9EBiol plants and photosynthesis

• What is the definition of tissues in biology?


  A group of cells
• What are living things made up of?

  Cells
• What is the definition of organs in biology?

  A group of tissues working together
• What is the equation for photosynthesis?

  6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• What does chlorophyll do in photosynthesis?

  It absorbs light energy
• Why is light energy necessary for photosynthesis?

  It is needed for the reaction to occur
• What are the main components of a plant cell and their functions?

  • Mitochondria: Aerobic respiration
  • Vacuole: Storage and maintaining turgor pressure
  • Cytoplasm: Site of chemical reactions with enzymes
  • Nucleus: Contains DNA and controls cell activities
  • Cell wall: Supports and strengthens the cell
  • Chloroplast: Site of photosynthesis
• What is the difference between aerobic and anaerobic respiration?

  Aerobic respiration uses oxygen, while anaerobic respiration occurs without enough oxygen
• What are the main structures of a leaf and their functions?

  • Palisade cells: Absorb light for photosynthesis
  • Phloem: Transports sugars from palisade cells
  • Xylem: Transports water and minerals from roots
  • Guard cells: Regulate the opening and closing of stomata
  • Waxy cuticle: Prevents water loss
  • Stomata: Allows gas exchange
  • Mesophyll: Contains spongy and palisade layers for photosynthesis
• What is the function of the upper epidermis in a leaf?

  It acts as a protective layer and prevents dehydration
• What is the role of palisade cells in a leaf?

  They are packed with chloroplasts to absorb light for photosynthesis
• What is the function of the spongy layer in a leaf?

  It allows easy diffusion of gases and supports the leaf structure
• What is the function of xylem in a plant?

  It transports water and minerals from the roots to the leaf cells
• What is the role of phloem in a plant?

  It transports sugars from the palisade cells to the rest of the plant
• How do stomata function in a leaf?

  They open to allow CO₂ in for photosynthesis and close to reduce water loss
• What do guard cells do in relation to stomata?

  They change shape to open or close the stomata pores
• What is the function of the lower epidermis in a leaf?

  It acts as a protective layer and contains stomata for gas exchange
• How does the waxy cuticle help a leaf?

  It prevents water loss and protects the leaf from dehydration
• What is differentiation in biology?

  It is the process by which a cell changes to become specialized for its job
• What are the characteristics of xylem and phloem cells?

  Xylem:

  • One-way movement
  • Transports water and minerals
  • Outer cells are not living
  • Movement occurs via transpiration stream

  
  

  Phloem:

  • Two-way movement
  • Transports sugars and nutrients
  • Cells are living
  • Process is called translocation
• What is transpiration in leaves?

  It is the process where water evaporates out of the stomata
• What is a disadvantage of transpiration?

  It leads to water loss from the plant
• How do guard cells help reduce water loss?

  They open and close the stomata to regulate water loss
• Why are stomata located on the underside of leaves in hot, dry conditions?

  To avoid sunlight and reduce evaporation
• What is the main function of gas exchange in plants?

  To take in CO₂ for photosynthesis and release oxygen
• How do guard cells affect stomata when they are full of water?

  They swell and open the stomata for gas exchange
• What is the purpose of a potometer in plant studies?

  • Estimates transpiration rate
  • Records starting position of a gas bubble
  • Measures distance moved by the bubble
  • Conditions must be constant (e.g., temperature, humidity)
• What factors affect the rate of transpiration?

  • Light intensity: More light opens stomata, increasing transpiration
  • Temperature: Higher temperatures increase evaporation and transpiration
  • Humidity: Drier air increases transpiration rate
  • Air flow: Windier conditions enhance diffusion and transpiration
• What happens to the rate of transpiration in relation to light intensity?

  It speeds up as light intensity increases
• How does temperature affect the rate of transpiration?

  Warmer temperatures increase the rate of transpiration
• How does humidity affect the rate of transpiration?

  Drier air increases the rate of transpiration
• How does air flow influence transpiration?

  Windier conditions increase the rate of transpiration
• What is the relationship between concentration gradient and the rate of diffusion?

  A steeper concentration gradient results in a faster rate of diffusion
• What is the transpiration stream?


  It is the movement of water pulled from the soil through the plant
• What is the role of the stomata in gas exchange?

  They allow CO₂ in for photosynthesis and oxygen out
• How do guard cells respond to dehydration?

  They become floppy and close the stomata