How do catabolic reactions drive anabolic reactions

[Ethan Godden]

Homework Statement

Explain how a cell can use catabolic reactions to drive anabolic reactions, despite energy loss in the form of entropy and heat.

Homework Equations

Catabolic Pathway: A series of reactions that results in the breakdown of larger,more-complex molcules into small, less complex molecules releasing energy in the process
Anabolic Pathway: Opposite of Catabolic Pathway
Change in Free Eneryg=ΔG=ΔH-TΔS where H is the enthalpy and S is the entropy.

The Attempt at a Solution

Since catabolic reactions release energy, this new energy can be used in anabolic reactions. The main question,however, is how do I know this is chemical energy that can be used? How do I not know this is energy is not lost due to heat? I believe this reason has to do with the fact there is negative ΔG for catabolic reactions meaning there is less free energy in the products, but I don't entirely understand how this shows there is potential energy to spare.

 

[Borek]

Part of the energy is always lost as heat.

Does it have to be all energy that is lost?

Think about a car. The engine gets hot, the exhaust gases are hot, yet it moves.

 

[epenguin]

if the question is how it happens, you will have to go to the library and find the most elementary textbook on biochemistry (unless you have one or a chapter). Maybe start with synthesis (anabolic) of something simple like polysaccharides (e.g. glycogen, starch). Just one example , otherwise it's too much. Then find out where the stuff needed for the synthesis comes from. You will be looking at stuff like ATP, oxidative phosphorylation,...