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Biology Unit 1 > Microscope > Flashcards

Flashcards in Microscope Deck (12):
1

What are the rules for biological drawing?

Observe the specimen and record what you see clearly and accurately. Labelled drawings and diagrams can be used.

2

What are some points you need to remember when observing through a microscope?

- Draw what you see, not what you think you should be seeing.
- Always use a sharp pencil
-Make your drawings large
-Make the lines clear and sharp
-Do not shade or colour in any areas
-Make sure the different parts of the drawing are in proportion
-Labels should be spaced neatly around the drawing

3

What is the difference between electron and light microscopes?

Electron microscopes have a higher resolution and magnification than light microscopes.

4

What is magnification?

Magnification is how much bigger a sample appears to be under the microscope than it is in real life.

5

What is resolution?

Resolution is the ability to distinguish between two points on an image i.e. the amount of detail

6

Pros and cons of electron microscopes

- Expensive to buy
-Expensive to produce electron beam.
-Large and requires special rooms.
-Lengthy and complex sample prep.
-Preparation distorts material.
-Vacuum is required.
-All images in black and white.
-Magnifies over 500 000 times.
-Specimens are dead, as they must be fixed in plastic and viewed in a vacuum
-The electron beam can damage specimens and they must be stained with an electron-dense chemical (usually heavy metals like osmium, lead or gold).

7

Pros and cons of light microscopes

-Cheap to purchase
-Cheap to operate.
-Small and portable.
-Simple and easy sample preparation.
-Material rarely distorted by preparation.
-Vacuum is not required.
-Natural colour of sample maintained.
-Magnifies objects only up to 2000 times
-Specimens can be living or dead
-Stains are often needed to make the cells visible

8

What are the main limitations of the electron microscope?

The inability to observe living specimens, difficulty of preparation of samples and expensive equipment are the main limitations.

9

What are the main limitations of the light microscope?

Low resolution and as a result cannot magnify above x1500 and still give a clear image

10

What is cell division? (mitosis)

The division of a cell into two daughter cells with the same genetic material.

11

Magnification

x 1000 x1000
mm μm nm

Example: 1mm 1000μm 1,000,000nm

12

Equations

Actual size = Image size ➗ Magnification
Magnification= Image size ➗ Actual size