MCB 2610 Lecture 13: Week 3 - Environment
25 May 2018
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AUTOTROPHS -> PHOTOTROPHS ( LIGHT AS SOURCE OF ENERGY) •
Another type of autotrophy is chemolithoautrophs -> C from CO2, CH4, formate, methanol "•
Get energy from inorganic reduced sources such as H2, NH3, Fe +2 and strip electrons from it -> inorganic sources become •
oxidized -> flows down the e- transport chain -> generate pmf -> ATP synthesis "
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Hydrogen oxidizers:
Use H2 as source of energy: "•
-Found in H2 rich environments!
—-> anaerobic water (muds) have high H2 levels !
—-> root nodules have high H2 levels!
—-> anywhere in environment where fermentation is taking place tend to have high H2 levels as well (keep fermentation
moves forward) !
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- gut ecosystems !
Loop nodules: "•
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1 mole of hydrogen -> ~56 kcal/ mol !
1 mole of glucose -> 12 NADH * 54 kcal/ mol !
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However, the total energy molecule is low relative to glucose or other CHO -> H2 oxidizer chew through H2 to make a living
and they have to consume a lot of it to survive -> big impact on the environment. !
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Iron oxidizers
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Iron: 4th most abundant element on the planet - it’s not available easily for use. Therefore, organism is often iron-limited. "•
Example: plants are often iron limited -> that’s why fertilizer is needed for plants since it has iron in it!
""pathogen are also iron limited -> blood or tissue -> pathogen has a hard time growing in the blood because the
blood is plenty of iron. It can only grow when it has plenty of iron in it !
" "" SOFEX : rise of carbon after the addition of iron -> cyanobacteria bloomed with added iron. !
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Fe 2+ (ferrous) "!
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1) Formed under!
Anaerobic condition from !
Fe3+ !
2) It is soluble anaerobically " " " " " " """""""""Fe 3+ is soluble under aerobic condition when """!
3) a source of energy for iron oxidizing bacteria " " " """"""""""""""the environment is acidic !
-> Thiobacillus sulfobolus !
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Anaerobic: Bacteria fight for iron using molecules called siderophores and complex Fe3+ -> bring it to the organism -> taken
up and the membrane -> Fe3+ reduced to Fe2+ !
However, Fe 2+ is soluble and stable in acidic environment even if it’s in aerobic environment.
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2Fe +2 + 2H+ + 1/2 O2 ———-> 2Fe+3 + H2O !
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How can ATP be made from this situation??? "
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Document Summary
Autotrophs -> phototrophs ( light as source of energy) Another type of autotrophy is chemolithoautrophs -> c from co2, ch4, formate, methanol. Get energy from inorganic reduced sources such as h2, nh3, fe +2 and strip electrons from it -> inorganic sources become oxidized -> ows down the e- transport chain -> generate pmf -> atp synthesis. > anaerobic water (muds) have high h2 levels. > anywhere in environment where fermentation is taking place tend to have high h2 levels as well (keep fermentation moves forward) 1 mole of hydrogen -> ~56 kcal/ mol. 1 mole of glucose -> 12 nadh * 54 kcal/ mol. Iron: 4th most abundant element on the planet - it"s not available easily for use. Example: plants are often iron limited -> that"s why fertilizer is needed for plants since it has iron in it blood is plenty of iron. It can only grow when it has plenty of iron in it.
