E. Bioenergetics

• Types of autotrophs

  • Organisms that get energy from the sun
  • Organisms that use energy from chemicals
• Photosynthesis


  The process where autotrophs use light energy to convert carbon dioxide and water into oxygen and energy-rich carbohydrates

  
• Chemosynthesis


  The process where autotrophs produce energy without light by using energy within the chemical bonds of inorganic molecules
• Types of heterotrophs

  • Herbivores
  • Carnivores
  • Omnivores
  • Detritivores
  • Decomposers
• Chloroplasts


  • Organelles found in plant cells and some other eukaryotic organisms
  • Conduct photosynthesis
  • Carry out almost all fatty acid synthesis in plants
  • Involved in a plant's immune response
• Thylakoids


  Saclike photosynthetic membranes in chloroplasts arranged in stacks called grana
• Photosynthesis


  The process of converting light energy into chemical energy by living organisms

  
• NADP+ and NADPH

  NADP+ is a compound that accepts and holds two high energy electrons along with a hydrogen ion, converting it to NADPH which can carry the high-energy electrons to chemical reactions
• Cellular respiration


  The process that releases energy by breaking down food molecules in the presence of oxygen
• Glycolysis


  The process where glucose is split into two molecules of pyruvic acid, producing 2 ATP and 2 NADH

  
• Cellular respiration equation


  C6H12O6 + 6O2 → 6CO2 + 6H2O
• Three main stages of cellular respiration

  • Glycolysis
  • Citric Acid Cycle
  • Electron Transport
• Glycolysis


  1. Glucose, a six-carbon sugar, is split into two molecules of a three-carbon sugar

  2. Produces 2 ATP, 2 pyruvic acid, and 2 NADH

  3. Can occur with or without oxygen

  
• Fermentation


  The combined process of glycolysis and a different pathway when oxygen is not present
• Types of fermentation

  • Alcoholic fermentation
  • Lactic acid fermentation
• Citric Acid Cycle


  1. Pyruvic acid from glycolysis enters the mitochondrion

  2. Acetyl-CoA is formed and added to a 4-carbon compound to form citric acid

  3. Citric acid is broken down, releasing 2 more CO2, 4 NADH, 1 FADH2, and 1 ATP
• Electron Transport


  1. High energy electrons from NADH and FADH2 are passed along the electron transport chain

  2. Hydrogen ions build up in the intermembrane space, creating a proton gradient

  3. ATP synthases use the proton gradient to convert ADP to ATP
• the Krebs cycle and electron transport - enable the cell to produce 34 more ATP molecules per glucose molecule in addition to the two ATP molecules obtained from glycolysis

  
• Cellular respiration

  Energy release process that uses C6H12O6 and O2 to produce CO2 and H2O
• Feeding relationships

  • Food chain
  • Food web
  • Trophic levels