B4

• What process must a plant carry out to grow and survive?

  Photosynthesis
• Where does photosynthesis take place in a plant?

  In the leaves, specifically chloroplasts
• What pigment in chloroplasts absorbs light?

  Chlorophyll
• What does chlorophyll absorb from the environment?

  Light energy
• What are the products of photosynthesis?

  Glucose and oxygen
• Write the chemical equation for photosynthesis using symbols.

  6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂
• Why is light written above the reaction line in the photosynthesis equation?

  Because the reaction requires light energy
• What type of reaction is photosynthesis classified as?

  Endothermic reaction
• How does energy transfer occur in photosynthesis?

  From the environment to chloroplasts by light
• How does carbon dioxide enter the leaves?

  Through the stomata
• How is water transported to the leaves?

  Via the xylem
• What is the main product that plants want from photosynthesis?

  Glucose
• What do plants sometimes use oxygen for?

  For respiration
• What do plants need to carry out photosynthesis?

  Light, carbon dioxide, temperature, chlorophyll
• What is one way glucose is used by plants?

  For cellular respiration to release energy
• What are the five main uses of glucose in plants?

  • Cellular respiration for energy
  • Making cellulose for cell walls
  • Making starch for long-term storage
  • Making amino acids with nitrate ions
  • Making oils and fats for energy storage
• Why is starch a better storage form of glucose?

  It is more compact and insoluble
• How does chlorophyll affect photosynthesis?

  Less chlorophyll means less photosynthesis
• When do plants typically break down starch to glucose?

  When photosynthesis isn't happening much
• How do plants make amino acids?

  By combining glucose with nitrate ions
• What can cause variations in chlorophyll levels in plants?

  Disease, environmental stress, lack of nutrients
• Why are oils and fats important for seeds?

  They serve as future energy resources
• What do plants use amino acids to make?

  Proteins
• What factors affect the rate of photosynthesis?

  • Light intensity
  • Temperature
  • Carbon dioxide concentration
  • Amount of chlorophyll
• What is the relationship between photosynthesis and plant growth rate?

  Growth rate depends on photosynthesis speed
• What are the limiting factors for photosynthesis?

  Light, carbon dioxide, and temperature
• What is plotted on the x-axis of photosynthesis graphs?

  Light intensity, carbon dioxide, temperature
• What happens to the rate of photosynthesis as light intensity increases?

  The rate of photosynthesis increases
• What does it mean when the graph of photosynthesis plateaus?

  Another factor is limiting photosynthesis
• How does carbon dioxide concentration affect photosynthesis?

  Higher concentration increases the rate
• What happens to the rate of photosynthesis when carbon dioxide is plentiful?

  Another factor becomes limiting
• How does temperature initially affect the rate of photosynthesis?

  The rate increases as temperature rises
• What happens to enzymes involved in photosynthesis at high temperatures?

  They begin to denature and stop working
• At what temperature are enzymes fully denatured?

  About 45 degrees Celsius
• What does a graph with two curves represent in photosynthesis experiments?

  Different experiments with varying conditions
• How can comparing two curves on a graph indicate a limiting factor?

  It shows which condition affects photosynthesis
• What can farmers do to create optimal conditions for photosynthesis?

  Use greenhouses, artificial light, and CO2
• Why do farmers use greenhouses?

  To trap heat and increase temperature
• How can farmers provide artificial light?

  To continue photosynthesis day and night
• What is a benefit of using a paraffin heater in greenhouses?

  It releases heat and carbon dioxide