Lab Exam 1 Flashcards
________ variable- The item being tested, the item expected to have an effect
Independent variable
_________ variable- Measure used to determine the outcome
Dependent variable
Consensus among researchers that a particular concept or process exists
Scientific theory
What is seen when looking into the oculars
Field of view
As the power gets greater, the field of view get smaller
Ability to see two separate objects as discrete entities
Resolving power (resolution)
How do you calculate total magnification?
Power of ocular times power of objective
The distance between bottom of the objective and the glass slide
Working distance
Lens that stays in focus with the magnification or focal length changes
Parfocal
_______ Image is what is projected into the objective lens
________ Image that is viewed through the ocular lines
Real
Virtual
Type type of microscope that has a dark object (partly transparent) that appears against bright background
Stain (methylene blue) darkens some parts more than others
Light microscopy (LM) with stain
Type of microscope where the object looks transparent
Organelles appear as light-dark patterns caused by variation in refractive index. This type of imaging gives an illusion of three-dimensionality.
Background may be dark or light.
Phase-contrast microscopy (PCM)
Specific fluorescent molecules label parts of the cell.
Fluorophore-labeled parts of the object show bright color against a dark background
Florescence microscopy (FM)
A high resolution of detail is present, much higher than with light microscope.
Shadowing of the object approximates actual three dimensionality.
Scanning electron microscopy (SEM)
A thin section of the specimen appears. Only some of the cells parts appear, those that happen to fall within the section.
High resolution of detail reveals objects such as ribosomes in viruses
Transmission electron microscopy (TEM)
why is immersion oil used?
To decrease refraction of light into the 100X Objective lens, improving the resolution.
The measure of how well microscope objective can gather light
Aperture
What are the cultural characteristics that are used to identify colonies on Agar?
- shape
- margin
- elevation
- size
- texture
- appearance
- pigmentation
- optical property
What are the different shapes of bacteria?
Coccus-round
Rod/bacillus-longer than wide
Coccobacillus-oval shape
Vibrio-bent rod (comma shape)
Spirochete-flexible spirally twisted structure
Pheomorphism-variable cell morphology depending on age of cell and environment (nutrients, temperature, etc.)
What are the different arrangements of cocci?
1 plane
- diplococcus- 2cells
- streptococcus- variable number of cells (chain)
2 perpendicular planes
- tetrad-4 cells
- sarcina-packet of 8-64 cells
Several planes
-staphylococcus-irregular clusters, number of cells varies
- Self replicating
- can be transferred from prokaryote to prokaryote
- Circular pieces of DNA
- contains only a few genes, such as genes for anabiotic resistance
Plasmids
Spherical or round shape bacterium
Coccus/cocci
When the shape of the bacterium is rod-shaped, or longer than it is wide
Bacillus
Bacterium that are shaped as short rods
Coccobacillus
Bacterium that looks like a bent rod is called…
Vibrio
Ex: vibrio cholera
When the bacterium shape is rigid wavy or coiling
Spirillium