energy

Examples of energy in the following topics:

• Types of Energy

  • The various types of energy include kinetic, potential, and chemical energy.
  • The potential energy stored in molecules can be converted to chemical energy, which can ultimately be converted to kinetic energy, enabling an organism to move.
  • Energy associated with objects in motion is called kinetic energy.
  • The jet engines are converting potential energy in fuel to the kinetic energy of movement.
  • This type of potential energy is called chemical energy, and like all potential energy, it can be used to do work.

• 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.
  • 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.
  • Energy is needed to perform heavy labor and exercise, but humans also use a great deal of energy while thinking and even while sleeping.
  • Just as energy is required to both build and demolish a building, energy is required for both the synthesis and breakdown of molecules.

• Free Energy

  • Free energy, called Gibbs free energy (G), is usable energy or energy that is available to do work.
  • Since chemical reactions release energy when energy-storing bonds are broken, how is the energy associated with chemical reactions quantified and expressed?
  • A measurement of free energy is used to quantitate these energy transfers.
  • In other words, Gibbs free energy is usable energy or energy that is available to do work.
  • Exergonic reactions release energy; endergonic reactions require energy to proceed.

• Activation Energy

  • Activation energy is the energy required for a reaction to occur, and determines its rate.
  • Why would an energy-releasing, negative ∆G reaction actually require some energy to proceed?
  • Since these are energy-storing bonds, they release energy when broken.
  • Free energy diagrams illustrate the energy profiles for a given reaction.
  • This figure implies that the activation energy is in the form of heat energy.

• Food Energy and ATP

  • Animals use energy for metabolism, obtaining that energy from the breakdown of food through the process of cellular respiration.
  • Animals need food to obtain energy and maintain homeostasis.
  • Adenosine triphosphate, or ATP, is the primary energy currency in cells.
  • ATP stores energy in phosphate ester bonds, releasing energy when the phosphodiester bonds are broken: ATP is converted to ADP and a phosphate group.
  • ATP is the energy molecule of the cell.

• Introduction to Light Energy

  • All electromagnetic radiation, or light energy, travels at a particular wavelength and carries a certain amount of energy.
  • The manner in which solar energy travels is described as waves.
  • The longer the wavelength, the less energy is carried.
  • Short, tight waves carry the most energy.
  • The sun emits energy in the form of electromagnetic radiation.

• Transforming Chemical Energy

  • 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.
  • The energy released during cellular respiration is then used in other biological processes.
  • This geothermal energy plant transforms thermal energy from deep in the ground into electrical energy, which can be easily used.

• 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.
  • The processes of all organisms—from bacteria to humans—require energy.
  • To get this energy, many organisms access stored energy by eating food.
  • But where does the stored energy in food originate?
  • All of this energy can be traced back to the process of photosynthesis and light energy from the sun.

• 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.
  • Photosynthetic autotrophs (photoautotrophs) use sunlight as an energy source, whereas chemosynthetic autotrophs (chemoautotrophs) use inorganic molecules as an energy source.
  • Photoautotrophs harness the solar energy of the sun by converting it to chemical energy in the form of ATP (and NADP).
  • 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.

• 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.
  • Energy exists in many different forms.
  • 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.
  • Plants can convert electromagnetic radiation (light energy) from the sun into chemical energy.