Nthe oxidation of pyruvate to acetyl coa, one carbon atom is released as co2. however, the oxidation of the remaining two carbon atoms—in acetate—to co2 requires a complex, eight-step pathway—the citric acid cycle. consider four possible explanations for why the last two carbons in acetate are converted to co2 in a complex cyclic pathway rather than through a simple, linear reaction.

the animal that would be cutest if scaled down to the size of a cat? elephant

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.