topic 4- bioenergetics

• What type of reaction is photosynthesis?

  Photosynthesis is an endothermic reaction.
• What is photosynthesis?

  Photosynthesis is the process by which plants make glucose from sunlight.
• How is energy transferred in photosynthesis?

  Energy is transferred from the environment to the chloroplasts by light.
• What is the equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen.

  
• What is the chemical symbol for carbon dioxide?


  CO​2
• What is the chemical symbol for water?

  H​2​O
• What is the chemical symbol for oxygen?

  O​2
• What is the chemical symbol for glucose?

  C​6​H​12​O​6
• What factors affect the rate of photosynthesis?

  Temperature, light intensity, carbon dioxide concentration, and amount of chlorophyll.

  
• How does temperature affect the rate of photosynthesis?

  As temperature increases, the rate of photosynthesis increases until enzymes begin to denature.
• What happens to enzymes at high temperatures during photosynthesis?

  Enzymes begin to denature, causing the rate of reaction to decrease.
• How does light intensity affect the rate of photosynthesis?

  For most plants, higher light intensity increases the rate of the reaction.

  
• How does carbon dioxide concentration affect the rate of photosynthesis?

  As carbon dioxide concentration increases, the rate of reaction increases.

  
• What role does chlorophyll play in photosynthesis?

  Chlorophyll converts light energy to food for the plant.
• What happens if chlorophyll levels are reduced?

  The rate of photosynthesis would decrease.
• How can the rate of photosynthesis be measured experimentally?

  • Measure oxygen production of a plant.
  • Use pondweed in a test tube with water.
  • Seal the top with a bung and attach a capillary tube.
  • Measure the distance the oxygen bubble moves.
  • Control variables like temperature and light intensity.
• What is a limiting factor in photosynthesis?

  A limiting factor is an environmental condition that restricts the rate of photosynthesis at low levels.
• How can a graph show limiting factors in photosynthesis?

  A graph shows one limiting factor if it has one line that levels off.
• What does a graph with two lines represent in photosynthesis experiments?

  A graph with two lines represents two limiting factors in two experiments.

  
• How is light intensity measured in experiments?

  Light intensity is measured in lux.
• What is the inverse square law in relation to light intensity?

  Light intensity is inversely proportional to the square of the distance.
• If a lamp is 2 meters away from a plant, what is the light intensity compared to its original value?

  The light intensity is a quarter of its original value.
• What are the uses of glucose produced in photosynthesis?

  1. For respiration
  2. Converted into insoluble starch for storage
  3. To produce fat or oil for storage
  4. To produce cellulose for cell walls
  5. Combined with nitrates to form amino acids for proteins
• What is respiration?

  Respiration is the process of transferring energy from glucose.
• What type of reaction is respiration?

  Respiration is an exothermic reaction.
• What are the two types of respiration?

  Aerobic and anaerobic respiration.
• What happens during exercise in relation to respiration?

  More energy is needed, so respiration occurs faster and more oxygen is supplied to cells.
• How does aerobic respiration differ from anaerobic respiration?

  Aerobic respiration uses oxygen, while anaerobic respiration does not.
• What is the equation for aerobic respiration?

  C​6​H​12​O​6​ + 6O​2​ → 6CO​2​ + 6H​2​O
• What is produced during anaerobic respiration in animals?

  Lactic acid is produced.
• What is produced during anaerobic respiration in plants and yeast?

  Ethanol and carbon dioxide are produced.
• What is oxygen debt?

  Oxygen debt is the amount of extra oxygen needed after exercise to break down lactic acid.
• What happens to lactic acid after exercise?

  Lactic acid is transported to the liver where it is converted back to glucose.
• What is metabolism?

  Metabolism is the sum of all the reactions in a cell or the body.
• What are examples of metabolic reactions?

  1. Glucose to starch, glycogen, and cellulose.
  2. Glycerol and fatty acids forming lipids.
  3. Glucose and nitrate ions forming amino acids.
  4. Reactions in respiration.
  5. Urea formation from protein breakdown.