Wk. 28

• Producers


  Use the sun's energy and matter from the environment to make food molecules
• Energy flow through a tree

  1. Sunlight energy is transferred first to food molecules

  2. Food molecules store energy the tree can use later

  3. Stored energy is released through chemical reactions that form new molecules, providing the tree with energy and growth for life processes

  4. Some energy is also released as heat
• Energy and matter


  • Energy is a nearly limitless source for plants
  • Matter is limited
  • Matter cycles between the living and nonliving parts of the environment
  • Energy changes form as it flows through a system but it is not created or destroyed
  • Energy transfers are necessary for chemical reactions that rearrange matter for growth and life processes
  • The matter eventually returns to the environment when the tree decomposes, completing the cycle
• Chemical reaction


  The process by which one or more substances change to produce one or more different substances
• Photosynthesis


  The process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to make food
• Cellular respiration


  The process by which cells use oxygen to produce energy from food
• Photosynthesis


  1. Plants use sunlight, carbon dioxide, and water to make food (sugar)

  2. Plants release oxygen into the air
• Cellular respiration


  1. Plants break down the glucose they made during photosynthesis to get energy

  2. Plants use oxygen from the air and release carbon dioxide as a waste product
• Photosynthesis and cellular respiration


  They are like a cycle - plants take in carbon dioxide and release oxygen during photosynthesis, and then they take in oxygen and release carbon dioxide during cellular respiration
• This cycle is essential for life on Earth because it keeps the air breathable for all living things and provides the energy needed for plants and animals to survive
• Chemical reaction


  The rearrangement of atoms to form new substances
• Each cell performs many chemical reactions every second
• During a chemical reaction, atoms are rearranged into different combinations
• The new molecules formed by chemical reactions in cells are used as matter and energy for life processes
• Chemical reaction


  • A process in which atoms are rearranged to produce new substances
  • The starting substances are called reactants
  • The substances formed are called products
  • Neither matter nor energy is created or destroyed during a chemical reaction
• Chemical equation


  1. Uses symbols to show the relationship between the starting materials and the materials produced in the reaction

  2. Each type of atom, or element, is indicated by its symbol
• Carbon-based molecules


  • They are the building blocks of living things
  • Carbon atoms can bond together to form large chains and other large molecules
  • All animal and plant cells use energy that comes from carbon-based molecules
• Photosynthesis


  A series of chemical reactions in which the cells of producers use energy from the sun to make carbon-based food molecules (sugars)
• Chloroplasts


  • Cell structures that capture light energy from the sun
  • Photosynthesis takes place in the chloroplasts
  • Chloroplasts are only found in the cells of plants and other producers that use photosynthesis
• Chemical bonds


  • Sources of energy
  • During photosynthesis, light energy is used to make sugar molecules
  • The sugar that is not used is often stored as starch in the plant's stem and roots
• You and nearly all living things need a constant supply of oxygen to live
• Cellular respiration


  • A process that uses oxygen to release the energy stored in food molecules
  • It takes place inside mitochondria
• Cellular respiration


  1. The first stage takes place in the cytoplasm, where each sugar molecule is broken down into smaller molecules

  2. The chemical reactions that take place in the mitochondria require a lot of oxygen
• Energy release in cellular respiration

  • A small amount of energy is released when the sugar molecules are broken down in the cytoplasm
  • A large amount of energy is released by the chemical reactions in the mitochondria
  • Cells use this energy for life processes
• Plants and other photosynthetic organisms absorb carbon dioxide and produce oxygen, making them a necessary part of any ecosystem
• Photosynthesis and cellular respiration

  • While animals only perform cellular respiration, plants perform photosynthesis and cellular respiration
  • Photosynthesis is important because plants produce most of the oxygen in the atmosphere that we need in cellular respiration
  • Cellular respiration is important because it produces energy for the body to do anything
  • Plants produce their own food, but without cellular respiration, plants cannot grow, reproduce, or repair tissues