microscope histo

Question 1

an instrument composed of several lenses used in magnifying objects too small to be seen by the naked eye

Answer 1

microscope

Question 2

inventor of the microscope

Answer 2

zacharias jansen

Question 3

improved the microscope; Father of Microbiology

Answer 3

Anton van Leeuwenhoek –

Question 4

USES VISIBLE LIGHT FOR ILLUMINATION

Answer 4

light microscope

Question 5

– uses visible light as light source; shows internal structure and outline of the transparent sheath

Answer 5

BRIGHT FIELD MICROSCOPE

Question 6

• examination of live microorganisms not seen under an ordinary light microscope
  
  • possess opaque disks
  • suitable for structures that cannot be stained or easily distorted
  • useful for detection of Spirochetes

Answer 6

DARKFIELD MICROSCOPE

Question 7

• used to facilitate detailed examination of the internal structures of living specimens
  
  • especially for transparent objects

Answer 7

PHASE CONTRAST MICROSCOPE

Question 8

• Principle in phase contrast microscope

Answer 8

Light Changes its speed when passing through cellular and extracellular structures with different refractive indices

Question 9

• produces images with a 3-D aspect as compared to phase-contrast microscopes
  
  • objects appear bright against a dark background

Answer 9

DIFFERENTIAL INTERFERENCE MICROSCOPE

Question 10

two types of DIFFERENTIAL INTERFERENCE MICROSCOPE

Answer 10

: Hoffman (modulation contrast)

Nomarski (differential contrast)

Question 11

• Uses a strong UV Light Source and special filters that select rays of different wavelength
  
  • Use of fluorescent compounds such as Acridine Orange, Rhodamine

Answer 11

FLUORESCENCE MICROSCOPY

Question 12

Principle of FLUORESCENCE MICROSCOPY

Answer 12

: Substances are exposed to light (radiation) at a wavelength, these emit light with a longer wavelength which is visible

Question 13

• more advantageous than regular bright field microscopes

- Uses small point of high intensity light (laser) and a pinhole aperture

Answer 13

CONFOCAL MICROSCOPE

Question 14

• Advantage of CONFOCAL MICROSCOPE

Answer 14

avoids stray light; produces more resolution

Question 15

• used for viewing highly organized molecules (crystals and lipids, cellulose, collagen, microtubules, microfilaments)
  
  • uses the principle of polarization wherein light can be rotated in one direction or another (“birefringence”)

Answer 15

POLARIZING MICROSCOPE

Question 16

Uses beams of electrons to produce a magnified image

Has greater resolving power as compared to light microscopes; Has higher resolution (1000fold increase)

Answer 16

electron microscopy

Question 17

• Allows magnifications of up to 400,000 times
  
  • Requires very thin sections (40-90nm)
  • Freeze Fracture Techniques are usually combined in TEM
  • Used to Examine Viruses or Internal UltraStructures of cells
  • Structures appear as black/gray or white

Answer 17

TEM

Question 18

• Studies the surface features of cells and viruses

- Provides a 3-D image of the surface

Answer 18

SCANNING ELECTRON MICROSCOPY

Question 19

It is particularly useful for evidence not requiring very high magnification (10x–125x).

Its large working distance makes it quite applicable for the microscopic examination of big, bulky items.

Answer 19

Stereo/Dissecting Microscopes

Question 20

: ability of the lenses to distinguish fine detail and structure
refers to the ability of the lenses to distinguish between two points a specified distance apart

Answer 20

Resolution

Question 21

—— wavelength: the —— the resolution

Answer 21

shorter; greater

Question 22

resolution is dependent on the —— used

Answer 22

Dependent on the Objective Used

Question 23

ability of the microscope to distinguish/separate 2 points distinctly

Answer 23

Resolving Power:

Question 24

a measure of the light bending ability of a medium (substances through which light passes)

Answer 24

Refractive Index

Question 25

distance between the objective and object being focused (slide)

Answer 25

Working distance:

Question 26

Magnification: Formula

Answer 26

magnification of ocular x objective magnification

Question 27

function of the wavelength and characteristic of the lenses gives the idea of how much light can enter the objective Measures light gathering ability of the microscope

Answer 27

Numerical Aperture:

Question 28

only slight adjustment is needed to focus the object being studied when the objective is shifted from one objective to another.

Answer 28

Parfocal:

Question 29

used to preserve the direction of light rays at the highest magnification.

Answer 29

Immersion Oil:

Question 30

See to it that the________objective is in position when the microscope is not in use

Answer 30

LPO

Question 31

Use -------------- in cleaning the objectives and stage

Answer 31

alcohol or xylol

Question 32

Do not apply too much xylol for it may ___________

Answer 32

loosen the screws

Question 33

Dry with ___________ immediately after application of xylol

Answer 33

soft tissue paper

Question 34

Clean the______ first with soft tissue paper ;

Answer 34

OCULAR

Question 35

see to it that the stage and objectives are free from __

Answer 35

OIL

Question 35

Invented the compound microscope

Answer 35

zacharias jansen

Question 36

optical system of bright field microscope

Answer 36

condenser objective eyepice

Question 36

Resolution of TEM

Answer 36

2.5 nm

Question 37

– collects and focuses a cone of light that illuminates the object to be observed

Answer 37

a. Condenser

Question 37

Resolution of SEM

Answer 37

2.0 nm

Question 38

enlarges and projects the image of the object in the direction of the eyepiece

Answer 38

b. Objective –

Question 38

Pathway of electron of TEM

Answer 38

Passes thru the specimen

Question 39

- further magnifies this image and projects it onto the viewer’s retina or a charge-coupled device

Answer 39

c. Eyepiece

Question 39

Pathway of electron of SEM

Answer 39

Reflected by a metal

Question 40

enlarges only the image obtained by the objective; does not improve resolution

Answer 40

-eyepiece

Question 40

Magnification of stereo/dissecting microscope

Answer 40

10x-125x

Question 41

-maximal resolving power:

Answer 41

~0.2 micrometer

Question 41

Numerical aperture of scanning

Answer 41

0.10

Question 42

-objects smaller than 0.2 micrometer -------

Answer 42

cannot be distinguished

Question 42

Numerical aperture of LPO

Answer 42

0.25

Question 43

-2 structures will be seen as __________ if they are separated by less than 0.2 micrometer

Answer 43

only one object

Question 43

Numerical aperture of HPO

Answer 43

0.65

Question 44

principle – when certain cellular substances are irradiated by light of a proper wavelength, they emit light with a longer wavelength

Answer 44

*Fluorescence

Question 44

Numerical aperture of OIO

Answer 44

1.25

Question 45

Acridine Orange, DAPI, Hoechst stain

Answer 45

*Fluorescent compounds:

Question 46

type of light microscope Produces an image only of material having repetitive, periodic macromolecular structure; features without such structures are not seen

Answer 46

polarizing

Question 47

-feature of crystalline substances or those with highly oriented molecules (cellulose, collagen, microtubules, actin filaments)

Answer 47

birefringence

Question 48

-areas through which electron passed readily: appear _____

Answer 48

brighter or electron lucent

Question 49

-areas where electrons were absorbed or deflected: appear _______

Answer 49

darker or more electron dense

Question 50

- added to the fixative or dehydrating solutions | - used to improve contrast and resolution in TEM

Answer 50

*Compounds with heavy metal ions

Question 51

-osmium tetroxide, lead citrate, uranyl compounds

Answer 51

*Compounds with heavy metal ions

Question 52

techniques that allow TEM study of cells without fixation or embedding

Answer 52

Cryofracture and freeze etching –

Question 53

– useful in the study of membrane structure - very small tissue specimens are rapidly frozen in liquid nitrogen and either fractured or cut with a knife - replica is produced

Answer 53

Cryofracture

Question 54

Type of EM surface of the specimen is first dried and spray coated with very thin layer of heavy metal (often gold) through which electrons do not pass readily

Answer 54

SEM

Question 55

Type of EM | images are usually easy to interpret because they present a 3D view that appears to be illuminated from above

Answer 55

SEM

Question 56

method of localizing newly synthesized macromolecules (DNA, RNA, protein, glycoproteins, polysaccharides)

Answer 56

AUTORADIOGRAPHY –

Question 57

This will help protect the objective lenses if they touch the slide.

Answer 57

Coverslip or cover glass

Question 58

When you move the slide to the right, the image goes to the

Answer 58

left!

Question 59

number of times the image was enlarged

Answer 59

magnification

Question 60

the higher the magnification the ________- working distance

Answer 60

LOWER

Question 61

Side of mirror when using natural light

Answer 61

plane

Question 62

side of mirror when using artificial light

Answer 62

concave