L27: Metabolism

• Why are workshops included in the curriculum for the course?

  To clarify, integrate, and practice key concepts while reducing the number of lectures.
• What are the two main processes involved in metabolism?

  Anabolism and catabolism.
• What does metabolism deal with in organisms?

  Chemical processes and energy conversions.
• What are the central pathways of metabolism mentioned in the overview?

  Glycolysis, Pentose Phosphate Pathway, and Citric Acid Cycle.
• What does bioenergetics require from thermodynamics?

  It tells us which reactions are spontaneous and how much energy is required or released.
• What does the first law of thermodynamics state?

  The total energy of a system and its surroundings is constant; energy cannot be created or destroyed.
• How can we describe energy in everyday terms?

  The more energy something has, the more capacity it has to carry out a change.
• How can we quantify the change in energy of a system?

  Using the equation $\Delta E_{system} =$$E_2 - E_1 =$$Q +$$W$.
• What does the change in enthalpy represent in a biochemical reaction?

  It is approximately the same as the change in energy for the reaction.
• What is an example of enthalpy in reactions?

  Heat transfer to an egg causes a change in the structure of proteins.
• How can we explain the difference in temperature between warm and cold tea?

  Energy is transferred from the cup to the surroundings, leading to a change in temperature.
• What happens to energy in an isolated system according to the second law of thermodynamics?

  Entropy is always increasing, indicating that disorder is increasing.
• What do the first and second laws of thermodynamics tell us about reactions?

  The first law indicates energy conservation, while the second law indicates which reactions will occur based on entropy changes.
• What does Gibbs Free Energy indicate about a reaction?

  Negative $\Delta G$ means the reaction provides energy for work, while positive $\Delta G$ means energy is required.
• What factors must be considered to determine if a reaction is spontaneous?

  Both enthalpy and entropy changes must be considered.
• Can a reaction with a decrease in entropy be spontaneous?

  Yes, if the system is not isolated.
• What happens to the entropy of water when it freezes?

  The entropy decreases as bonds are formed, releasing energy.
• What does a negative $\Delta G$ indicate about a reaction?


  The reaction proceeds spontaneously with a loss of free energy.
• What does $\Delta G =$$0$ signify in a system?


  It indicates that no free energy change takes place, meaning the system is at dynamic equilibrium.
• What does it mean when $\Delta G$ is negative for diamonds turning into graphite?


  Diamonds are thermodynamically stable, but the conversion rate is very slow.
• How does Gibbs Free Energy relate to reaction rates?

  Gibbs Free Energy does not predict reaction rates; reactions may require catalysis to proceed.
• What are some ways to control enzyme activity?

  Through regulation of transcription, translation, allosteric regulation, and phosphorylation.
• What is the significance of hexokinase in the phosphorylation of glucose?

  Hexokinase catalyzes the reaction, allowing it to occur at a significant rate.
• What are the key points regarding Gibbs Free Energy and enzyme regulation?

  • Gibbs Free Energy indicates energy available to do work.
  • It tells us whether reactions are spontaneous.
  • It depends on both entropy and enthalpy changes.
  • It does not affect reaction rates.
  • Enzyme regulation is crucial for regulating metabolism.
  • Enzymes do not affect Gibbs Free Energy.