Please answer the below biochemistry question. Question 12 1 pts Based on the ab

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Please answer the below biochemistry question.

Question 12 1 pts Based on the abstract from a publication below (Proceeding of National Academy of Science USA 2015), answer the following question. Abstract Plant mitochondria have a fully operational tricarboxylic acid (TCA) cycle that plays a central role in generating ATP and providing carbon skeletons for a range of biosyntheti processes in both heterotrophic and photosynthetic tissues. The cycle enzyme-encoding genes have been well characterized in terms of transcriptional and effector-mediated regulation and have also been subjected to reverse genetic analysis. However, despite this wealth of attention, a central question remains unanswered: "What regulates flux through this pathway in vivo?" Previous proteomic experiments with Arabidopsis discussed below have revealed that a number of mitochondrial enzymes, including members of the TCA cycle and affiliated pathways, harbor thioredoxin (TRX)-binding sites and are potentially redox-regulated. We have followed up on this possibility and found TRX to be a redox-sensitive mediator of TCA cycle flux. In this investigation, we first characterized, at the enzyme and metabolite levels, mutants of the mitochondrial TRX pathway in Arabidopsis: the NADP-TRX reductase a and b double mutant (ntra ntrb) and the mitochondrially located thioredoxin o1(trxo1) mutant. These studies were followed by a comparative evaluation of the redistribution of isotopes when 13c-glucose, 13C-malate, or 13C-pyruvate was provided as a substrate to leaves of mutant or WT plants. In a complementary approach, we evaluated the in vitro activities of a range of TCA cycle and associated enzymes under varying redox states. The combined dataset suggests that TRX may deactivate both mitochondrial succinate dehydrogenase and fumarase and activate the cytosolic ATP-citrate lyase in vivo, acting as a direct regulator of carbon flow through the TCA cycle and providing a mechanism for the coordination of cellular function. Question: Cytoplasmic acetyl-CoA is essential for the production of fatty acids and sterols and for protein acetylation. ATP-citrate lyase can convert citrate to acetyl-CoA If the plant cell in Arabidopsis needs to produce fatty acids TRX deactivates mitochondrial succinate dehydrogenase, fumarase, as well as cytosolic ATP-citrate lyase TRX activates mitochondrial succinate dehydrogenase, fumarase, and deactivates cytosolic ATP-citrate lyase TRX deactivates mitochondrial succinate dehydrogenase and fumarase, and activates cytosolic ATP-citrate lyase TRX activates mitochondrial succinate dehydrogenase, fumarase, and cytosolic ATP-citrate lyase

Explanation / Answer

TRX deactivates mitochondrial succinaate dehydrogenase and furanase , and activtaes cytosolic ATP-citrate lyase

an alternative mode of acetyl-CoA biosynthesis mediated by ATP citrate lyase (ACL)

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