LABORATORY REVIEW
CELL RESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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glycolysis
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carbon dioxide fixation
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the Krebs cycle.
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the electron transport chain.
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Detailed explanation-1: -The Krebs cycle itself actually begins when acetyl-CoA combines with a four-carbon molecule called OAA (oxaloacetate) (see Figure above). This produces citric acid, which has six carbonatoms. This is why the Krebs cycle is also called the citric acid cycle.
Detailed explanation-2: -The remaining steps of the Krebs cycle regenerate oxaloacetic acid from succinate: Succinate is oxidized to form the four-carbon molecule called fumerate.
Detailed explanation-3: -In cellular respiration, a two-carbon molecule combines with a four-carbon molecule to form citric acid as part of what? The Krebs cycle.
Detailed explanation-4: -The citric acid cycle begins with the transfer of a two-carbon acetyl group from acetyl-CoA to the four-carbon acceptor compound (oxaloacetate) to form a six-carbon compound (citrate).
Detailed explanation-5: -At the end of this series of reactions, the four-carbon starting molecule, oxaloacetate, is regenerated, allowing the cycle to begin again.