Micro-Lab Test 1

Front 1

When carrying a microscpe...
One hand should be under the base of the microscope to support its weight and one hand should be on the arm for balance.

Back 1

The limit of resolution of the unaided human eye is 0.2 mm. For the typical light microscope, the limit is 0.2 µm.

Front 2

a. The condenser height and diaphragm can be adjusted.
b. Illumination of the specimen is increased when condenser is raised and diaphragm is opened

Back 2

Unlike the voltage control, condenser adjustments will increase illumination without affecting the bulb life.

Front 3

The maximum resolution of oil immersion lens is achieved by: 1.using a layer of oil
2 using a blue filter over the light source
3.raising condenser to its highest point
4.opening the condenser diaphragm.

Back 3

The oil immersion lens has the smallest working distance and one runs the risk of striking the slide with the lens when trying to achieve focus. Starting with the low power lens, which has a larger working distance, and progressing up to the oil immersion lens is advised.

Front 4

Oil is used with the oil immersion lens because the small working distance does not allow enough light to enter the lens. The oil, which has the same refractive index as glass, directs more light into the lens.

Back 4

As the power of the objective lens increases, the working distance decreases.

Front 5

Condenser Lens
** collects and focuses light from lamp onto specimen on slide
** A diaphragm is used to regulate light passing thru..

Back 5

Low power Objective Lens
** provides lowest magnification
** course focus knob should be adjusted only when using this...

Front 6

High-dry Objective Lens

** provides second highest magnification.

Back 6

Oil immersion Objective Lens
** provides highest magnification
** has shortest working distance.

Front 7

Ocular Lens

**aka-eyepiece,often come in parts
**diopter adjustments can be made

Back 7

Acetone is NOT the safest solvent for cleaning an objective lens.

Front 8

only lint-free optically safe tissue used to wipe off microscope lenses.

Back 8

once focus is achieved at one magnification, a higher power objective can be rotated without fear of striking the slide.

Front 9

The resolving power of a microscope is a function of
-the numerical aperture of the lens
-the wavelength of light

Back 9

The course and fine focus knobs adjust the distance between
-the stage and objective lens

Front 10

A microscope that maintains focus when the objective magnification is increased is called
-parfocal

Back 10

The total magnification achieved when using a 100X oil immersion lens with 10X binocular eyepieces
- 1000X

Front 11

The most useful adjustment for increasing image contrast in low power magnification is
-closing down the diaphragm

Back 11

Before the oil immersion lens is rotated into place, you should
*center the object of interest in the preceding lens
*place a drop of oil on the slide

Front 12

Darkfield microscopy is preferred for live unstained specimens or thin cells like spirochetes that are difficult to resolve by staining and brightfield microscopy.

Back 12

Dark field condenser causes all light rays to by pass objective, light in a dark field comes from:

Reflection of oblique rays off of objects passes through the lens system.

Front 13

Advantage of cardioid over star diaphragm:
A cardioid condenser allows more light to pass through the lens system and allows use of more powerful objectives.

Back 13

A simple star diaphragm can be made cutting various sizes of round disks of opaque paper and cementing them to transparent celluloid disks that fit in the slot.

Front 14

Phase-contrast over Staining:

Staining kills live cells and does not allow observation of movement.

Back 14

Direct rays are produced when light passes straight through a transparent medium without changing amplitude or phase. Diffracted rays are produced when light is bent during retardation by the medium due to density differences and are phase-shifted ¼ wavelength.

Front 15

Coincidence results when direct and diffracted waves are brought into phase with one another, where the amplitude is the sum of the two waves, and creates a brighter image. Interference occurs when two waves of equal amplitude are in reverse phase and cancel each other to produce a dark image. Coincidence and interference created greater contrast in specimen being viewed.

Back 15

Bright-phase microscopy produces a brighter image (amplitude summation) with a dark background while dark-phase microscopy produces a dark image (amplitude interference) and a lighter background.

Front 16

Two items can be used to check alignment of annulus & phase-ring:

Centering telescope
Optovar

Back 16

A phase-contrast microscope differs from a brightfield by having
*diaphragm with an annular stop
*phase plate in the objective lens

Front 17

If direct rays passing through an object are advanced 1/4 wavelength by the phase ring, the diffracted rays are:
in reverse phase with the
direct rays

Back 17

Amplitude summation occurs in phase-contrast optics when both direct and diffracted rays are:
in phase

Front 18

The phase-contrast microscope is best suited for observing:

living organisms on a slide
with a cover glass

Back 18

Algae and protozoa are classified in the domain Eukarya. Cyanobateria are classified in the domain Prokarya.

Front 19

a. Algae and plants are both photosynthetic and have cell walls composed of cellulose.
b. Algae, however, can be single-celled and motile.

Back 19

Protozoa utilize flagella, cilia, or pseudopodia (amoeboid movement) for motility. Flagella and cilia are fibrous, extracellular, protein appendages that wave. Flagella are longer and singular whereas cilia are shorter and more numerous. Pseudopodia are cytoplasmic projections that enable a “crawling” motion.

Front 20

a. Cyanobacteria are aka "blue-green algae"

b. Cyanobacteria are prokaryotic cells that, unlike eukaryotic algae, lack a nucleus and chloroplasts, although they do contain chlorophyll.

Back 20

Overgrowths or blooms of microscopic algae cause “Red Tides” and the cellular pigments are responsible for the oceans taking on a red color

Front 21

Malaria is caused by the genus Plasmodium, a Protista found in the group Apicomplexa.

Back 21

Protozoa has:
nucleus
flagella
cilia
pseudopodia

Front 22

Algae has:
nucleus flagella
chloroplasts cell wall
photosynthetic pigment(s)

Back 22

Cyanobacteria has:

photosynthetic pigment(s)
cell wall

Front 23

Amoeboid cells = pseudopodia
Flagellates = flagella
Ciliates = Cilia
Diatoms = gliding

Back 23

Chloroplastida = chlorophyll a & b, flagella, cell wall, chloroplasts, starch

Front 24

Chrysophyceae = chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, oils, leucosin

Back 24

Euglenozoa = chlorophyll a & b, flagella, chloroplasts paramylon

Front 25

Phaeophyceae = chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, laminarin, mannitol

Back 25

Bacillariophyta = chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, laminarian, oils

Front 26

Malaria is caused by the genus Plasmodium, a Protista found in the group Apicomplexa.

Back 26

Protozoa has:
nucleus
flagella
cilia
pseudopodia

Front 27

Algae has:
nucleus flagella
chloroplasts cell wall
photosynthetic pigment(s)

Back 27

Cyanobacteria has:

photosynthetic pigment(s)
cell wall

Front 28

Amoeboid cells = pseudopodia
Flagellates = flagella
Ciliates = Cilia
Diatoms = gliding

Back 28

Chloroplastida =
chlorophyll a & b, flagella, cell wall, chloroplasts, starch

Front 29

Chrysophyceae =
chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, oils, leucosin

Back 29

Euglenozoa =
chlorophyll a & b, flagella, chloroplasts, paramylon

Front 30

Phaeophyceae =
chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, laminarin, mannitol

Back 30

Bacillariophyta =
chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, laminarian, oils

Front 31

Dinoflagellates =
chlorophyll a & c, fucoxanthin, cell wall, chloroplasts, laminarian, starch, oil, fat

Back 31

Cyanobacteria =
chlorophyll a, c-phycocyanin, c-phycoerythrin, cell wall

Front 32

Bacterial colonies are generally smooth and small as compared to fungal colonies, which are large and “fuzzy”.

Back 32

Since each colony is produced from a single cell, the number of colonies indicates the number of cells originally present or level of contamination. Colony size reflects growth rate or motility.

Front 33

Bacteria, such as the staphylococci and the diphtheroids, are part of the normal skin flora. Molds, however, are likely transient contaminants picked up from the environment.

Back 33

Microbial levels on skin are best controlled by hand washing, on surfaces in the environment with use of disinfectants like bleach, and in the air by HEPA filtration systems.

Front 34

Compare bacteria to eukaryotic:
Size=
Bacteria are smaller, about 0.5
to 10 µm in diameter.

Back 34

Compare bacteria to eukaryotic:
Organization of genetic material=
Bacterial DNA is not enclosed in
a nucleus but rather is organized
in the cytoplasm.

Front 35

Compare bacteria to eukaryotic:
Ribosomes=
Bacteria have 70S ribosomes.

Back 35

Compare bacteria to eukaryotic:
Cell Wall=
Bacteria have a cell wall
composed of peptidoglycan

Front 36

Compare bacteria to eukaryotic:
Respiration & Photosynthesis=
Bacteria lack mitochondria and
chloroplasts but can carry out
respiration and photosynthesis

Back 36

Compare bacteria to eukaryotic:
Motility mechanisms=
Bacteria may have flagella that
are simpler in structure but may
be more numerous.

Front 37

5 characteristics of FUNGI:
1. Eukaryotic
2. heterotrophic
3. lack tissue differentiation
4. cells walls of chitin or other
polysaccharide
5. propagate by spores.

Back 37

Modern schemes of classification use genetic analysis to determine relatedness between species while traditional schemes rely on morphological characteristics and reproductive mechanisms to determine relatedness. Traditional methods are used in this exercise because examination of morphological characteristics is easily accomplished in the laboratory.

Front 38

Important phenotypic characteristics used to identify fungi include colony appearance, types of hyphae, sexual spores, and asexual spores.

Back 38

Molds are filamentous fungi that produce hyphae while yeasts are fungi that lack hyphae. Yeasts may form reproductive buds called pseudohyphae.

Front 39

Hyphae are microscopic filaments produced by molds and a macroscopic mass of hyphae is called a mycelium.

Back 39

Fungal hyphae are coenocytic if they are unbroken by crosswalls, or septa. These fungi are also termed nonseptate.

Front 40

Asexual spores of fungi include sporangiospores as well as several types of conidia, such as phialospores, blastospores, arthrospores and chlamydospores.

Back 40

Sexual spores of fungi include zygospores, ascospores and basidiospores.

Front 41

Sporangiospores are asexual spores produced within a thin-walled sac called a sporangium. Sporangiospores may or may not be motile. Conidia are asexual non-motile spores that form on specialized hyphae called conidiophores.

Back 41

Macroscopically, bacterial colonies are smoother and shinier (wet looking) than fungal colonies, which generally appear dry and cottony. Microscopically, fungal cells are far larger than bacteria, with a visible nucleus and vacuoles. Morphologically, molds may display hyphae, sporangia and spores while yeast may show budding and pseudohyphae. Bacterial cells appear far more uniform, with no specialized structures.

Front 42

Cells from a solid medium are placed in a drop of liquid on the slide and then smeared. This is not necessary for a loop of cells from a liquid culture.

Back 42

If too many cell are used to create a smear, it will be difficult to distinguish individual cell shapes and arrangements from large clumps of cells. Also staining and destaining techniques do not work well on clumped and layered cells in a smear.

Front 43

Heat fixation of smears kills the bacterial cells and causes them to adhere to the glass so that they do not get washed off during staining. Overheating can damage and dehydrate the cells causing them to distort in shape. Also the glass can crack or shatter if overheated.

Back 43

Basic dyes, which carry positive charge (e.g. methylene blue), will adhere to negatively charged cell surface structures (e.g. phospholipids) because of charge attraction. Acidic dyes will not adhere.

Front 44

Darkfield microscopy of unstained cells creates and image most similar to negative staining.

Back 44

Fluorescent dyes linked to antibodies specific to the bacterial capsule can be used to tag and visualize the capsule by fluorescence microscopy.

Front 45

Encapsulated strains of S. pneumoniae are protected against phagocytosis in the host and are more likely to cause infection than unencapsulated strains.

Back 45

Which bacterial staining technique:
A basic dye is utilized to stain bacterial cells.

Simple & Capsule

Front 46

Which bacterial staining technique:
A stain that does not penetrate cells is used to color the background.
Negative& capsule

Back 46

Which bacterial staining technique:
Useful for visualizing spirochaetes.
Negative

Front 47

Which bacterial staining technique:
Useful for visualizing the glycocalyx of certain bacterial species.
Capsule

Back 47

Which bacterial staining technique:
Cells are mixed with a stain before they are smeared on the slide.
Negative & capsule

Front 48

Which bacterial staining technique:
Heat fixation of the slide is not recommended.

Negative (gentle heat for capsule)

Back 48

Which bacterial staining technique:
Water is used to remove excess stain from the slide.
Simple & capsule

Front 49

For the simple stain procedure, one can use:
crystal violet
methylene blue

Back 49

for the negative stain procedure, one can use:
india ink
nigrosin

Front 50

Before heat fixation, a wet smear of bacterial cells on a slide must:

air-dry

Back 50

Bacterial capsules can consist of :

polysaccharide
polypeptides w/unique amino acids