Chapter 1: week 1

Question 1

3 Concepts Of Microscopy

Answer 1

1. Magnification
2. Contrast
3. Resolving Power/ Resolution

Question 2

3 Concepts of Microscopy: Magnification

Answer 2

the amount that the image of an object is enlarged

the number of times the image is enlarged

Question 3

3 Concepts of Microscopy: Contrast

Answer 3

the degree to which image details stand out against its background
(striking difference between similar objects)
-we use stains to increase contrast

Question 4

3 Concepts of Microscopy: Resolving power/ Resolution

Answer 4

the ability of a lens to separate between small objects that are close together
(quality of lens)

Question 5

Field of View

Answer 5

when looking into the oculars, the portion of the slide that can be observed

Question 6

Parfocal

Answer 6

when you change from one objective to another, the specimen will remain very nearly in focus

Question 7

Parcentral

Answer 7

when changing objectives the specimen will stay in the center of the field of view
(when focused properly)

Question 8

Use of Light in Microscopy

Answer 8

to be able to see objects (specimen) through a microscope, light must be either reflected from the object or transmitted through the object

Question 9

Properties of Light

Answer 9

1. Reflection
2. Transmission
3. Absorption
4. Refraction

Question 10

Properties of Light: Reflection

Answer 10

Light may be reflected back from the object
(bounce off as it hits object)
-the particular wavelengths reflected back to the eye determine the perceived color

Question 11

Properties of Light: Transmission

Answer 11

refers to the passage of light through an object

Question 12

Properties of Light: Absorption

Answer 12

if light rays neither pass through nor bounce off, but are taken up by the object
-the absorbed light rays are reemitted as longer wavelengths, a phenomenon known as fluorescence

Question 13

Properties of Light: Refraction

Answer 13

the bending of light as it passes from one medium to another of a different density

Question 14

Types of Microscopes

Answer 14

1. Light Microscope

2. Electron Microscope

Question 15

Types of Microscopes: Light Microscope

Answer 15

-maximum magnification = 2000x
-living or non-living specimens
-color image
(use visible light)

Question 16

Types of Microscopes: Electron Microscope

Answer 16

• Maximum Magnification = 1,000,000x or more
• non-living specimens only
• black and white image

Question 17

Types of Light Microscopes

Answer 17

1. Stereo-dissecting Light

2. Compound Light

Question 18

Types of Light Microscopes: Stereo-dissecting Light

Answer 18

• 3D view of specimen = used to view large specimens
  ex: frogs, worms, insects
• illuminated from above and below
• Magnification up to 45x

Question 19

Types of Light Microscope: Compound Light

Answer 19

-2D views of the specimen = used to view thin sections of specimens

Question 20

Types of Electron Microscopes

Answer 20

1. Scanning (SEM)

2. Transmission (TEM)

Question 21

Types of Electron Microscopes: Scanning (SEM)

Answer 21

-3D views of specimens = used to view external surfaces of specimens
(think about scanning the outside (external))

Question 22

Types of Electron Microscopes: Transmission (TEM)

Answer 22

-2D views of specimens = used to view internal structures of species
(think about transmission= through so you see internally (inside))

Question 23

Microscope Parts

Answer 23

• Oculars/Eyepieces
• Body/Body Tube
• Arm
• Nosepiece
• Objectives
• Stage/ Mechanical Stage
• Stage adjustment knobs
• Rheostat
• Substage Condenser
• Diaphragm control dial
• Light source/ illuminator
• Base
• Fine adjustment knob
• Coarse adjustment knob

Question 24

Microscope Parts: Oculars/ Eyepieces

Answer 24

magnify the image 10 fold.
(re-magnifies the image formed by the objective lenses)
-oculars move to accommodate your interpupillary distance- distance between the pupils of your eyes

Question 25

Microscope Parts: Body/ Body Tube

Answer 25

contains mirrors that bend the light into the ocular | transmits the image from the objective lens to the ocular lens

Question 26

Microscope Parts: Nosepiece/ Revolving nosepiece

Answer 26

the objectives are attached | -grab black ring of nosepiece to rotate the objectives

Question 27

Microscope Parts: Objectives

Answer 27

contain lenses that magnify the image | -it has 4x(scanning), 10x(low power), 40x(high dry power), and 100x(oil immersion)

Question 28

Microscope Parts: Arm

Answer 28

supports the nosepiece, holds the on/ off toggle and focus adjustment knobs

Question 29

Microscope Parts: Stage/ Mechanical stage

Answer 29

black, flat platform on which your slide rests

Question 30

Microscope Parts: Stage adjustment knob

Answer 30

moves the mechanical stage | -left, right, toward or away from you

Question 31

Microscope Parts: Rheostat

Answer 31

increases or decreases light output from the light source

Question 32

Microscope Parts: Substage Condenser

Answer 32

made of atleast 2 lenses that focus the light passing through the specimen and improve image sharpness

Question 33

Microscope Parts: Diaphragm control dial

Answer 33

controls the amount of light entering the substage condenser from the light source (adjusts the light) (has each objectives magnificaton as light power ex. 4x, 10x, 40x and 100x)

Question 34

Microscope Parts: Light source/ Illuminator

Answer 34

illuminator is a halogen bulb that produces light | light source

Question 35

Microscope Parts: Base

Answer 35

holds the light source and supports rest of microscope

Question 36

Microscope Parts: Fine adjustment knob

Answer 36

possible to bring the image into sharp focus when rotating the knob. - Raises + Lowers the stage in small increments - use with high dry 40x and oil immersion 100x

Question 37

Microscope Parts: Coarse adjustment knob

Answer 37

moves the stage up and down by larger increments and allows you to bring the image into focus -use with scanning 4x and low power 10x only

Question 38

Total Magnification

Answer 38

the magnification, or power of a lens is indicated by a whole number followed by an "X" -the total magnification of a microscope is obtained by multiplying the power of the ocular times the power of the objective

Question 39

Formula for Total Magnification

Answer 39

TM = Ocular Power X Objective Power

Question 40

Total Magnification for each objective

Answer 40

Name Ocular Mag. Objective Mag. Total Mag. Scanning 10x x 4x = 40x low 10x x 10x = 100x High 10x x 40x = 400x Oil 10x x 100x = 1000x

Question 41

Working Distance

Answer 41

approximate distance from the objective to the specimen (slide) -working distance decreases as you increase magnification by changing objectives

Question 42

Depth of Field

Answer 42

refers to the thickness of the plane of focus - with a large depth of field, all the threads can be in focused at the same time - with a smaller or narrower depth of field, only one thread or part of one thread can be focused, everything else will be out of focus