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Theme 2.1 Microbiology > Bacterial growth and metabolism > Flashcards

Bacterial growth and metabolism Flashcards

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Biology 101 flashcards
1
Q

What is Metabolism?

A

Metabolism refers to all the biochemical reactions that occur in a cell or organism.

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2
Q

What is bacterial metabolism?

A

Bacterial metabolism focuses on the chemical diversity of substrate oxidations and dissimilation reactions (reactions by which substrate molecules are broken down), which normally function in bacteria to generate energy.

The bacterial cell is a highly specialized energy transformer

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3
Q

What is heterotrophic metabolism?

A

Heterotrophic metabolism is the biologic oxidation of organic compounds, such as glucose, to yield ATP and simpler organic (or inorganic) compounds, which are needed by the bacterial cell for biosynthetic or assimilatory reactions

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4
Q

What is respiration?

A

Respiration is a type of heterotrophic metabolism that uses oxygen and in which 38 moles of ATP are derived from the oxidation of 1 mole of glucose, yielding 380,000 cal.

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5
Q

What is fermentation?

A

In fermentation, another type of heterotrophic metabolism, an organic compound rather than oxygen is the terminal electron (or hydrogen) acceptor.

Less energy is generated from this incomplete form of glucose oxidation, but the process supports anaerobic growth.

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6
Q

What is the Krebs Cycle?

A

The Krebs cycle is the oxidative process in respiration by which pyruvate (via acetyl coenzyme A) is completely decarboxylated to CO2. The pathway yields 15 moles of ATP (150,000 calories).

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7
Q

What is the Glyoxylate Cycle?

A

The glyoxylate cycle, which occurs in some bacteria, is a modification of the Krebs cycle. Acetyl coenzyme A is generated directly from the oxidation of fatty acids or other lipid compounds.

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8
Q

Electron Transport and Oxidative Phosphorylation

A

In the final stage of respiration, ATP is formed through a series of electron transfer reactions within the cytoplasmic membrane that drive the oxidative phosphorylation of ADP to ATP. Bacteria use various flavins, cytochrome, and non-heme iron components as well as multiple cytochrome oxidases for this process.

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9
Q

What are Heterotrophs and Autotrophs?

A

> Heterotroph
an organism that obtains carbon in an organic form made by other living organisms

Autotroph
> an organism that uses CO2 (an inorganic gas) as its carbon source
> not dependent on other living things

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10
Q

What are the types of Heterotrophs?

A
  1. Saprobes

2. Parasites/pathogens

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11
Q

What are the ways of nutritional movement in Bacteria?

A
  1. Osmosis
  2. Facilitated diffusion
  3. Active transport
  4. Endocytosis
    > Phagocytosis
    > Pinocytosis
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12
Q

What is extracellular digestion?

A

> digestion of complex nutrient material into simple, absorbable nutrients

> accomplished through the secretion of enzymes (exoenzymes) into the extracellular environment

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13
Q

What are the environmental influences on microbial growth?

A
  1. temperature
  2. oxygen requirements
  3. pH
  4. Osmotic pressure
  5. UV light
  6. Barophiles
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14
Q

Temperature types

A
  1. Minimum temperature
    the lowest temperature that permits a microbe’s growth and metabolism
  2. Maximum temperature
    the highest temperature that permits a microbe’s growth and metabolism
  3. Optimum temperature
    promotes the fastest rate of growth and metabolism
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15
Q

What are the temperature adaptation groups?

A
  1. Psychrophiles
    optimum temperature 15oC
    capable of growth at 0 - 20oC
  2. Mesophiles
    optimum temperature 40oC
    Range 10o - 40oC (45)
    most human pathogens
  3. Thermophiles
    optimum temperature 60oC
    capable of growth at 40 - 70oC
  4. Hyperthermophiles
    Archaea that grow optimally above 80°C
    hot-water vents
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16
Q
  1. Psychrophiles
A

optimum temperature 15oC

capable of growth at 0 - 20oC

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17
Q
  1. Mesophiles
A

optimum temperature 40oC
Range 10o - 40oC (45)
most human pathogens

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18
Q
  1. Thermophiles
A

optimum temperature 60oC

capable of growth at 40 - 70oC

19
Q
  1. Hyperthermophiles
A

Archaea that grow optimally above 80°C

hot-water vents

20
Q

What are the different Oxygen requirements and degrees of dependence?

A
  1. Aerobe
    - requires oxygen
  2. Obligate aerobe
    - cannot grow without oxygen
  3. Anaerobe
    - does not require oxygen
  4. Obligate anaerobes die in the presence of oxygen
  5. Aerotolerant bacteria
    • not affected at all by oxygen, evenly spread along the test tube.
  6. Facultative anaerobe and aerobe
    - capable of growth in the absence OR presence of oxygen.
21
Q

The pH scale

A

The pH Scale

-Ranges from 0 - 14

-pH below 7 is acidic
[H+] > [OH-]

-pH above 7 is alkaline
[OH-] > [H+]

-pH of 7 is neutral
[H+] = [OH-]

22
Q

What are the different types of organisms that have different pH optimum levels?

A
  1. Acidophiles
    optimum pH is relatively to highly acidic
  2. Neutrophiles
    optimum pH ranges about pH 7 (plus or minus)
  3. Alkaphiles
    optimum pH is relatively to highly basic
23
Q

How does Osmotic pressure influence microbial growth?

A

-Bacteria are 80% water, so they Require water to grow.

-Sufficiently hypertonic media at concentrations greater than those inside the cell cause water loss from the cell
>Osmosis
> The fluid leaves the bacteria causing the cell to contract = Causes the cell membrane to separate

Plasmolysis
Cell shrinkage

Extreme or obligate halophiles
Adapted to and require high salt concentrations

24
Q

Plasmolysis

A

Cell shrinkage

25
Q

What are extreme or obligate halophiles?

A

Adapted to and require high salt concentrations

26
Q

How does UV light affect microbial growth?

A

-UV light is great for killing bacteria

  • Damages the DNA (making little breaks)
  • in sufficient quantities, the breaking can kill the organisms
  • in a lower range causes mutagenesis

> Endospores tend to be resistant and
can survive much longer exposures

27
Q

How do Barophiles affect microbial growth?

A

-Bacteria in oceans grow at moderately high hydrostatic pressures.

> membranes and enzymes depend on pressure to maintain their three-dimensional, functional shape

  1. Barotolerants
    Grows at pressures from 100-500
  2. Barophilic
    400-500
  3. Extreme barophilic
    Higher than 500
28
Q

Microbial association can be: 2 types

A
  1. Symbiotic

2. Non-symbiotic

29
Q

Symbiotic associations

A

When organisms live in close nutritional relationships

30
Q

What are the types of symbiotic associations? (3)

A
  1. Mutualism
    Obligatory
    Dependent
    Both members benefit
  2. Commensalism
    One member benefits
    Other member not harmed
  3. Parasitism
    Parasite is dependent and benefits
    Host is harmed
31
Q

What are the types of Non-symbiotic associations?

A

When organisms are free-living, relationships not required for survival

32
Q

Synergism

A

members cooperate and share nutrients

33
Q

Antagonism

A

some members are inhibited or destroyed by others

34
Q

What are BIOFILMS?

A

Complex relationships among numerous microorganisms.

Develop an extracellular matrix which:

  1. Adheres cells to one another.
  2. Allows attachment to a substrate.
  3. Sequesters nutrients.
  4. May protect the individual population of bacteria in the biofilm.
35
Q

What is BINARY FISSION?

A

> Prokaryotes reproduce asexually

> one cell becomes two: basis for population growth

Process:
parent cell enlarges
duplicates its chromosome
forms a central septum 
divides the cell into two daughter cells
36
Q

What is the process of binary fission?

A 
Process:
1. parent cell enlarges
2. duplicates its chromosome
3. forms a central septum 
divides the cell into two daughter cells
37
Q

In population growth: what is Generation/doubling time?

A

Generation/doubling time:

  • Is the time required for a complete fission cycle.
  • Length of the generation time is a measure of the growth rate of an organism.
  • Some populations can grow from a small number of cells to several million in only a few hours!!
38
Q

In Prokaryotic growth: What are the phases in the Bacterial Growth curve?

A
  1. Lag phase
  2. Logarithmic phase
  3. Stationary phase
  4. Decline phase
39
Q

Bacterial Growth Curve + describe their phases

A
  1. lag phase
    no cell division occurs while bacteria adapt to their new environment
  2. logarithmic (log) phase
    The exponential growth of the population occurs
    Human disease symptoms usually develop
  3. stationary phase
    When reproductive and death rates equalize
  4. decline (exponential death) phase
    accumulation of waste products and scarcity of resources
40
Q

What are the other Methods of Analyzing Population Growth?

A
  1. Turbidity
  2. Direct microscopic count
  3. Coulter counting
41
Q

Turbidity - describe

A

.

42
Q

Direct microscopic count - describe

A

.

43
Q

Electric counting - describe

A

.

Theme 2.1 Microbiology (10 decks)

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