Unit 2-- Lecture 7 (Microbial Metabolism) Flashcards

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1
Q

All life requires:

A

Electron flow: to drive all life process

Energy: to move electrons

Materials: to make cell parts
—-nutrients

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2
Q

Macronutrients

A

Major elements in cell macromolecules

C, O, H, N, P, S

Ions necessary for protein function

Mg2+, Ca2+, Fe2+, K+

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3
Q

Micronutrients

A

Trace elements necessary for enzyme function

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4
Q

Heterotrophs

A

Use organic carbon

C-H bonds

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5
Q

Autotrophs

A

Use carbon dioxide (CO2)

No hydrogens

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6
Q

Phototrophs

A

Light energy excites electrons

Excited molecules are electron donors

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7
Q

Chemotrophs

A

Chemicals are electron donors

Oxidation of chemical

Oxidation: donation of electrons (lose)

Reduction: accepting electrons (gain)

OIL RIG

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8
Q

Lithotrophs

A

Inorganic molecules are electron donors

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9
Q

Organotrophs

A

Organic molecules are electron donors

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10
Q

Respiration

A

Inorganic molecules

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11
Q

Fermentation

A

Organic molecules

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12
Q

Passive Diffusion

A

Some gases pass freely through membranes
—-O2, CO2

Follows gradient of material

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13
Q

Facilitated Diffusion

A

Transporters pass material into/out of cell

Follows gradient of material

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14
Q

ABC Transporters (Active Transport)

A

Use ATP energy to pass material into cell

Transport material against gradient

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15
Q

Symport and Antiport

A

Gradient of one molecule transports another
—-electron transport creates Proton-Motive Force (PMF)
—-PMF transports other molecules

Transports material against its gradient

Symport: same direction

Antiport: opposite direction

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16
Q

Phosphotransferase System–PTS (Active Transport)

A

Uses high-energy phosphate to pass material into cell

Modifies material as it enters cell
—-gradient is maintained, pushing material into cell

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17
Q

Catabolism

A

Breaking down molecules for energy

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18
Q

Anabolism

A

Using energy to build cell components

Reducing entropy, creating order

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19
Q

Metabolism

A

Balance between catabolism and anabolism

Central biochemical pathways used for both
—-TCA cycle
—-glycolysis
—-pentose phosphate shunt

20
Q

Enzymes

A

Biological catalysts

Nearly always proteins

Active site

Substrate(s)

Cofactors
—-metals
—-vitamins

21
Q

Gibbs Free Energy

A

dG = dH - TdS

dH: change in enthalpy (heat)

dS: change in entropy (disorder)

dG must be negative for reaction to occur

dG depends on reaction concentration
dG = dG* + RT ln ([C][D]/[A][B])

Low product concentration can drive reaction

22
Q

Activation Energy

A

the minimum energy required to cause a process (such as a chemical reaction) to occur

23
Q

Exergonic Reaction

A

a chemical reaction where the change in the free energy is negative

occurs spontaneously

24
Q

Endergonic Reaction

A

positive change in free energy

requires energy to be driven

does not occur spontaneously

25
Q

Gradient

A

Stored energy

26
Q

NAD(H)

A

Nicotinamide adenine dinucleotide

Temporary acceptor

2 electrons, 1 proton

Limited amount in cell

NADP: anabolism

NAD: catabolism

27
Q

Phosphorylation energy

A

Less energy than oxidoreduction

ATP most common

28
Q

ATP

A

Adenosine triphosphate

Components:
—-base (adenine)
—-sugar (ribose)
—-phosphate (3)

High-energy phosphate bonds

29
Q

Substrate-level phosphorylation

A

ATP can be hydrolyzed to do work in the cell

Some molecules can be used to form ATP

30
Q

Catabolism

A

Electron donors:
—-lithotrophy: inorganic molecules
—-organotrophy: organic molecules
—-phototrophy: use light energy to reduce compounds, then use these as electron donors

Electron acceptors:
—-respiration: inorganic molecules
—-fermentation: organic molecules

31
Q

Three pathways

A

Glycolysis
Entner-Doudoroff
Pentose Phosphate

32
Q

Glycolysis (Stage 1)

A

Glucose —> fructose 1,6-bisphosphate

6 C –> -1 ATP –> 6 C –> -1ATP –> 6 C

33
Q

Glycolysis (Stage 2)

A

Fructose 1,6-bisphosphate –> 1,3 bisphosphoglycerate

6 C –> 3 C + 3 C –> 2 NADH –> 2X 3 C

34
Q

Glycolysis (Stage 3)

A

1,3 bisphosphoglycerate –> 3 PGA –> 2 PGA

2X 3 C –> +2 ATP –> 2X 3 C –> 2X 3 C

35
Q

Glycolysis (Stage 4)

A

2 PGA –> pyruvate

2X 3 C –> +2 ATP –> 2X 3 C

Net yield: 2 ATP

36
Q

Entner Doudoroff (Stage 1)

A

Glucose –> 6-phosphogluconate –> 2-keto 3-deoxy 6-phosphogluconate

6 C –> -1 ATP –> 6 C –> NADPH –> 6 C –> 6 C

37
Q

Entner Doudoroff (Stage 2)

A

2-keto 3-deoxy 6-phosphogluconate –> PGAL + pyruvate –> 1,3 bisphosphoglycerate

6 C –> 3 C + 3 C –> NADH –> 3 C

38
Q

Entner Doudoroff (Stage 3)

A

1,3 bisphosphoglycerate –> 3 PGA –> 2 PGA

3 C –> +1 ATP –> 3 C –> 3 C

39
Q

Entner Doudoroff (Stage 4)

A

2 PGA –> pyruvate

3 C –> +1 ATP –> 3 C

40
Q

Glycolysis

A

Use glucose
2 ATP used
2 NADH formed
4 ATP made
Net: 2 ATP
2 pyruvate formed
6 intermediates formed

6 C to 3 C

41
Q

Entner Doudoroff

A

Use glucose
1 ATP used
1 NADH and 1 NADPH formed
2 ATP made
Net: 1 ATP
2 pyruvate formed
5 intermediates formed

6 C to 3 C

42
Q

Pentose Phosphate Shunt

A

Like ED, forms 6-phosphogluconate
—-converted to ribulose-5-phosphate

Produces 1 ATP, no NADH, 2 NADPH for biosynthesis

Main purpose: to make 3-7 carbon intermediates
—-main way we get 4, 5, and 7 C intermediates

43
Q

Pyruvate Dehydrogenase

A

Pyruvate + NAD+ + CoA —> Acetyl-CoA + CO2 + NADH + H+

Multiprotein complex

3 Cofactors
—-TPP (enzyme 1)
—-Lipoamide (enzyme 2)
—-FAD (enzyme 3)

CoA
NAD

44
Q

TCA–Citric Acid–Krebs Cycle

A

Where complete oxidation occurs

45
Q

All pathways have substrate-level phosphorylation

A

but not pyruvate dehydrogenase

46
Q

Total oxidation of pyruvate

A

For each pyruvate oxidized:
—-3 CO2 produced by decarboxylation
—-4 NADH and 1 FADH2 produced by redox reactions
—-1 ATP produced by substrate-level phosphorylation

Oxidative phosphorylation

47
Q

Aromatic Catabolism

A

Aromatic compounds converted to pyruvate

Used for bioremediation
—-oil spills
—-industrial sites
—-toxic compounds

Catechol as entry point