Lecture 4

Question 1

Magnification

Answer 1

Enlarging an object visually, not physically

Question 2

Resolution

Answer 2

How much detail can be seen, how close two objects can be and still be separated clearly in the image

Question 3

Contrast

Answer 3

How distinct the specimen is from the background, can be enhanced by staining or optical tricks

Question 4

Immersion Oil

Answer 4

The image isn’t distorted in oil. It is improved. It increases the resolution

Question 5

Bright Field Microscope

Answer 5

Has 3 lens. Focuses the light to a point on an object.

Question 6

Dark Field Microscope

Answer 6

Uses a special condenser; metal plate goes over the light source to scatter the light beam; the back group is dark and the objects in view light up

Question 7

Dark Field Condenser

Answer 7

Shines the light in a circle on the outer rim. Not directly on the object

Question 8

Phase Contrast Microscope

Answer 8

Uses phase-shifting of refracted light caused by photon drag to enhance contrast

Question 9

Phase Plate

Answer 9

Phase shifting element on the phase contrast microscope

Question 10

Differential Interference Contrast Microscope

Answer 10

Also called Interference Microscope. It uses 2 beams of 90degree polarized light to detect 3D details in the sample

Question 11

Wollaston Prism

Answer 11

It separates polarized light and redirects it

Question 12

90degree Polarized Light

Answer 12

The Differential Interference Contrast Microscope uses 2 beams of this light to detect 3D details

Question 13

Fluorescence Microscope

Answer 13

Uses the dye flurophore. Uses excitation wavelength as illuminating light. The partials glow fluorescently.

Question 14

Confocal Scanning Laser Microscope

Answer 14

Uses an aperture to shut out light from all but one focal plane of the object. You look at a 3D colorful multi layer image of the object

Question 15

Confocal Pinhole

Answer 15

A smaller pinhole allows a small amount of light is better for viewing the image

Question 16

Transmission Electron Microscope

Answer 16

TEM. Electron beam passes through the specimen just like a beam of light. The beam is an x-ray. And instead of lenses it uses magnets

Question 17

Scanning Electron Microscope

Answer 17

SEM. Detects electrons and x-rays scattered from a surface. Dramatic 3D views at variable magnification. It is a weaker beam and needs a much more sensitive detector.

Question 18

Electron Cryotomography

Answer 18

At cold temperatures and views multiple angles at the same time. Its a CAT scan for microbes. Its views parts inside of a specimen. Needs a really weak beam

Question 19

Atomic Force Microscope

Answer 19

4D microscopy. Electron field is monitored at the tip of a nanotube probe. Field varies as probe is pushed over a surface. Can see atoms

Question 20

Simple Stain

Answer 20

Basic (+) dye attaches to (-) phospholipid head groups

Question 21

Differential Stain

Answer 21

More than one stain is used. pink=thin(Gram -)

Purple=thick(Gram +)

Question 22

Acid-Fast Stain

Answer 22

Differentiates based on waxy coating impervious to acidified alcohol. Red= acid-fast, blue=not

Question 23

Negative Stain

Answer 23

Stains the background not the cell. To show the uncharged electrons. Uses partials to stain the background instead of dyes