Micro test 1.txt
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Which type of bacteria can make spores?
Only certain gram+ bacilli
How do spores look after gram staining?
Spores do not gram stain so they show as clear.
Why do spores not gram stain?
Bc there are no cell walls associated with bacterial spores.
What has to happen before bacteria will for
It must feel threatened by hostile conditions
Name 6 hostile conditions bacteria may face:
- - extreme changes in temp
- - change in pH
- - dry conditions
- - antibiotics
- - O2 levels
- - lack of nutrients/food
How many spores can 1 bacilli make?
How long does it take spores to develop?
Some 6-8 min; 10 min; 30+ minutes.
What is a vegatative cell?
A cell that can not or is not making a spore. Cocci and spiral are always vegatative.
What is a sporulating cell?
A cell making a spore. Gram+ bacilli making a spore.
Name 5 types of sporulating bacteria
Anthrax, C. diff, tetanus, botulism, gas gangrene
Name 5 things that can kill a spore
- - intense heat (1300 F +)
- - autoclaving
- - hibiclens (chemical)
- - cidex
- - tetanus vaccine
- - lab table disinfectant
What does not kill spores?
Alcohol, hydrogen peroxide; mild radiation, sunlight, household cleaners
What is a solute?
Something that will be dissolved
What is a solvent?
Disolves the solute (water)
When the solution has a higher concentration of solute and a lower concentration of solvent
The movement of water molecules from an area of low solute concentration to an area of high solute concentration
If you place a bacteria in a hypertonic solution what will happen?
Water will move out of the bacteria causing it to shrivel and die.
What are the four steps to gram staining?
- 1. Flood with crystal violet (primary stain)
- 2. Flood with iodine (mordant)
- 3. Use decolorizer (95% alcohol)
- 4. Flood with safranin (counter stain)
List 5 characteristics of gram+ cell walls
- - thick peptidoglycan layer
- - tightly bonded polysaccharides
- - cell wall and cell membrane close together
- - holds in purple from crystal violet
- - no porins
List 5 char of gram- cell walls
- - thin peptidoglycan layer
- - loosely bonded polysaccharides
- - cell wall and cell membrane further apart
- - stains pinkish red from safranin
- - contains porins (integral proteins with a pore)
Name the 4 types of flagellum
- - monotrichous: one flagella
- - lophotrichous: group or cluster of flagella found at one end
- - amphitrichous: onr flagella at ea end
- - peritrichous: completly covered in flagella
Name two bacterial movements in responses to stimuli and describe
Phototaxis: movmnt by light
Chemotaxis: movmnt by chemicals
What are fimbriae used for?
They monitor changes in stimuli; similar to a nervous system
What are pili and how are they used?
A reproductive structure used to transfer genetic material
What organelles are NOT found in bacterial cells?
Nucleus, nuclear envelope, rough ER, smooth ER, golgi apparatus, lysosomes and mitochondria
Name 9 ways bacteria can be classified
- 1. Shape
- 2. Oxygen needs
- 3. Movement
- 4. Gram staining (+ -)
- 5. Cell wall thickness
- 6. Ability to form a capsule
- 7. Ability to make a spore
- 8. Type of hemolysis
- 9. Ability to release a toxin
Who is the father of modern microbiology and what were some of his contributions?
Rabies vaccine, germ theory, disproved abiogenesis
Name 5 things that can be learned from the Genus of a species?
- Discoverers name
- Disease name
- Place of discovery
- Shape or clustering
- Color pigment on blood agar
Name 8 reasons bacteria are important to our lives.
- 1. Can make oxygen
- 2. Keeps immune system in balance
- 3. Can decompose and recycle nutrients
- 4. Beginning of the food chain
- 5. Make vitamins in our colon
- 6. Used to make food
- 7. Make drugs
- 8. Make sulfur and nitrogen for plants
How is bacteria measured?
How big is a micron?
It equals 1/25 of 400ths of an inch
What are the four stages of the bacterial growth curve?
Lag, growth, stationary, death
What happens during the lag phase?
Bact adapt to growth conditions
What happens during the growth phase?
Exponential growth in population
What happens during the stationary phase?
Growth rate slows due to nutrient depletion, decreased O2, and accumulation of toxins
What happens during the death phase?
Bact run out of nutrients and die.
Organism that feeds on something dead
An organism that feeds on something living and harms it. (all pathogenic bacteria)
Define faculatative saprophyte
This bacteria prefers to feed on something living but can feed on something dead
Can live in the presence of free atmo O2
Can live in the absence of free atmo O2
Define Obligate anerobe
Must live in absence of free O2
How is bacteria effected by drying?
Can kill it
What are the four steps in binary fission?
- 1. DNA replication
- 2. Chromosome segregation
- 3. Cytokinesis
- 4. Septum completion, daughter cells are formed
Define binary fission.
A process in which a cell grows twice its normal size and divides in half to produce two daughter cells of equal size.
What is snapping and how does it vary from binary fission?
- Variation of binary fission that differs by:
- A) only the inner portion of the cell wall is deposited across the dividing cell
- B) tension develops and the daughter cell is attached by a hinge
- C) the daughter cell may sepArate from its original attachment site.
What is budding?
An outgrowth of the original cell ( bud) receives a copy of the genetic material and enlarges. The bud separates from the parent cell. The parent will continue to make additional buds.
What is conjugation?
The transfer of genetic material through the conjuction pili.
Where are the genes for conjugation found?
On the plasmids (F+). F- cells lack conjugation genes and also lack pili.
What is the most common bact to undergo conjugation?
E. coli; conjugation can occur btwn two diff species. Bacterium and yeast or bacterium and plant.
What is the process of bact conjugation?
- 1. Donor cell attaches to recipient cell with its pilus. The pilus pulls the cells together.
- 2. The cells contact one another
- 3. One strand of plasmid dna transfers to the recipient.
- 4. The recipjent becomes an F+ cell.
- 5. The donor replaces its donation Section of dna.
- 6. The new F+ cell is ready to live a full productive life.
Two diff bact species living together; one enhances the growth of the other.
Two diff bact ljving together; one inhibits the other.
What effect does the following have on bact:
- high salt/sugar
- - heat will kill or slow down
- - cold will kill or slow down
- - acididty: bact love pH of 6-8 if very acidic or basic will die
- - electricity does nothing
- - radiation can kill at very high doses
- - high salt/sugar can make a hypertonic enviro and cause the bact to shrivel and die
What is bacterial hemolysis?
Red blood cell destruction
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