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Microbial Growth/microorganisms Flashcards

(72 cards)

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1
Q

What are microorganisms?

A

-living organisms
-subject of microbiology
Microbiology is a biology of microorganisms (tiny organisms visible only under a miscroscope)

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2
Q

Who discovered bacteria?

A

Anthony Van Leeuwenhoek

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3
Q

Life is a?

A

Genetic program with metabolism and growth to aid replication

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4
Q

What are the 3 domains of life?

A

Bacteria, archaea and prokaryotes

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5
Q

Explain bacteria, archaea and eukarya?

A

Bacteria and Archaea are prokaryotes: will always be microorganisms

Eukarya are eukaryotes: microorganisms and macro organisms (uni cellular and multicellular)

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6
Q

Organisms and biological entities studied by microbiologists can be?

A

Cellular or acellular

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7
Q

Give examples of cellular organisms?

A
  • fungi (yeasts,molds)
  • Protists (algae)
  • bacteria (e Coli)
  • archaea (methanogens)
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8
Q

Give examples of acellular organisms? (1 cell)

A
  • viruses (protein and nuclei acid)
  • viroids (composed of RNA)
  • satellites (composed of nucleic acid enclosed in a protein shell)
  • prions (protein)
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9
Q

Who introduced the term bacterium and when?

A

Christian Gottfried Ehrenberg (German naturalist) in 1828

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10
Q

How do microorganisms appear to life?

A
  • self generation (from non living matter)

- generation from themselves

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11
Q

Instead of a nucleus what does a prokaryote have?

A

A nucleiod

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12
Q

How is it better to be a smaller cell than a bigger one?

A

Smaller cells have larger area to volume ratio therefore they exchange substances faster

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13
Q

How are smaller cells at advantages (bc of fast exchange?)

A

Bc metabolism, reproduction and cell communication occur faster therefore greater chances of survival and evolution

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14
Q

What are the 4 main classes of compounds that differentiate a living cell from a non living cell?

A

Proteins (structural components of the cell, enzymes and regulators, synthesised in ribosomes)

Nucleic acids (genetic material: DNA/RNA)

Lipids (components of cell membrane, cell wall, storage granule)

Polysaccharide (components of cell walls and capsule)

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15
Q

Chemistry of life includes what processes?

A

Synthesis and decay (anabolism and catabolism

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16
Q

What are nutrients ?

A

Substances required for metabolism and reproduction of cells
Macronutrients are required in large amounts
Micronutrients are required in small amounts

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17
Q

What is metabolism ?

A

Uptake is nutrients into the environment, their transformation within the cell and elimination of wastes into the environment. (The cell is an open environment)

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18
Q

What do metabolic activities do for the cell?

A

They make them chemically very complex and diverse (cell is an open system)

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19
Q

What is reproduction (growth) in terms of a cell?

A

Chemicals from the environment are turned into new cells under the direction of preexisting cells

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20
Q

What is reproduction based on?

A

Replication of DNA

Equal distribution of replicated DNA into 2 cells after division of the initial cell

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21
Q

Why is reproduction important ?

A
  • it’s the fundamental feauture of life
    -ensures existence of species and their evolution
    It’s a core way of colonisation of a host by pathogenic microbes causing diseases
    Impo part in many technological processes
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22
Q

What’s differentiation ?

A

Formation of a new cell structure such as a spore, usually as part of a cellular life cycle
Differentiation is NOT a compulsory property of all microbial cells but those species that form spores survive better unfavourable conditions

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23
Q

What’s communication ? And what’s a consequence of it

A

Cells communicate or interact primarily by means of chemicals that are released or taken up
One of he consequences of cell communication is the ‘quorum sensing mechanism’. It allows a population to sense critical amount of cells and stop divisions.

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24
Q

Is movement compulsory ?

A

Living organisms are often capable of self propulsion. Motility is not a compulsory property of all microbes.

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25
What’s evolution ?
Cells evolve to display new biological properties. Phylogenetic trees show the evolutionary relationships between cells.
26
What are coding functions ?
Genetic processes based on information encoded by DNA
27
What are machine functions ?
Biochemical and physiological processes based on metabolism.
28
What’s binary fission?
See pictures in album
29
What’s a basic technique in microbiology to count viability of cells?
Using serial dilutions.
30
What are 5 stages of microbial growth in a closed system ?
``` Lag phase Log phase Stationary phase Death phase Long term stationary phase ```
31
How does temp affect growth?
There is an optimum temp for growth (above this enzymes denature)
32
Does sodium chloride affect microbial growth?
Yes, there’s an optimum NaCl conc level on moderate halophile growth
33
What does evaporation of sea water result in?
Crystalliser ponds with: concentration and precipitation of calcium carbonate, calcium sulphate, NaCl and MgCl
34
What happens at the last stage of halite formation? (Before MgCl is precipitated)
The square bacteria dominate 80% of the total microbial biomass
35
Chemistry of life includes 2 complementary processes known as?
Synthesis and breakdown: anabolism (energy consuming) and catabolism (energy releasing) Anabolism and catabolism=metabolism
36
Do synthesis and breakdown occur only in living cells?
No anywhere in nature behind living organism
37
What are the main features of chemical reactions outside of living cells?
- occur spontaneously - without particular control - wherever whenever possible - rapid reactions
38
What are the main feautures Of biochem reactions (IN living cells)?
- they occur in a certain order and in certain components of the cell - they are under strict control due to regulatory mechanisms - don’t occur at any time - very slow due to catalysts
39
Chemical compounds from the cell are formed from?
Small no of nutrients
40
What are nutrients ?
Substances required for metabolism and reproduction of cells
41
Macronutrients and micronutrients are required in what amount ?
Macronutrients are required in larger amounts | Micronutrients are required in small amounts
42
What is nutrition ?
The process of uptake and initial processing of nutrients
43
Do prokaryotes have specialised structures for nutrition?
No in contrast to higher organisms prokaryotes don’t. | The whole prokaryotic cells is involved into nutrition all the time during active reproduction
44
What happens when nutrition is limited due to lack of nutrients?
The bacterial growth is inhibited, many bacterial species could undergo sporulation (temporary state of conservation)
45
What’s anabolism?
It requires energy as it’s the synthesis of cell constituents from simpler molecules
46
What’s catabolism?
Releases energy. Leads to the breakdown of complex compounds into simple substances
47
When do anabolism and catabolism occur in living cells?
All the time. They could occur at the same time representing 2 alternative trends of metabolism.
48
What are chemotrophs?
They oxidise a broad range of organic and inorganic compounds to produce ATP
49
What are phototrophic organisms?
Convert solar energy to chemical energy and produce ATP.
50
Whats the difference between autotrophs and heterotrophs?
Autotrophs use inorganic CO2 as a single source of carbon, (eg- phototrophs/chemolitotrophs) heterotrophs need one or more organic compounds as a source of carbon (eg chemoorganotrophs)
51
What are the 2 major forms of autotrophy?
Oxygenic photosynthesis- o2 is evolved (in Cyanobacteria) Anoxygenic photosynthesis- oxygen is not produced (purple and green bacteria)
52
Differences in processes of obtaining energy makes what?
Makes a basis for metabolic diversity of all microorganisms, not only bacteria or archaea Differences in metabolism form a basis for structural differences that are integrated in morphological diversity of organisms
53
Basic scheme of catabolism is ?
Proteins into amino acids Polysaccharides into pyruvate and that into Acetyl CoA and that into kerbs cycle into ATP Lipids into fatty acids
54
What does catabolism include?
Fermentation and respiration If there’s no o2: fermentation occurs be if there is o2: respiration occurs These are 2 ways of conservation of energy from organic sources of carbon
55
Both fermantation and respiration occur when?
After glycolysis
56
Citric acid cycle is what?
A way of generating ATP via respiration after glycolysis
57
Citrix acid/Kreb cycle has bioenergetic and biosynthesis roles such as?
It produces important compounds for anabolism (biosynthesis) A-ketoglurate and oxalacetate (precursors of amino acids) Succinyl CoA
58
What is carbon for cells?
A major macronutrient for all living cells (50% dry weight) A component for all macromolecules Methane is the simplest organic compound- can from many variations of organic matter
59
What’s the second most abundant element of the cell? (12% of dry weight)
Nitrogen- included into proteins, nucleic acids and other cell components Nitrogen is available in organic and mostly inorganic forms (ammonia, nitrate)
60
What do most bacteria use as a single nitrogen source?
Most use ammonia, some use nitrates and nitrogen fixing bacteria use N2 as a single nitrogen source
61
What are the other essential macronutrients ?
Phosphorus- needed for nucleic acids and phospholipids Sulphur- for amino acids cysteine and methionine Potassium- required for many enzymes: protein synthesis Magnesium- needed for stability of ribosomes memebranes and nucleic acids Calcium (not essential for many microorganisms) stabilises cell walls Sodium (required by some microrganisms) not all
62
Essentially macromolecules continued- where do cells obtain iron from?
Iron- plays a role in respiration. Needed in less amounts that other macronutrients Cells obtain iron from different insoluble minerals by specialised components: siderophores Siderophores are different organic compounds that bind to iron and transport it into cells
63
Give examples of siderophores,
Enterobactins | Some prokaryotes can grow without Fe and have Mn2+ instead of Fe containing enzymes
64
How many micronutrients are needed?
They are needed in trace amounts
65
What are growth factors
``` Organic compounds (vitamins amino acids etc) needed by some cells in small amount Vitamins are the most required growth factors ```
66
What is a culture medium?
Nutritional mixtures for cultivation of microorganisms in Lab and industry Can be chemically defined or undefined
67
What media are used for isolation of particular species or for comparative studies ?
Selective, differential and enriched media
68
What is solid media useful for ?
Isolation and maintenance of pure microbial cultures. | They immobilise cells, allowing them to grow and form visible isolated aggregates of cells.
69
What’s liquid media used for ?
Rapid and large scale cultivation of pure microbial cultures.
70
Explain bacteria plant symbioses
It occurs between legumes and some nitrogen fixing bacteria (rhizobium) The plant provides the energy source needed by the root nodule bacteria, and the bacteria provide fixed nitrogen for the growth of the plant
71
Explain how rhizobium ( nitrogen fixing bacteria) do bacteria plant symbioses
Rhizobial cells enter into the root hair via the root hair tip and cause nodule formation Rhizobia multiply rapidly first in the plant cells and are transformed into swollen branched bacteroids
72
What does symbiotic nitrogen fixation do?
Enhances the production of many important crops

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