-
Are bacteria larger than viruses?
yes
-
What are the different components of bacteria?
- capsule
- cell wall
- cell membrane
- cytoplasm
- mesosomes
- flagella
- pili
- plasmid
- endospore
-
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?
penicillin
-
What is another name for a cell membrane?
cytoplasmic 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?
no
-
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?
- ribosomes
- storage granules
-
What do ribosomes do?
protein synthesis
-
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?
no
-
What is phototaxis?
move toward or away from the light
-
What is chemotaxis?
move in response to chemicals
-
Can flagella be seen without staining?
no
-
What is flagella made of?
protein
-
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?
yes
-
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?
no
-
What is another name for endospore?
spore
-
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?
- heat
- desiccation
- 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?
- central
- terminal (at the end)
- subterminal (near the end)
-
Do endospores resist staining?
yes
-
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)
- spiral
- 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
|
|
