OpenStax Biology 2e
The first law of thermodynamics deals with the total amount of energy in the universe. It states that this total amount of energy is constant. In other words, there has always been, and always will be, exactly the same amount of energy in the universe. Energy exists in many different forms. According to the first law of thermodynamics, energy may transfer from place to place or transform into different forms, but it cannot be created or destroyed. The transfers and transformations of energy take place around us all the time. Light bulbs transform electrical energy into light energy. Gas stoves transform chemical energy from natural gas into heat energy. Plants perform one of the most biologically useful energy transformations on earth: that of converting sunlight energy into the chemical energy stored within organic molecules.– What law states that the total energy of an isolated system remains constant and it is said to be conserved over time?
The challenge for all living organisms is to obtain energy from their surroundings in forms that they can transfer or transform into usable energy to do work. Living cells have evolved to meet this challenge very well. Chemical energy stored within organic molecules such as sugars and fats transforms through a series of cellular chemical reactions into energy within ATP molecules. Energy in ATP molecules is easily accessible to do work. Examples of the types of work that cells need to do include building complex molecules, transporting materials, powering the beating motion of cilia or flagella, contracting muscle fibers to create movement, and reproduction.– In thermodynamics, what is one in which no heat is gained or lost by the system?
Sensible heat is the energy associated with the temperature of a body. It is greater in a warm body than a cold one. Warm water that is heated in the tropics and cooled in high latitudes brings sensible heat poleward. Warm winds carry sensible heat from one place to another. When picking up water along the way, the winds can change some of the sensible heat into latent heat. Latent heat is the energy associated with changing the “phase” of a substance. This change in phase involves changing the state from gas to fluid or from fluid to solid, or the reverse. The enormous amounts of latent heat involved in evaporation and precipitation of water makes the hydrologic cycle a central player in the operation of the climate machine.
Clark, M., Douglas, M., Choi, J. Biology 2e. Houston, Texas: OpenStax. Access for free at: https://openstax.org/details/books/biology-2e