A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas organelles in the lighter fraction could produce ATP in the dark. Explain these results. What is present in the light fractionate that is absent in the heavier fractionate? What is present in the heavier fractionate, that is absent in the light fractionate? Why are these components important to a clear explanation?

Chloroplasts and mitochondria.

Explanation:

In the given question,

1. The heavy fraction produces ATP in the presence of light which means that the light is required for the synthesis of ATP and the organelle associated with the light is Chloroplast.

2. The lighter fraction produces ATP in the dark condition that means no light is required for ATP synthesis and the organelles associated with this is known as Mitochondria.

These organelles can be predicted based on their role in the ATP synthesis and the requirement of light condition for ATP synthesis.

Thus, Chloroplasts and mitochondria is correct.

a plastic spoon that has a temperature of 78° f is placed into a bowl of soup that has a temperature of 84° f. which of these correctly describes what will happen?

energy as heat moves from the soup to the spoon.

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.