plant structures

• What is photosynthesis?

  The process plants use to make food
• Why are plants called producers?

  They produce their own food
• What is biomass?

  The mass of living material in a food chain
• What is the photosynthesis equation?

  • Carbon dioxide + water → light energy → glucose + oxygen
• What happens during photosynthesis?

  Energy transfers from light to chemical energy
• What does a yellow indicator solution indicate?

  High carbon dioxide concentration
• Why does bottle A have a low carbon dioxide concentration?

  Photosynthesis occurs faster than respiration
• Why does a leaf covered in black paper make no food?

  It blocks light from reaching chlorophyll
• What are endothermic reactions?

  Reactions that take in energy from surroundings
• What limits the rate of photosynthesis?

  Low temperature, dim light, low carbon dioxide
• How can you measure the effect of light intensity on photosynthesis?

  By measuring oxygen release from pondweed
• What happens at point A on the graph of photosynthesis rate?

  Light intensity is limiting the rate
• What happens at point B on the graph of photosynthesis rate?

  Another factor limits the rate of photosynthesis
• Why is carbon dioxide a limiting factor?

  It increases the rate of photosynthesis
• What happens if temperature is too high during photosynthesis?

  Enzymes start to denature
• Why is measuring oxygen given off a way to measure photosynthesis rate?

  Oxygen is a product of photosynthesis
• What is transpiration?

  The loss of water by evaporation from leaves
• What are stomata?

  Small openings on the leaf surface
• How do guard cells control stomata?

  They swell to open and lose water to close
• What does a high light intensity do to transpiration?

  It causes stomata to open, increasing transpiration
• How does air movement affect transpiration?

  It increases transpiration by maintaining diffusion gradient
• How does temperature affect transpiration?

  Higher temperature increases the rate of transpiration
• How do you calculate the rate of transpiration?

  Distance moved by bubble divided by time
• What is translocation?

  The transport of sucrose around a plant
• What is the role of phloem?

  Transport dissolved sugars around the plant
• Why will radioactive carbon be detected in phloem?

  It is used to make glucose and sucrose
• How can you show sucrose moves up and down a plant?

  Detect radioactivity above and below the leaf
• What factors affect transpiration rate?

  Light intensity, air movement, temperature
• What is the method to measure transpiration using a potometer?

  Measure distance moved by air bubble
• How do you calculate the percentage change in mass?

  Change in mass divided by original mass
• If a bubble moved 50 mm in 5 minutes, what is the rate of transpiration?

  10 mm per minute
• What are the adaptations of xylem vessels for transporting water?

  • Dead cells with no cytoplasm
  • Strengthened with lignin rings
  • No end walls for easy water flow
• What are the adaptations of root hair cells for water uptake?

  • Long extensions for large surface area
  • Increased surface area for osmosis
  • Facilitates mineral ion entry by diffusion
• What is the role of companion cells in phloem?

  • Supply energy for active transport
  • Support sieve tube elements
  • Facilitate sucrose transport
• What is the significance of stomata in plants?

  • Allow gas exchange
  • Control water loss
  • Regulate photosynthesis
• What is the relationship between light intensity and photosynthesis?

  • Higher light intensity increases photosynthesis rate
  • Light intensity is a limiting factor
  • Photosynthesis ceases without light
• What are 3 factors which affect the rate of photosynthesis?

  • Light
  • Temperature
  • Carbon dioxide