Specialised cells

• What happens to the stoma when guard cells are turgid?

  The stoma is open
• What is the function of guard cells?

  Control the opening of stomata
• What are the adaptations of guard cells?

  • Thicker inner cell walls facing air
  • Thinner outer cell walls facing adjacent cells
  • High density of chloroplasts and mitochondria
• Why are the inner cell walls of guard cells thicker?

  To allow the cell to bend when turgid
• What is the shape of palisade cells?

  Tall and thin
• What is the function of palisade cells?

  Carry out photosynthesis
• What are the adaptations of palisade cells for photosynthesis?

  • Large number of chloroplasts
  • Tall and thin shape for light penetration
• What do cilia do in the lungs?

  Push dirt and microbes away
• What is the function of cilia?

  Move substances across tissue surface
• What are the adaptations of cilia?

  • Hair-like structures that beat in coordination
  • Goblet cells secrete mucus to trap particles
• What is the function of squamous epithelium?

  Provide a surface covering
• What are the adaptations of squamous epithelium?

  • Single layer of flattened cells
  • Thin cross-section reduces diffusion distance
  • Permeable for easy gas diffusion
• What is the function of root hairs?

  Absorb water and mineral ions
• What are the adaptations of root hairs?

  • Extension of cytoplasm increases surface area
  • Thinner walls for easier water movement
  • Permanent vacuole maintains water potential gradient
  • Mitochondria for active transport
• Why are chloroplasts not found in root hair cells?

  No light for photosynthesis underground
• What is the function of sperm cells?

  Reproduction and fertilization
• What are the adaptations of sperm cells?

  • Head contains haploid nucleus
  • Acrosome has digestive enzymes
  • Mid-piece packed with mitochondria
  • Tail propels the sperm cell
• How does the tail of sperm cells assist in reproduction?

  Propels them towards the egg
• What is the function of neutrophils?

  Destroy pathogens by phagocytosis
• What are the adaptations of neutrophils?

  • Flexible shape to squeeze through capillaries
  • Form pseudopodia to engulf microorganisms
  • Large number of lysosomes for digestion
  • Flexible nuclear membrane for penetration
• What is the shape of erythrocytes?

  Biconcave
• What is the function of erythrocytes?

  Transport oxygen and carbon dioxide
• What are the adaptations of erythrocytes?

  • Biconcave shape increases surface area
  • High amounts of haemoglobin for oxygen binding
  • No nucleus for maximum oxygen capacity
  • Elastic membrane for flexibility