Microscopy

Question 1

How big is a micrometre?

Answer 1

1/1000 of 1mm

Question 2

How big is a nanometre?

Answer 2

1/1,000 of 1 micrometre or 1/1,000,000 of 1mm

Question 3

How big is a picometre?

Answer 3

1/1000 of 1 nanometre

or

1/1,000,000 of 1 micrometre

or

1,000,000,000 of 1mm

Question 4

Symbol for micrometre

Answer 4

µm

Question 5

Symbol for nanometre

Answer 5

nm

Question 6

Symbol for picometre

Answer 6

pm

Question 7

What does the size of light mean in microscopy terms?

Answer 7

The wavelength (λ) or colour used in a particular situation

Question 8

Types of light microscopy

Answer 8

Brightfield Fluorescence Confocal

Question 9

Types of electron microscopy

Answer 9

Transmission Scanning

Question 10

What is the differences between light and electron microscopy?

Answer 10

Electron has a much higher magnification

Light microscopy allows observations of live cells and tissues while they need to be killed in electron

Question 11

Equation for magnification

Answer 11

Magnification = Image size/object size

Question 12

Magnification

What does object size refer to?

Answer 12

The size of the actual thing in reality

Question 13

Resolution

Answer 13

The fineness of detail that can be distinguished in an image

Question 14

Why do we stain cells and tissues in microscopy

Answer 14

Because they are colourless, transparent and pretty much invisible

Staining makes them a lot more visable

Question 15

Ways you can stain or label cells

Answer 15

Chemical stains/dyes

Enzyme labels

Fluorescent labels

Electron dense labels

Question 16

Haematoxylin

Answer 16

Stains nuclei blue

Question 17

Eosin

Answer 17

Stains everything other then the nuclei pink

Question 18

Fluorescent microscopy

Answer 18

Uses fluorescent labels

Allows multiple labelling

Can be used with conventional light microscopes

Question 19

Light vs electron wavelengths

Answer 19

Light wavelengths are much longer

Electron wavelengths give more information about the surface

Question 20

Which type of wavelength is better at giving more information about a surface?

Answer 20

Electron

Question 21

How does fluorescence work?

Answer 21

Fluorescent molecule is excited

When they begin to return to normal to their normal state they admit a shorter wavelength than the stimulant

Question 22

Key components used for confocal microscopy

Answer 22

Research microscope equipped for fluorescence

Lasers of various output wavelengths

Scanning mechanism

Light detectors and amplifiers

Computer with substantial processing power

Suitable fluorcromes

Question 23

Confocal microscope

Answer 23

Uses a pinhole to eliminate out of focus light and give a much clearer image

Question 24

Fluorescent proteins

Answer 24

Continually produced within living cells

Very bright and non-toxic

Expression and sub-cellular localisation can be controlled using molecular biology techniques

Can be used in other organisms like mammals and fungi

Question 25

Why can fluorescent proteins be used in imagery of live cells?

Answer 25

Non-toxic so wont harm the cell

Permanent markers that stay in the cells and can be passed onto to daughter cells

Question 26

Types of electron microscopy

Answer 26

Transition electron microscopy (TEM)

Scanning electron microscopy (SEM)

3D electron microscopy

Question 27

Transition electron microscopy

Answer 27

Form of electron microscopy

Takes images of very thin sections

Question 28

Scanning electron microscopy

Answer 28

Add a coating of gold, about 1 molecule thick

Can’t do colour

Question 29

3D electron microscopy

Answer 29

Takes an image

Takes a tiny slice off the top off the object

Takes another image

Repeats until it has many images that can be layered to make a 3D model of the object

Question 30

What is flourescent microscopy often used in

Answer 30

Immunocytochemistry and living cell imaging