b4-bioenergetics

• photosynthesis: the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product
• carbon dioxide + water ---> glucose + oxygen
• 6CO2 + 6H2O -> C6H12O6 + 6O2
• plants use glucose for:

  • respiration
  • cellulose- strengthens cell walls
  • making amino acids- made into proteins
  • stored as oils/fats
  • stored as starch
• rate of photosynthesis is affected by:

  • temperature
  • light intensity
  • carbon dioxide levels
  • chlorophyll can also be a limiting factor because then the plant cannot absorb as much light
• light intensity equation:

  • light intensity is inversely proportional to distance
  • light intensity (proportion symbol) 1/distance^2
• to create ideal conditions for farming you could

  • grow them in a greenhouse, which trap the suns heat and make sure that the temperature doesnt become limiting
  • in winter a farmer could also use a heater to keep temperature at an ideal level
  • light is always needed for photosynthesis so commercial farmers often supply artificial light after the sun goes down
  • farmers can also increase carbon dioxide levels by using parrafin heaters which makes carbon-dioxide as it burns
• respiration is the process of transferring energy from glucose which goes on in every cell
• how organisms use energy transferred by respiration:

  • to build complex molecules, to maintain body temperature, to carry out chemical reactions such as allowing muscles to contract
• anaerobic respiration occurs when there isn't enough oxygen available
• aerobic respiration occurs in mitochondria
• metabolism is the sum of all the chemical reactions in a cell or organism
• aerobic respiration:

  • glucose + oxygen --> carbon dioxide + water
• anaerobic respiration in humans

  • glucose --> lactic acid
• anaerobic respiration in plants + yeast

  • glucose ---> ethanol + carbon dioxide
• when you exercise you respire more:

  • muscles need energy from respiration to contract, when you exercise some of your muscles contract more frequently so you need more energy
• anaerobic respiration leads to oxygen debt