Carnitine helps in -

Ans. is 'b' i.e., Transport of fatty acids from cytosol to mitochondria o Activated long chain fatty acid (acyl CoA) cannot penetrate inner mitochondrial membrane.o Acyl group of acyl CoA is transferred to carnitine, resulting in formation of acylcarnitine.o Acylcarnitine is then transported across the inner mitochondrial membrane into the mitochondrial matrix by translocase.o Once inside the mitochondrion, acyl group of acylcarnitine is transferred back to CoA, resulting in formation of acyl-CoA which undergoes b-oxidation.o Production of malonyl-CoA is the initialQ and rate limiting step in fatty acid synthesis.o Acetyl-CoA needs to be converted to activated form, which will serve as the donor of carbon units to growing fatty- acid chain.o Malonyl-CoAQ) a 3-carbon compound is such activated form.o It is produced by carboxylation of acetyl-CoA, a reaction catalyzed by acetyl-CoA caroxy laseQ. Acety 1-CoA carboxylase requires biotin as a cofactorQ.o Acetyl-CoA carboxylase is a multienzyme protein containing variable number of identical subunits, each containingbiotin carboxylase, biotin carboxyl carrier protein and transcarboxylase.o The reaction also requires HCO3- (as a source of CO2) and ATPo The reaction takes place in two steps: (i) Carboxylation of biotin involving HCO3 and ATP, and (ii) transfer of the carboxyl group to acetyl-CoA to form malonyl-CoA.