Bio Energy

• What is energy?

  Energy is the capacity to do work.
• What is thermodynamics?

  Thermodynamics is the study of energy transformations.
• What does the second law of thermodynamics state?

  Every energy transfer or transformation increases the entropy of the universe.
• How is entropy defined?

  Entropy is a measure of disorder or the number of energy levels in a system.
• What happens during spontaneous processes according to the second law of thermodynamics?

  Spontaneous processes increase the entropy of the universe.
• What is the effect of non-spontaneous processes on entropy?


  Non-spontaneous processes decrease entropy and require work to occur.
• Do living things follow the second law of thermodynamics?

  Yes, living things follow the second law of thermodynamics.
• What is free energy?

  Free energy is the energy available to do work in a system.
• How can we measure the change in energy during a chemical reaction?

  The change in free energy (ΔG) is the difference between the free energy of the final state and the initial state.
• What occurs at chemical equilibrium?

  At chemical equilibrium, forward and reverse reactions occur at the same rate.
• What do spontaneous processes move towards?

  Spontaneous processes move towards equilibrium.
• What is metabolism?

  Metabolism includes catabolism and anabolism in biological systems.
• What is a catabolic pathway?

  A catabolic pathway releases free energy in a series of steps/reactions.
• What happens to the products of each reaction in a catabolic pathway?

  The product of each reaction becomes the reactant of the next reaction.
• Does a catabolic pathway reach equilibrium?


  No, the system in a catabolic pathway never reaches equilibrium.
• How are exergonic and endergonic reactions related?


  Exergonic reactions are coupled to endergonic reactions.
• What role does ATP play in coupled reactions?


  ATP acts as the coupler for reactions.
• What is an exergonic reaction?

  A reaction that releases energy
• What is activation energy?

  The energy required to start a reaction by breaking bonds in the reactant molecules
• What are factors that can lower activation energy?

  Enzymes and temperature
• Can factors that lower activation energy work in biological systems?

  Yes, enzymes can lower activation energy in biological systems
• What is the role of enzymes in chemical reactions?

  Enzymes lower the activation energy required for reactions
• How do enzymes work?

  By providing an active site for substrates to bind and facilitating reactions
• What is an active site of an enzyme?

  The region where substrates bind to the enzyme
• What is substrate specificity in enzymes?

  Enzymes are specific to certain substrates due to their active sites
• What is the induced fit model of enzyme action?

  The model where the enzyme changes shape to fit the substrate upon binding
• What are the steps in the enzyme cycle?

  1. Substrate binds to the active site
  2. Enzyme-substrate complex forms
  3. Reaction occurs, converting substrates to products
  4. Products are released
  5. Enzyme is free to bind to new substrates
• How does an enzyme lower activation energy?

  By orienting substrates favorably and applying mechanical stress on bonds
• What is one way enzymes create a favorable chemical microenvironment?

  By providing conditions that favor the transition state
• How might enzymes assist in transferring protons or electrons?

  By accepting or donating them during the conversion of substrates to products
• What are cofactors?

  Metal ions that assist enzymes in catalyzing reactions
• Give examples of cofactors.

  Mg²⁺, Fe²⁺, Zn²⁺
• What are coenzymes?

  Small organic cofactors that help enzyme-substrate complexes form
• What are examples of coenzymes?

  Coenzyme A, NAD⁺, NADP⁺
• What factors can affect enzyme activity?

  Substrate concentration and inhibitors
• What are competitive inhibitors?

  Inhibitors that bind to the active site of an enzyme
• What are noncompetitive inhibitors?

  Inhibitors that bind to an alternate site on the enzyme
• How do noncompetitive inhibitors affect enzyme activity?

  They change the shape of the active site, preventing substrate binding
• What is feedback regulation in enzyme activity?

  The end product of a pathway inhibits an earlier enzyme in the pathway
• What is allosteric regulation of enzymes?

  • Regulation where a molecule binds to a site other than the active site
  • Causes a change in enzyme shape
  • Can either activate or inhibit enzyme activity