Microbial World Flashcards
How are Fungi classified? What are their unique characterisitcs?
Eukaryotic.
Possess cell walls made of chitin.
Produce sexual spores.
what are the unicellular and multicellular Fungi?
Uni=Yeasts
Multi=Molds
How are Protozoa classified? What are their unique characteristics?
Single celled Eukaryotes.
Most reproduce asexually, some sexually.
Defined by means of locomotion with cilia, flagella, and pseudopodia.
How are Algae classified? What are the unique characteristics?
Uni or Multicellular Eukaryotes.
Non-pathogenic except for red tides and shellfish poisoning.
What are the characteristics of Prokaryotes?
Unicellular and lack nucllei.
Reproduce asexually.
Smaller and found everywhere there is sufficient moisture.
Some found in extreme environments.
What is the average wavelength of visible light?
550 nm
What is magnification>
Use of lenses to increase apparent size of object.
What is resolution?
closest you can get 2 objects and still see them as seperate.
What is the formula for resolving power?
0.61 y/NA (numerical Aperature)
What are Glycocalyces?
Gelatinous, sticky substance surrounding the outside of a cell. Usually composed of polysaccharides.
What are the two types of Glycocalyces?
- Capsule: Composed of organized repeating units, firmly attached to cell surface.
- Slime Layer: loosely atatched to cell surface, water soluble.
What are the characteristics of flagella? Made up of what?
Long, propeller-like structures responsible for movement. Rigid, protein helices that rotate. Made up of Flagellin protein.
What are the movements of Flagella?
Run: movements in single direction, directed by positive stimuli (right direction)
Tumble: Abrupt random changes in direction, directed by negative stimuli (wrong direction).
What are Fimbriae?
non-motile, sticky extensions used to adhere to things.
What are pili? What are they made of?
non-motile, long hollow tubules used to join two bacterial cells and transfer DNA. Made of Pilin.
Bacterial Cell walls are made up of what?
Peptidoglycan composed of sugars NAG and NAM, connected by tetrapeptide cross bridges.
What are the characteristics of Gram-Positive bacterial cell walls?
Thick layer of peptidoglycan.
Contains unique teichoic acids.
Retains crystal violet dye in gram staining.
What are the characteristics of Gram-Negative bacterial cell walls?
Thin layer of peptidoglycan.
Have outer bilayer membrane composed of phospholipids, porins and LPS (lipopolysaccharide).
Dont retain dye well and look pink.
What is Lypopolysaccharide also known as? What is contained in it and what does it cause? Where is it found?
Found in gram-negative bacteria. Also know as an endotoxin. Lipid protion known as lipid A, which is released from dead cells and can trigger fever, vasodilation, inflammation, shock, blood clotting.
What are the characteristics of Acid fast cell walls?
Layers of wax-like lipid, up to 60% or wall made from mycolic acids. Also contains arabinogalactan.
What is the periplasmic space? Found?
area between outer membrane and plasma membrane. Found in Gram negative bacteria.
What produce endospores? What do they do?
Produced by Gram-positive rods. Vegatative cell turns into one endospore, which can germinate and form the cell.
What is an endotoxin? Exotoxin?
- Endo=Heat stable lipopolysaccharides proteins that are structural components of gram-negative bacteria, released when cell wall breaks down.
- Exo=heat labile proteins secreted by certain bacteria.
What is a bright-field microscope?
Uses series of lenses for magnification, as light rays pass through the specimen and through objective lens.Uses oil immersion.
What is dark-field microscope?
Prevents light rays from reaching the specimen, only oblique rays illuminate. These light rays scattered by specimen enter objective lens.
What is contrast microscope? What are the two types?
Light rays in phase produce brighter image, while light rays out of phase produce darker image.
- Phase-Contrast
- Differential Interference Contrast (DIC).
What are fluorescent microscopes?
Direct UV light at specimen, Fluorochromes absorb the UV light and radiate energy back as longer visible wavelength.
What is an electron microscope? What are the two types? Which produce the clearest images?
Use electrons to gain a greater resolving power.
- Transmission Electron Microscope (TEM)
- Scanning Electron Microsope (SEM)
SEM produces the best images.
What do Acidic and basic dyes stain?
Acidic=Alkaline (+) structures
Basic= acidic (-) structures.
