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Are bacteria larger than viruses?
What are the different components of bacteria?
- cell wall
- cell membrane
What is the capsule?
- outmost covering of many, but not all bacteria
- slimy, jelly like
What is the capsule composed of?
carbohydrates and protein
What is the function of the capsule?
- protects agains phagocytosis
- promotes attachment to objects and to each other
- produces infectivity - ability to produce disease, if no capsule is produced it may not be pathogenic
- prevents nutrient loss and dehydration
- provides antigenicity - causes production of antibodies
What are the two layers of the cell wall?
What is the function of the cell wall?
- gives rigidity to bacterial cells
- maintains shape and size
Which types of bacteria do not have cell walls?
mycoplasma and spiral bacteria
Which drugs interfere with bacterial cell wall syntheses?
What is another name for a cell membrane?
Which layer is the cell membrane?
inner most layer
What does the cell membrane do?
separates cytoplasm from cell wall
Does the cell membrane help keep the cell's shape?
What is the cytoplasm?
fluid in the cell
What are the two areas of cytoplasm?
- cytoplasmic area
- nuclear area
What is in the cytoplasmic area?
- storage granules
What do ribosomes do?
What is nucleoid?
nuclear area of cytoplasm
What is in the nucleoid?
- rich in DNA
- transmits this information to new cells during cellular reproduction
What are mesosomes?
- invaginations of the cell membrane
- increases surface area of cell membrane for secretion and cell division
What is flagella?
long, whip-like appendage made of protein
What is the purpose of flagella?
locomotion and motility
Do we use flagella to identify bacteria?
What is phototaxis?
move toward or away from the light
What is chemotaxis?
move in response to chemicals
Can flagella be seen without staining?
What is flagella made of?
What can antiflagellar antibodies do?
agglutinate flagella and impairs mobility of the bacteria
What are the four types of arrangement of flagella?
- monotrichous: 1 at one pole
- lophotrichous: tuft at one pole
- amphitrichous: 1 or tuft at each pole
- peritrichous: all around cell
What are pili?
long whip-like hollow tubes
Can there be more than one pili per cell?
Which bacteria do we mainly see pili?
gram negative bacteria
Can we see pili with a light microscope?
no, has to use a electron microscope
What is the function of pili?
- do not function in locomotion
- transfer DNA from one bacterium to another
- adhesiveness is main function - to other bacteria, to objects
By genetically altering the adhesive tips of their pili, certain bacteria are able to _____ and _____.
- adhere to and colonize different cell types with different receptors
- evade antibodies made against the previous pili
What is a plasmid?
circular, double-stranded, self-replicating unit of DNA
What does plasmid contain?
contains genes to transfer drug resistance - R factor
What is an endospore?
a thick-walled, refractile body, able to withstand adverse environmental conditions for long periods, produced within the vegetative cells of certain bacteria
Can all bacteria form spores?
What is another name for endospore?
Are bacterial spores reproduction?
no, they are survival form
What happens to the endospore under favorable conditions?
the spore will germinate to form a vegetative bacterium (functioning form)
What is sporulation?
formation of a spore
Why are spores formed?
occurs to allow continuity of life
Do spores have a low or high rate of metabolism?
low rate of metabolism
Can spores live without nutrients?
yes, for decades
What are endospores resistant to?
- chemical (including stain)
Are endospores the same in each cell?
no, they vary in size, shape, and location
What are the different spore locations within a cell?
- terminal (at the end)
- subterminal (near the end)
Do endospores resist staining?
What is the common size of bacteria?
- 0.5 - 1.0 microns in width
- 2 - 5 microns in length
How big are cocci?
0.75 - 1.2 microns in diameter
How big are rods?
width of 0.1 to 2 microns and length of 2 - 5 microns
How big are spirochetes?
3 - 5 microns long
What are the 4 different shapes of bacteria?
- coccus (spherical)
- bacillius (rod shaped)
- pleomorphic (shape ranges from cocci to rods)
How are bacteria arranged?
some bacteria remain attached after dividing, forming chains, clusters
What are the different types of arrangements?
- single - one alone
- pair - 2 (diplococcus)
- chain - more than 2 in a line
- cluster - grape-like bunch
- tetrad - 4 in a square
- palisade - chinese letter pattern
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