General Exam III Qs Flashcards
Aerobic Respiration
-general jist, who’s involved
NADH donates electrons, O2 electron carrier (they get dumped on it),
protons pumped, come back in and ATP is synthesized from ADP + Pi
**feel free to confusedly look at the slides, pg 33 geochemical cycling
Electron carrier for aerobic respiration?
O2
Electron carrier(s) for anaerobic respiration?
nitrates and nitries I think???
but then complex cNor will reduce nitrous oxide (N2O) to N2 gas
Denitrification is an _______ process
anaerobic process, (usually happens in saturated soils that go quickly anoxic)
Denitrification
(define, and who does this?)
hint: blank reduces to blank etc
reductive pathway, adds electrons to nitrates and nitrites that convert them back to N2 gas
NO3- -> NO2- -> NO -> N2O -> N2 (gas)
carried out by many proks and maybe some fungi?
Anaerobic respiration
NADH donates electrons, ATP produced through ATP synthase and proton gradient driving that energy,
complex cNor reduces N2O to N2 gas
**reductive process
**how denitrification happens
The Carbon Cycle
whos involved, two ways it goes & names
Carbon fixation (CO2 to organic form, CH2O) (performed by autotrophs)
Decomposition: organic to inorganic form-
Heterotrophs (we) do this, breathing out CO2 gas
Inorganic form of carbon?
CO2, we can’t use it
Organic form of carbon?
(what are these?)
(CH2O)n (carbohydrates)
What organisms can fix carbon?
(and examples)
Autotrophs,
algae, cyanobacs, plants
What organisms change organic carbon to inorganic carbon? (Decomposition)
heterotrophs (us) we be injesting organic carbon and then breathin out CO2
What cycle most often used to carry out carbon fixation?
The Calvin Cycle
(how celestialautotrophs convert sunlight to chemical energy (sugars)
(not celestial, **photoautotrophs LMAO christ jesus I couldn’t remember the name)
Photoautotroph:
(what it is, and examples)
energy from sunlight
ex. algae, cyanobacs, plants
Chemoautotroph:
(what are, and examples)
(they get their energy from where?)
energy from chemicals
(chemilithoautotroph) fake helpful remember name
energy usually comes from H2S, Fe2+ (reduced minerals)
usually deep sea organisms, bacs/archea (purple non sulfer bacteria an ex)
Photoheterotroph:
(what are, and examples)
energy from sun, cannot fix their own carbon,
get organic carbon from others
(prominent in the Great Salt Lake) ((red coloration due to bacterial rhodalson, use sunlight to form ATP, then eat dead material for fixed carbon)) Dead seagulls everywhere, great for these bacs
Chemoheterotroph:
(what are and examples)
you bich!!
they get energy from chemicals, get organic carbon by eating organic materials by others
(if it eats, probably this)
-animals, most bacs, protozoa
The Calvin Cycle
(
oh lordy just review the slides,
begins with Ribulose 1,5-bisphosphate
but it’s employed by photoautotrophs to turn CO2 into sugar essentially
unit II geochemical cycling pg 39
uses CO2 and water to make organic carbon source (sugars and stuff)
Calvin cycle done by who now, and originally done by who?
Calvin cycle originally developed in cyanobacteria, but then went into euks to form chloroplasts (nice!)
Who does the Calvin cycle begin with?
Ribulose 1,5-bisphosphate
(Rubisco the enzyme acts on it
Alternative method for carbon fixation that isn’t Calvin cycle?
It goes by many names;
-Tricarboxylic cycle (TCA=citric acid)
-Backwards Krebb’s cycle, so not Krebb’s cycle
-Citric acid cycle
(Krebb’s cycle is all about oxidizing, this is a reductive process)
Reductive TCA cycle:
what is, and why happens?
lordy lordy slides time bb
unit II geochemical cycling pg 43
leads to the fixation of two molecules of CO2 and the production of one molecule of acetyl-CoA
a reductive process to fix inorganic carbon to the organic form, CO2 to acetyl CoA
What organisms carry out the Reductive TCA cycle?
carried out by chemoautotrophs (bacs and arcs)
(if you cant use the sun you do this)
(pretty broad amount of organisms that use this) ((typically without light))
Pretty cool, just a backwards pathway
-Methanogenic autotrophs
-Sulfur-oxidizing autotrophs
-Sulfur-reducing autotrophs
-Anaerobic ammonium oxidation (Anammox) bacteria
-Thermoacidophiles
What is the Krebs cycle?
Uses what to do what?
Uses oxygen to make energy (ATP)
What’s the starting chemical of the the Reductive TCA Cycle? (usually or at least in the slides lol)
Oxaloacetate
Ultimately who is responsible for euks coming into existence?
Cyanobacteria bb!!
-responsible for creating the oxygen that allowed the rest of us to develop (because they developed the pathway of photosynthesis)**
The Great Story of Oxygen:
It’s long, review notes in conjunction with slides pg 48 geochemical cycling
But basically ~3.2 billion years oxygen began to accumulate in atmosphere
Around what time did O2 accumulate to 1%?
2Billion years O2 content rose to 1%
Around what time did 20% O2 accumulate in atmosphere (and what did this do?)
-1 billion years ago 20% oxygen (animals and plants (aquatic) appeared)
~1.4 billion years endosymbiotic event occurred, simple eukaryotes appear
-archea was brought into other cell, archea became the nucleus
Once O2 get’s 4 electrons it becomes;
water, H2O
How did full on cells become able to photosynthesize?
Cyanobacteria one day entered a cell, and became the chloroplasts, enabling algae and plants to exist
Where does the og electron come from?
(and allows what to happen)
The og electron comes from water, which makes the efficient metabolism possible
Sulfur metabolism
usually happens where, most common inorganic form of sulfur
usually volcanic,
SO42- most common type seen oot and aboot in the wild
SO4(2-) characteristics
-highly oxidized
-very stable
-must be extensively reduced to H2S prior to assimilation
H2S can be used to make
cysteine and other
organic sulfur
compounds
In Sulfur metabolism, what is ATP doing and why?
idk man
ATP is used in first and second steps
ATP first provides 2 phosphates
Forms AMP (a nucleic acid)
ATP provideds 2nd just a phosphate (byproduct of ADP)
Purpose of all this first part is to activate the molecule prior to reduction
What happens when a phosphate is added to a molecule?
The molecule is destabilized
((higher energy, more reactive))
-usually preps it to react with something else
What does ATP usually provide/what does that look like?
(if ATP becomes ADP+Pi just providing energy, usually provides energy or a phosphate group)
**in essence* energy or a phosphate group
ATP doesn’t just provide energy, sometimes provides a phosphate group to destabilize molecule, sometimes donates a couple phosphates
What can sulfite do that sulfate can’t really?
Sulfite less stable, able to accept additional electrons from NADPH
End product of sulfur cycle?
Ends with H2S (Hydrogen sulfide, highly reduced form of sulfur)
NADPH + H+ to NAD+ means what?
-Reduction bb
NADPH-
what it do?
Always donates electrons, represents reducing power (usually in anabolic rxns)
What’s special about a reduced molecule?
It’s full of high energy electrons (lots of energy) and real reactive
ready to do/make stuff!!
Phosphorus exists in what one form in nature?
PO4-
Phospate bb
no gas phase, interconverts from organic to inorganic form
Where the nature phosphorous at?
Soil and rocks
-dissolves into water
Phosphorus Cycle:
2 steps, what are they?
PO4- 1) Adsorption: (inorganic to organic)
soil and rocks, dissolves in water
(done by bacs, algae, plants)
PO4- 2) Decomposition:
Nucleotides, Phospholipids
(done by bacs and fungi)
Phosphorus Adsorption: (inorganic to organic)
what form inorganic, done by who
inorganic form: soil and rocks, dissolves in water
(done by bacs, algae, plants)
Phosphorus Decomposition:
(organic to inorganic)
what form organic, done by who
organic form: Nucleotides, Phospholipids
(done by bacs and fungi)
What is this Metabolism?
sum total of all the biochemical reactions occurring in the cell
Catabolism reactions-
what do, and delta G is what?
breaking down reactions of larger molecules for energy (creates disorder) (generally spontaneous)
Anabolism reactions-
what do and deltaG is what?
building up biosynthesis reactions, biosynthesis of macromolecular cell components from smaller molecular units (creates order)
(generally not spontaneous, requires input of energy)
What 3 things do living organisms obtain from the catabolism of organic molecules?
1) Energy ATP
2) Electrons
-(source of potential energy) NADH (NADH usually used in catabolic pathways)
-needed to form covalent bonds (NADPH usually used in anabolic pathways)
3) Building blocks needed for anabolic reactions
-amino acids
-nucleotides
-fatty acids
-sugars
-elements CHOPKINS CaFe
What do electrons provide for living organisms?
(2 main things)
-(source of potential energy) NADH (NADH usually used in catabolic pathways)
-needed to form covalent bonds (NADPH usually used in anabolic pathways)
What do the Laws of Thermodynamics tell us? (help us predict what?)
Used to make energy-related predictions:
1 If rxn can occur
2 which direction it will occur
3 can predict WHY a rxn occurs
First Law of Thermodynamics:
Energy is always conserved, it can be transferred from one form to another, but cannot be destroyed nor created
The energy be flowin
og source the sun
Sunlight: radiant energy
(the og energy)
where it go?
-> can be transformed to heat energy
-> Chemical energy
-> Electrical energy
(each can be transferred between each other)
What does it mean for us that all energy be transferred?
In essence: we can account for all the energy that enters and leaves our biosphere (v cool)
Second Law of Thermodynamics:
In every physical or chemical change, the universe always tends toward greater disorder or randomness (entropy)
Examples of the 2nd law of thermodynamics:
(instances ((like all)) tending towards disorder:)
-dandelion
-burning paper
-draining of battery
-evaporation of gasoline
From a concentration, to less concentrated
What does Order represent?
(hint, what is it?)
Order=Potential energy
Order is a source of potential energy bb
Where does energy travel?
“energy travels in one direction” towards disorder
(from sun to us to cold heart of space)
