Microbiology Flashcards
Bacteria
Bacteria are prokaryotes, meaning that their ribosomes and genetic materials are free-floating in the cytoplasm
The 3 major shapes of bacteria
Coccus
Bacillus
Spirillum
Coccus
Spherical bacteria that can join together to make diplococci, streptococci, staphylococci.
Diplococci
Two bacteria joined together
Streptococci
Chains of spherical bacteria
Staphylococci
Clusters of spherical bacteria
Bacillus
Rod-shaped bacteria
Diplobacilli
Two rod-shaped bacteria joined together
Streptobacilli
Chains of rod-shaped bacteria
Spirillum
Spiral-shaped bacteria
Gram Stain
- Application of crystal violet and iodine which create a complex that adheres to the outermost layer of bacteria
- Application of a decolorizer (alcohol), which either removes the stain, or traps it inside the membrane.
- Restain (safranin), which colors gram negative
Gram Positive
The outermost layer is a thick peptidoglycan cell wall. Gram positive bacteria retain the stain in the cell wall during the gram stain because the cell wall is dehydrated.
Gram Negative
The outermost layer is thin and composed of lipids. The entire outer membrane is removed in the Gram Stain, removing the color with it. The restain stains the gram negative bacteria
Viruses
Cannot reproduce without a host, and are not considered to be living
True or false: A virus’ genetic material can be either DNA or RNA
True
Capsid
A protein structure of a virus that contains the genetic material
Lytic Cycle
A virus injects its own DNA into a host cell, taking control of the cell’s genetic machinery, and inducing the cell to replicate the viral DNA instead of its own DNA. Eventually the cell will lyse and release viral DNA into the extracellular matrix, which then continue the cycle by infecting a new cell.
Virulent
Viruses that replicate by the lytic cycle, killing their host cells
Provirus
A stage of a virus that is less harmful. The bacteriophage becomes integrated into the bacterial genome as a provirus, and lies dormant in the lysogenic cycle
