3: Microscope

Question 1

A simple microscope has only ? Lens.

Answer 1

One

Question 2

In a compound microscope the image from the objective lens is magnified again by?

Answer 2

Ocular lens

Question 3

Objective lens x ocular lens =

Answer 3

Total magnification

Question 4

What is the ability of the lenses to distinguish two points?

Answer 4

Resolution

Question 5

Different units of measurement:

Answer 5

• 1 μm = 10⁻⁶ m = 10³ nm
• 1 nm = 10⁻⁹ m = 10⁻⁶ mm
• 1000 nm = 1 μm
• 0.001 μm = 1 nm

Question 6

Shorter wavelengths of light provide greater?

Answer 6

resolution

Question 7

What is the light-bending ability of a medium?

Answer 7

Refractive index

Question 8

What oil is used to keep light from bending?

Answer 8

Immersion oil

Question 9

What objects are visible against a bright background?

Answer 9

Dark objects

Question 10

• Accentuates diffraction of the light that passes through a specimen

Answer 10

Phase-Contrast Microscopy

Question 11

• Accentuates diffraction of the light that passes through a specimen; uses two beams of light

Answer 11

Differential Interference Contrast Microscopy

Question 12

• Dark objects are visible against a bright background.
• Light reflected off the specimen does not,enter the objective lens

Answer 12

Brightfield illumination

Question 13

• uses UV light
• fluorescent substance absorb UV light and emit visible light
• cells may be stained with fluorescent dyes(flourochromes)
• used to confirm rabies infection

Answer 13

Fluorescence microscopy

Question 14

• Ultrathin sections of specimens.
• Light passes through specimen, then an electromagnetic lens, to a screen or film.
• Specimens may be stained with heavy metal salts

Answer 14

Transmission Electron Microscopy(TEM)

Question 15

• An electron gun produces a beam of electrons that scans the surface of a whole specimen.
• Secondary electrons emitted from the specimen produce the image.

Answer 15

Scanning Electron Microscopy (SEM)

Question 16

• Scanning tunneling microscopy uses a metal probe to scan a specimen.
• Resolution 1/100 of an atom.
• Atomic force microscopy uses a metal and diamond probe inserted into the specimen.
• Produces 3-D images.

Answer 16

Scanning-Probe Miscroscopy

Question 17

A thin film of a solution of microbes on a slide is called? It is usually fixed to attach the microbes to the side and kill the microbes.

Answer 17

Smear

Question 18

What cells have little contrast with the surrounding medium? However, researchers do make discoveries about cell behavior looking at live specimens.

Answer 18

Live or unstained

Question 19

Stain consist of both?

Answer 19

Positive and negative ion

Question 20

In a basic dye, the chromophore is a?

Answer 20

cation

Question 21

In an acidic dye, the chromophore is an

Answer 21

anion

Question 22

Staining the background instead of the cell is called?

Answer 22

negative staining

Question 23

What stain classifies bacteria into gram-positive and gram-negative?

Answer 23

Gram stain

Question 24

What bacteria is tend to be killed by penicillin and detergents?

Answer 24

Gram-positive bacteria

Question 25

What bacteria are more resistant antibiotics?

Answer 25

Gram-negative bacteria

Question 26

Cells that retain a basic stain in the presence of acid-alcohol are called?

Answer 26

acid-fast

Question 27

What cells lose the basic stain when rinsed with acid-alcohol, and are usually counterstained (with a diferent color basic stain) to see them?

Answer 27

Non-acid-fast cells

Question 28

Negative staining is useful for?

Answer 28

capsules

Question 29

Heat is required to drive a stain into?

Answer 29

endospores

Question 30

Flagella staining requires a ? to make the flagella wide enough to see.

Answer 30

mordant