A molecule which aids the function of an enzyme by transferring a chemical group from one molecule to another
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Name the order of the steps in aerobic respiration
Glycolysis, link reaction, krebs cycle, oxidative phosphorylation
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Where does glycolysis take place? and what does it make?
In the cytoplasm. Makes pyruvate from glucose
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Name and explain the first step of glycolysis.
Phosphorylation. Glucose is phosphorylated by adding a phosphate from a molecule of ATP, creating molecule of hexose phosphate and ADP. Then hexose phosphate is phosphorylated by ATP, creating hexose bisphosphate and ADP. Split into 2 molecules of TP
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Name and explain he second step of glycolysis.
Oxidation. TP is oxidised, forming 2 molecules pyruvate. NAD collects hydrogen creating 2 reduced NAD. 4 ATP produced, so net gain of 2 ATP.
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Explain the processes in the link reaction
Pyruvate is actively transported into the matrix of the mitochondria. Pyruvate is decarboxylated (one carbon atom is removed as CO2). Pyruvate is oxidised by NAD, forms acetate and reduced NAD. Acetate combined with CoA forming acetyl CoA. No ATP.
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What is the Krebs cycle an overall name for and where does it occur?
A series of redox reactions. Occurs in matrix.
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Name and explain the first step of krebs cycle.
Formation of citrate. Acetyl CoA combines with oxaloacetate, forming citrate (citric acid). The reaction is catalysed by citrate synthase. CoA goes back to link reaction to be reused.
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Name and explain the second step of the krebs cycle.
Formation of a 5 carbon compund. 6C citrate converted to a 5C molecule by carboxylation. Dehydrogenation also occurs, producing reduced NAD from NAD.
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Name and explain the third step of the krebs cycle.
Regeneration of oxaloacetate. 5C molecule converted to a 4C molecule using intermediate compounds.Decarboxylation and dehydrogenation occur, producing a molecule of reduced FAD and 2 molecules reduced NAD.
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Regeneration of oxaloacetate continued...
ATP is produced by a direct transfer of a phosphate group from an intermediate compound to ADP. (substrate level phosphorylation). Citrate has now been converted to oxaloacetate.
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Explain step 1 of oxidative phosphorylation
Hydrogen atoms are released from reduced NAD and reduced FAD as they're oxidised to NAD and FAD. Hydrogen atoms split into H+ ions and electrons.
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Explain step 2 of oxidative phosphorylation
The electrons move along the electron transport chain (located in inner mitochondrial membrane) and lose energy at each carrier.
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Explain step 3 of oxidative phosphorylation
This energy is used by electron carriers to pump protons from mitochondrial matrix to intermembrane space.
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Explain step 4 of oxidative phosphorylation
This causes a higher concentrations of protons in intermembrane space than mitochondrial matrix (called electrochemical gradient).
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Explain step 5 of oxidative phosphorylation
Protons move down this gradient back into mitochondrial matrix via ATP synthase
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Explain step 6 of oxidative phosphorylation
This movement drives the synthesis of ATP from ADP and inorganic phosphate (chemiosmosis-production of ATP driven by H+ ions movement across membrane)
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Explain step 7 of oxidative phosphorylation
In the mitochondrial matrix at the end of the transport chain, the protons, electrons and oxygen (from blood) combine to form water. (oxygen is the final electron acceptor)
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Other cards in this set
Card 2
Front
Define coenzyme
Back
A molecule which aids the function of an enzyme by transferring a chemical group from one molecule to another
Card 3
Front
Name the order of the steps in aerobic respiration
Back
Card 4
Front
Where does glycolysis take place? and what does it make?
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