Microscopy NF

Question 1

What Is A Microscope

Answer 1

An instrument which enables you to magnify and object hundreds, thousands and even hundreds of thousands of times.

Question 2

What Were The First Types Of Microscopes To Be Discovered?

Answer 2

Light microscopes - 16th and 17th century.

Question 3

What Does Cell Theory State?

Answer 3

1. Both plant and animal tissue is composed of cells.
2. Cells are the basic unit for all life.
3. Cells only develop from existing cells.

Question 4

What Are The Advantages Of Light MIcroscopy?

Answer 4

• It is readily available.
• It is relatively cheap.
• It can be used in the field.
• Can observe living organisms or dead specimen.

Question 5

How Does A Compound Light Microscope Work?

Answer 5

• It has two lenses - the objective lens and the eyepiece lens.
• The objective lens is placed near the specimen. The eyepiece lens is the lens through which a specimen is viewed.
• The objective lens produces a magnified image, which is magnified again by the eyepiece lens.
• This objective/eyepiece lens configuration allows for much higher magnification and reduced chromatic aberration than that in a simple light microscope.

Question 6

How To Prepare A Dry Mount

Answer 6

• Solid specimens are viewed whole or cut into very thin slices with a sharp blade (Sectioning.)
• The specimen placed on the centre of the slide and a cover slip is placed over the sample.

Question 7

How To Prepare A Wet Mound

Answer 7

• Specimen is suspended in a liquid such as water or immersion oil.
• A cover slip is placed from an angle.

Question 8

How To Prepare A Squash Slide

Answer 8

• A wet mount is prepared first.
• A lens tissue is used to gently press down the cover slip.
• Potential damage to a cover slip can be avoided by squashing the sample between the two microscope slides.
• Good technique for soft samples.

Question 9

How To Prepare A Smear Slide

Answer 9

• The edge of a slide is used to smear the sample, creating a thin, even coating on another slide.
• A cover slip is placed over the sample.

Question 10

What Are The Stages Involved In The Production Of Pre-Prepared Slides?

Answer 10

1. Fixing - chemicals used to preserve specimens in a near natural state.
2. Sectioning - specimens are dehydrated with alcohols and placed in a mould of wax or resin to form a hard block.
3. Staining - Specimens are often treated with stains to show different structures.
4. Mounting - specimens are then secured to a microscope slide and a cover slip placed on top.

Question 11

Criteria For Drawing Scientific Drawings

Answer 11

• Include a title.
• State magnification.
• Use a sharp pencil for drawings and labels.
• Use white, unlined paper.
• Use as much paper as possible for drawing.
• Draw smooth, continuous lines.
• Do not shade.
• Draw clearly defined structures.
• Ensure proportions are correct.
• Label lines should not cross and should not have arrow heads.
• Label lines should be parallel to the top of the page and drawn with a ruler.