Bioenergetics

• In which organisms does photosynthesis occur?

  In plants and algae
• How does carbon dioxide enter the leaves of plants?

  By diffusion
• How does water enter the roots of plants?

  By osmosis
• What role does chlorophyll play in photosynthesis?

  It absorbs sunlight
• What is produced as a waste product of photosynthesis?

  Oxygen
• What is the summary word equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen
• What type of reaction is photosynthesis described as?

  An endothermic reaction
• What happens to the glucose produced in photosynthesis?

  It can be used in respiration, converted to starch, made into fats or oils, used to produce cellulose, or combined with nitrates to make amino acids
• What are the limiting factors in photosynthesis?

  Light intensity, carbon dioxide concentration, temperature, and amount of chlorophyll
• What does the graph of light intensity versus rate of photosynthesis indicate in region one?

  Light intensity is the limiting factor
• What happens in region two of the light intensity versus rate of photosynthesis graph?

  Light intensity is no longer limiting
• In the carbon dioxide concentration graph, what does region one indicate?

  Carbon dioxide concentration is the limiting factor
• What occurs in region two of the carbon dioxide concentration graph?

  Carbon dioxide concentration is no longer limiting
• How does temperature affect the rate of photosynthesis?

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

  They denature and lose their shape
• How can knowledge of limiting factors help greenhouse growers?

  It helps to maintain optimal conditions for maximizing photosynthesis and profits
• What does the graph of light intensity versus rate of photosynthesis show at different conditions?

  Higher carbon dioxide concentration and temperature can increase the maximum rate of photosynthesis
• What is the method for measuring the rate of photosynthesis using pondweed?

  Count the number of bubbles produced per minute or measure the volume of oxygen produced
• What is the purpose of adding sodium bicarbonate to the water in the photosynthesis experiment?

  To ensure carbon dioxide is in excess
• What does the inverse square law state about light intensity?

  Light intensity is proportional to distance
• If the distance from the lamp is doubled, what happens to the light intensity according to the inverse square law?

  It becomes a quarter of the original intensity
• If the light intensity at 10 cm is 180 Lux, what is the light intensity at 20 cm?

  45 Lux
• If the rate of photosynthesis is 60 bubbles per minute at 10 cm, what will it be at 20 cm?

  15 bubbles per minute
• What are the uses of glucose produced in photosynthesis?

  • Used in respiration for energy
  • Converted to insoluble starch for storage
  • Made into fats or oils for energy storage
  • Used to produce cellulose for cell wall strength
  • Combined with nitrates to make amino acids for protein synthesis
• What are the effects of limiting factors on the rate of photosynthesis?

  • Light intensity: Increases rate until saturation
  • Carbon dioxide concentration: Increases rate until saturation
  • Temperature: Increases rate until enzymes denature
• What are the control variables in the photosynthesis experiment with pondweed?

  • Same pondweed
  • Same length of pondweed
  • Same temperature
  • Same carbon dioxide concentration
  • Repeat the experiment multiple times for accuracy
• How does changing the color of light affect the rate of photosynthesis?

  • Different colors of light are absorbed differently by plants
  • Green light is poorly absorbed and reflected
  • Red and blue light are more effective for photosynthesis
• What is the significance of the inverse square law in relation to light intensity and distance?

  • Light intensity decreases as distance increases
  • Specifically, light intensity is inversely proportional to the square of the distance
  • Important for understanding how light affects photosynthesis
• How does the rate of photosynthesis change when the distance from the lamp is increased from 10 cm to 20 cm?

  The rate of photosynthesis decreases to 15 bubbles per minute.
• If the distance from the lamp is doubled from 10 cm to 20 cm, what happens to the light intensity according to the inverse square law?

  The light intensity becomes a quarter of its original value.
• What is the rate of photosynthesis at 20 cm?

  15 bubbles per minute.
• What is the rate of photosynthesis at 30 cm?

  7 bubbles per minute.
• What happens to the rate of photosynthesis when the distance is increased from 30 cm to 60 cm?

  The rate of photosynthesis decreases to 2 bubbles per minute.
• What is respiration and how does it function in living organisms?

  Respiration provides energy for processes in all living things and occurs continuously in living cells.
• What are the two types of respiration?

  Aerobic and anaerobic respiration.
• What is the equation for aerobic respiration?

  Glucose + Oxygen → Carbon Dioxide + Water.
• What are the waste products of aerobic respiration?

  Carbon dioxide and water.
• How does anaerobic respiration differ in animal cells compared to plant and yeast cells?

  In animal cells, glucose is converted to lactic acid, while in plants and yeast, it is converted to ethanol and carbon dioxide.
• What is fermentation and its significance in baking?

  Fermentation is the process by which yeast converts glucose to ethanol and carbon dioxide, causing dough to rise.
• What is oxygen debt?

  Oxygen debt is the amount of extra oxygen needed after exercise to react with lactic acid and remove it from cells.