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BM211 microbiology > Block A > Flashcards

Block A Flashcards

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Biology 101 flashcards
1
Q

what is the carbon cycle

A

decomposition of organic matter realising CO2 through respiration

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2
Q

what is the nitrogen cycle

A

converts nitrogen gas into forms that plants and animals can use such as ammonia, nitrite and nitrate

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3
Q

what is the sulphur cycle

A

some microorganisms can oxidize sulfur compounds, such as hydrogen sulfide (H2S), and convert them into sulfuric acid (H2SO4)

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4
Q

what is the phosphorus cycle

A

involved in the release of phosphate (PO43-) from minerals, which is an essential nutrient for plants and animals

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5
Q

iron cycle

A

some microorganisms can oxidize iron compounds, such as ferrous iron (Fe2+), and convert them into ferric iron (Fe3+)

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6
Q

what kind of microorganisms survive at high temperatures

A

thermophiles and hyperthermophiles can survive and grow at temperatures as high as 176°F (80°C) and even higher such as volcanic hot springs, geysers, and deep-sea hydrothermal vents.

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7
Q

what kind of microorganisms survive at low temperatures

A

psychrophiles can survive and grow at temperatures as low as -112°F (-80°C) such as polar ice, permafrost, and deep-sea sediments.

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8
Q

what kind of microorganisms survive at high pressures

A

piezophiles can survive and grow at pressures as high as 1,800 times atmospheric pressure such as deep-sea hydrothermal vents and subsurface oil reservoirs.

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9
Q

what kind of microorganisms survive at high salinities

A

halophiles can survive and grow in environments with very high salt concentrations, such as salt flats and salt mines.

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10
Q

what kind of microorganisms survive at high radiation

A

Deinococcus radiodurans can survive and grow in environments with high levels of radiation, such as nuclear waste sites and space.

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11
Q

what kind of microorganisms survive at high acidity

A

acidophiles can survive and grow in environments with very high acidity, such as acid mine drainage, acid hot springs, and acid soils.

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12
Q

structure of prokaryote

A

No membrane-enclosed organelles, no nucleus,
generally smaller than eukaryotic cells

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13
Q

structure of eukaryote

A

DNA enclosed in a membrane-bound nucleus
Cells are generally larger and more complex
Contain organelles

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14
Q

what kind of DNA is found within eukaryotic

A

linear found within the nucleus

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15
Q

what kind of DNA is found within prokaryotic cells

A

singular, circular DNA molecules called a chromosome

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16
Q

what is metabolism

A

chemical transformation of nutrients

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17
Q

what is reproduction

A

generation of two cells from one

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18
Q

what is differentiation

A

synthesis of new substances or structures that modify the cell

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19
Q

what is communication

A

generation of and response to chemical signals

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20
Q

what is evolution

A

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

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21
Q

what is phylogeny

A

evolutionary relationships between organisms, rRNA is excellent for determining phylogeny

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22
Q

Comparative rRNA sequencing has defined three distinct lineages of cells called domains:

A

bacteria (prokaryotic)
archaea (prokaryotic)
eukarya (eukaryote)

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23
Q

positive impacts of microbial activities on agriculture

A

nitrogen-fixing bacteria, cellulose-degrading microbes in the rumen, regeneration of nutrients in soil

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24
Q

negative impacts of microbial activities on agriculture

A

diseases in plants and animals

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25
Q

negative impacts of microorganisms on food

A

can cause food spoilage, many foods require methods of preservation

26
Q

positive impacts of microorganisms on food

A

microbial transformations yield dairy products and other food products including sauerkraut, pickles, leavened breads and beer

27
Q

who was first to describe microbes

A

Robert hooke (1635-1703)

28
Q

what are homodimeric proteins

A

proteins composed of two identical polypeptides

29
Q

what is the oldest known microorganism

A

fossilised stromatolites- 3.5 billion years ago

30
Q

what is the mass of bacteria on earth

A

5x10^30 grams

31
Q

what enzyme catalyses DNA supercoiling

A

DNA Gyrase

32
Q

what is a chromosome

A

Large, encodes all essential genes and more

33
Q

what are plasmids

A

small, many copies, non essential but advantageous genes (e.g. antibiotic resistance)

34
Q

what are homedimeric proteins

A

proteins composed of two identical polypeptides

35
Q

what are outcomes after DNA binding

A

DNA-binding protein may catalyze a specific reaction on the DNA molecule (i.e., transcription by RNA polymerase)
The binding event can block transcription 
(negative regulation)
The binding event can activate transcription 
(positive regulation)

36
Q

what is an inducer

A

substance that induces enzyme synthesis

37
Q

what is a corepressor

A

substance that represses enzyme synthesis

38
Q

what are effectors

A

collective term for inducers and repressors
Effectors affect transcription indirectly by binding to specific DNA-binding proteins
Repressor molecules bind to an allosteric repressor protein
Allosteric repressor becomes active and binds to region of DNA near promoter called the operator

39
Q

what are operons

A

cluster of genes arranged in a linear fashion whose expression is under control of a single operator
Operator is located downstream of the promoter
Transcription is physically blocked when repressor binds to operator

40
Q

what is a repressor

A

can control enzyme induction, addition of inducer inactivates repressor, and transcription can proceed.
repressor’s role is inhibitory so its called negative control

41
Q

what is negative control

A

a regulatory mechanism that stops transcription

42
Q

what is positive control

A

regulator protein activates the binding of RNA polymerase to DNA

43
Q

negative control repression

A

prevents the synthesis of an enzyme in response to signal, enzymes affected by repression make up small fraction of total proteins, typically effects anabolic enzymes and

44
Q

negative control induction

A

production of an enzyme in response to a signal, typically affects catabolic enzymes, enzymes are synthesised only when they are needed

45
Q

positive control activation

A

genes for maltose are spread out over the chromosome in several operons. each operon has an activator-binding site

46
Q

global control systems

A

regulate expression of many different genes simultaneously

47
Q

what is quorum sensing

A

mechanism by which bacteria assess their population density

48
Q

what shape is coccus

A

spherical or ovoid

49
Q

what shape is rod

A

cylindrical shape

50
Q

phototrophs energy source

A

photosynthetic, energy from sunlight

51
Q

chemotrophs energy source

A

energy from oxidation of chemicals

52
Q

what is autotrophic

A

an organism that can make organic molecules from inorganic nutrients

53
Q

what is heterotrophic

A

an organism that cannot make organic molecules from inorganic nutrients, depends on OM for energy generation and precursors for cell material

54
Q

what are cyanobacteria

A

type of photoautotrophs that use hydrogen atoms from water to reduce carbon dioxide to form carbohydrates, produce oxygen gas

55
Q

what are lichens

A

an association between two partners: an ascomycete (fungus) and a cyanobacterium.
Cyanobacteria provide organic compounds via photosynthesis, and can fix nitrogen
Fungus provides protection, water retention, extracts minerals and nutrients from substrate

56
Q

what do chemoautotrophs do

A

fix carbon dioxide to make organic compounds, obtain energy from mainly inorganic chemicals

57
Q

what are halobacteria

A

a type of photoheterotrophs, that possess the protein bacteriorhodopsin, light energy is used to transfer protons across the membrane out of the cell, resulting protein gradient is used to generate ATP, cannot fix CO2

58
Q

what are chemoheterotrophs

A

the most common nutritional mode, uses organic compounds for both carbon requirement and energy generation. most bacterial pathogens are chemoheterotrophs

59
Q

what is a regulon

A

multiple operons controlled by the same regulatory protein

60
Q

who was first to describe bacteria

A

Antoni van Leeuwenhoek (1632-1723)

61
Q

who founded the field of bacterial classification and discovered bacterial endospores

A

Ferdinand cohn (1828-1898)

BM211 microbiology (5 decks)

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