Cell structure

Question 1

How to stain slides?

Answer 1

1. Allow to dry
2. Heat it by a Bunsen burner

Question 2

Why are samples cut into sections?

Answer 2

To allow light to pass through easily

Question 3

Where is crystal violet used?

Answer 3

Stains cell walls purple, used in gram staining

Question 4

Where is methylene blue used?

Answer 4

Stains nucleus of animal cells to give contrast

Question 5

Where is Congo red used?

Answer 5

Negative stain that is not taking by the cell but provides a contrast between the cell and the background

Question 6

Dry mount

Answer 6

Solid specimens, thin slices called sectioning, coverslip on top

Question 7

Wet mount

Answer 7

Wet specimens, suspended in water or oil, coverslip placed on an angle

Question 8

Squash mount

Answer 8

soft specimens, wet mount squashed between the slide and coverslip

Question 9

Smear mount

Answer 9

the edge of the slide is used to smear the sample creating an even coat

Question 10

Which object is divided into 100 sections?

Answer 10

eyepiece graticule

Question 11

Equation for magnification factor

Answer 11

1 graticule division = number of micrometers ÷ number of graticule division

Question 12

Equation for measurement

Answer 12

graticule divisions x magnification factor = measurement (µm)

Question 13

Define resolution

Answer 13

Resolution is the ability to distinguish between two separate points

Question 14

The concept of resolution

Answer 14

Limit of resolution is about one half of the wavelength of the radiation used to view the specimen

Question 15

Define magnification

Answer 15

Magnification is how many times bigger the image of a specimen observed is in compared to the actual (real-life) size of the specimen

Question 16

What are the two types of lenses?

Answer 16

1. A series of (usually 3) objective lenses, each with a different magnification
2. An eyepiece lens, which often has a magnification of x10

Question 17

TEM (transmission electron microscope)

Answer 17

uses beams of electrons that pass through the specimen before being viewed. Only those transmitted are seen. It allows us to see thin sections of specimens (inside the cell).

Question 18

SEM (scanning electron microscope)

Answer 18

an electron beam is used to scan the surfaces of structures and only the reflected beam is observed.

Question 19

Light microscope procedure

Answer 19

Shine light through specimens, this light is passed through the objective lens (changeable) and then through the eyepiece lens (x10)

Question 20

Resolution of electron microscope

Answer 20

0.5 nm

Question 21

Resolution of light microscope

Answer 21

200 nm

Question 22

Which microscope uses vacuum? Why?

Answer 22

Electron microscope, because if there was air the electrons would scatter all around