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57 Cards in this Set
- Front
- Back
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Cellular Respiration
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Slow oxidation of energy rich molecules to extract potential energy and convert it into ATP
A catabolic process... Some reactions involved still have a positive delta G Three parts: Glycolysis CA cycle ETC |
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Controlled Combustion
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Energy is slowly released in a step wise fashion with the energy being transferred from molecule to molecule
Many small little activation energies to be overcome |
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Direct Burning
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Consists of 1 large EA to be overcome
All energy is released as heat = bad because it is not an efficent method of energy transfer |
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Substrate Level Phosphorylation
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A mode of ATP synthesis that requires an enzyme that transfers a phosphate group from a high energy substrate to a molecule of ADP
Produces ATP |
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Energy Coupling
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ATP is brought into close contract with a reactant molecule involved in an endergonic reaction
When ATP is hydrolyzed, the phosphate group is transferred to the reactant molecule The reactant molecule is then phosphorylated, making it less stable |
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ATP
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Contains a large amount of fee energy bc they possess high energy phosphate bonds
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ATP
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Contains large amounts of free energy due to high energy phosphate bonds
Consists of 5 carbon sugar, ribose, linked to the nitrogenous base adenine, and a chain of three phosphate groups |
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Catabolic Pathways
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Negative delta G
Breaking something down Energy is released Reactions can be exergonic or endergonic |
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Anabolic Pathways
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Positive delta G
Building something up Energy is consumed |
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NAD+ vs FADH
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NAD+ = 1 proton, 2 electron carrier
FADH2 = 1 electron carrier |
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Where does glycolysis take place?
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The cytosol
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Glycolysis description
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Anaerobic - does not require oxygen
NET = 2 ATP and 2 NADH Final Product = 2 pyruvate molecules |
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Glycolysis I
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2 molecules of ATP are consumed
ATP phosphorylates glucose |
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Kinase
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ATP is consumed because of the enzyme kinase
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Why is glucose phosphorylated in glycolysis I?
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1) Makes glucose more reactive
2)Makes glucose charged to prevent it from diffusing outside the cell |
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Glycolysis II
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Four ATP and 2NADH molecules are produced
No carbon is lost - all 6 of the carbons in glucose are converted into two 3-carbon pyruvates |
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How is ATP produced in glycolysis II?
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Substrate level phosphorylation
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Pyruvate Oxidation
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Converts pyruvate into actetyl-CoA
The product of glycolysis, pyruvate, must pass through both membranes - from the cytosol to the matrix Passing through the inner membrane required a membrane carrier |
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Pyruvate Oxidation Steps
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1) Begins with a decarboxylation reaction where the carboxyl group is removed
2) The remaining two carbons are oxidized to produce acetate 3) A dehydrogenation reaction leads to the transfer of two electrons and one proton to NAD+, forming NADH 4) The acetyl group then reacts with coenzyme A |
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Where does the citric acid cycle occur?
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In the mitochondrial matrix
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Citric Acid Cycle
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Consists of 8 enzyme catalyzed reactions
The reactions result in the oxidation of the acetyl groups into carbon dioxide NET/Actetyl CoA = 3 NADH, 1 FADH2 & 1 ATP ***Recall the the acetyl groups contain two carbons. THEREFORE THERE ARE TWO CO2 MOLECULES RELEASED Substrate level phosphorylation is used once again |
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The Pyruvate Dehydrogenase Complex
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A complex of 3 enzymes that transform pyruvate into acetyl CoA
"pyruvate decarboxylation" Acetyl CoA is then used in the citric acid cycle *LINKS glycolysis and the CA cycle Pyruvate is in the cytosol of the cell and must go into the mitochondrial matrix |
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Pyruvate Dehydrogenase Deficiency
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The enzyme responsible for transforming pyruvate into acetyl-coA is defective
Without functional dehydrogenase, pyruvate builds up in the cells, triggering fermentation This leads to a build up of lactic acid The brain needs glucose since it is only receiving pyruvate it gets messed The ability to generate ATP is restricted which causes brain misfunction |
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Ketogenic Diet
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A diet high in fat with little carb
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Respiratory Breakdown of Fats
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Triglycerides are hydrolyzed into glycerol and fatty acids
Glycerol in converted FA are split into two carbon fragments, which enter the citric acid cycle as acetyl coA Fatty acid tails are removed |
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Respiratory Breakdown of Protein
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Proteins are hydrolyzed into AA before oxidation
Amino group is removed as it enters as acetyl co A |
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High amount of ATP compared to ADP
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Cell is in energy abundant condition
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High amount of ADP compared to ATP
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Cell is in energy poor condition
Cellular respiration will speed up so ATP can be raised |
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High NADH compared to NAD+
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Cell has lots of reducing power
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High NAD+ compared to NADH
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Cell doesen't have enough reducing power
Glycolysis and the CA cycle will speed up No effect on ETC |
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High lactate compared to pyruvate
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Not a lot of oxygen present
Citric acid cycle will speed up |
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High pyruvate compared to lactate
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Lots of oxygen present, fermentation will speed up
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Where does the CA cycle occur?
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In the aqueous compartment of the matrix of the mitochondria
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ETC Goals
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All of the carbon in glucose has been ocidized and released as carbon dioxide following the CA cycle
Potential energy originally present in glucose now exists in the form of NADH and FADH2 ETC extracts the energy from NADH and FADH2 to make additional ATP |
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Electron shuttles
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Ubiquinone and cytochrome C
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4 Protein complexes of ETC
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NADH dehydrogenase
Succinate dehydrogenase Cytochrome complex Cytochrome oxidase |
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Ubiquinone
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A hydrophobic molecule found in the core of the membrane
Shuttles electrons from complex I & II to complex III |
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Cytochrome C
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Located in the intermembrane space
Transfers electrons from complex III to complex IV |
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Role of NADH in ETC
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Purpose is to oxidize NADH
1) NADH dehydrogenase removes an electron from NADH, releasing NAD+ and a proton 2) The electron is used to reduce Q 3) Q ferries the electron to the cytochrome complex by cytochrome C 4) Electron flows through cytochrome C 5) Electron combines with oxygen to produce water |
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Driving Force of Flow of Electrons down ETC
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Spontaneous process
Complexes I, III, IV are bound to their specific prosthetic groups The prostheric groups alternated between reduced oxidized and reduced states: they donate and recieve electrons Electron carriers are ordered from low to high free energy... or from low to high redox potential Go down the chain = more electronegative |
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Electron Carriers
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Do not get oxidized/reduced
No intrinsic electron transfer ability FMN has a greater affinity then NADH Electrons are donated to oxygen |
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Where does ETC occur
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The inner mitochondrial membrane
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Chemiosmosis
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Electron transfer from NADH or FADH2 does not create ATP
The free energy of NADH & FADH2 is used to pump protons across the inner membrane Protons accumulate in the inner membrane space & pH drops This is a source of potential energy Complexes I and IV use the energy released from electron transport to pump protons Ubiquinone picks up protons from the matrix as they accept electrons |
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PMF
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Stored energy do to a chemical and electrical gradient across the membrane
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PMF & electrical circuits
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Lightbulb = electrons flow in a cycle, passing over LB and causing it to glow
PMF = H+ flow in a cycle, passing over synthesis of ATP |
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What type of process is the synthesis of ATP?
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Endergonic
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Glutamate and ETC
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Rate of respirtation decreases
BC a proton gradient is being established There is no ADP so ATP synthesis cant be driven Gets harder and harder to pump protons |
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ADP and ETC
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Decreases severely
ADP can synthesize ATP, and the PMF is dissipated though ATP synthase |
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CA CYCLE in pro and euk
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Euk = matrix
Pro = cytosol |
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Oligomyocin and ETC
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Rate slows down
Prveents protons from moving through ATP synthase ATP synthesized and the rate is slower because it is harder to respirate |
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Uncoupler and ETC
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Speeds up
Allows for free diffusion of protons across membrane PMF drops alot highest rate of ETC |
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Oxidative Phosphorylation
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The mode of ATP synthesis that is linked to the oxidation of energy rich molecules by an ETC
Relies on the action of ATP synthase |
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Oligomyocin
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An inhibitor of ATP synthase
Binds to the proton pore of ATP synthase and prvents protons from flowing back through the pore |
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Effect of uncoupling agents on ATP synthesis
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Gives protons a choice of going through the uncoupling protein or through ATP synthase
Energy of a proton gradient is lost as heat Non-shivering thermogenesis = heat production throught he regulation of an uncoupling protein |
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Not enough oxygen =
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Pyruvate does not enter the mitochondria, stays in the cytosol and is converted into ethanol and lactate
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Role of NADH in sensing hypoxia
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H1F beta is always made and detected
H1F alpha is degraded in the presence of oxygen |
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Effect of H1F1 on pyruvate metabolism
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Drives the synthesis of kinase
This specific kinase phosphorylates the dehydrogenase complex and shuts it down Now pyruvate cant enter the mitochondria, fermentation occurs |
