chemical energy

Examples of chemical energy in the following topics:

• Types of Energy

  • The various types of energy include kinetic, potential, and chemical energy.
  • On a chemical level, the bonds that hold the atoms of molecules together have potential energy.
  • This type of potential energy is called chemical energy, and like all potential energy, it can be used to do work.
  • For example, chemical energy is contained in the gasoline molecules that are used to power cars.
  • The molecules in gasoline (octane, the chemical formula shown) contain chemical energy.

• The Role of Energy and Metabolism

  • All organisms require energy to complete tasks; metabolism is the set of the chemical reactions that release energy for cellular processes.
  • Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.
  • Plants convert light energy from the sun into chemical energy stored in molecules during the process of photosynthesis.
  • Some of these chemical reactions are spontaneous and release energy, whereas others require energy to proceed.
  • For every action that requires energy, many chemical reactions take place to provide chemical energy to the systems of the body, including muscles, nerves, heart, lungs, and brain.

• Transforming Chemical Energy

  • Cellular respiration is the process of transforming chemical energy into forms usable by the cell or organism.
  • An electrical energy plant converts energy from one form to another form that can be more easily used .
  • For example, geothermal energy plants start with underground thermal energy (heat) and transform it into electrical energy that will be transported to homes and factories.
  • ATP is the principle form of stored energy used for cellular functions and is frequently referred to as the energy currency of the cell.
  • This geothermal energy plant transforms thermal energy from deep in the ground into electrical energy, which can be easily used.

• The First Law of Thermodynamics

  • Thermodynamics is the study of heat energy and other types of energy, such as work, and the various ways energy is transferred within chemical systems.
  • For instance, light bulbs transform electrical energy into light energy, and gas stoves transform chemical energy from natural gas into heat energy.
  • Plants perform one of the most biologically useful transformations of energy on Earth: they convert the energy of sunlight into the chemical energy stored within organic molecules.
  • Humans can convert the chemical energy in food, like this ice cream cone, into kinetic energy by riding a bicycle.
  • Plants can convert electromagnetic radiation (light energy) from the sun into chemical energy.

• Metabolism of Carbohydrates

  • These large polysaccharides contain many chemical bonds and therefore store a lot of chemical energy.
  • When these molecules are broken down during metabolism, the energy in the chemical bonds is released and can be harnessed for cellular processes.
  • Inside the cell, each sugar molecule is broken down through a complex series of chemical reactions.
  • As chemical energy is released from the bonds in the monosaccharide, it is harnessed to synthesize high-energy adenosine triphosphate (ATP) molecules.
  • During photosynthesis, plants convert light energy into chemical energy by building carbon dioxide gas molecules (CO2) into sugar molecules like glucose.

• The Purpose and Process of Photosynthesis

  • The process of photosynthesis converts light energy to chemical energy, which can be used by organisms for different metabolic processes.
  • To get this energy, many organisms access stored energy by eating food.
  • All of this energy can be traced back to the process of photosynthesis and light energy from the sun.
  • It is the only biological process that captures energy from outer space (sunlight) and converts it into chemical energy in the form of G3P ( Glyceraldehyde 3-phosphate) which in turn can be made into sugars and other molecular compounds.
  • A third very interesting group of bacteria synthesize sugars, not by using sunlight's energy, but by extracting energy from inorganic chemical compounds; hence, they are referred to as chemoautotrophs.

• Free Energy

  • Since chemical reactions release energy when energy-storing bonds are broken, how is the energy associated with chemical reactions quantified and expressed?
  • Gibbs free energy specifically refers to the energy associated with a chemical reaction that is available after accounting for entropy.
  • Every chemical reaction involves a change in free energy, called delta G (∆G).
  • If a chemical reaction requires an input of energy rather than releasing energy, then the ∆G for that reaction will be a positive value.
  • An important concept in the study of metabolism and energy is that of chemical equilibrium.

• Strategies for Acquiring Energy

  • All living things require energy in one form or another since energy is required by most, complex, metabolic pathways (often in the form of ATP); life itself is an energy-driven process.
  • It is important to understand how organisms acquire energy and how that energy is passed from one organism to another through food webs and their constituent food chains.
  • Photoautotrophs harness the solar energy of the sun by converting it to chemical energy in the form of ATP (and NADP).
  • Many chemoautotrophs in hydrothermal vents use hydrogen sulfide (H2S), which is released from the vents, as a source of chemical energy.
  • This allows chemoautotrophs to synthesize complex organic molecules, such as glucose, for their own energy and in turn supplies energy to the rest of the ecosystem.

• Metabolic Pathways

  • An anabolic pathway requires energy and builds molecules while a catabolic pathway produces energy and breaks down molecules.
  • Catabolic pathways involve the degradation of complex molecules into simpler ones, releasing the chemical energy stored in the bonds of those molecules.
  • Other energy-storing molecules, such as lipids, are also broken down through similar catabolic reactions to release energy and make ATP.
  • Chemical reactions in metabolic pathways rarely take place spontaneously.
  • Enzymes are important for catalyzing all types of biological reactions: those that require energy as well as those that release energy.

• Activation Energy

  • This small amount of energy input necessary for all chemical reactions to occur is called the activation energy (or free energy of activation) and is abbreviated EA.
  • During chemical reactions, certain chemical bonds are broken and new ones are formed.
  • Heat energy (the total bond energy of reactants or products in a chemical reaction) speeds up the motion of molecules, increasing the frequency and force with which they collide.
  • The higher the activation energy, the slower the chemical reaction will be.
  • The Arrhenius equations relates the rate of a chemical reaction to the magnitude of the activation energy: