module 2 - 2.1 microscopy

Question 1

why is a swan neck flask used?

Answer 1

so that the bacteria is unable to get in, neck is too long and thin

Question 2

what is resolution?

Answer 2

the ability to see 2 objects that are close together
NOT CLARITY

Question 3

why must cells be stained?

Answer 3

• to be able to see the internal organelles - increases contrast between cell components
• most cellular life has no colour

Question 4

what is a dry mount?

Answer 4

• specimen viewed whole or cut into very thin slices (sectioning)
• placed on center of slide, cover slip on top

Question 5

what would you view on a dry mount?

Answer 5

hair, pollen etc

Question 6

what is a wet mount?

Answer 6

• specimen suspended in liquid like water or immersion oil
• cover slip placed from an angle

Question 7

what would you view under a wet mount?

Answer 7

aquatic samples

Question 8

what is a squash slide?

Answer 8

• wet mount prepared
• lens tissue used to gently press down the cover slip

Question 9

what would you view under a squash slide and why?

Answer 9

root tips etc.
good for soft samples, avoids damage

Question 10

what is a smear slide?

Answer 10

• edge of slide is used in a smear sample (creates thin, even coating on another slide)
• cover slip then placed over slide

Question 11

what would you view under a smear slide?

Answer 11

cells in blood

Question 12

what is single staining?

Answer 12

using a single stain in slide preparation

Question 13

what is differential staining?

Answer 13

using 2 or more stains to increase the visual contrast between parts of a cell

Question 14

what is the charge of the nuclei?

Answer 14

negative

Question 15

what is the charge of methalin blue?

Answer 15

positive

Question 16

what kind of staining is used in Gram stains?

Answer 16

differential staining

Question 17

why does a refractive medium in a wet mount have to be similar to the glass?

Answer 17

to prevent diffraction between liquid and glass - preventing image distortion

Question 18

what is the full cell theory?

Answer 18

1. all living organisms are composed of one or more cells
2. the cell is the basic unit of structure in organisms
3. cells arise from pre-existing cells

Question 19

what colour is Gram Staining with slime layer?

Answer 19

purple

Question 20

what colour is Gram staining without slime layer?

Answer 20

pink