Biological Processes and Reversible Reactions

[Lauren Chen 1F]

During lecture, Dr. Lavelle stated that biochemical systems often use highly irreversible reactions to speed up their process. Can someone please clarify how this occurs?

[SandraChane_1B]

This occurs because irreversible reaction require less energy and are therefore more energetically favorable. This is why they are more often used by biological systems, since they are quicker and more likely to occur.

[Tala Hamdan 3B]

The reason that biological processes use highly irreversible reactions is that biological systems must remain at equilibrium (or homeostasis in other words), therefore changes in the body must occur in small increments so that they are more efficient (less energy is lost). According to the 2nd law of thermodynamics, energy is always lost as heat during reactions. This means that the reverse reaction cannot occur on its own since the system has lost the initial energy needed to do so. Also, biological processes occur for specific reasons, this means that steps must be taken in order for the complete function of a system to be carried out. If the reactions of each step were reversible, the end goal would never be reached.