Photosynthesis

• What type of organisms are plants classified as?

  Autotrophs
• Why are plants called producers in food chains?

  They make their own food using light
• What type of reaction is photosynthesis?

  Endothermic reaction
• How is energy transferred during photosynthesis?

  From the environment to chloroplasts by light
• Where does most photosynthesis take place in plants?

  In the leaves
• What type of cells are specialized for photosynthesis?

  Mesophyll cells
• What do mesophyll cells contain to absorb light energy?

  Chloroplasts containing chlorophyll
• What is the purpose of the sugars produced by photosynthesis?

  To make substances and release energy
• what's the word equation for photosynthesis?

  carbon dioxide+water->glucose+oxygen
• what's the symbol equation for photosynthesis?

  6CO2 + 6H2O -> C6H12O6 + 6O2
• how are the reactants obtained for photosynthesis?

  • carbon dioxide - diffuses into the leaf through the stomata
  • water - taken up by the roots and transported through the xylem to the leaves
  • glucose - used to make substances needed by the plant; used in respiration to release energy
  • oxygen - diffuses out of the leaf through the stomata; used in respiration
• What are the three essential components for photosynthesis in plants?

  Light, water, and carbon dioxide
• How do light and carbon dioxide availability affect photosynthesis?

  They influence the rate of photosynthesis
• Why is water not considered a limiting factor in photosynthesis?

  Because plants transpire more water than needed
• What other environmental factors can affect the rate of photosynthesis?

  Temperature and amount of chlorophyll
• How does the amount of chlorophyll in chloroplasts influence photosynthesis?

  More chlorophyll increases the rate of photosynthesis
• What role does temperature play in photosynthesis?

  It affects the enzymatic reactions involved
• If a plant receives insufficient light, what effect will it have on photosynthesis?

  It will decrease the rate of photosynthesis
• How would a decrease in carbon dioxide levels affect photosynthesis?

  It would slow down the rate of photosynthesis
• What is the relationship between transpiration and water availability for photosynthesis?

  Transpiration usually exceeds water needs for photosynthesis
• Why is it important for plants to have adequate light for photosynthesis?

  Light is essential for energy conversion in photosynthesis
• How does temperature affect the kinetic energy of particles in photosynthesis?

  Temperature affects the kinetic energy of particles
• What happens to the movement of carbon dioxide and water in plants as temperature changes?

  Temperature affects the speed of their movement
• What is the effect of lower temperatures on particle collisions in photosynthesis?

  Fewer successful collisions occur over time
• How does increasing temperature influence the likelihood of collisions between reactants and enzymes?

  It increases the likelihood of collisions
• What is the consequence of increased collisions between reactants and enzymes in photosynthesis?

  It results in the formation of products
• What happens to enzymes at higher temperatures during photosynthesis?

  Enzymes can become denatured
• What does it mean for an enzyme to be denatured?

  The active site changes shape and is no longer complementary
• How does enzyme denaturation affect the rate of photosynthesis?

  It reduces the overall rate of photosynthesis
• how does light affect photosynthesis?

  • The intensity of the light available to the plant will depend on the amount of energy that it has to carry out photosynthesis
  • The more light a plant receives, the faster the rate of photosynthesis
  • This trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is now in short supply.
• what happens at low light intensities?

  At low light intensities, increasing the intensity will initially increase the rate of photosynthesis. At a certain point, increasing the light intensity stops increasing the rate. The rate becomes constant regardless of how much light intensity increases as something else is limiting the rate.
• how does carbon dioxide affect photosynthesis?

  • Carbon dioxide is one of the raw materials required for photosynthesis
  • This means the more carbon dioxide that is present, the faster the reaction can occur
  • This trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is now in short supply
• how does chlorophyll affect photosynthesis?

  • The number of chloroplasts (as they contain the pigment chlorophyll which absorbs light energy for photosynthesis) will affect the rate of photosynthesis
  • The more chloroplasts a plant has, the faster the rate of photosynthesis
  • The amount of chlorophyll can be affected by:
  • diseases (such as tobacco mosaic virus)
  • lack of nutrients (such as magnesium)
  • loss of leaves (fewer leaves means fewer chloroplasts)
• inverse square law

  • The inverse square law shows the relationship between light intensity and distance.
  • As the distance increases the light intensity decreases. This means that they are inversely proportional to each other
  • Light intensity and distance are inversely proportional to each other
  • This means that as the distance doubles you decrease the intensity of the light will be four times less
• what is the light intensity equation?

  light intensity = 1/distance squared
• Where do commercial horticulturists grow their plants?

  In a greenhouse
• Why do horticulturists use greenhouses?

  To control limiting factors of photosynthesis
• What is the economic importance of controlling limiting factors in greenhouses?

  To maximize photosynthesis while maintaining profit
• What are the associated costs of keeping plants in a greenhouse?

  Higher costs but increased crop yield
• How does increased yield from greenhouses affect farmers financially?

  They can harvest crops more frequently