Bioenergetics

• What is metabolism?


  Metabolism is the sum of all the chemical reactions occurring in an organism.
• Why do all of life’s processes occur?

  They occur due to chemical reactions.
• What are the two types of metabolic reactions?

  • Catabolism: Breaks down molecules and releases energy.
  • Anabolism: Combines monomers to build polymers and requires energy.
• What is catabolism?


  Catabolism refers to chemical reactions that break down molecules.
• What do catabolic reactions release?


  They release potential energy found in the chemical bonds between monomers.
• Why are catabolic reactions considered exergonic?


  Because they release heat energy to the environment.
• What is an example of a catabolic reaction?


  Hydrolysis is an example of a catabolic reaction.
• What is anabolism?

  Anabolism refers to chemical reactions that combine monomers to build polymers.
• What do anabolic reactions usually require?


  They usually require an input of kinetic energy to create bonds between the monomers.
• Why are anabolic reactions considered endergonic?


  Because they absorb energy from the environment, storing it for later use.
• What is an example of an anabolic reaction?


  Dehydration is an example of an anabolic reaction.
• What is energy defined as?


  Energy is the ability to do work or make things move.
• What are the types of energy mentioned in the study material?

  1. Kinetic Energy: Energy of movement.
  2. Free Energy: Energy available to do work.
  3. Potential Energy: Energy in stored form.
  4. Thermal Energy: Heat released during reactions.
• What does kinetic energy refer to in biology?


  Kinetic energy refers to the energy of movement, commonly the movement of electrons or protons.
• How is free energy represented?


  Free energy is represented by the symbol △G.
• What does potential energy refer to in biology?


  Potential energy refers to the measure of energy in its stored form, commonly in chemical bonds.
• What is thermal energy?


  Thermal energy is a form of kinetic energy that refers to the heat released into the environment during chemical reactions.
• What is the 1st Law of Thermodynamics also known as?


  It is also known as the Law of Conservation of Energy.
• What does the 1st Law of Thermodynamics state?


  It states that energy cannot be created or destroyed in an isolated system.
• What does the 2nd Law of Thermodynamics state?


  It states that the entropy of any isolated system always increases.
• What is entropy?


  Entropy is a thermodynamic quantity representing the unavailability of a system’s thermal energy for conversion into mechanical work.
• What are metabolic pathways?


  • Enzyme-regulated sets of biochemical reactions.
  • Lead to either anabolic or catabolic pathways.
  • Each step consists of a separate chemical reaction.
  • Products of one reaction are typically substrates for the next.
• What happens to processes that are not energetically favorable?


  They will occur if there is energy available to power them.
• What is ATP?


  ATP stands for Adenosine-Triphosphate.
• What is ATP composed of?


  ATP is composed of a nucleotide, ribose, and three attached phosphates.
• Why is ATP made unstable?


  It is made unstable by the three adjacent negative charges in the phosphate tails.
• What happens during the conversion of ATP to ADP?


  It releases energy, which is used to power many metabolic processes.
• What is the chemical equation for the conversion of ATP to ADP?


  ATP + H₂O → ADP + Pi
• What is the significance of the hydrolysis of ATP?


  The hydrolysis of ATP is reversible through dehydration, important for metabolic processes.
• What is the free energy (△G) for hydrolysis of one ATP?


  The free energy is -14 kcal/mol or -57 kJ/mol.
• What does a negative free energy value indicate?


  A negative value indicates that the reaction is very spontaneous.
• What is a coupled reaction?


  A coupled reaction happens when an energetically favorable reaction is linked with an energetically unfavorable reaction.
• What are enzymes?


  Enzymes are proteins that catalyze chemical reactions and increase the rate of biological reactions.
• How do enzymes catalyze reactions?


  They lower the activation energy required for a reaction to occur.
• What is the substance acted upon by an enzyme called?


  The substance is called the substrate.
• Where does the substrate bind on the enzyme?

  The substrate binds to the active site of the enzyme.
• What must be true for the substrate and enzyme to bind effectively?


  The shape and charges of the substrate and enzyme must be complementary and compatible.
• What is induced fit in enzymes?


  Induced fit is when the enzyme undergoes a slight change in shape after the substrate binds, helping to catalyze the reaction.
• What factors affect enzyme activity?

  Temperature, pH, concentration of enzymes and substrates, and salinity affect enzyme activity.
• What happens to enzymes if temperature or pH is moved away from optimal conditions?


  Enzymes will begin to denature, changing shape and losing function.