chapter 4

• What is the process of photosynthesis primarily used for?

  To convert carbon dioxide and water into glucose
• Where does photosynthesis take place in plant cells?

  In chloroplasts
• What pigment in chloroplasts absorbs light for photosynthesis?

  Chlorophyll
• How is energy transferred to chloroplasts?

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

  Endothermic
• What is the chemical equation for photosynthesis?

  6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• How do plants utilize glucose produced in photosynthesis?

  • For respiration to transfer energy
  • To make cellulose for cell walls
  • To create amino acids with nitrate ions
  • To store as oils or fats in seeds
  • To store as starch in roots, stems, and leaves
• What factors affect the rate of photosynthesis?

  Light intensity, CO₂ concentration, and temperature
• What happens when a plant is short of water regarding photosynthesis?

  Water becomes a limiting factor
• What does it mean when a factor is a limiting factor in photosynthesis?

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

  Light
• What is the limiting factor for photosynthesis in winter?

  Temperature
• What can affect the amount of chlorophyll in a plant?

  Disease and environmental stress
• How does light intensity affect the rate of photosynthesis?

  It increases steadily until a limiting factor occurs
• What happens to the rate of photosynthesis when light intensity is increased beyond a certain point?

  It levels off due to another limiting factor
• How can light intensity be measured in a lab experiment?

  Using a light meter or calculating from distance
• What happens to the rate of photosynthesis when CO₂ concentration is increased?

  It increases until another factor limits it
• Why does temperature affect the rate of photosynthesis?

  It affects the enzymes involved in the process
• What happens to enzymes at high temperatures during photosynthesis?

  They can become damaged
• What is the maximum temperature at which enzymes for photosynthesis can function?

  About 45 degrees Celsius
• How can the rate of photosynthesis be measured using Canadian pondweed?

  1. Place a light source at a distance from the pondweed.
  2. Allow photosynthesis for a set time.
  3. Measure the length of the gas bubble in capillary tubes.
  4. Control variables like temperature and time.
  5. Repeat the experiment for accuracy.
  6. Change distances to observe effects.
• What does the inverse square law state about light intensity and distance?

  Light intensity is inversely proportional to distance squared
• How does halving the distance from a light source affect light intensity?

  It increases light intensity four times
• What is the ideal way to create conditions for photosynthesis in a greenhouse?

  Control temperature, light, and CO₂ levels
• What is respiration in biological terms?

  Transfer of energy from glucose breakdown
• What are the benefits of using a greenhouse for plant growth?

  • Traps heat for optimal temperature
  • Provides artificial light for extended growth
  • Increases CO₂ levels for better photosynthesis
  • Protects plants from pests and diseases
  • Allows for controlled nutrient supply
• What type of reaction is respiration?

  Exothermic
• How does respiration differ from breathing?

  Respiration is energy transfer, not breathing
• How do organisms use energy from respiration?

  1. Build larger molecules from smaller ones
  2. Allow muscles to contract in animals
  3. Maintain body temperature in mammals and birds
• What is aerobic respiration?

  Respiration using oxygen
• What is metabolism?

  • Total of all chemical reactions in a cell
  • Controlled by enzymes
  • Includes building larger molecules and breaking them down
• Where does aerobic respiration primarily occur?

  Inside mitochondria
• What is the equation for aerobic respiration?

  C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
• What is anaerobic respiration?

  Respiration without oxygen
• What is produced during anaerobic respiration in muscles?

  Lactic acid
• Why is anaerobic respiration less efficient than aerobic respiration?

  Glucose is not fully oxidized
• What do plants and yeast produce during anaerobic respiration?

  Ethanol and carbon dioxide
• What is fermentation in yeast cells?

  • Anaerobic respiration in yeast
  • Produces ethanol and carbon dioxide
  • Used in bread and alcoholic drinks
• How does exercise affect respiration in muscles?

  Increases respiration for more energy
• What happens to breathing and heart rate during exercise?

  Both increase to supply more oxygen