Test 2

Question 1

Size of lens aperture

Answer 1

As the magnification increases, the aperture size of the lenses decreases. Resolution is higher, more details will be revealed.

Question 2

Working Distance

Answer 2

The space between the objective lens and the slide/specimen/stage.

Question 3

Length of the body tube

Answer 3

160mm (16cm)

Question 4

Body Tube Length

Answer 4

Body tubes transmits image from objective to ocular. Longer the tube, increase in magnification.

Question 5

Refraction

Answer 5

The ability of transparent media to bend light and in the process alter the appearance of the image formed by light.

Question 6

Refractive Index

Answer 6

Different materials have different degrees of refraction. Compares how much each material alters the appearance of light.

Question 7

Relationship in refractive index

Answer 7

The higher the refractive index, the stronger the refraction.

Question 8

What is the effect/benefit of Immersion oil on refraction?

Answer 8

• Removes air from the working distance
• Makes refractive indexes appear more even
• Enables the lens to trap previously refracted light
• Allows the image to fit within the aperture of the lens
• Focusses the final image better
• Achieves a higher image resolution

Question 9

Bright Filed Microscope: Design and Image

Answer 9

It is typically binocular with a condenser, Objective, and Ocular Lenses. It shows an image of a specimen by contrasting it against a brightly-lit background, which can be fine-tuned with an Iris-Diaphragm.

Question 10

Darkfield Microscope : Design and Image

Answer 10

Compound Light Microscope that uses an opaque disc to limit transmission of light through the condenser. The resulting dark background creates adequate contrast; transmitted light is reflected off the surface of unstained, transparent, live specimens that appear to glow in the dark.

Question 11

PHASE CONTRAST MICROSCOPY

a. Explain how it works
b. Determine how it is designed differently from other Microscopes
c. Describe appearance of the image formed

Answer 11

a. Has an Annular Diaphragm that breaks a single beam of light into multiple rays of light shades to highlight details of structure.
b. The Objective Lens has a Phase Ring (or Diffraction Plate) that creates several phases and shades from a single light beam.
c. This produces high final image definition and contrast without staining.

Question 12

DIFFERENTIAL INTERFERENCE CONTRAST MICROSCOPY

a. Explain how it works
b. Determine how it is designed differently from other Microscopes
c. Describe appearance of the image formed

Answer 12

a. The two light beams pass through a special condenser. No staining is required; however, a special condenser splits the beam of light with a prism and the individual light rays travel at different speeds that is transmitted as different colors. This ‘rainbow effect’ floods the specimen with colored-light that produces a brightly-colored image. Another prism in the objective lens maintains the color of the image.
b. It uses two light beams to form the final image.
c. The two light beams create a 3-D image, the prisms add color, and the lenses produce depth and high resolution.

Question 13

FLUORESCENCE MICROSCOPY

a. Explain how it works and describe its final image

Answer 13

a. uses the short wavelength of (UV) light to form an image. Images formed are not visible without a special dye called Fluorochrome that makes them glow in UV-light. It is especially valuable for observing positive reactions between antibodies and antigens: the fluorescent dye binds to antibodies and makes a positive reaction visible by attracting billions of glowing antibodies to surface antigens. In a negative result, antibodies, which are only about 15 nm, will not be visible or glow.

Question 14

How wavelength and Resolution are related

Answer 14

The speed is expressed as wavelength, which is measured in (nm). In general, resolution is higher at shorter wavelengths. Although better image quality is produced if light is manipulated properly, the highest useful magnification of a light microscope is about 2,000X. At this magnification, resolution is limited to 200 nanometers (nm) and viruses are not visible.

Question 15

Determine how fluorescent microscopy is designed differently from other Microscopes

Answer 15

Images formed are not visible without a special dye called Fluorochrome that makes them glow in UV-light.

Question 16

Differentiate Fluorochrome and Chromophore

Answer 16

chromophore is chemistry thats part of the molecule of a dye responsible for its color, while fluorophore is biochemistry molecule or functional group which is capable of fluorescence.

Question 17

. ELECTRON MICROSCOPY

a. Explain how it works

Answer 17

Electron Microscope uses electrons for illumination because they have shorter wavelength and yield higher resolution than light. The better resolution permits higher useful magnification that reveals more details. However, electrons are 100,000 times beyond the range of visible light. Therefore, the final electro-micrograph image is not brightly-colored; instead, it shows shades between black and white, like an x-ray image. These shades of grey are assigned different colors artificially to highlight their diversity.

Question 18

. ELECTRON MICROSCOPY

b. Identify parts and functions

Answer 18

The Electron Microscope transmits the Electro-Micrograph through the tube and spreads the electron image using an Electromagnetic Objective Lens, resulting in magnification. The Electro-Magnetic Projector Lens re-magnifies the image, just like the Ocular Lens, projecting it to an Electron-sensitive screen. The electrons imprint a magnified image of the specimen on a Fluorescent screen, viewable with an Eyepiece. Since two sets of lenses magnify the final image, an Electron Microscope meets the criteria for a Compound Microscope.

Question 19

. ELECTRON MICROSCOPY

c. Describe image formation and view

Answer 19

The illuminator of the Electron Microscope is located at the top unlike the Light Microscope, where it is below. Electrons are accelerated down the air-tight tube from the electron source and focused on the specimen by an Electro-Magnetic Condenser. When the electrons interact with the specimen, and Electron image or Electro-Micrograph is formed.

Question 20

. ELECTRON MICROSCOPY

d. Determine how magnification and illumination occur

Answer 20

Uses Electro-Magnetic Fields. Glass lenses cannot be used in an Electron Microscope because electrons do not penetrate them very well. Therefore, Electron Microscopes operate under vacuum and samples must literally be “thinner than air” for proper processing.

The illuminator of the Electron Microscope is located at the top. Electrons are accelerated down the air-tight tube from the electron source and focused on the specimen by an Electro-Magnetic Condenser. When the electrons interact with the specimen, and Electron image or Electro-Micrograph is formed.

Question 21

. ELECTRON MICROSCOPY

e. Compare and contrast the two types

Answer 21

1. The Electron Microscope transmits the Electro-Micrograph through the tube and spreads the electron image using an 2.Electromagnetic Objective Lens, resulting in magnification.
2. The Electro-Magnetic Projector Lens re-magnifies the image, just like the Ocular Lens, projecting it to an Electron-sensitive screen.
3. The electrons imprint a magnified image of the specimen on a Fluorescent screen, view able with an Eyepiece.
4. Since two sets of lenses magnify the final image, an Electron Microscope meets the criteria for a Compound Microscope.

Question 22

RESOLUTION: Compare limits of Resolution for:

a. Human Eye (Normal vision)
b. Light Microscope (LM)
c. Scanning Electron Microscope (SEM)
d. Transmission Electron Microscope (TEM)

Answer 22

a. Human Eye (Normal vision)- (200 um) Micrometers
b. Light Microscope (LM)- (200 nm)
c. Scanning Electron Microscope (SEM)- (10 nm)
d. Transmission Electron Microscope (TEM)- ( 10 pm)

Question 23

DYES, STAINS, & MICROSCOPY

a. Recall what a dye is, how it is formed, and origin of its color

Answer 23

Dyes are permanently-colored organic salts that imprint their colors on biological materials like cells or microbes. Like every salt, including table salt, a dye is formed when an acid reacts with a base; therefore, the two ions of a salt come from an acid and a base. The Positively-charged Cation (+) and Negatively-charged Anion (–) have opposite charges that attract and react with each other to form new compounds.

Question 24

DYES, STAINS, & MICROSCOPY

b. Describe the reaction that forms a salt or dye

Answer 24

The Anion from the Acid and the Cation from the Base form a SALT. Left-over ions that did not form a salt, become Water. A SALT can only be a dye if any of its ions has color-“Chromophore”. A dye may acquire color from a colored Cation (+), colored Anion (-), or both ions.

Question 25

DYES, STAINS, & MICROSCOPY c. Determine the fate of all ions in Acid-Base reactions

Answer 25

The Anion from the Acid and the Cation from the Base form a SALT. Left-over ions that did not form a salt, become Water. These are always the two products of Acid-Base reactions. A SALT can only be a dye if any of its ions has color. The colored ion of a dye is a Chromophore. A dye may acquire color from a colored Cation (+), colored Anion (-), or both ions

Question 26

. DYES, STAINS, & MICROSCOPY d. Compare Negative and Direct/Positive Staining

Answer 26

The cells of microbes tend to have a net negative charge, as is the case with human, animal, or plant cells. This draws the opposite charges of the Cations from the Dye into the negatively-charged cell. If the Cation has color, the cell becomes stained. Rinsing removes the stain from the slide and background but the smear retains color, resulting in Direct or Positive Staining. Basic dyes are used for direct staining of the bacterial smears, leaving the background clear. Microbiology uses Basic dyes for 90% of staining procedures. Some bacterial structures are, however, best seen if they remain clear. In this case, the cation, which is attracted to the cell, should not have color but the anion should, so that its chromophore can stain the background; this is Negative staining.

Question 27

8. DYES, STAINS, & MICROSCOPY | e. Explain interaction between dyes and cells

Answer 27

Staining simply adds color to a cell so that it contrasts with its background. Dyes are permanently-colored organic salts that imprint their colors on biological materials like cells or microbes.

Question 28

CHEMICAL GROUPS OF DYES | a. Name some dyes and their Chemical Groups

Answer 28

* Methylene Blue * Safranin * Crystal Violet * Malachite Green * Carbol Fuchsin BASIC dyes are used a lot, ACIDIC dyes are used less, and NEUTRAL dyes are rarely ever used.

Question 29

CHEMICAL GROUPS OF DYES b. Determine how each group is used

Answer 29

BASIC dyes are used a lot ACIDIC dyes are used less NEUTRAL dyes are rarely ever used.

Question 30

CHEMICAL GROUPS OF DYES c. Define Simple Staining, the steps, and results

Answer 30

SIMPLE STAINING Like a simple microscope, Simple Staining uses just one dye: by default, a basic dye is used, because it highlights the specimen with color in contrast to a clear background. PROCEDURE Make a smear of the specimen on a glass slide. Air-dry the smear on the slide Heat-Fix Stain heat-fixed smear with a Single dye, like Methylene Blue or Safranin (1 min) Rinse-off excess dye in the background with water. Dry Slide and viewed with oil-immersion lens. Simple staining shows the colored specimen against a clear background. Regardless of how many types of bacteria are present, Simple Staining colors them alike with a single dye. Therefore, Simple staining is not a decision-making technique. Rather, the procedure is useful for comparing cells by physical characteristics like shape, size, arrangement, and texture.

Question 31

CHEMICAL GROUPS OF DYES d. Describe how samples are prepared for staining

Answer 31

Therefore, it is spread thin on a transparent glass slide as a Smear. Since stains are liquids, there is always a risk that they could wash away the specimen. Therefore, the smear is air-dried before staining. Just before staining, the dried smear is fixed using a physical fixing agent, like heat, by rapidly passing it over open flame. Fixing secures the smear to the slide, prevents loss of specimen, and preserves its structure.

Question 32

CELLS AND KINGDOMS | a. Review history and Scientists linked to Cells, Microscopy, and Stains

Answer 32

*van Leuwenhoek- 1673 "First one to ever see a cell, because they were moving, called them animalcules. Discovered microorganism "Father of Microorganisms" Invented first microscope." *Robert Hook- 1665 "Built the first compound microscope. Saw back of a tree specimen and was able to identify a cell wall. Bunged together. " *Matthias Schleiden-1838 "First one to conclude that all plants are made of cells." *Theodor Schwann- 1839 "Sliced the tissue/animal ect. and every slide of tissue was made of cells. Development of the cell theory." *Hans Christian Joachim Gram- 1884 "The Gram stain is the most important staining procedure in Microbiology. "

Question 33

Cell theory

Answer 33

All living things are made of cells. Theodor Schwann 1839

Question 34

CELLS AND KINGDOMS b. Name major Cell types, Platforms, and compare their sizes

Answer 34

Cell type: Platforms: Sizes: Prokaryotes 1 0.2-2.0 um Eukaryotes: 10-100um Human/animal 2 Plant/ Algea 3

Question 35

CELLS AND KINGDOMS c. Compare characteristics of Cells Contrast

Answer 35

``` Common to all 3: Cytoplasm Plasma Membrane Robosomes Nucleic Acid: DNA,RNA ``` Contrast: Plant: Animal Cell: 1. Cell Wall 1. No Cell Wall 2. Vacuole 2. Lysosomes 3.Chloroplast 3.Centrioles 4.Basal Body/Flagella/ Cilia

Question 36

CELLS AND KINGDOMS d. List the Kingdoms and identify the Cell Platform for each.

Answer 36

Kingdoms: Prokaryotic: Euka-Animal: Euka-Plant: Archaea √ X X Eubacteria √ X X Protista X √ √ Fungi X X √ Plantae X X √ Animalia X √ X

Question 37

CELLS AND KINGDOMS e. How are cells in one Kingdom unique or different from others?

Answer 37

Protista is the only kingdom that is both animal and plant !

Question 38

CELLS AND KINGDOMS f. How many Kingdoms are Prokaryotic, Eukaryotic, Unicellular, or Multi-cellular?

Answer 38

Kingdom Structure Prokaryotes:- Bacteria Unicellular Archaea Unicellular ``` Eukaryotes:- Protista Unicellular Fungi Unicellular or Multicellular Animalia Multicellular Plantae Multicellular ```

Question 39

Transmission Electron Microscopy vs. Scanning Electron Microscopy

Answer 39

Transmission Electron Microscopy, the specimen for electron microscopy is almost as thin as air, allowing the electrons to transmit the image as a 2- dimensional, high resolution, electro-micrograph. Scanning Electron Microscopy also requires a very thin specimen but the electromagnetic lenses are not diffentiated but help to accelerate primary electrons through the tube to interact with the specimen and produce a scan of the sample by emitting secondary electrons from the surface of the specimen, which are analyzed in an Electron Collector that projects the image on a video screen. This final Scannning electro-micrograph (SEM) looks 3-dimensional

Question 40

Microscope parts and function:

Answer 40

Eyepiece: The lens the viewer looks through to see the specimen. The eyepiece usually contains a 10X or 15X power lens. Body tube (Head): The body tube connects the eyepiece to the objective lenses. Arm: The arm connects the body tube to the base of the microscope. Coarse adjustment: Brings the specimen into general focus. Fine adjustment: Fine tunes the focus and increases the detail of the specimen. Nosepiece: A rotating turret that houses the objective lenses. The viewer spins the nosepiece to select different objective lenses. Objective lenses: One of the most important parts of a compound microscope, as they are the lenses closest to the specimen.A standard microscope has three, four, or five objective lenses that range in power from 4X to 100X. When focusing the microscope, be careful that the objective lens doesn’t touch the slide, as it could break the slide and destroy the specimen. Stage: The flat platform where the slide is placed. Stage Control: These knobs move the stage left and right or up and down. Aperture: The hole in the middle of the stage that allows light from the illuminator to reach the specimen. Iris diaphragm: Adjusts the amount of light that reaches the specimen. Condenser: Gathers and focuses light from the illuminator onto the specimen being viewed.

Question 41

Prokaryotes

Answer 41

lack a cell nucleus: two domains, bacteria and archaea. Bacteria:They lack a nucleus and other membrane-bound organelles, and can function and reproduce as individual cells, but often aggregate in multicellular colonies Archaea: are also single-celled organisms that lack nuclei.

Question 42

Eukaryotes

Answer 42

:contain organelles such as the cell nucleus, the Golgi apparatus and mitochondria in their cells Protists: multicellular, and slime molds have unique life cycles that involve switching between unicellular, colonial, and multicellular forms. Animals: multicellular but at least one animal group, include: dust mites, spider mites. ect Fungi:(mushroom, large growth of fungis nasty looking) unicellular species, such as baker's yeast, candida albicans. Plants: (green chained, round fuzzy green splots) green algae are a large group of photosynthetic eukaryotes that include many microscopic organisms.