Lecture 7

Question 1

Inorganic metabolism is used for what type of bacteria?

Answer 1

Chemolithoautotroph

Question 2

Assimilatory inorganic metabolism

Answer 2

Reduction of inorganic compounds and their incorporation into organic compounds

Ex Nitrogen fixation

Question 3

Inorganic molecule derivatives are used in metabolic ways related to?

Answer 3

Energy metabolism and biosynthesis

Question 4

Dissimilatory pathways

Answer 4

Inorganic compounds are used instead of oxygen as electron acceptor: anaerobic respiration

Question 5

In dissimilatory pathways what happens to reduced products?

Answer 5

Reduced products are excreted into the environment

Question 6

Oxidative pathways

Answer 6

Inorganic compounds such as H2,NH3,So,H2S, and Fe2+ are oxidized as a source of electrons and energy: chemolithotrophs

Question 7

Chemolithotrophs

Answer 7

Prokaryotes that derive energy and electrons from oxidation of inorganic compounds

Question 8

What do most chemolithotrophs and chemoautotrophs use as a carbon source?

Answer 8

CO2

Question 9

Many lithotrophs are ____ some are _____ and few are_______

Answer 9

Aerobic, facultative anaerobes, obligate anaerobes

Question 10

Chemolithotrophs need ATP and NADH for

Answer 10

Carbon Metabolism and biosynthesis

Question 11

Some electron donors have redox potential higher than NAD+ or NADH True or False

Answer 11

True

Question 12

In reverse electron transport electrons are transfers UQ and cytochromes. True or False

Answer 12

True

Question 13

Some of the electrons used to reducing O2 generate what?

Answer 13

Proton motive force

Question 14

Which electron transport is generates more energy forward or reverse?

Answer 14

Reverse electron transport chain generates 5X more energy

Question 15

In electron transport what type of energy is available

Answer 15

Proton motive force

Question 16

Which type of compound is more efficient organic or inorganic?

Answer 16

Organic compounds are more efficient.

Question 17

Ammonia-oxidizing Bacteria

Answer 17

Bacteria that use ammonia as a source of energy.

They oxidize ammonia to nitrite.

Question 18

What are the the two types of nitrifying bacteria

Answer 18

Those that;

Convert ammonia to nitrite

And

Convert nitrite to nitrate

Question 19

Ammonia oxidation: nitrosomonas

Answer 19

Bacteria oxidizing ammonia to nitrite

Question 20

Step 1 in ammonia oxidation in nitrosomonas

Answer 20

Ammonia (NH3) is oxidized to Hydroxylamine (NH2OHO) by ammonia monooxygenase (AMO)

Question 21

Step 1 in ammonia oxidation in nitrosomonas explained in two steps?

Answer 21

Reaction 1
(NH3) is oxidized to (NH2OH) hydroxylamine by AMO

Consuming two electrons available from the oxidation of hydroxylamine through a membrane bound cytochrome C

Redox potential of NH2OH/NH3+ (+.899V) is higher than 1/2O2/H20

Question 22

When NH2OH is oxidized by HAO (Hydroxylamine oxidoreductase) what is released?

Answer 22

Four electrons

Question 23

In ammonia oxidation in nitrosomonas when hydroxylamine oxidize by HAO four electron are released what are the uses of these electrons?

Answer 23

1. Two electron are routed back to AMO used for oxidation of ammonia
2. Rest is used to generate PMF through Cyt oxidase and also reduce NAD+ through electron transport to NADH

Question 24

Name one genera of nitrate oxidation

Answer 24

Nitrobacter

Question 25

Nitrobacter is what type of autotroph

Answer 25

Falcutative

Question 26

How does electrons travel in nitrite oxidizer? | Step 1

Answer 26

Electron transport scheme is not fully elucidated But Electrons travel from nitrite to oxygen via periplasmic Cyt C +420mV to +270mV

Question 27

What is the energy provided to drive electrons nitrite oxidation?

Answer 27

PMF provides energy to drive electrons

Question 28

From Cyt C the electrons flow in two ways what are they? | How are they powered?

Answer 28

1. Electrons flow from Cyt c back across the membrane through cytaa3 oxidase Power: membrane potential is created by outward pumping of proton by Cytaa3. 2. Electrons are reversed from Cytc to NAD+ through two coupling sites Power: reversed electron flow to NAD+ coupled to influx of protons (PMF)

Question 29

What are the CO2 fixation systems?

Answer 29

Calvin cycle Reductive TCA cycle Acetyl-CoA pathway

Question 30

Aerobic chemolithotrophs and photolithotrophs commonly fix CO2 by Calvin cycle but they can also do this by what other cycle?

Answer 30

Reductive TCA cycle

Question 31

The Calvin cycle is most common CO2 pathway fixation pathway in...

Answer 31

Aerobic Chemolithotrophs and photolithotrophs

Question 32

Explain the two stages of Calvin cycle

Answer 32

1. Reductive carboxylation of ribulose-1,5-biphosphate to produce two molecules molecules of 3-phosphoglycerate, who’s is reduced to PGALD 2. sugar rearrangements regenerating RuBP by using some PGALD produced in stage 1

Question 33

CO2 is condensed to ribulose -1,5-biphosphate produce_____ and then that gets reduced ______

Answer 33

Two molecules of 3-phosphoglycerate Two molecules of PGALD

Question 34

Two PGALD are made in Calvin cycle how are they used?

Answer 34

1. One PGALD is isomerized to dihydroxyacetone phosphate 2. The other PGALD is condensed with dihydroxyactone phosphate to form fructose-1,6-diphosphate through reverse reaction of the EMP pathway

Question 35

Through carbon rearrangement how many F6P molecules and PGALD are needed to make 2 ribulose 5 phosphate

Answer 35

2 F6P 6 PGALD Ribulose 5 phosphate

Question 36

What is the enzyme use to go form ribulose-5- phosphate to ribulose-1,5-biphosphate? What are the effectors of the enzyme

Answer 36

Enzyme: phosphoribulokinase NADH (+) Activates AMP, PEP (-) inhibits

Question 37

What’s are the key enzymes of the Calvin cycle ?

Answer 37

Ribulose-1,5-biphosphate carboxylase Phosphoribulokinase

Question 38

In Reductive TCA citrate synthase gets replaced with what enzyme?

Answer 38

Citrate lease

Question 39

In reductive TCA succinate dehydrogenase is replaced with

Answer 39

Fumarate reductase

Question 40

Alpha-ketoglutarate dehyhdrodgenase is replaces by

Answer 40

Alpha-ketoglutarate synthase

Question 41

Pyruvate dehydrodenase is replaced with

Answer 41

Pyruvate synthase

Question 42

Pyruvate kinase is replaced with

Answer 42

Pep synthetase

Question 43

Ammonia produced via nitrogen fixation is incorporated into cell material via?

Answer 43

Glutamine and glutamate synthase

Question 44

The nitrogen molecule is very _____. To reduce nitrogen what is the industry pressure and temperature.

Answer 44

Stable 200 atm 800 C

Question 45

Nitrogen fixation takes place when?

Answer 45

N2 is the only major source of nitrogen

Question 46

The genes of nitrogen fixation are repressed by?

Answer 46

Exogenously supplied sources of nitrogen