Unit 1: Microscopy

Question 1

used simple microscope in 17th century with single lens and was similar to a magnifying glass.

Answer 1

Antoni Van Leeuwenhoek

Question 2

built microscopes, which
have multiple lenses.

Answer 2

Robert Hooke

Question 3

credited with making
the 1st compound microscope around 1600.

Answer 3

Zaccharias Janssen

Question 4

developed a better
microscope in 1830

Answer 4

Joseph Jackson Lister

Question 5

refers to the use of any kind of microscope that uses visible light to observe specimens

Answer 5

Light Microscopy

Question 6

Light Microscopy

• uses visible light as its source of
  illumination
• Specimens appears against a
  bright background.

1. Dark objects are visible against a bright bg; stained
2. Light objects are visible against dark bg; unstained

Answer 6

Compound Light Microscopy (LM)
1. Brightfield Microscopy
2. Darkfield Microscopy

Question 7

Light Microscopy

permits detailed examination of internal structures in living microorganisms.

Answer 7

Phase-contrast Microscopy

Question 8

Light Microscopy

provides a colored, 3D
image of the object being observed.

Answer 8

Differential Interference Contrast (DIC) Microscopy

Question 9

Light Microscopy

takes advantage of fluorescence, the ability of substances to absorb short wavelengths of light and give off light at a longer

Answer 9

Fluorescence Microscopy

Question 10

Light Microscopy

uses lasers and special optics for “optical sectioning” of fluorescently-stained specimens.

Answer 10

Confocal Microscopy

Question 11

▪ Focus a beam of electrons through a specimen (TEM) or
onto its surface (SEM) instead of light is used. ▪ Electromagnet instead of glass lenses, control focus, illumination, and magnification

Answer 11

Electron Microscopy

Question 11

▪ Focus a beam of electrons through a specimen (TEM) or
onto its surface (SEM) instead of light is used. ▪ Electromagnet instead of glass lenses, control focus, illumination, and magnification

Answer 11

Electron Microscopy

Question 12

Electron Microscopy

provides for detailed study of the internal
ultrastructure in thin section of cells.

Answer 12

Transmission Electron Microscope

Question 13

to study the surface
features of cells and viruses.

Answer 13

Scanning Electron Microscope

Question 14

▪ Have been developed since early 1980s, used various kinds of probes to examine the
surface of the specimen at very close range.
✓ Without modifying the
specimen or damage it.
✓ To map atomic and molecularshapes
✓ To characterize magnetic and
chemical properties
✓ To determine temperature variation inside cell

Answer 14

SCANNED-PROBED MICROSCOPY

Question 15

Scanned-probed Microscopy

• uses a thin metal tungsten
  probe
• Provides very detailed views of
  molecules inside cells

Answer 15

Scanning Tunneling Microscopy
(STM)

Question 16

Scanned-Probed Microscopy

• metal-anddiamond probe is gently forced down onto specimen.
• Its movement is recorded and a 3D image is produced.

Answer 16

Atomic Force Microscopy (AFM)

Question 17

coloring the microorganisms with a dye that
emphasizes certain structures.

Answer 17

staining

Question 18

thin film of material containing the
microorganisms is spread over the surface of the slide.

Answer 18

smear

Question 19

Stains are salts composed of positive and a negative ion, one of which is colored and is known as the

Answer 19

chromophore

Question 20

positive ion; which includes crystal violet,
methylene blue, malachite green and safranin.

Answer 20

basic stains

Question 21

negative ion; which includes Picric acid,
eosin and nigrosin are common acidic stains (good for capsules)

Answer 21

acidic stains

Question 22

staining techniques

It is an aqueous or alcohol solution
of a single basic dye.

Answer 22

simple staining

Question 23

used to improved
bonding between the stain and the
specimen

Answer 23

mordant

Question 24

staining techniques

React differently with different kinds of bacteria and can be used to distinguish among them

Answer 24

differential staining

Question 25

developed in 1884 by** Hans Christian Graham**.
▪ Classify bacteria into 2 large
groups.
✓ Gram-positive & gram-negative

Answer 25

Gram stain

Question 26

staining techniques

Cells that retain a basic stain in the
presence of acidalcohol are called
acid-fast.

Answer 26

acid fast staining

Question 27

staining techniques

Used to color and isolate
specific parts of microorganisms
such as endospores and flagella
and to reveal the presence of
capsule.

Answer 27

special stains