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biology 1290 > bacterial growth > Flashcards

bacterial growth Flashcards

chapter 5

1
Q

what is a cell cycle

A

events through which a cell passes during its life span

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2
Q

what is apart of cell cycle

A

binary fission

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3
Q

what is the 3 cell cycle stages that E.coli goes through?

A

growth phase
DNA replication phase
Binary fission

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4
Q

growth phase

A

cell increases in size. since cell wall is inflexible, enzymes break the bonds in peptidoglycan so cells can increase

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5
Q

DNA Replication phase

A

bacterial chromosomes are copied and the two strands separate which involves cytoskeleton

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6
Q

binary fission phase

A

septum form; splits into two identical cells and they organize into a fission ring structure.

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7
Q

what is generation time

A

a time required to go through one cycle and produce 2 daughters

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8
Q

oligotrophs

A

bacteria cells spends most of their existence in a nutrient limited space

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9
Q

the 4 phases of microbial growth

A
  • lag phase
  • log phase
  • stationary phase
  • decline phase
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10
Q

lag phase

A

bacteria cells are adapting to their new environment

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11
Q

log phase

A

when cell double in growth

- where human disease usually develop

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12
Q

stationary phase

A

when reproduction and death rates equalize.

- when oxygen decreases and waste accumulates

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13
Q

decline phase

A

when wast products accumulate and lack of resources causes population to die

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14
Q

persister cells

A

cells can stop dividing but maintain a low rate of metabolism under stress and do this in log phase

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15
Q

endospores

A

happen in response to nutrient

- they are highly resistant structure formed by bacillus when nutrients supplies are low

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16
Q

formation of bacterial spores

A

A. asymmetric cell division- when a septum separates one dna molecule and a small section of cytoplasm
B. Early sporulation: peptidoglycan cortex forms between the 2 membranes prespores, the DNA fragments.
the spore coat assembles around the cortex
late sporulation: the spore coat is completed and the mother cell is ruptured freeing spores

C. Germination: spore germinated to produce a new vegetative cell

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17
Q

psychrophiles

A

make up the largest portion of prokaryotes and the grow below 15 degrees

18
Q

mesophiles

A

live in a temp range between 10 to 45 degrees

19
Q

thermophiles

A

live best around 60 degrees, in hot springs

20
Q

hyperthermophiles

A

are archaea that grow optimally above 80 degrees, in hot water vents, seafloor

21
Q

microaerophiles

A

they love in low oxygen environments

22
Q

thioglycollate broth

A

is used to test organisms’s oxygen sensitivity

23
Q

aerotolerant species

A

are insensitive to oxygen

24
Q

capnophilic bacteria

A

require an atmosphere low in oxygen and rich in carbs

25
Q

what pH do species grow best at

A

ph 7

26
Q

acidophiles

A

are acid- tolerant prokaryotes

ex) those used to turn milk into buttermilk, sour cream etc.

27
Q

barophiles

A

can withstand high hydrostatic pressure.

they can live under high pressure like under the ocean

28
Q

agar

A

complex polysaccharide from cell wall of red algae

  • solidifies below 40 degrees
  • most microbes cannot digest it
  • dissolves in 100 degrees
  • can culture hyperthermophiles
29
Q

nutrient broth agar

A

peptones (from amino acids) mix from digested proteins

30
Q

synthetic media

A

when we know exactly whats in the chemical

31
Q

complex media

A

is when a chemical composition is NOT known.

  • it contains nutrients released from partial hydrolysis of yeast, beef or proteins
  • supports growth of microbes
32
Q

selective media

A

contains ingredients to inhibit growth of certain species while allowing others to grow.

  • methylene blue and crystal violet can inhibit growth of gram negatives
  • high salt for halophiles
33
Q

differential medium

A

presence o visible changes in the medium of differences in appearance of colonies

34
Q

enriched media

A

fastidious organisms require special nutrients to help promote cell growth

35
Q

the pour plate method

A

is an isolation method allows separation of species through dilution of a sample of nutrient agar tubes.

36
Q

the streak plate

A

uses a flamed sterile loop to spread out individual cells form discrete colonies of species

37
Q

the most probable number test

A

is used in samples that have a low number of organisms or that will not grow on agar media

38
Q

turbidity

A

is cloudiness and it measured by spectrophotometer

39
Q

standard plate count

A

a broth cultured sample that is placed in sterile culture dish and melted nutrient agar is added.

40
Q

direct- microscopic count

A

a procedure that has a counting chamber used to estimate the total number of live and dead cells in a culture sample

biology 1290 (10 decks)

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