope

Question 7

why is staining used in light microscopes?

Answer 7

to allow for differentiation between ultrastructure of cells

Question 8

how do transmission and scanning electron microscopes work?

Answer 8

Transmission: electrons are fired through a specimen and focused to produce an image. Scanning: beam of electrons sent across the surface of a specimen and the reflected electrons are collected. 3D images can be produced.

Question 9

what is a positive and negative of light microscopes?

Answer 9

poor resolution due to the long wavelength of light, however living samples can be examined and colour can be obtained.

Question 10

what are some positives of Transmission electron microscopes and how do they work?

Answer 10

high magnification and resolution, electrons pass through the specimen to create an image (cross section)

Question 11

what are some pros of scanning electron microscopes, how do they work?

Answer 11

both have high resolution and magnification- electrons bounce off the surface of the specimen to create an image.

Question 12

what are dry mounts?

Answer 12

specimens viewed with just a cover slip over the top

Question 13

whats a wet mount?

Answer 13

water or stain added before cover slip is applied.

Question 14

what are squash slides?

Answer 14

wet mounts where you push them down to ensure light can pass through.

Question 15

whats a smear slide?

Answer 15

edge of another slide is used to smear the sample across another slide to create a thin even sample.

Question 16

how do you use eye piece graticules?

Answer 16

1. line up the stage micrometer and graticule whilst looking through eyepiece
2. count how many divisions on eyepiece fit into one division on the micrometer scale
3. each division on micrometer is 10um, so can be used to calculate one division of graticlue is at that magnification. e.g. if 2, one division is 5um)