Exam 2 Quiz 1

Question 1

Two main functions of a microscope

Answer 1

1. magnification
2. resolution

Question 2

parfocal

Answer 2

should not have to be adjusted between objective changes

Question 3

Total magnification =

Answer 3

objective x ocular

Question 4

resolution

Answer 4

-ability to define two adjacent objects as distinct and separate
-described mathematically by ernst abe in 1870

Question 5

resolution depends on

Answer 5

1. physical properties of light: wavelength
2. numerical aperture (Na): light gathering capability of a lens

Question 6

equation for resolution

Answer 6

R=0.61(wavelength) / NA

Question 7

how to enhance resolution

Answer 7

-decrease the wavelength of light used
-increase numerical aperture

Question 8

NA =

Answer 8

nSin theta

Question 9

n=

Answer 9

refractive index

Question 10

refractive index of air

Answer 10

1

Question 11

refractive index of oil

Answer 11

1.5

Question 12

cone in a 4x

Answer 12

-further from slide, skinnier cone

Question 13

Dark field microscopy

Answer 13

-opaque light disk tha blocks light so it hits at an angle
-image forms from refractive light only
-used on organisms that are hard to stain (thin, ex. spirochetes)

Question 14

Phase contrast microscopy

Answer 14

-phase plate where light source has refracted and unrefracted parts
-allows to see unstained organisms
-good for seeing motility, reproduction, and inclusion bodies, sample looks dark and grey

Question 15

refracted light goes throuh

Answer 15

phase platen

Question 16

non refracted light goes through

Answer 16

phase ring

Question 17

Immunofluorescence

Answer 17

-fluorophore attached to sample via antibiotic, can also use GFP tag
-only visibly excited at certain wavelengths and capture emission through the wavelengths
-mercury vapor arc lamp

Question 18

Confocal microscopy

Answer 18

-concentrate excitation within specific focal point
-add confocal pinhole on microscope
-scans and reads across
-makes a stacked image or Z series to allow for a 3D cell image

Question 19

Electron scope

Answer 19

-use electrons
-smaller wavelength, higher resolution
-electromagnetic lenses
-vacuum
-dead/dry
-black and white image

Question 20

Transmission electron scope

Answer 20

-electron source
-condenser lens
-20-100 nm specimen cross section
- 2D image

Question 21

Scanning electron microscope

Answer 21

-electron hitting the sample and passing through
-collect backscattered and secondary electrons
-3D image but only of surface
-x-ray diffraction for elemental analysis

Question 22

backscattered electrons

Answer 22

originate on the electron beam

Question 23

secondary electrons

Answer 23

electrons from atoms within the sample that got kicked out via metal

Question 24

hanging drop method

Answer 24

-unstained microorganisms
-try to preserve a more natural environment for motility

Question 25

steps for hanging drop method

Answer 25

-bring the stage all the way up
-4x objective first
-move to 10x objective and focus on the edge of drop
-move to 40x objective

Question 26

5 things needed to do when storing the microscope

Answer 26

-stage all the way down
-4x objective in play
-cord wrapped around and neck secured
-cover it
-stage in first, arm out

Question 27

4x objective

Answer 27

widest field, lowest resolution

Question 28

40x objective

Answer 28

lowest field, highest resolution