Microscopy

Question 1

Light Microscopy

Answer 1

any type of microscope using visible light

Question 2

Compound light microscopy

Answer 2

uses light and two or more lenses to obtain higher magnification

Question 3

Total magnification

Answer 3

objective lens x ocular lens

Question 4

Ocular lens

Answer 4

look through it

Question 5

Stage

Answer 5

holds glass slide

Question 6

Objective lens

Answer 6

magnification power of 4x, 10x, 40x, 100x

Question 7

Condenser

Answer 7

lens, focuses light into a fine point

Question 8

Diaphragm

Answer 8

controls amount of light entering the condenser

Question 9

Light Source

Answer 9

underneath the stage and lens

Question 10

Course/Fine Focus Knob

Answer 10

course first focuses, then fine focus for optimal clarity

Question 11

Resolving power

Answer 11

(at least 0.4 nm) can distinguish between two points
-Shorter wavelengths of light provide greater resolution
-Infrared (red), pixelated resolution

Question 12

Refractive Index

Answer 12

Measure of the light bending ability of a medium, refracts after passing through a specimen

Question 13

Immersion oil

Answer 13

used to keep light from refracting

Question 14

Brightfield Illumination

Answer 14

-White background
-Most commonly used
-Dark objects are visible against a bright background

Question 15

Darkfield

Answer 15

-Black background
-Light objects are visible against a dark background
-opaque disk placed in condenser
-Only light reflected off of the specimen enters the objective lens

Question 16

Phase Contrast

Answer 16

-Internal structures/texture
-inside topography of the specimen can be seen

Question 17

Fluorescence

Answer 17

-Uses UV light (short wavelength)
-Absorb UV light and emit a longer wavelength (visible light)
-Cells may be stained with fluorescent dyes

Question 18

Confocal

Answer 18

-Cells are stained with fluorochrome dyes
-Blue light (short wavelength) excites a single plane of a specimen
-Sliced into sliver, better solution
-illuminated, 3D image is constructed

Question 19

Transmission Electron Microscopy (TEM)

Answer 19

-Beams of electrons passes through ultra thin sections of a specimen, passing through an electromagnetic and projector lens
-May be stained with heavy metal salts for contrast
-Magnifies 10,000 to 10,000,000x; resolution of 10pm

Question 20

Scanning Electron Microscopy (SEM)

Answer 20

-An electron gun produces a beam of electrons that scans the surface of an entire specimen
-Secondary electrons emitted from the specimen produce a 3D image
-Magnifies objects 1,000 to 500,000x; resolution of 10 nm

Question 21

Simple Stain

Answer 21

use of a single basic dye

Question 22

Gram-positive

Answer 22

thick peptidoglycan layer
-purple (picks up lots of dye)

Question 23

Gram-negative

Answer 23

thin peptidoglycan layer
-red (less dye)

Question 24

Acid-Fast Stain

Answer 24

Binds only to bacteria that have a waxy material in their cell walls

Question 25

Special Stains

Answer 25

Capsule Stain Endospore Stain Flagella Stain