Lectures 4-7 Flashcards
True or False: A large number of pathogens are bacteria
False
True or False: Bacteria can be photosynthetic and non-photosynthetic
True - Cyanobacteria are photosynthetic
What is a “Coccus” bacterium shape?
A spherical, round or ovoid shape that is 200 nm
What is a “Bacillus” bacteria shape?
Rod-shaped
What is a “Vibrio” bacteria shape?
A curved-rod or comma shape
What is a “Coccobacillus” bacteria shape?
A very short rod-shape (longer than coccus, shorter than bacillus) - 2 nm in length
What is a “Spirillum” bacteria shape?
A spiral or gently-curved shape
What is a “Spirochete” bacteria shape?
A tightly-coiled spiral shape that is roughly 500 nm
What are the cell walls of archaea made of?
Pseudopeptidoglycan
What is the Domain of eukaryotes?
Eukarya
What organisms are in Eukarya?
1) Protists
2) Fungi
3) Plants
4) Animals
What are the different protists?
Algae and Protozoa
What is one of the most defining characteristics of fungi outside of their chitin cell wall?
They are heterotrophic
What are the four characteristics of viruses?
1) Acellular
2) Consist of proteins and genetic material (DNA or RNA)
3) They need a host in order to survive
4) They can infect all types of cells
What is Light Microscopy?
A type of microscopy that resolves images according to the absorption of light
What are the four types of Light Microscopy?
1) Bright Field Microscopy - Specimens appear as a dark silhouette against a light background through direct light transmissions
2) Dark Field Microscopy - Technique where an angled light is used to create a bright image of specimens against a dark background
3) Phase-Contrast Microscopy - Enhances the contrast of transparent specimens and organelles to the background/cytoplasm
4) Fluorescence Microscopy - The specimen absorbs light of a defined wavelength and emits light of lower energy, causing species fluoresces
What is Electron Microscopy?
A type of microscopy that uses beams of electrons to resolve smaller (than visible light) details
What is the difference between a Scanning Electron Microscope (SEM) and a Transmission Electron Microscope (TEM)
A Scanning Electron Microscope (SEM) creates a 3D image by detecting reflecting electrons.
A Transmission Electron Microscope (TEM) uses electrons that are passing through thin sections of the sample to create a 2D image
What is a Simple Stain?
A simple stain adds a dark colour specifically to cells, but not the external medium or surrounding tissue
ex.) Methylene Blue
What is a Differential Stain
A differential stain stains one kind of cell, but not another
ex.) Gram stain
What does Gram staining differentiate?
Gram staining differentiates two types of bacteria:
1) Gram-positive bacteria retain the stain due to a thicker cell wall and appear purple
2) Gram-negative bacteria do not retain the stain and appear and pinkish-reddish colour
What is an Acid-Fast Stain?
An acid-fast stain differentiates gram-positive cells with mycolic acids in their cell walls, and gram-positive cells that do not.
