bioenergetics

• What does photosynthesis produce using light?

  Glucose and oxygen
• What is the process of photosynthesis?

  It changes carbon dioxide and water into glucose and oxygen
• Where does photosynthesis take place in plants?

  In chloroplasts
• What pigments are found in chloroplasts?

  Chlorophyll
• How is energy transferred to chloroplasts?

  By light from the environment
• What type of reaction is photosynthesis?

  Endothermic
• What is the word equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen
• What is the symbol equation for photosynthesis?

  $6CO₂ +$$6H₂O → C₆H₁₂O₆ +$$6O₂$
• What are the five main uses of glucose in plants?

  • For respiration
  • Making cellulose
  • Making amino acids
  • Stored as oils or fats
  • Stored as starch
• How do plants use glucose for respiration?

  It transfers energy from glucose
• What is glucose converted into for making strong plant cell walls?

  Cellulose
• How are amino acids made in plants?

  By combining glucose with nitrate ions
• What do plants store glucose as in seeds?

  Oils or fats
• Why is starch better for storage than glucose?

  Starch is insoluble and doesn't draw in water
• What three factors affect the rate of photosynthesis?

  Light intensity, CO₂ concentration, temperature
• What does it mean if a factor is a limiting factor in photosynthesis?

  It stops photosynthesis from happening faster
• What is the limiting factor at night?

  Light
• What is often the limiting factor in winter?

  Temperature
• What is usually the limiting factor when conditions are warm and bright?

  CO₂ concentration
• How can chlorophyll be a limiting factor in photosynthesis?

  It affects light absorption in chloroplasts
• What can affect the amount of chlorophyll in a plant?

  Disease or environmental stress
• What happens to chloroplasts when a plant is stressed?

  They can become damaged or produce less chlorophyll
• How does the rate of photosynthesis relate to oxygen production in pondweed?

  More oxygen indicates a faster rate of photosynthesis
• What are the steps of the oxygen production experiment using pondweed?

  1. Place light source at a distance from pondweed
  2. Allow pondweed to photosynthesise for a set time
  3. Collect oxygen in a capillary tube
  4. Measure the gas bubble length
  5. Control variables like temperature and time
  6. Repeat and calculate mean volume of O₂
  7. Change light source distance for further experiments
• What does the inverse square law state about light intensity and distance?

  Light intensity decreases as distance increases
• What happens to light intensity if the distance is doubled?

  It becomes four times smaller
• How do you calculate light intensity using the inverse square law?

  Light intensity = 1/d²
• What is the light intensity when the lamp is 10 cm from the pondweed?

  $0.01 \text{ a.u.}$
• What are the effects of temperature on the rate of photosynthesis?

  • Low temperatures slow enzyme activity
  • High temperatures can damage enzymes
  • Optimal temperature is necessary for maximum rate
• What do the graphs of photosynthesis rates show?

  • Light intensity and temperature affect rates
  • Rates increase linearly until a limiting factor
  • Different limiting factors can be identified
• What does light intensity refer to in photosynthesis?

  The amount of light available for photosynthesis
• What happens to light intensity as distance from the light source increases?

  Light intensity decreases as distance increases
• What does the proportional symbol in light intensity ∝ 1/distance² indicate?

  Light intensity is inversely proportional to distance squared
• If the distance from the light source is doubled, how does light intensity change?

  It becomes four times smaller
• How does light intensity change if the distance is tripled?

  It becomes nine times smaller
• What is the formula to calculate light intensity using the inverse square law?

  Light intensity = 1/d²
• What does 'a.u.' stand for in light intensity measurements?

  Arbitrary units
• What is the light intensity when the lamp is 10 cm from the pondweed?

  0.01 a.u.
• What are the ideal conditions for farming in greenhouses?

  • Traps Sun's heat
  • Maintains optimal temperature
  • Provides artificial light
  • Increases carbon dioxide levels
  • Keeps plants free from pests
  • Adds fertilizers for growth
• Why do farmers use heaters in greenhouses during winter?

  To maintain the ideal temperature