1- Chapter 1 Flashcards
What is your microbiome?
The total complement of microbial cells in your body
What is a microbial culture?
Medium?
Culture- collection of cells that have grown in a nutrient medium
Medium- liquid or solid nutrient mixture that contains all nutrients required for microorganism growth
What is the cytoplasm made of?
Aqueous mixture of macromolecules, organic molecules, inorganic ions, and ribosomes
Where are prokaryotic and eukaryotic cells found in the three domains: Eukarya, bacteria, and Archaea?
Prokaryotic cells are found in Bacteria and Archaea
Eukaryotic cells are found in Eukarya
What is the difference between a nucleus and a nucleoid?
A nucleus is found in eukaryotic cells
Nucleoid is found in prokaryotic cells
What are the three properties of all cells?
Metabolism
Growth
Evolution
What are extremophiles?
Microbes that can live in environments much too harsh for other forms of life
Define the physiochemical limits of life
How old is earth and how long ago did cells appear on earth?
Earth is 4.6 billion years old
Microbial cells appeared between 3.8 and 4.3 billion years ago
What are nodules in legumes?
Nodules are structures that have bacteria that convert nitrogen in the atmosphere to ammonia through nitrogen fixation
What are rumens and ruminants?
Rumens are microbial ecosystems where microbial communities digest and Ferment polysaccharide cellulose
Ruminants are animals like deer goats etc that eat the rumen stuff
What is wastewater treatment?
Relies on microbes to treat water contaminated with human waste so that it can be reused or returned safely to the environment
Waterborne diseases can result from lack of wastewater treatment
What is bioremediation?
Microorganisms are used to transform spilled oil and other toxic pollutants
What is resolution in microscopes?
What is resolutions limit?
Ability to distinguish two adjacent objects as distinct and separate
0.2 um is limit
What are oil immersion lenses?
Lenses where oil increases the light gathering ability of a lens
Are dyes negatively or positively charged?
Positively charged to see the negatively charged parts of cells
What are gram stains?
What colour are gram positive?
What colour are gram negative?
Render different kinds of cells different colours
Gram positive is purple violet
Gram negative is pink
How can cells be made to fluoresce for fluorescence microscopy?
Cells fluoresce either because they contain naturally fluorescent substances or they’re stained with fluorescent dye
What is differential interference contrast microscopy (DIC)?
Light microscopy that uses a polarizer that passed through a prism to create two beams and results in a 3D picture
What is confocal scanning laser microscopy?
Computer microscope that couples a laser to a fluorescence microscope
High contrast 3D image
Scans up and down the layers of a specimen giving an image for each layer
What is transmission electron microscopy and scanning electron microscopy?
TEM is used to examine cells and cell structure at high magnification and resolution
Electrons can’t penetrate cell structure well so must cut into cell to see clearly
SEM is where specimen is coated with a thin film of metal and electron beam scans back and forth presenting the structure of the cell
Why do electron microscopes have better resolution than light microscopes?
Electrons have much shorter wavelengths than that of visible light and wavelength affects resolution
What is spontaneous generation?
Belief that life arose spontaneously from non living materials
What does sterile mean?
Free of bacteria or other living microorganisms
What is Louis Pasteur known for?
Ending the controversy over spontaneous generation
Created pasteurization that preserves milk and other foods by heat treatment
What was Robert Koch’s experiment with rats and disease transfer?
He found that if you took blood from a rat with anthrax and gave it to a healthy rat, it got anthrax too
Led to Koch’s postulates
What is a pure culture?
A population of identical cells
What is the enrichment culture technique?
Use of a growth media to favour the growth of a particular microorganism
What is chemolithotrophy?
The oxidation of inorganic compounds to yield energy
Why is RNA an excellent candidate for phylogenic analysis?
4 points
Universally distributed
Functionally constant
Highly conserved
Adequate length to show evolutionary relationships
What is the phylogenic tree?
A diagram that depicts the evolutionary history (the phylogeny) of all cells and reveals the three domains
What are the four groups of bacteria that make up 90% of bacteria?
Actinobacteria
Firmicutes
Proteobacteria
Bacteroidetes
What phylum of archaea is found in soils and oceans? What about wetlands and the guts of animals
Thaumarchaeota found in oceans and soil
Methanogens found in wetlands and guts of animals
Why are viruses not on the tree of life?
They are parasites that can only replicate within the cytoplasm of the host cell
They have no cytoplasmic membrane, cytoplasm and ribosomes
Cannot serve energy and do not carry out metabolic processes
Is the power of light microscopy limited by our ability to magnify?
No it’s resolution not magnification
What are the four types of light microscopy?
Bright field
Phase contrast
Dark field
Fluorescence
How does phase contrast microscopy work?
Phase ring amplifies differences in the refractive index of cell and surroundings
Improves contrast without using stain
