Bioenergetic

• To produce glucose molecules for photosynthesis energy is required this is because the reaction are endothermic which means it takes in heat.The energy required is sunlight which is trapped in chlorophyll green chemical which is found in chloroplast
• Factors affecting photosynthesis are temperature, carbon dioxide concentration , light intensity and chlorophyll concentration
• Temperature: As the temperature increases so does the rate of photosynthesis this is because more energy is provided for the reaction.

  As the temperature reaches its optimum the rate of photosynthesis drops to zero because the enzymes controlling photosynthesis have been destroyed
• Carbon dioxide: As the concentration of CO2 increases so does the rate of photosynthesis. This is because carbon dioxide is needed in the reaction.
• Light intensity: As the light intensity increases so does the rate of photosynthesis. This is because more energy is provided for the reaction
• Chlorophyll concentration: This does not vary in the short term but may change if plants are grown in soil without enough minerals to make chlorophyll
• The glucose produced in photosynthesis may be

  • used for respiration
  • converted into insoluble starch for storage
  • used to produce fat or oil for storage
  • used to produce cellulose, which strengthens the cell wall
  • used to produce amino acids for protein synthesis

  To produce proteins, plants also use nitrate ions that are absorbed from the soil
• Photosynthesis absorbs light energy and uses it to make glucose.
• Equation for photosynthesis

  Carbon dioxide + water → glucose+ Oxygen

  CO2. H20. C6H1206. 02
• Respiration is an example of an exothermic reaction. It releases energy from glucose molecules for use by the body.

  Organisms need this energy:

  • for chemical reactions to build larger molecules
  • For movement
  • to keep warm
• Aerobic Respiration

  Glucose + oxygen → carbon dioxide +water

  C6H12O6. O2. CO2. H2O
• Anaerobic respiration

  glucose →lactic acid

  Glucose →ethanol+carbon dioxide
• In anaerobic respiration the energy is transferred much less than aerobic respiration because glucose is not completely broken down
• Anaerobic respiration in yeast cells is called fermentation and has economic importance in the manufacture of bread and alcoholic drinks
• During exercise the human body reacts to the increases demand for energy. The hear rate , breathing rate and breath volume increase during exercise to supply the muscle with more oxygengenated blood.

  If oxygen is insufficient than anaerobic respiration takes place in the muscles. The incomplete oxidation of glucose causes build up lactic acid and creates an oxygen debt. During long periods of vagarious activity muscle become fatigued and stop contracting efficiently
• Metabolism is the sum of all reactions in a cell or the body
• Metabolism includes

  • Conversion of glucose to starch, glycogen and cellulose
  • Respiration
  • breakdown of excess proteins to form urea for excretion
  • The formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids
  • the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins