Animal and plant organisation

• What are the four main components of blood?

  Red blood cells, white blood cells, plasma, platelets
• What is the function of platelets?

  Prevent blood loss and stop infections
• Why is the human circulatory system considered a double circulatory system?

  Blood passes through the heart twice per circuit
• How does the structure of an artery relate to its function?

  Thick, elastic walls carry blood under high pressure
• How does the structure of a vein relate to its function?

  Thin walls and valves carry blood at low pressure
• How does the structure of a capillary relate to its function?

  One cell thick walls provide short diffusion distance
• List the structures air passes through when breathing in.

  Mouth, nose, trachea, bronchi, bronchioles, alveoli
• What is the function of red blood cells?

  Bind to oxygen and transport it around the body
• What is the function of white blood cells?

  Defend the body against pathogens
• What is the function of plasma?

  Transport blood cells and substances around the body
• Why is a leaf considered an organ?

  It has tissues working together for photosynthesis
• How is the upper epidermis of a leaf adapted for its function?

  Single layer of transparent cells allows light passage
• How is the palisade mesophyll adapted for its function?

  Tightly packed cells with chloroplasts absorb light
• How is the spongy mesophyll adapted for its function?

  Air spaces increase surface area for gas diffusion
• What is the function of guard cells?

  Control the opening and closing of stomata
• What are three adaptations of the xylem?

  Made of dead cells, no end walls, lignin strengthened
• What is the function of the phloem?

  Transport dissolved sugars from leaves to plant
• What is the purpose of translocation?

  Transport sugars for respiration, growth, and storage
• Define the term transpiration.

  Movement of water from roots to leaves
• What is the purpose of transpiration?

  Provide water for turgidity and photosynthesis
• Name four factors that affect the rate of transpiration.

  Temperature, light intensity, humidity, wind speed
• What effect does temperature have on the rate of transpiration?

  Higher temperatures increase the rate of transpiration
• What effect does humidity have on the rate of transpiration?

  Higher humidity decreases the rate of transpiration
• Why does increased light intensity increase the rate of transpiration?

  Stomata open wider for carbon dioxide intake
• What is the function of the stomata?

  Allow diffusion of gases into and out of the plant
• Where are most stomata found?

  Underside of leaves
• What is the advantage of having a high number of stomata on the underside of leaves?

  Reduces water loss through evaporation