PHYSIOLOGY
MUSCLE ENERGETICS GLYCOLYSIS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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nucleus
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mitochondria and cytosol
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endoplasmic reticulum
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peroxisomes
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Detailed explanation-1: -Pyruvate carboxylase belongs to the family of biotin-dependent carboxylases and is composed of four identical subunits (∼130 kDa each) organized as a tetramer. It is present in many organisms including bacteria, fungi, plants, and animals. Pyruvate carboxylase is situated in mitochondria in most eukaryotic organisms.
Detailed explanation-2: -In mammals, PC is expressed in a tissue-specific manner, with its activity found to be highest in the liver and kidney (gluconeogenic tissues), in adipose tissue and lactating mammary gland (lipogenic tissues), and in pancreatic islets.
Detailed explanation-3: -Pyruvate is produced in the cytoplasm and is then transported into the mitochondria, where it is converted to acetyl-CoA; acetyl-CoA subsequently reacts with oxaloacetate to form citrate, thus entering the tricarboxylic acid (TCA) cycle.
Detailed explanation-4: -In aerobic conditions, pyruvate is primarily transported into the mitochondrial matrix and converted to acetyl-coenzyme A (acetyl-CoA) and carbon dioxide by the pyruvate dehydrogenase complex (PDC).