Microscopy

Question 1

Magnification meaning

Answer 1

Is the number of times greater the image is than the specimen

Question 2

Resolution meaning

Answer 2

Is the ability to distinguish between two points on an image. The higher resolution the sharper the image

Question 3

Steps to prepare wet mount slides

Answer 3

1. add a drop of water to a slide
2. Place the specimen in the water
3. place the edge of a coverslip on the slide so that it touches the edge of the water
4. slowly lower the coverslip to prevent forming and trapping air bubbles.

Question 4

Electron microscope

Answer 4

The electron microscope uses electrons instead of light to produce detailed images with high magnification

Question 5

What are the 2 types of electron microscope

Answer 5

Transmission electron microscope (TEM)
Scanning electron microscope (SEM)

Question 6

Types of staining:

Answer 6

iodine, eosin and haematoxylin, methylene blue, gram stain

Question 7

Staining-Iodine

Answer 7

-simple technique using diluted iodine solution
-Helps to give contrast to cell structure
-will bind to starch and turn blue-black (plant cells)

Question 8

Staining-Eosin and haematoxylin

Answer 8

-Contrast stain used for tissue examination e.g cervical smears
-haematoxylin turns the nuclei blue
-eosin turns the cytoplasm as well as other parts pink

Question 9

Staining-Methylene blue

Answer 9

-Simple stain for animal cells and blood smears to make nuclei, DNA and RNA more visible
-Dead cells take up the satin more easily than living cells

Question 10

Staining- Gram’s staining

Answer 10

-Uses two different ‘counterstains’: crystal violet and safranin
-used to distinguish between gram ‘positive’ and ‘negative’ bacteria
-positive cells have a thick (peptidoglycan) outer layer that’s traps the crystal violet and stain purple.
-Negative cells have only a thin outer layer and stain pink