Microbiology & Microorganisms Flashcards
Why is microbiology important?
Microbes are the largest mass of living material on Earth
What is the cytoplasmic membrane?
Barrier that separates the inside of the cell from the outside environment
What is the cytoplasm?
Aqueous mixture of macromolecules, ions, and proteins
What do ribosomes do?
Synthesize proteins
What is a genome?
A cell’s full complement of genes
What is a plasmid?
A piece of DNA that carries non-essential genes
What are protists?
Unicellular or multicellular without differentiation into tissues
What are protozoa?
Animal-like microorganisms
What are algae?
Photosynthetic plant-like microorganisms
How do prokaryotes divide?
Binary fission
Are archaea ever pathogenic?
Nope
What are archaea known for?
Living in extreme environments
What is unique about viruses?
They cannot reproduce outside of a host cell
How can rRNA sequencing calculate evolutionary distance?
The more difference in the sequence means farther away on the phylogenetic tree
What is the phylogenetic tree?
A graphic representation of the evolutionary distance between organisms
What are 3 characteristics that all Bacteria share?
1) Most characteristic in common
2) Greater than 97% sequence similarity
3) High degree of genome similarity
What are 3 rules for nomenclature of species?
1) Names are italicized or underlind
2) Genus capitalized, epithet not
3) Genus name may be abbreviated the second time it is used
Who developed pasteurization?
Louis Pasteur
What are Koch’s postulates?
1) The suspected pathogen must be present in all cases of the disease and absent from healthy animals
2) The suspected pathogen must be grown in pure culture
3) Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
4) The suspected pathogen must be reisolated and shown to be the same as the original
What temperature does agar melt at?
97 C
What temperature does agar solidify at?
43 C
What are the steps of the streak plate technique?
1) One edge of a place is inoculated with a concentrated sample of bacteria
2) Sample is diluted by streaking it across the plate
3) Plate is incubated
4) Individual cells grow to form colonies
What is a colony?
A mass of cells that (ideally) arose from one single cell
What are the steps of the spread plate technique?
1) Sample is diluted before plating
2) Diluted sample can be spread over the plate with a sterile spreader
3) Separate cells grow into colonies on the surface of the plate
What is the purpose of spread and pour plates?
To calculate the concentration of bacteria in a population
What is the minimum temperature that bacteria can live in?
-13 C
What are bacteria likely growing on if they live in ice?
Organic carbon trapped in the ice
What is used as a model of bacterial cell shape, growth, and morphogenetic?
Bacillus subtilis
Why is bacillus subtilis used as a model for study of bacterial cells?
Its cells are relatively large and easy to visualize
What does lacking a cell wall allow cells to do?
Fuse and readily exchange genes
