Introduction Flashcards

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1
Q

What limits life on Earth?

A

Temperature, pH, water availability, radiation, nutrients

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2
Q

Give four examples of Earth processes that are catalysed by microorganisms

A

Maintaining chemical balance, mineral formation, mineral diagenesis, mineral dissolution

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3
Q

What groups are prokaryotes?

A

Bacteria and archaea

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4
Q

Describe prokaryotes

A

No nucleus or organelles, small, no meiosis, single DNA molecule

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5
Q

Describe eukaryotes

A

Nucleus, organelles (inc. mitochondris, chloroplasts), meiosis, chromosomes

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6
Q

What does meiosis lead to?

A

Genetic variation

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7
Q

Compare the suitable conditions for prokaryotes versus eukaryotes

A

Prokaryotes are much less limited by conditions, including temperature, pH, salinity, and organic/inorganic energy sources

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8
Q

Define heterotrophy

A

Gaining energy and carbon for growth from the oxidation of organic compounds

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9
Q

Define autotrophy

A

Forming nutritional organic substnaces from simple inorganic substances
Fixing its own nitrogen

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10
Q

Define chemolithotrophy

A

Gaining enegry from oxidation of inorganic compounds, taking up carbon as CO2, HCO3^-, or CO3^2-

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11
Q

Give six examples of elements needed by microorganisms

A

Carbon, nitrogen, phosphorus, sulphur, iron, trace elements

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12
Q

What do microorganisms need for the production of ATP?

A

Electron donor and electron acceptor

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13
Q

What are electron donors? Give two examples

A

Elements/moleucles that act as oxidising agents
Glucose and Fe(II)

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14
Q

What are electron acceptors? Give an example

A

Elements/molecules that act as reducing agents
Oxygen

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15
Q

Describe energy metabolism

A

Electron flow from fuels to oxidants

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16
Q

What causes the stratification of microbial communities?

A

Some substrates are easier to oxidise/reduce than others

17
Q

Why is oxygen absent in many sediments?

A

The metabolism of oxygen generates the most energy so it is used first

18
Q

What is the cascade of terminal electron accepting processes?

A

The order in which substrates are reduced during energy metabolism

19
Q

Give three examples of fuels in energy metabolism

A

Sunlight, glucose (organic), hydrogen (inorganic)

20
Q

Give two examples of oxidants in energy metabolism

A

Fumarate (organic), carbon dioxide (inorganic)

21
Q

What can energy metabolism be used for?

A

Remediation of organics/metals

22
Q

What can anaerobic respiration cause?

A

Alteration of the physical/chemical structure of sediments

23
Q

Describe the central dogma

A

DNA is transcribed to RNA (no Ts), RNA is translated to polypeptides

24
Q

Describe DNA

A

Has a sugar phosphate backbone and complimentary strands
Base pairings: A-T, G-T

25
Q

Describe the primary structure of proteins

A

Amino acid sequence of polypeptide chain

26
Q

Describe the secondary structure of proteins

A

Local interactions between stretches of polypeptide chain produces α-helix or β-pleated sheet

27
Q

Describe the tertiary structure of proteins

A

3d structure of entire polypeptide chain

28
Q

Describe bonding in carbohydrates

A

The type dictates which polymer is produced

29
Q

Describe Gram-positive bacteria

A

Thick outer layer of peptidoglycan (a carbohydrate)
Stains purple (retains stain containing iodine)

30
Q

Describe Gram-negative bacteria

A

Thin layer of peptidoglycan is surrounded by lipopolysaccharide and protein
Colourless or the colour of the counterstain (red)

31
Q

Describe the lipid bilayer of microbes

A

Each side has a polar head
Embedded with proteins for transport and energy generation

32
Q

Describe the production of ATP

A

Charges are separted by a semi-permeable membrane, H+ is pumped out by the e- transport chain, producing protonmotive force (pmf), ATPase converts pmf into energy, allowing H+ to flow back in, this energy is used to synthesise ATP