Chapter 4 - Microscopy, Staining, Classification

Question 1

Why is the metric system used in science?

Answer 1

The metric system is a decimal system. Each unit is one tenth the size of the next smallest unit. This makes dealing with very small units easier than the English system.

Question 2

One thousandth of a millimeter

Answer 2

micrometer

Question 3

One thousandth of a micrometer

Answer 3

nanometer

Question 4

the distance between two corresponding parts of a wave of a radiation beam

Answer 4

wavelength

Question 5

Increase in the apparent size of an object

Answer 5

magnificiation

Question 6

refraction

Answer 6

the bending of light

Question 7

why does a lens bend light

Answer 7

the leading edge of the light beam slows as it enters a lens and the beam bends. Light also bends as it leaves the lens and reeenters the air.

Question 8

the ability to distinguish two points that are close together

Answer 8

resolution

Question 9

Formula for resolution

Answer 9

resolution = 0.61 X wavelength/numerical aperture

Question 10

the ability of a lens to gather light

Answer 10

numerical aperature

Question 11

Differences in intensity between two objects or between and object and its background

Answer 11

contrast

Question 12

Microscope with single lens

Answer 12

simple microscope

Question 13

microscope with multiple lenses

Answer 13

compound microscope

Question 14

lenses closest to the eyes

Answer 14

ocular lenses

Question 15

total magnification

Answer 15

objective lens magnification X ocular lens magnification

Question 16

directs light through a specimen

Answer 16

condenser lens

Question 17

a microscopic image

Answer 17

micrograph

Question 18

microscope that uses an ultraviolet light to fluoresce objects

Answer 18

fluorescent microscope

Question 19

microscope that uses fluorescent dyes or stains and ultraviolet lasers

Answer 19

confocal microscope

Question 20

microscope that generates a beam of electrons that ultimately produce an image on a computer screen.

Answer 20

transmission electron microscope

Question 21

Disadvantages of scanning and transmission electron microscope

Answer 21

Requires a vacuum, so the organism to be scanned must be dead

Question 22

microscope that passes a beam of electrons across a surface

Answer 22

scanning electron microscope

Question 23

microscope which measures the flow of electrons to and from a probe and the surface of a specimen

Answer 23

scanning tunneling microscope

Question 24

microscope that traverses the tip of a pointed probe across the surface of a specimen

Answer 24

atomic force microscope

Question 25

staining

Answer 25

coloring specimens with stains

Question 26

thin film of organisms on a slide

Answer 26

smear

Question 27

positively charged dye that stain acidic surfaces. work best in high pH

Answer 27

basic dyes

Question 28

dyes that stains alkaline structures

Answer 28

acidic dye

Question 29

Distinguishes between purple staining gram-postive cells and pink gram-negative cells

Answer 29

Gram stain method

Question 30

colors all cells

Answer 30

primary stain

Question 31

binds to a dye and makes it less soluble

Answer 31

mordant

Question 32

breaks down the cell wall of Gram-negative cells, allowing the stand and mordant to be washed away

Answer 32

decolorizing agent

Question 33

works on cells with thick lipid layer in their cell wall

Answer 33

acid fast staining

Question 34

dormant cells, highly resistant to destruction

Answer 34

endospores

Question 35

a stain that stains the background behind a cell because it does not bind with negatively charged cells

Answer 35

negative stain

Question 36

what is a negative stain used for?

Answer 36

mostly to identify negatively charged bacterial capsules