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30 Cards in this Set
- Front
- Back
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Cellular respiration is the process by which cells:
A- Oxidize organic fuels to CO2 and H20 B- Consume O2 and produce CO2 C- Convert O2 to H2O D- Breakdown sugars to CO2 and H20 |
B
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the breakdown of fuels to CO2 and H20 is __________
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oxidation
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the breakdown of sugars to CO2 and H20 is ____________
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oxidation
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Amino acids, fatty acids, and glucose are oxidized and enter the TCA as what?
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acetyl-CoA
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the first reaction of the citric acid cycle, which generates citrate, is what type of reaction?
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a condensation reaction
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for every molecule of glucose, how many molecules of CO2 are released in the TCA?
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4 (each acetyl-CoA releases two molecules of CO2--one molecule t each of the two oxidative decarboxylation reaction steps)
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which of the following is TRUE about the pyruvate dehydrogenase complex?
A-It converts pyruvate to oxaloacetate B- It catalyzes oxidative decarboxylatoin C- It is located in the cytosol of eukaryotic cells D- It requires NADH |
B (the PDH complex catalyzes the oxidative decarboxylation of pyruvate to release CO2 and generate acetyl-CoA)
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where is the pyruvate dehydrogenase complex located?
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in the cytosol of prokaryotic cells and in the mitochondria of eukaryotic cells.
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does the pyruvte dehydrogenase complex consume or generate NADH?
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generates
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what role does coenzyme A play in the TCA?
A- It is an electron carrier B- It carries hydride ions C- It is an acyl group carrier D- It is an oxidizing agent |
C- It is an acyl group carrier
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coenzmye A forms a ________ bond with acyl groups and activates them for group transfer to other molecules. In the TCA, coenzyme A activates _______, allowing its transfer to oxaloacetate to form citrate
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thioester
acetate |
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Which of following is TRUE about all of the dehydrogenase enzymes that participate in the citric acid cycle?
A- They catalyze condensation reactions B- They generate CO2 C- They convert a single bond to a double bond D- They generate reduced electron carriers |
D--(the 4 dehydrogenase enzymes that participate in the TCA trnasfer electrons to the coenzymes NAD+ or FAD to generate the reduced electron carriers NADH and FADH2, which in turn transfer electrons in the respiratory chain.
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do the dehydrogenase enzymes generate CO2?
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only two of them do.
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what types of reactions do phosphorylases catalyze?
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Displacement reactions in which an attacking phosphate becomes covalently attached at the point of bond breakage.
an example is glycogen phosphorylase, which catalyzes phosphorolysis of glycogen, producing glucose -1-phosphate |
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phosphatases catalyze the removal of what groups?
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removal of a phosphoryl group from a phosphate ester
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Kinases catalyze the transfer of what to what?
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transfer of a phosphoryl group from a nucleoside trisphosphate to an acceptor molecule. (like ATP)
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Which of the following enzymes catalyze a condensation reaction in which no nucleoside triphosphate is required as an ernergy source?
A- Kinase B- Synthases C-Ligases D- Synthetases |
B- Synthases
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Ligases catalyze condensation reactions in which two atoms are joined using the energy of _____
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ATP
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Synthetases catalyze condensation reactions that use _____
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ATP
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Kinases ___ _____ catalyze condensation reactions
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Do NOT
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which of the following conditions has a negative effect on the pyruvate dehydrogenase complex/
A- A high ration of ADP/ATP B- A hight level of Ca2+ C- A high ration of NAD+/NADH D- A high ration of acetyl-CoA/CoA |
D
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In non-vertebrate organisms, the glycoxylate cycle is needed to convert
A- triacylglycerols to fatty acids B- acetate to carbohydrates C- glyoxylate to ATP D- oxaloacetate to malate |
B--(acetate is usually derived from fatty acid breakdown)
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In what way are the glyoxylate cycle and citric acid cycles linked?
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Succinate produced in the glyoxylate cycle enters the TCA (one net molecule of succinate is produced in each cycle of the glyoxylate cycle and then enters the TCA)
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The TCA is an amphibolic pathway, which means that...
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It serves in both anabolic and catabolic processes
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Biotin
A- serves as a cofactor in dehydrogentaion reactions B- transfers one-carbon groups C-Is a cofactor that transfers acetyl groups D- carrier CO2 groups |
D- carrier CO2 groups
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Biotin, which is a cofactor in ___________ reactions, is a specialized carrier of CO2 groups. For example, it serves as the prosthetic group of the enzyme _________ __________, which transfers a CO2 group to pyruvate to generate _____________
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oxaloacetate
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Which of the following citric acid cycle reaction steps is NOT inhibited by a high (NADH)/(NAD+) ?
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conversion of succinyl-CoA to succinate
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the steps that are inhibited by a high ratio of NADH to NAD+ are those that generate _______ or that commit a substrate for entry into the ctiric acid cycle.
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NADH
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Some plants that have been genertically engineered to express elevated levels of citrate synthase have increase crop productivity because
A- citric acid increases soil pH B- Citric acid production is a rate-limiting step C- Citric acid chelates metal ions D- Citric acid is toxic to some plant pathogens |
C
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Anaplerotic reactions, such as the conversoin of pyruvate to oxaloacetate, are useful to the TCA because they...
A-generate a steady supply of intermediates for the TCA B- Produce molecules needed to regulate the TCA C- Link the TCA to the glycoxylate cycle D- Siphon away excess intermediates from the TCA cycle |
A
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