biology

• Energy flows into an ecosystem as

  Sunlight
• In a cell, ATP is used continuously and must be regenerated continuously
• Some of the energy released in cellular respiration is lost as

  Heat
• Photosynthesis generates

  Oxygen and glucose used by the mitochondria of eukaryotes as fuel for cellular respiration
• ATP

  Adenosine Triphosphate, energy rich (like a charged battery)
• Cellular respiration


  Breaks down glucose into simpler substances and releases the stored energy
• Food provides living things with the chemical building blocks they need to grow and reproduce
• How ADP Becomes ATP

  1. ADP has 2 phosphate groups and ATP has three phosphate groups

  2. When a cell has energy available, it can store small amounts of it by adding a phosphate group to ADP

  3. Adding a phosphate to ADP forms a molecule of ATP

  4. The addition of the third phosphate stores energy

  5. When a cell needs energy, the third phosphate will be removed, releasing energy
• ADP

  Adenosine Diphosphate, energy poor (like a dead battery)
• Energy is not recycled, it follows a one-way path through our ecosystem
• The waste products of respiration

  Are the raw materials for photosynthesis
• Some of the energy released in cellular respiration is used to make

  ATP from ADP
• Energy leaves an ecosystem as

  Heat
• Food serves as a source of


  • Raw materials for the cells of the body
  • Energy
• The waste products of respiration

  • CO2
  • H2O
• ATP molecule


  The basic energy source of all living cells
• Chemical elements essential to life are recycled
• Cellular activities powered by ATP

  • Photosynthesis
  • Protein synthesis
  • Muscle contraction
  • Active transport across the cell membrane
• Photosynthesis converts

  Light energy from the sun into chemical energy, which is stored in carbohydrates and other organic compounds
• Cellular respiration


  The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
• CO2 and H2O

  Are the raw materials for photosynthesis
• The energy stored in glucose will be released bit by bit and this energy will be used to produce ATP. The energy cannot be released from the glucose all at once. It would be the equivalent of the gas tank in your car exploding in one single reaction, rather than in the small controlled combustions that drive your car
• While only green plants carry out photosynthesis, ALL living things carry out respiration
• Types of respiration

  • Aerobic Respiration
  • Anaerobic Respiration
• Glycolysis


  The process in which one molecule of glucose is oxidized to produce two molecules of pyruvic acid
• Photosynthesis


  Green plants only
• The waste products of respiration

  CO2 and H2O
• Glycolysis occurs in the cytoplasm, while the Krebs cycle and electron transport chain occur in the mitochondria
• Even though cellular respiration is an energy-releasing process, the cell must invest a small amount of energy to get the reaction started
• Converting glucose to ATP

  Part of cellular respiration
• Photosynthesis equation

  • C6H12O6 + O2
• Equation for respiration

  • C6H12O6 + O2 -> CO2 + H2O + 38 ATP
• Respiration equation


  • CO2 + H2O
• There is much energy stored in glucose. This energy must be released in small, controlled steps. If all the energy from glucose were released at once, most of it would be lost as heat and light
• Another advantage is that glycolysis does not require oxygen. Energy can be produced for the cell even if no oxygen is present
• Aerobic respiration will yield many more ATP than glycolysis
• In the absence of oxygen, the pyruvic acid will enter the anaerobic pathways of fermentation
• Glycolysis only produces a gain of 2 ATP per molecule of glucose, but the process is so fast that 1000’s of ATP are produced in just a few milliseconds
• Steps in Glycolysis

  1. ATP Production

  2. NADH Production
• Disadvantage: If the cell relied only on glycolysis for ATP production, the cell would quickly run out of NAD+ to accept the hydrogen el. Without NAD+, the cell cannot keep glycolysis going and ATP production would stop. To keep glycolysis going, the NADH must deliver their high-energy cargo of electrons to another pathway, and then return to glycolysis to be used again