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Clinical Bacteriology > Module 2.2- Bacterial Growth and Nutrition > Flashcards

Module 2.2- Bacterial Growth and Nutrition Flashcards

1
Q

microbial growth pertains to:

A

number of cells

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2
Q

groups of cells large enough to be seen without a microscope

A

colony

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3
Q

Bacteria increase in number by an asexual means of reproduction which is

A

binary fission

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4
Q

3 stages of binary fission

A
  1. increase cellular structure, components, and mass
  2. chromosomes are replicated and segregated
  3. a septum forms and divides progeny cells
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5
Q

refers to the time required for the bacterial cell to divide, thus doubling their population

A

generation time

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6
Q

generation time is mathematically expressed as

A

GT = t/n
(t =time for 1 generation)
(n =number of generation

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7
Q

graph that represents the number (expressed as logarithm) of viable cells in a bacterial population over a period of time

A

bacterial growth curve

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8
Q

4 distinct phases of growth when bacteria are cultivated in liquid medium in a closed system or batch culture

A
  1. lag phase
  2. log phase (exponential growth phase)
  3. stationary phase
  4. decline phase
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9
Q

bacterial phase of adaptation to their new environment, and undergoing a period of intense metabolic activity involving, though there is little or no cell division.

A

lag phase

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10
Q

phase where cell division proceeds at maximal rate and the bacterial population is in the state of balanced growth, i.e., the number of cells increase proportionally over the same period of time

A

log phase (exponential growth)

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11
Q

Bacterial population in this phase is preferred for laboratory testing, e.g., motility, staining

A

log phase (exponential growth)

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12
Q

the bacterial population is decreasing in a logarithmic rate.

A

Decline (or death) phase

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13
Q

growth curve becomes horizontal and at its greatest population density,

A

Stationary phase

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14
Q

Stationary phase is also known as

A

plateau phase

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15
Q

The bacterial population is in the state of balanced growth,

A

Log (or exponential) phase

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16
Q

cell division stops completely and the number of deaths exceed the number of new cells formed,

A

Decline (or death) phase

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17
Q

This is the period of equilibrium where the total number of viable microorganisms remains constant. This may result from a balance between cell division and cell death, or the population may simply cease to divide but remain metabolically active.

A

stationary phase

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18
Q

2 requirements for bacterial growth

A

nutrional and physical requirements

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19
Q

4 main nutritional requirements of bacteria

A
  1. major elements (C, H, O, N, S, P, K, Mg, Fe, Ca)
  2. trace elements (Mg, Co, Z, Cu, Mo)
  3. Carbon and energy
  4. Growth factors
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20
Q

Nutritional requirement that are supplied by inorganic ions, water molecules, small molecules, and macromolecules, and serve as either structural or functional role in the cells.

A

major elements

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21
Q

Nutritional requirement that is needed by certain cells in small amounts that is difficult to detect or measure, and are present as contaminants of water or other cell membrane components.

A

trace elements

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22
Q

nutritional requirements classified as organic compounds that are essential for growth that the organism is UNABLE TO SYNTHESIZE, and fulfill a specific role in biosynthesis

A

growth factors

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23
Q

nutritional requirement that is the structural backbone of living matter

A

carbon

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24
Q

Three categories of growth factors

A
  1. purines and pyrimidines
  2. amino acids
  3. vitamins
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25
Q

growth factors that are required for synthesis of nucleic acid.

A

purines and pyrimidines

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26
Q

growth factors that are used by some bacteria for synthesis of proteins, especially by certain pathogenic bacteria requiring specific types of growth factors for their isolation outside a host’s body.

A

amino acids

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27
Q

2 amino acids that Neisseria requires

A

cystine and cysteine

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28
Q

growth factors needed by some bacteria as coenzymes and

functional groups of some enzymes.

A

Vitamins

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29
Q

Bacteria that have special nutritional requirements, esp. growth factors are described as

A

fastidious

30
Q

Four major physical requirements of a bacteria

A
  1. gaseous requirement
  2. Temperature
  3. pH
  4. Ionic strength/osmotic pressure.
31
Q

gas that has the greatest impact on bacterial growth.

A

Oxygen

32
Q

An organism able to grow in the

presence of atmospheric O2

A

aerobe

33
Q

An organism that can grow in the absence of atmospheric O2

A

anaerobe

34
Q

completely dependent on atmospheric O2 (20-21% concentration) for growth.

A

Obligate aerobe

35
Q

does not tolerate O2 at all and die in its presence (> 0.5% concentration)

A

Obligate or strict anaerobe

36
Q

is an aerobe but can grow in the

absence of O2.

A

Facultative anaerobe

37
Q

an anaerobe but can grow in the

presence of O2..

A

Aerotolerant anaerobe

38
Q

requires reduced O2 (2-10%) concentration.

A

Microaerophile

39
Q

forms of oxygen free radicals

A
  1. Singlet oxygen
  2. Superoxide radical or superoxide anion
  3. Peroxide anion
  4. Hydroxyl radical
40
Q

an extremely reactive molecule produced by both living and non-living processes.

A

Singlet oxygen

41
Q

formed in small amounts during the normal respiration of organisms that use oxygen as a final electron acceptor, forming water.

A

Superoxide radical

42
Q

forms when an oxygen molecule combines with another oxygen molecule.

A

Peroxide anion

43
Q

formed in the cell cytoplasm by ionizing radiation.

A

Hydroxyl radical

44
Q

examples of bacteria enzymes that allow them to detoxify harmful forms of oxygen and not be affected by its presence.

A
  1. Superoxide dismutase
  2. Catalase
  3. Peroxidase
45
Q

converts the superoxide radical

into molecular oxygen (O2) and hydrogen peroxide (H2O2).

A

Superoxide dismutase

46
Q

produced by some bacteria in response to the formation of toxic hydrogen peroxide (H2O2) during normal aerobic respiration. It converts H2O2 into water and oxygen.

A

Catalase

47
Q

Another enzyme that breaks down hydrogen peroxide. However, it differs from catalase in that its reaction does not produce oxygen.

A

Peroxidase

48
Q

a chemical that absorbs O2 gas and renders it unavailable to the bacteria where only he surface, which is directly exposed to atmospheric O2, will be oxic.

A

thioglycollate

49
Q

Bacteria that grow best at a higher (3% to 10%) CO2 tension than is normally present in the atmosphere (0.1%)

A

capnophile or capneic

50
Q

lowest temperature at which the species will grow.

A

Minimum temperature

51
Q

the temperature at which the species grows best.

A

optimum temperature

52
Q

the highest temperature at which growth is possible.

A

Maximum temperature

53
Q

cold- loving microbes

A

Psychrophiles

54
Q

Psychrophiles grow best at

A

0C–15C

54
Q

Psychrophiles grow best at

A

0C–15C

55
Q

moderate-temperature- loving microbes

A

Mesophiles

56
Q

Mesophiles optimum temperature for growth fall into the range of

A

20C to 40C

57
Q

Pathogenic bacteria fall under this category.

A

Mesophiles

58
Q

Pathogenic bacteria fall under this category.

A

Mesophiles

59
Q

the optimal temperature of pathogenic bacteria

A

37C

60
Q

heat-loving microbes

A

Thermophiles

61
Q

general range of growth of Thermophiles

A

45C - 80C

62
Q

Most bacteria grow best in a narrow pH range near neutrality, between ___

A

6.5 and 7.5.

63
Q

bacteria that grow best

at a pH range of 1.0 to 5.5.

A

Acidophiles

64
Q

bacteria that grow in environments with a pH greater that 8.5.

A

Alkalinophiles

65
Q

grow best at a pH between 6.0

to 8.0

A

Neutrophiles

66
Q

require environment with high solute (e.g., salt or sugar)

concentration

A

Osmophile

67
Q

requires a high salt (NaCl) concentration for growth.

A

Halophile

68
Q

has the ability to withstand large changes in salt concentration.

A

Halotolerant

69
Q

open systems in which microbial populations are maintained by continuing to supply fresh nutrients to the incubation vessel while simultaneously removing toxic
wastes and excess microorganisms.

A

continuous cultures

70
Q

most common type of continuous

culture device used is

A

chemostat.

Clinical Bacteriology (12 decks)

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