Bionergetics WHOLE TOPIC

• Photosynthesis


  The process by which plants make glucose from sunlight
• Endothermic reaction


  Energy is transferred from the environment to the chloroplasts by light
• Photosynthesis equation

  Carbon dioxide + Water → Glucose + Oxygen
• Chemical symbols for compounds

  • Carbon dioxide: CO​2
  • Water: H​2​O
  • Oxygen: O​2
  • Glucose: C​6​H​12​O​6
• The rate of photosynthesis is affected by a number of factors
• Factors affecting the rate of photosynthesis

  • Temperature
  • Light Intensity
  • Carbon dioxide concentration
  • Amount of chlorophyll

  
• With an increase in temperature

  The rate of photosynthesis increases until enzymes begin to denature
• The higher the light intensity


  The faster the rate of the reaction for most plants
• As the concentration of carbon dioxide increases


  The rate of reaction increases
• Chlorophyll


  A pigment in the leaf that converts light energy to food for the plant
• If chlorophyll levels are reduced through a magnesium deficiency, then the rate of photosynthesis would decrease
• Measuring the rate of photosynthesis

  1. Place pondweed in water

  2. Seal with a bung

  3. Attach capillary tube

  4. Measure oxygen production
• Many variables can be changed to observe their effect on photosynthesis
• Variables that can be changed in the experiment

  • Temperature
  • Time
  • Light intensity
• It is important to control all factors that may affect photosynthesis except your independent variable
• Limiting factor

  An environmental condition that restricts any increase in the rate of photosynthesis
• A graph involves one limiting factor if it has one line which levels off
• A graph with two lines represents two limiting factors in two experiments
• Light intensity is measured in lux
• At 50 lux light intensity


  It was the limiting factor compared to the 100 lux experiment
• Farmers can use the knowledge of limiting factors to enhance the conditions in the greenhouse for a greater rate of photosynthesis
• Inverse proportion

  A relationship between two factors where one increases while one decreases
• Light intensity is inversely proportional to the square of the distance
• Light intensity ∝ 1/distance​2
• Uses of glucose from photosynthesis

  • For respiration
  • Converted into insoluble starch for storage
  • To produce fat or oil for storage
  • To produce cellulose to strengthen cell walls
  • Combined with nitrates to form amino acids which produce proteins
• Respiration occurs in every cell in the body
• Respiration


  The process of transferring energy from glucose so living processes can occur
• Exothermic


  Energy is transferred to the environment
• Types of respiration

  • Aerobic
  • Anaerobic
• Aerobic respiration


  Uses oxygen and yields the most energy
• Aerobic respiration equation

  C​6 ​H​12​O​6​ + O​2​ → CO​2​ + H​2​O
• Anaerobic respiration


  Occurs when there is not enough oxygen and does not yield as much energy
• Anaerobic respiration is only used as a last resort
• Anaerobic respiration in animals

  Glucose → Lactic acid
• Anaerobic respiration in plants and yeast

  Glucose → Ethanol + Carbon dioxide
• Lactic acid builds up creating an oxygen debt
• Oxygen debt

  The amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid
• Blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose
• Metabolism

  The sum of all the reactions in a cell or the body
• The energy transferred in the cells by respiration is used in the processes of metabolism to make new molecules