Sample interview questions: Describe the behavior of metabolic reactions and their relation to thermodynamics.
Sample answer:
Behavior of Metabolic Reactions:
Metabolic reactions are chemical conversions that occur within living cells. These reactions are catalyzed by specific proteins called enzymes.
- Exergonic reactions release free energy (ΔG < 0) and are typically irreversible. They drive biological processes such as muscle contractions, nerve impulses, and cell division.
- Endergonic reactions require the input of free energy (ΔG > 0) and are often used to build complex molecules, such as proteins and nucleic acids.
Thermodynamical Aspects:
Thermodynamical concepts provide a framework for understanding the behavior of these reactions:
- Enthalpy (H): Change in heat content of a system during a reaction. Exergonic reactions release heat (ΔH < 0), while endergonic reactions require heat input (ΔH > 0).
- Entropy (S): Change in the disorder or randomness of a system. Reactions that increase disorder have a positive ΔS, while those that decrease disorder have a negative ΔS.
- Gibbs Free Energy (G): Function that incorporates both enthalpy and temperature. It is the maximum amount of useful work that can be obtained from a reaction (ΔG = ΔH – TΔS).
Coupling of Reactions:
Biological systems often use coupled reactions to overcome the unfavorable thermodynamics of endergonic processes. In this scenario:
- An exer… Read full answer