Chapter 8 – Cellular Energy Section 1 – How Organisms Obtain Energy

 All living organisms use energy to carry out all biological processes. How Organisms Obtain Energy Cellular Energy Section 1

Transformation of Energy  Energy is the ability to do work. How Organisms Obtain Energy Cellular Energy  Thermodynamics is the study of the flow and transformation of energy in the universe. Section 1

Laws of Thermodynamics  1 st Law—Law of Conservation of Energy Energy can be converted from one form to another, but it cannot be created nor destroyed. How Organisms Obtain Energy Cellular Energy  2 nd Law—energy cannot be converted without the loss of usable energy. Energy that is lost is generally converted to thermal energy. Entropy is the measure of unusable energy in a system. (food chain) Section 1

Autotrophs and Heterotrophs  Autotrophs - organisms that make their own food, most through photosynthesis (plants). How Organisms Obtain Energy Cellular Energy  Heterotrophs - organisms that need to ingest food to obtain energy (humans). Section 1

Metabolism  All of the chemical reactions in a cell. A metabolic pathway is a series of chemical reactions in which the product of one reaction is the substrate for the next reaction. How Organisms Obtain Energy Cellular Energy Section 1

Metabolism  2 types of metabolic pathways: Catabolic – release energy by breaking down larger molecules into smaller molecules. Anabolic – use energy released by catabolic pathways to build larger molecules from smaller molecules.  Results in a continuous flow of energy within an organism. How Organisms Obtain Energy Cellular Energy Section 1

Photosynthesis is an anabolic pathway –Light energy from the sun is converted to chemical energy (glucose) for use by the cell. Cellular respiration is a catabolic pathway –Organic molecules are broken down to release energy (in the form of ATP) for use by the cell. How Organisms Obtain Energy Metabolism

ATP: The Unit of Cellular Energy  Adenosine Triphosphate (ATP)  ATP is the most abundant energy- carrier molecule in cells.  All chemical reactions that occur in a cell use ATP as the energy source. How Organisms Obtain Energy Cellular Energy Section 1

ATP: The Unit of Cellular Energy  ATP is synthesized by cells through the process of cellular respiration.  Made up of an adenine base, ribose sugar, and 3 phosphate groups. How Organisms Obtain Energy Cellular Energy Section 1

ATP: The Unit of Cellular Energy  ATP releases energy when the bond between the second and third phosphate group is broken.  Forms a molecule called ADP and a free phosphate group. alhtg How Organisms Obtain Energy Cellular Energy Section 1

ATP: The Unit of Cellular Energy How Organisms Obtain Energy Cellular Energy Section 1