Plant structures and their functions

• What are the main producers of food in ecosystems?

  Plants and algae
• What process do plants and algae use to synthesize food from sunlight?

  Photosynthesis
• What type of reaction is photosynthesis?

  Endothermic reaction
• Where does photosynthesis occur in plants?

  In chloroplasts
• What is the equation for photosynthesis?

  Light + carbon dioxide + water → glucose + oxygen
• What is the chemical symbol for carbon dioxide?

  CO₂
• What is the chemical symbol for water?

  H₂O
• What is the chemical symbol for oxygen?

  O₂
• What is the chemical formula for glucose?

  C₆H₁₂O₆
• What is a limiting factor in photosynthesis?

  An environmental condition that restricts the rate of photosynthesis
• How does temperature affect the rate of photosynthesis?

  It increases the rate up to a certain point before enzymes denature
• What happens to the rate of photosynthesis as light intensity increases?

  The rate of photosynthesis generally increases

  
• How does carbon dioxide concentration affect photosynthesis?

  As concentration increases, the rate of reaction increases

  
• What factors can limit the rate of photosynthesis?

  • Temperature
  • Light intensity
  • Carbon dioxide concentration

  
• How can you measure the rate of photosynthesis in a plant?

  By measuring the oxygen production of the plant
• Describe the setup for measuring the rate of photosynthesis using pondweed.

  • Place pondweed in a sealed test tube with water
  • Use a capillary tube connected to a syringe
  • Position a lamp at a measured distance
  • Measure the distance the oxygen bubble moves
• What is the purpose of controlling variables in a photosynthesis experiment?

  To ensure a valid experiment
• What does a graph with one line leveling off indicate in terms of limiting factors?

  It indicates one limiting factor affecting the rate of photosynthesis
• What does a graph with two lines represent in photosynthesis experiments?

  It represents two limiting factors in two different experiments

  
• How is light intensity measured in photosynthesis experiments?

  In lux

  
• What is the inverse square law in relation to light intensity and distance?

  Light intensity is inversely proportional to the square of the distance
• If a lamp is 2 meters away from a plant, what is the light intensity compared to its original value?

  It is a quarter of its original value
• What are the adaptations of root hair cells?

  • Large surface area for water uptake
  • Large permanent vacuole for water movement
  • Mitochondria for energy in active transport
• What are the adaptations of xylem cells?

  • Lignified dead cells form hollow tubes
  • Lignin deposited in spirals for pressure resistance
• What are the adaptations of phloem cells?

  • Sieve plates for substance movement
  • Alive cells with energy supplied by companion cells
  • Transport sucrose around the plant
• What is transpiration?

  The loss of water vapor from leaves and stems
• How does transpiration occur in plants?

  Water evaporates at open stomata during gas exchange
• What role do guard cells play in transpiration?

  They open and close stomata
• Why are more stomata found on the bottom of leaves?

  To minimize water loss while allowing gas exchange
• What is translocation in plants?

  The movement of food substances through the phloem
• Where does translocation occur in plants?

  Only in the phloem
• What are sources and sinks in the context of translocation?

  Sources are where substances are made, sinks are where they are used or stored
• How can the location of sources and sinks change with the seasons?

  They can switch places depending on the season
• What are the adaptations of leaves for photosynthesis?

  • Broad surface area for light absorption
  • Thin structure for efficient gas exchange
  • Contain chlorophyll for capturing light energy
• What is the process by which water leaves the plant via evaporation called?

  Transpiration
• Where are more stomata typically found on a leaf, and why?

  On the bottom of the leaf to minimize water loss and allow gas exchange
• What is translocation in plants?

  The movement of food substances like sucrose in the phloem
• In which part of the plant does translocation occur?

  In the phloem
• What are the 'sources' and 'sinks' in the context of translocation?


  Sources are where sucrose is made, and sinks are where it is used or stored
• How can the location of sources and sinks change with the seasons?

  In spring, the source may be in the root and the sink in the leaf, and vice versa in summer