2.1- Cell structure Flashcards Preview

AS- Biology > 2.1- Cell structure > Flashcards

Flashcards in 2.1- Cell structure Deck (76)
Loading flashcards...
1

What are the 4 main types of microscopes?

Optical
Laser scanning/confocal
Transmission electron
Scanning electron

2

What is the maximum magnification of an optical microscope?

X1500

3

What is the maximum magnification of a laser scanning microscope?

X1500

4

What is the maximum magnification of a transmission electron microscope?

X2000000

5

What is the maximum magnification of a scanning electron microscope?

X200,000

6

What is the resolution of a optical microscope?

200nm

7

What is the resolution of a laser scanning microscope?

160nm

8

What is the resolution of a transmission electron microscope?

0.1nm

9

What is the resolution of a scanning electron microscope?

0.1nm

10

How do optical microscopes work?

They shine a light through a sample

11

What are the pros of optical microscopes?

Relatively inexpensive
Need mimimum training to operate
Can study living organisms

12

What are the cons of optical microscopes?

Low magnification and resolution
specimens often need staining to show organelles

13

How do laser scanning microscopes work?

they use laser beams to analyse a sample and look at different depths of the sample

14

What are the pros of laser scanning microscopes?

Images are higher resolution than optical microscopes
Lasers can scan to different depths

15

What are the cons of laser scanning microscopes

Relatively low resolution and magnification
Expensive equipment that requires high level training
Specimens require staining

16

How do transmission electron microscopes work?

They use electromagnets to transmit a beam of electrons through a sample.
Denser parts absorb more electrons and appear darker

17

What are the pros of transmission electron microscopes?

They have the highes magnification and resolution of any microscope

18

What are the cons of transmission electron microscopes?

large and expensive machinery needs lots of training to use
specimen must be dead
Staining is potentially hazardous

19

How does a scanning electron microscope work?

They fire a beam of electrons at the specimen which knocks electrons off any surface it hits. these electrons are detected to produce a 3D scan

20

What are the pros of Scanning electron microscopes?

Can form 3D images of a sample
Magnification and resolution is much higher then light microscopes

21

What are the cons of scanning electron microscopes?

Large and expensive machinery is required which needs high level training
Specimen must be dead
Specimen needs to be mounted In a vacuum

22

What is the definition of magnification?

How much bigger an image appears enlarged by a microscope compared to the original object viewed with a naked eye

23

What is the definition of resolution?

The ability to distinguish between 2 objects that are close together

24

What is the formula for magnification?

Image Size/Object Size

25

What are graticules?

scales placed in a icroscope to allow the user to measure the size of a specimen. before the specimen can be measured, the eyepiece graticule must be calibrated

26

What are the 2 different ways we can compare a slide for viewing?

Dry Mount
Wet Mount

27

How do we dry mound a microscope slide?

Take a thin slice of the specimen and place it in the middle of the slide using tweezers. then place a cover slip on top.

28

How do we wet mount a microscope slide?

Place a small drop of water on a slide and then place the specimen on top and cover with a cover slip.
Add stain at the edge of the slip.

29

What are 3 ways of viewing a sample that is transparent or colourless?

Light interference
Dark background
Staining

30

What is an ultrastrusture?

The detailed structure of cells that can only be seen with high magnification electron microscopes.