Microscopy

Question 1

What is magnification

Answer 1

how much bigger sample is under microscope compared to actual size.

Question 2

What is resolution

Answer 2

Ability to distinguish between two points on image.
amount of detail

Question 3

how do you calculate total magnification

Answer 3

objective magni x eyepiece magni

Question 4

in a light microscope what are specimens exposed to ?

Answer 4

Light

Question 5

what distance must objects be in a light microscope to be seen as one object

Answer 5

less than 200nm apart

Question 6

what is light microscopes magnification limited to

Answer 6

1500x and is limited by its resolving power

Question 7

what are specimens exposed to in an electron microscope

Answer 7

Electrons

Question 8

why do electron microscopes produce images with better resolution

Answer 8

as electrons have shorter wavelength than light

Question 9

What are the two types of electron microscopes

Answer 9

Scanning (S.E.M)
Transmission (T.E.M)

Question 10

how are specimens prepped for S.E.M

Answer 10

coated in thin layer of metal (gold,platinum,tungsten)

Question 11

why are specimens coated for S.E.M

Answer 11

improve conductivity and contrast

Question 12

what happens to the electrons in S.E.M

Answer 12

reflected of the surface

Question 13

what image does S.E.M produce

Answer 13

3D image of whole cells/tissues

Question 14

how are specimens prepared for T.E.M

Answer 14

very thin slices stained with heavy metal

Question 15

what happens to the electrons in T.E.M

Answer 15

absorbed by heavily stained parts

Question 16

what image does T.E.M make

Answer 16

2D image of inside the cells/organelles

Question 17

what are the 4 different preparation methods

Answer 17

1.Dry mount
2.wet mount
3.squash slide
4.smear slide

Question 18

how do you prepare slides with the dry mount method

Answer 18

thin slice of specimen placed on slide with cover slip over it

Question 19

how do you prepare slides with the wet mount method

Answer 19

small drops of liquid on slide specimen

Cover slip on top + ensure no air bubbles

Question 20

how do you prepare slides with the squash slide method

Answer 20

-use soft specimen so can look at cell division.
-use wet mount method then place cover slip over specimen

Question 21

how do you prepare specimen with the smear slide method

Answer 21

Often used for blood samples.
-use edge of slide to smear sample making it thin. At 45 degree angle
-cover slip over sample

Question 22

what is an artefact

Answer 22

structural detail caused by processing specimen e.g air bubbles

Question 23

purpose of staining

Answer 23

help see cell structures

Question 24

what is purpose of differential staining

Answer 24

bind to specific cell structures and stain them differently so can be easily identified

Question 25

what does methylene blue stain help see

Answer 25

nuclei

Question 26

what does iodine help see

Answer 26

stains starch to see plant cell walls

Question 27

what is gram staining

Answer 27

stain bacterial cell walls.

Question 28

how do you calculate magnification

Answer 28

image size/actual size

Question 29

what is eyepiece graticule

Answer 29

-fine scale
-fits inside the eyepiece lens
-units are arbitrary

Question 30

what is the stage micrometer

Answer 30

-scale fitted on cover slip.
-size of divisions known