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
When the bacteria shape is thin, and has multiple (four or more) Full twist along the length of the cell
Spirochetes
Ex: Treponema pallidum (syphilis)
And Borrelia burdorferi (Lyme disease)
What prefix is used for chains of cells?
Strepto-
If spherical cells separate along two planes they will form clusters of 4 cells called ______. If it then divides again on a third plane, the result is a _______
Tetrads, sarcina
If spherical cells separate along random planes the result is irregular grape light cluster called…
Staphylococcus
Some bacteria may be _________, meaning that their typical morphology may become altered in response to age and environmental conditions
Pleomorphic
These type of stains utilize a single dye and are used to determine cell shape, size, and arrangement.
Simple stains
Basic dyes include…
Are they positive or negative stains?
Crystal violet, safranin, methylene blue, malachite green, carbol fuschin
Positive stains
Can positive or negative staining be heat fixed?
Only positive
What are the acidic dyes?
Is used in negative or positive Staining?
Nigrosin, and India ink
Negative staining
An example of a special stain?
Flagella stain
Differential stains include
- acid-fast stain
- Capsule stain
- endospores stain
- Graham negative and positive
_________ and _______ stains utilize more than one stain.
Differential, special
An example of a capsule forming organism
Klebsiella pneumoniae
This type of staining includes acidic stain to stain the background and a basic stain to stain the cells leaving their clear capsules
Capsule stain
Examples of spore forming bacteria
Bacillus and clostridium
Endospores are difficult to stain because of their tough outer protein coats made of peptidoglycan and _________.
Dipicolinic acid
Acid-fast positive cells are ____
Acid-fast negative cells are ____
Hot pink (from carbol fuschin) Blue or green
Acid fast positive cells have a waxy substance called ______ in their cell wall that enables them to resist decolorization.
This makes them highly resistant to desiccation and disinfectants
Because it is so resistant, heat is used as a mordant to drive the primary stain into the cell wall.
Mycolic acid
Atrichous - Monotrichous- Amphitrichous- Lophortrichous- Peritrichoous-
Atrichous - no flagella
Monotrichous- Single Flagella
Amphitrichous-One flagella coming from each end
Lophortrichous-multiple flagella located at the same spot on the Bacteria
Peritrichoous- flagella all over its surface
Bacteria have cell membranes of ________ fatty acid chains
Unbranched
When doing a Gram stain, failure to add iodine would result in…
Both gram-positive and gram-negative bacteria will stain red. Gram-positive bacteria will be false negative
What term describes a single bacterium that is oval in shape?
Coccobacillus
Bacillus subtilis
What is the gram reaction?
What is the cellular morphology and arrangement?
Gram-positive
Streptobacilli
staphylococcus epidermis
What is the gram reaction?
What is the cellular morphology and arrangement?
Gram-positive
Staphylococcus
Escherichia coil
What is the gram reaction?
What is the cellular morphology and arrangement?
Gram negative
Coccobacillus
When shifting from 4X lens to 40X Lens only fine focus will be needed to resolve image. What is this example of?
Parfocal
Archaea cell membranes are made of ________ hydrocarbon chains
Branched
The description of microbial growth in broth as being ________ means that the broth in the tube appears cloudy.
Turbid
The four major macromolecules that comprise cells
- carbohydrates
- Lipids
- proteins
- nucleic acid‘s
Growth media provides the elements that most bacteria need for growth which include…
Carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur
__________ organisms have complex growth requirements and are thus more challenging to grow in the lab
Fastidious
General-purpose or all-purpose media examples…
Tryptic soy broth, tryptic soy agar (TSA) plate
What’s an example of differential media?
Nitrate broth
Steps of the scientific theory
- observe
- ask a question
- research/gather data
- hypothesis
- experiment
- test hypothesis
- draw conclusions
- Report/refine hypothesis
What is the most widely used staining procedure in bacteriology?
Gram stain (differential stain)
What procedure is used for acid fast staining?
Ziehl-Neelson procedure
What dyes are used for the endospore stain in procedure?
Malachite green and heat
Safranin
What stain is used for the flagella stain?
Carbol fuchsin
