Microscopy 2.1.1 (a,b,c,d,e,f)

Question 1

role of objective lens

Answer 1

produces a magnified image

Question 2

role of eyepiece lens

Answer 2

further magnifies the image

Question 3

structure of light microscope

Answer 3

Question 4

what are the types of sample preparation?

Answer 4

dry mount
wet mount
squash slides
smear slides

Question 5

what is a wet mount used for?

Answer 5

to observe aquatic samples

Question 6

what is a wet mount?

Answer 6

the sample is suspended in a liquid and a cover slip is placed at an angle

Question 7

what is a squash slide?

Answer 7

a wet mount is prepared and then the lens is used to squash the sample

Question 8

what is a smear slide used for?

Answer 8

blood samples

Question 9

what is differential staining?

Answer 9

used to differentiate between two types of organisms which are difficult to identify

Question 10

examples of differential staining

Answer 10

gram stain
acid-fast

Question 11

what is gram staining?

Answer 11

done to separate bacteria into two groups:
- gram positive
- gram negative

Question 12

what colour are gram-positive bacteria when dyed?

Answer 12

crystal violet

Question 13

what colour are gram-negative bacteria when dyed?

Answer 13

colourless

Question 14

difference between gram-positive and gram-negative bacteria

Answer 14

gram-negative has thinner cell walls

Question 15

what is magnification?

Answer 15

how many times larger an image is than the actual object viewed

Question 16

what is resolution?

Answer 16

the ability to differentiate between individual objects as separate entities

Question 17

why can electrons increase the resolution?

Answer 17

beams of electrons have wavelengths which are shorter than light
therefore they can be seen easier

Question 18

equation for magnification?

Answer 18

magnification = image size / actual size

Question 19

from mm to µm

Answer 19

x1000

Question 20

from µm to nm

Answer 20

x 1000

Question 21

from m to mm

Answer 21

x1000

Question 22

what are two important components of a microscope for measurements?

Answer 22

an eyepiece graticule
a stage micrometer

Question 23

what is an eyepiece graticule?

Answer 23

has a scale which is calibrated using a stage micrometer

allows you to measure image actual size

Question 24

what is a stage micrometer used for?

Answer 24

to calibrate an eyepiece graticule

Question 25

what is total magnification?

Answer 25

eyepiece lens magnification x objective lens magnification

Question 26

what are the three types of microscopy?

Answer 26

light
electron
laser confocal

Question 27

how is electron microscopy carried out?

Answer 27

a beam of electrons illuminates the sample

Question 28

adv of electron

Answer 28

high magnifications
high resolution

Question 29

disv of electron

Answer 29

expensive
hard to move
sample must be dead
black and white image produced

Question 30

what are the two types of electron microscopy?

Answer 30

transmission electron microscope
scanning electron microscope

Question 31

TEM vs SEM

Answer 31

has better resolution than SEM with 0.5 nm
produces 2D images

Question 32

SEM vs TEM

Answer 32

has a lower resolution
produces 3D images

Question 33

adv of light microscope

Answer 33

cheap to buy and operate
easy to move
easy to operate
can use alive samples
coloured image

Question 34

disv of light microscope

Answer 34

weaker magnification and resolution

Question 35

what is an artefact?

Answer 35

an object which is produced by the process of microscopy and can be seen under microscopy

Question 36

what does laser confocal microscopy produce?

Answer 36

an image with a 3D structure from which different layers can be observed