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Biology 5.1 Energy and Living Things. Photosynthesis and Cellular Respiration. Chapter Objectives. Today, Students will. . . Analyze flow of energy through living systems Compare the metabolism of autotrophs with that of heterotrophs Describe the role of ATP in metabolism
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Biology 5.1 Energy and Living Things Photosynthesis and Cellular Respiration
Chapter Objectives Today, Students will. . . • Analyze flow of energy through living systems • Compare the metabolism of autotrophs with that of heterotrophs • Describe the role of ATP in metabolism • Describe how energy is released from ATP
Energy in Living Systems • You get your energy from the food you eat. • Where does the energy in your food come from? • Directly, or indirectly, almost all energy for living things comes from the sun. • Plants convert light energy to chemical energy through photosynthesis; • animals consume the plants, • other animals consume the smaller animals, • we consume the larger animals. Flow of Energy through a System
Building Molecules that Store Energy • Metabolisminvolves either using energy to build molecules, or breaking down molecules in which energy is stored. • Photosynthesisis the process by which light energy is converted to chemical energy. • Autotrophs are organisms that use energy from sunlightto make organic compounds.
Autotrophs • Autotrophs, especially plants, are photosynthetic organisms. Photosynthetic organisms • Take in carbon dioxide (CO2) and water (H2O) • Use the energy from sunlight as a power source to create a reaction • Convert the carbon dioxide + water into food for the plant in the form of sugars • Give off oxygen as a product of this reaction
Heterotrophs • The chemical energy in inorganic compounds can be transferred to other organic compounds or to organisms that consume food. • Heterotrophs are organisms that must get energy from food instead of directly from sunlight. • We (humans) are Heterotrophsbecause we get our energy from food through the process of cellular respiration. Plants are autotrophs. All other organisms in this food web are Heterotrophs.
Cellular Respiration • Cellular respiration is a process similar to burning fuel. • Cellular respiration is a metabolic process which releases the energy in food to make ATP. • This ATP provides cells with the energy they need to carry out cellular activities.
Transfer of Energy to ATP • The word burn is often used to describe how cells get energy. • The “burning of food” in a living cell is very different than burning wood in a fire. • When a log burns, energy is released quickly as heat and light.
Transfer of Energy to ATP • But in cells, chemical energy stored in food molecules is released gradually in a series of steps. • These steps are a series of “enzyme-assisted chemical reactions”.
Transfer of Energy to ATP • When cells break down food molecules, some of the energy in the molecules is released as heat. • Most of the remaining energy is stored temporarily in molecules of ATP. Mitochondria Making ATP
Transfer of Energy to ATP • ATP is like a rechargeable battery that can take a charge, hold it, and deliver it’s energy to other locations in the cell when needed at a later time. • The energy released from ATP can be used to start other chemical reactions, such as those that build molecules. Mitochondria Making ATP
What is ATP? • Recall that ATP is a nucleotide with two extra energy absorbing phosphate groups. • The three phosphate groups in ATP form a chain that branches from a 5 carbon sugar called ribose.
What is ATP? • This phosphate tail is unstablebecause the phosphate groups are negatively charged and repel each other. • The phosphate groups store energy like a compressed spring does. • This energy is released when the bonds that hold the phosphategroups together are broken.
ATP • Breaking this outer phosphate bond requires an input of activation energy. • The energy produced by the cell however is much greater than the activation energy used. • The result is a release of energy that the cell uses to power it’s metabolism (chemical reactions).
Reflect and Review • Did we. . . . • Identify the primary source of energy that flows through most living things? • Understand the difference between an autotroph and a heterotroph when it comes to where they get their energy from? • Describe the role of ATP in metabolism?
Computer Lab Assignment • Go on the internet and produce a short one page flow chart in PowerPoint that • Demonstrates the flow of energy in a food chain from the sun to the autotrophs to heterotrophs to yourself as food 3 examples of food chains
