Tutorial M2 - gluconeogensis PDF

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gluconeogensis...

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TUTORIAL M2 C Consider the following statements about the TCA (Krebs or Citric Acid) cycle and oxidative phosphorylation and decide whether each is correct, incorrect (or partially correct). Statement set 1 •

In the presence of oxygen glycolysis can yield a net production of 6 molecules of ATP per molecule of glucose.

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In the presence of oxygen glycolysis can yield a net production of 8 molecules of ATP per molecule of glucose.

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In the absence of oxygen glycolysis can yield a net production of 2 molecules of ATP per molecule of glucose.

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In the absence of oxygen glycolysis can yield a net production of 4 molecules of ATP per molecule of glucose.

Statement set 2 •

During the transformation of acetyl CoA to acetate a molecule of ATP is produced to conserve free energy that would otherwise be lost.

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During the transformation of succinyl CoA to succinate a molecule of ATP is produced to conserve free energy that would otherwise be lost.

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Oxidation of succinate to fumarate by succinate dehydrogenase leads to the formation of two molecules of ATP per molecule of succinate oxidised.

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Oxidation of succinate to fumarate by succinate dehydrogenase leads to the formation of three molecules of ATP per molecule of succinate oxidised.

Statement set 3 •

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Oxidative processes in the electron transport chain are independent of the phosphorylation of ADP to ATP in mitochondria. Oxidative processes in the electron transport chain and the phosphorylation of ADP to ATP in mitochondria are tightly coupled processes.

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The processes are coupled by a proton gradient across the mitochondrial outer membrane.

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The proton gradient or electromotive force (EMF) is generated by expulsion of protons and is used to drive the enzymic synthesis of ATP.

Statement set 4 •

In the presence of oxygen glycolysis and the TCA cycle contribute equally to ATP production.

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In the presence of oxygen the TCA cycle produces more ATP than does glycolysis.

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The only function of glycolysis is the production of ATP.

Statement set 5 •

Electrons are transferred from cytochromes a to c during mitochondrial electron transport.

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Cytochrome oxidase reduces oxygen.

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Four redox enzyme complexes contribute to the electron transport chain.

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Four redox enzyme complexes translocate protons during coupled electron transport.

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The Fo component is the catalytic subunit of the ATP synthase.

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Utilisation of succinate substrate gives a P:O ratio of 2.

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Oxidative phosphorylation in eukaryotes and in prokaryotes is a membrane-bound process.

For the next session please access the following paper: Spriet L (2007) “Regulation of substrate use during the marathon.” Sports Med. 37:332-336.

This paper may be obtained online at http://www.sciencedirect.com/. Access from the North campus site of the university does not need a username and password; whereas for access from elsewhere you will need to consult the subject librarian, George Knapp (email: [email protected]). Please read and understand this paper in advance of the tutorial...