Where is citrate exported from mitochondria for fatty acid synthesis and what enzyme cleaves it?

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Multiple Choice

Where is citrate exported from mitochondria for fatty acid synthesis and what enzyme cleaves it?

Citrate acts as a carrier to move acetyl units from mitochondria to the cytosol, where fatty acid synthesis happens. When energy status favors lipogenesis, citrate is exported from the mitochondrial matrix into the cytosol via the citrate shuttle. In the cytosol, ATP-citrate lyase cleaves citrate into acetyl-CoA and oxaloacetate. The acetyl-CoA then serves as the building block for fatty acid synthesis (with assistance from other steps like acetyl-CoA carboxylase forming malonyl-CoA). The other options mix up where citrate goes or which enzyme cleaves it—for example, citrate synthase works inside mitochondria to form citrate, not cleave it in the cytosol, and acetyl-CoA carboxylase uses acetyl-CoA rather than cleaving citrate.

Citrate acts as a carrier to move acetyl units from mitochondria to the cytosol, where fatty acid synthesis happens. When energy status favors lipogenesis, citrate is exported from the mitochondrial matrix into the cytosol via the citrate shuttle. In the cytosol, ATP-citrate lyase cleaves citrate into acetyl-CoA and oxaloacetate. The acetyl-CoA then serves as the building block for fatty acid synthesis (with assistance from other steps like acetyl-CoA carboxylase forming malonyl-CoA). The other options mix up where citrate goes or which enzyme cleaves it—for example, citrate synthase works inside mitochondria to form citrate, not cleave it in the cytosol, and acetyl-CoA carboxylase uses acetyl-CoA rather than cleaving citrate.

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