Block A 1 Flashcards

1
Q

3 things that microorganisms are involved in

A

-production of food and drinks
-decomposition of organic matter
-maintenance of earth’s ecosystems

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2
Q

oldest known microorganism and age

A

fossilised stromatolites
3.5 billion years old

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3
Q

estimated mass of bacteria on earth

A

5x10^30 grams

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4
Q

where are most of the estimated biomass found

A

soil and oceans

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5
Q

what is the carbon cycle

A

decomposition of organic matter releases CO2 through respiration
also plays role in formation of fossil fuels by converting dead plant and animal material into hydrocarbons

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6
Q

what is the nitrogen cycle

A

convert N2 into forms plants and animals can use, eg ammonia (NH3), nitrite (NO2-), and nitrate (NO3-)

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7
Q

what is the name given to the process used in the nitrogen cycle

A

nitrogen fixation
essential for growth of plants and survival of many organisms

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8
Q

what is the sulfur cycle

A

oxidisation of sulfur compounds (eg hydrogen sulphide (H2S)) and conversion into sulfuric acid (H2SO4)

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9
Q

what does the sulfur cycle play a role in

A

geochemical cycling of sulfur and formation of sulfur minerals

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10
Q

what is the phosphorus cycle

A

release of phosphate from minerals, an essential nutrient for plants and animals

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11
Q

what does the phosphorus cycle play a role in

A

formation of bone and teeth
by converting phosphates into hydroxyapatite

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12
Q

what is the iron cycle

A

oxidisation of iron compounds (ferrous iron) and conversion into ferric iron

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13
Q

what does the iron cycle play a role in

A

geochemical cycling of iron and the formation of iron minerals

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14
Q

what organism survives at high temps

A

thermophiles and hyperthermophiles
176°F (80°C) and higher
volcanic hot springs, geysers, and deep sea hydrothermal vents

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15
Q

what organism survives at low temps

A

psychrophiles
-112°F (-80°C) polar ice, permafrost

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16
Q

what organism survives at high pressures

A

piezophiles
1800x atmospheric pressure
deep sea hydrothermal vents and subsurface oil reservoirs

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17
Q

what organism survives at high salinities

A

halophiles
salt flats and salt mines

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18
Q

what organism survives at high radiation

A

deinococcus radiodurans
nuclear waste sites, space

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19
Q

what organism survives at high acidity

A

acidophiles
acid mine drainage, acid hot springs, acid soils

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20
Q

why do plants require microbes to survive

A

microbial symbionts (rhizobia) which live in their roots convert atmospheric N2 into a form that plants can use and is essential for growth of plants (nitrogen fixation)

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21
Q

why do animals require microbes to survive

A

microorganisms digest their food
eg ruminant microbes break down plant materiak and termite microbes digest wood

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22
Q

why do animals require microbes to survive

A

microorganisms digest their food
eg ruminant microbes break down plant materiak and termite microbes digest wood

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23
Q

why do humans require microbes to survive

A

gut microbiome is important for digestion, metabolism, immunity, and production of vitamins and other essential compounds

24
Q

why does marine life require microbes to survive

A

responsible for primary production
the process of converting dissolved inorganic compounds into organic compounds, which forms the base of the ocean food web

25
Q

why does soil require microbes to survive

A

break down dead plants and animals, releasing nutrients back into soil
help maintain soil structure by forming microbial aggregates that help to retain water and air

26
Q

structure of prokaryotes

A

no membrane enclosed organelles
no nucleus
generally smaller than eukaryotic cells

27
Q

structure of eukaryotes

A

DNA enclosed in a membrane bound nucleus
cells are generally larger and more complex
contain organelles

28
Q

eukaryotic DNA

A

linear and found within nucleus
usually more than one chr
typically 2 copies of each chr

29
Q

prokaryotic DNA

A

single circular DNA mol called chromosome
also may have small amounts of extrachromosomal DNA called plasmids (may confer special properties, antibiotic resistance)

30
Q

what is a genome

A

a cell’s full complement of genes

31
Q

E.coli genome compared with the human cell

A

-e coli
4.64 mil base pairs
4300 genes
-human cell
1000X more DNA per cell than E coli
7X more genes than E.coli

32
Q

what is metabolism

A

chemical transformation of nutrients

33
Q

what is reproduction

A

generation of two cells from one

34
Q

what is differentiation

A

synthesis of new substances or structures that modify the cell (only in some microbes)

35
Q

what is communication

A

generation of, and response to, chemical signals (only in some microbes)

36
Q

what is movement

A

via self propulsion, many forms in microbes

37
Q

what is evolution

A

the process of change over time that results in new varieties and species of organisms

38
Q

what is phylogeny

A

evolutionary relationships between organisms
relationships can be deduced by comparing genetic info in the different specimens
relationships visualized on a phylogenetic tree

39
Q

what type of RNA is excellent for determining phylogeny

A

rRNA

40
Q

comparative rRNA sequencing has defined 3 distinct lineages of cells called domains, what are they

A

bacteria (prokaryotic)
archaea (prokaryotic)
eukarya (eukaryotic)

41
Q

what 2 are more closely related (bacteria, archaea, or eukarya)

A

archaea are more closely related to eukarya than bacteria

42
Q

what are microbial communities

A

microorganisms exist in nature in populations of interacting assemblages

43
Q

what does habitat mean

A

environment in which a microbial population lives in

44
Q

what is an ecosystem

A

refers to all living organisms plus physical and chemical constituents of their environment

45
Q

what is the study of microbial ecology

A

study of microbes in their natural environment

46
Q

what is the diversity and abundances of microbes controlled by

A

resources (nutrients) and environmental conditions (temp, pH, O2)

47
Q

what can the activities of microbial communities affect

A

the chemical and physical properties of their habitiats

48
Q

what are extremophiles and what environments do they grow in

A

bacteria and archaea
-very hot or very cold
-very acidic or very caustic
-very salty or osmotically stressing
-very high pressure

49
Q

where are most microbial cells found

A

oceanic and terrestrial subsurfaces

50
Q

cells are key reservoirs of what essential nutrients

A

C, P, N

51
Q

positive impacts of microorganisms and agriculture

A

N-fixing bacteria
cellulose degrading microbes in the rumen
regeneration of nutrients in soil and water

52
Q

negative impacts of microoganisms and agriculture

A

disease in plants and animals

53
Q

negative impacts of microorganisms and food

A

cause food spoilage, methods of preservation are needed

54
Q

positive impacts of microorganisms and food

A

fermentation
cheeses, yogurt, buttermilk
beer, leavened breads etc

55
Q

microorganisms, energy, and the environment

A

role of microbes in production of biofuels
eg methane, ethanol, hydrogen
role of microbes in cleaning up pollutants (bioremediation)

56
Q

what did pastuer discover

A

-living organisms discriminate between optical isomers
-alcoholic fermentation was a biologically mediated process
-theory of spontaneous generation
leading to development of methods for controlling growth of microorganisms

57
Q

what did koch discover

A