Unit 2-- Lecture 7 (Microbial Metabolism)

Question 1

All life requires:

Answer 1

Electron flow: to drive all life process

Energy: to move electrons

Materials: to make cell parts
—-nutrients

Question 2

Macronutrients

Answer 2

Major elements in cell macromolecules

C, O, H, N, P, S

Ions necessary for protein function

Mg2+, Ca2+, Fe2+, K+

Question 3

Micronutrients

Answer 3

Trace elements necessary for enzyme function

Question 4

Heterotrophs

Answer 4

Use organic carbon

C-H bonds

Question 5

Autotrophs

Answer 5

Use carbon dioxide (CO2)

No hydrogens

Question 6

Phototrophs

Answer 6

Light energy excites electrons

Excited molecules are electron donors

Question 7

Chemotrophs

Answer 7

Chemicals are electron donors

Oxidation of chemical

Oxidation: donation of electrons (lose)

Reduction: accepting electrons (gain)

OIL RIG

Question 8

Lithotrophs

Answer 8

Inorganic molecules are electron donors

Question 9

Organotrophs

Answer 9

Organic molecules are electron donors

Question 10

Respiration

Answer 10

Inorganic molecules

Question 11

Fermentation

Answer 11

Organic molecules

Question 12

Passive Diffusion

Answer 12

Some gases pass freely through membranes
—-O2, CO2

Follows gradient of material

Question 13

Facilitated Diffusion

Answer 13

Transporters pass material into/out of cell

Follows gradient of material

Question 14

ABC Transporters (Active Transport)

Answer 14

Use ATP energy to pass material into cell

Transport material against gradient

Question 15

Symport and Antiport

Answer 15

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

Question 16

Phosphotransferase System–PTS (Active Transport)

Answer 16

Uses high-energy phosphate to pass material into cell

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

Question 17

Catabolism

Answer 17

Breaking down molecules for energy

Question 18

Anabolism

Answer 18

Using energy to build cell components

Reducing entropy, creating order

Question 19

Metabolism

Answer 19

Balance between catabolism and anabolism

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

Question 20

Enzymes

Answer 20

Biological catalysts

Nearly always proteins

Active site

Substrate(s)

Cofactors
—-metals
—-vitamins

Question 21

Gibbs Free Energy

Answer 21

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

Question 22

Activation Energy

Answer 22

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

Question 23

Exergonic Reaction

Answer 23

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

occurs spontaneously

Question 24

Endergonic Reaction

Answer 24

positive change in free energy

requires energy to be driven

does not occur spontaneously

Question 25

Gradient

Answer 25

Stored energy

Question 26

NAD(H)

Answer 26

Nicotinamide adenine dinucleotide Temporary acceptor 2 electrons, 1 proton Limited amount in cell NADP: anabolism NAD: catabolism

Question 27

Phosphorylation energy

Answer 27

Less energy than oxidoreduction ATP most common

Question 28

ATP

Answer 28

Adenosine triphosphate Components: ----base (adenine) ----sugar (ribose) ----phosphate (3) High-energy phosphate bonds

Question 29

Substrate-level phosphorylation

Answer 29

ATP can be hydrolyzed to do work in the cell Some molecules can be used to form ATP

Question 30

Catabolism

Answer 30

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

Question 31

Three pathways

Answer 31

Glycolysis Entner-Doudoroff Pentose Phosphate

Question 32

Glycolysis (Stage 1)

Answer 32

Glucose ---> fructose 1,6-bisphosphate 6 C --> -1 ATP --> 6 C --> -1ATP --> 6 C

Question 33

Glycolysis (Stage 2)

Answer 33

Fructose 1,6-bisphosphate --> 1,3 bisphosphoglycerate 6 C --> 3 C + 3 C --> 2 NADH --> 2X 3 C

Question 34

Glycolysis (Stage 3)

Answer 34

1,3 bisphosphoglycerate --> 3 PGA --> 2 PGA 2X 3 C --> +2 ATP --> 2X 3 C --> 2X 3 C

Question 35

Glycolysis (Stage 4)

Answer 35

2 PGA --> pyruvate 2X 3 C --> +2 ATP --> 2X 3 C Net yield: 2 ATP

Question 36

Entner Doudoroff (Stage 1)

Answer 36

Glucose --> 6-phosphogluconate --> 2-keto 3-deoxy 6-phosphogluconate 6 C --> -1 ATP --> 6 C --> NADPH --> 6 C --> 6 C

Question 37

Entner Doudoroff (Stage 2)

Answer 37

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

Question 38

Entner Doudoroff (Stage 3)

Answer 38

1,3 bisphosphoglycerate --> 3 PGA --> 2 PGA 3 C --> +1 ATP --> 3 C --> 3 C

Question 39

Entner Doudoroff (Stage 4)

Answer 39

2 PGA --> pyruvate 3 C --> +1 ATP --> 3 C

Question 40

Glycolysis

Answer 40

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

Question 41

Entner Doudoroff

Answer 41

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

Question 42

Pentose Phosphate Shunt

Answer 42

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

Question 43

Pyruvate Dehydrogenase

Answer 43

Pyruvate + NAD+ + CoA ---> Acetyl-CoA + CO2 + NADH + H+ Multiprotein complex 3 Cofactors ----TPP (enzyme 1) ----Lipoamide (enzyme 2) ----FAD (enzyme 3) CoA NAD

Question 44

TCA--Citric Acid--Krebs Cycle

Answer 44

Where complete oxidation occurs

Question 45

All pathways have substrate-level phosphorylation

Answer 45

but not pyruvate dehydrogenase

Question 46

Total oxidation of pyruvate

Answer 46

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

Question 47

Aromatic Catabolism

Answer 47

Aromatic compounds converted to pyruvate Used for bioremediation ----oil spills ----industrial sites ----toxic compounds Catechol as entry point