B1.3- respiration

• Respiration


  Cellular respiration is a universal chemical process, continuously occurring that supplies ATP in all living cells. Respiration is an exothermic reaction as it releases heat.

  
• Respiration


  • Releases energy
  • Occurs in all living cells
  • Exothermic reaction

  
• Uses of energy


  • Muscle contraction
  • Protein synthesis (e.g. enzymes, hormones)
  • Cell division
  • Growth
  • Active transport
  • Nerve impulses
  • Maintaining a constant body temperature
• Living organisms get their energy from reactions like this (but not reactions which are violent enough to produce flames)
• ATP


  • Adenosine tri phosphate
  • Stores energy in the phosphate bonds
  • Cells release the energy by breaking these bonds
  • The more ATP you have the more energy you have
  • Some processes are more "expensive" than others
• Respiration is not the same thing as breathing

  
• The chemical reactions of respiration involve enzyme action and take place in all living cells all of the time

  
• The reaction produces carbon dioxide and water, and releases energy
• Aerobic respiration


  Oxygen is used in the breakdown of glucose to release energy
• Aerobic respiration


  1. Glucose + oxygen

  2. Carbon dioxide + water + energy

  
• 1 molecule of glucose reacts with 6 molecules of oxygen to produce 6 molecules of carbon dioxide and 6 molecules of water

  
• 4 experiments are set up to demonstrate parts of the aerobic respiration equation

  
• Anaerobic respiration


  The chemical reactions in cells that breakdown nutrient molecules to release energy without using oxygen
• Anaerobic respiration


  1. Glucose

  2. Lactic acid + energy
• Anaerobic respiration


  Releases much less energy per glucose molecule than aerobic respiration
• What happens during exercise

  1. Muscles contract to cause movement

  2. Muscles start to respire anaerobically

  3. Glucose is partly broken down into lactic acid, releasing only a small amount of energy
• Anaerobic respiration equation (chemical)

  1. C6H12O6

  2. 2C3H6O3 + energy
• Lactic acid


  Toxic, builds up in the blood and muscles causing tiredness and aches, and an oxygen debt
• Muscles can only respire anaerobically


  For a short period of time
• What happens after vigorous exercise

  1. Heart continues to pump fast to transport lactic acid in the blood from muscles to liver to be broken down

  2. Breathing remains deep to supply the extra oxygen (oxygen debt) needed to break down the lactic acid in the liver by aerobic respiration
• Sprinters may not breathe at all during their race

  But breathe very deeply at the end of it
• Anaerobic respiration


  The chemical reactions in cells that breakdown nutrient molecules to release energy without using oxygen
• Fermentation


  Anaerobic respiration in yeast
• Yeast


  A single celled fungus
• Anaerobic respiration in yeast

  1. Glucose

  2. Alcohol

  3. Carbon dioxide

  4. Energy
• The balanced chemical equation for anaerobic respiration in yeast is: C6H12O6 → 2C2H5OH + 2CO2 + energy
• Yeast is a single celled fungus
• Anaerobic respiration is the chemical reactions in cells that breakdown nutrient molecules to release energy without using oxygen
• In yeast, anaerobic respiration is also called fermentation
• Biological molecules


  • Carbohydrates
  • Proteins
  • Fats
• Living organisms are built from organic biological molecules that contain carbon
• Biological molecules


  • Carbohydrates (contain C, H and O)
  • Fats (contain C, H and O but have less O than carbohydrates)
  • Proteins (contain C, H, O and N)
• Digestion and assimilation of biological molecules

  1. Enzymes in the digestive tract digest large molecules (polymers) into small molecules (monomers)

  2. Monomers are absorbed

  3. Monomers are built back up into large molecules (polymers) in the body

  
• Metabolism


  The reactions in the body that use the biological molecules
• Metabolic rate


  The speed at which cells transfer energy from their chemical stores to provide the energy needed for reactions
• Biological molecules


  • Carbohydrates
  • Proteins
  • Lipids
• Carbohydrates


  • Substrates in respiration
  • Energy stores
  • Structural in cell walls
• Carbohydrate polymers


  • Glycogen in animals
  • Starch or cellulose in plants
• Enzyme to digest carbohydrates

  Amylase (a carbohydrase)
• Proteins


  • Used for growth and repair
  • Can be used in respiration
  • Make enzymes