Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology OCRA > Microscopy > Flashcards

Microscopy Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the points in cell theory?

A

Tissues are made up of cells
Cells are basic unit of all life
Cells only develop from existing cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define magnification.

A

How many times bigger an image appears, compared to the real specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define resolution?

A

Ability of a microscope to distinguish between 2 pints that are close together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Would happen if the resolution was higher?

A

Clearer the image so more detail can be seen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does resolution depend on?

A

Wavelength.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does it mean that light has a long wavelength?

A

Light microscope= poor resolution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does it mean that an electron beam has a short wavelength?

A

Electrón microscope = higher resolution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

On most microscopes what magnification is the objective lens?

A

X4, X10 or X40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

On most microscopes what magnification is the eye piece lens?

A

X10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you work out the total magnification?

A

Objective lens x eyepiece lens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is a stain added when preparing slides?

A

Adds contrast to help differentiate between the different parts
Makes it visiable by looking 5e structures to be seen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the safety procedure for a microscope?

A

Always carry a microscope with both hands taking the weight at the base
Always store microscopes with the lowest power lens in place
Always cover the microscope with a dust sheet when not in use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Production of prepared slides: what is the purpose of fixing?

A

Chemicals are sued to preserve the specimen in as near natural state as possible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Production of prepared slides: what is the purpose of sectioning?

A

Specimen is dehydrated with alcohol then placed in a wax mould to harden it then sliced very thinly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Production of prepared slides: what is the purpose of staining?

A

Provides contrast. Different parts of the specimen my take up different stains giving them different colours which the eye can detect.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Production of prepared slides: what is the purpose of mounting?

A

Specimens secured to a microscope slide with a permanent coverslip on top.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why are red blood cells thinner in the middle?

A

Bicóncavo shape, so mor slight can get through so looks paler.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do atoms form molecules?

A

Making bonds with each other.

19
Q

Electron: TEM- what re the feature of one?

A

Electron gun and anode.
Vacuum
Condenser electromagnetic lens
Specimen
Objective electromagnetic lens
Projector electromagnetic lens
Screen or photographic plate.

20
Q

Electron: TEM- what does the electron gun produce?

A

Beam of electrons

21
Q

Electron: TEM- why does there need to be a vacuum?

A

No air otherwise it could deflect electrons

22
Q

Electron: TEM- what does the condenser electromagnetic lens do?

A

Direct the electron beam onto the specimen.

23
Q

Electron: TEM- why is the specimen places on the grid?

A

Glass slide would stop electrons getting through

24
Q

Electron: TEM- what does the objective electromagnetic lens do?

A

Produces an image

25
Q

Electron: TEM- why does the projector electromagnetic lenses do?

A

Focus the magnified image into the screen.

26
Q

Electron: TEM- what does the score or photographic plate do?

A

Shows the image of the specimen

27
Q

Electron: TEM- how do you get the colour contrast?

A

Denser parts of the specimen absorb electrons and less dense parts let them through.
Where it is topped it is it will be dark where they go through it is white.

28
Q

Electron: TEM- what is the result?

A

2d black and white image which shows internal detail of the specimen.

29
Q

Electron: TEM- why is the maximum magnification?

A

Up to 1000000 X

30
Q

Electron: TEM- what is the maximum resolution?

A

0.5 nm

31
Q

Electron: TEM- what re the limitations?

A

Needs to be sliced very thinly to allow electrons through.
Vacuum- on,y dead specimens.

32
Q

Electron: TEM- what is the grid that the specimen sits on made out of?

A

Copper

33
Q

Electron: SEM- how do these work?

A

Scam a beam of electrons across the surface of a specimen nd may reflected electrons are collected.

34
Q

Electron: SEM- what type of image does it give?

A

3d surface imge

35
Q

Electron: SEM- what type of image does it give?

A

3d

36
Q

Electron: SEM- what is the maximum magnification?

A

500000 X

37
Q

Electron: SEM- why is the maximum resolution?

A

3-10nm

38
Q

Electron: SEM- what are the limitations?

A

Vacuum, specimens have to be cut thinly so specimen dead.

39
Q

Electron: SEM- why re the advantages compared to the TEM?

A

Don’t need to be cut quite as thinly as the electrons don’t need to pass through.

40
Q

Electron: SEM- what are the disadvantages compared to the TEM?

A

Images are lower magnification and resolution

41
Q

Electron: what can staining be used on?

A

Heavy metal alts such as lead.

42
Q

Electron: how does the staining work?

A

Attach to some parts of the specimen and not others.
He y metal ions scatter the electrons that are fired at the sample giving contrast between the structures.

43
Q

Electron: how are the images produced in staining, what can be can be changed and how?

A

Black and white.
Colour can be added after- false colour to make them easier to see and interpret.

A Level Biology OCRA (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions