Bacterial Cell Flashcards
Bacteria with no cell wall
- Mycoplasma
- Ureaplasma
- Spiroplasma
- Anaeroplasma
2 alternating dissacharides in peptidoglycan/murein layer
- N-acetyl-D-glucosamine
2. N- acetyl-D-muramic acid
small circular molecule of DNA containing accessory information
Plasmids
most commonly found in gram negative bacteria, each carries genes for its own replication. It can confer resistance to antibiotices
Plasmids
What is the chromosomal DNA of prokaryotes?
Circular, complexed with RNA
Typical size of bacteria
- 4 - 2 micrometer in diameter
0. 5 - 5 micrometer in length
Site of energy production in prokaryotes
Cytoplasmic membrane
Present in most prokaryotes as an organized capsule or unorganized slime layer
Glycocalyx
gives the bacterial cell shape and strength to withstand changes in environmental osmotic pressures
Cell wall
Protects against mechanical disruption of the cell
cell wall
Offers some barrier to the passage of larger substances
cell wall
Characteristics of Gram positive cell wall
- Thich cell wall
2. Presence of techoic and lipotechoic acid
provides rigidity to cell wall by attracting cations such as magnesium and calcium
Teichoic acid
Characteristics of Gram negative cell wall
- Thin peptidoglycan later
- Periplasmic space
- outer membrane
Componentes of the outer membrane
- proteins
- phospholipids
- lipopolysaccahride
It acts as a barrier to hydrophobic compounds and harmful substances
Outer membrane
It acts as a sieve, allowing water-soluble molecules to enter through protein-lined channels called porins
Outer membrane
It provides attachment sites that enhance attachment to host cells
outer membrane
How long are the cells saturated/flooded with primary stain in gram staining?
60 seconds or 1 minute
How long will the mordant stay before rinsing off in gram staining?
60 seconds or 1 minute
How long is the slide rinsed with alcohol in gram staining?
20 seconds or until there is no run off of color
Color of gram positive bacteria
mid - dark purple
Color of gram negative bacteria
pink - red
what decolorizer is used in gram staining?
acetone alcohol