Exchange & transport in animals

• Why is it necessary to transport substances into and out of organisms?

  To provide vital substances for life and remove waste products to prevent accumulation.
• What do plants need to take in during photosynthesis?

  Plants need to take in carbon dioxide and dissolved nutrients and water.
• What is the role of the kidney in animals?

  The kidney removes waste such as urea and excess ions from the body.
• What happens if excess urea is not removed from the body?

  It builds up in the body and becomes toxic.
• What condition can result from excess carbon dioxide building up in the blood?

  It can lead to a condition called acidosis.
• What are the characteristics of specialised exchange surfaces?

  • Short distance for diffusion
  • Large surface area

  
• What is the function of root hair cells in plants?


  They are specialised to take up water and nutrients from the soil.
• How do the walls of nephrons in the kidney facilitate their function?

  They have thin walls and a large surface area for efficient reabsorption of substances.
• What is the role of alveoli in the lungs?

  Oxygen is transferred to the blood and carbon dioxide is transferred to the lungs.
• What are villi and where are they found?

  Villi are projections in the small intestine that help absorb digested food into the bloodstream.
• How do fish gills facilitate gas exchange?

  Water passes over the gills, allowing oxygen to diffuse into the blood and carbon dioxide to diffuse into the water.
• What is the function of stomata in plant leaves?

  Stomata allow carbon dioxide to enter for photosynthesis and oxygen and water vapor to exit.
• What adaptations do organisms have for efficient diffusion?

  • Large surface area
  • Thin membrane
  • Efficient blood supply/ventilation
• Why is a large surface area beneficial for diffusion?

  A larger surface area allows more particles to move through, resulting in a faster rate of diffusion.

  
• How does a thin membrane affect diffusion?

  A thin membrane provides a short diffusion pathway, allowing the process to occur faster.

  
• How does an efficient blood supply affect diffusion in the lungs?

  It creates a steep concentration gradient, so diffusion occurs faster.
• What is the Surface Area to Volume Ratio?

  It is the size of the surface area of the organism compared to its volume.

  
• How is the Surface Area to Volume Ratio calculated?

  By finding the volume (length x width x height) and surface area (length x width) and writing the ratio in the smallest whole numbers.
• What does a large Surface Area to Volume Ratio indicate about an organism's need for specialised exchange surfaces?

  If the ratio is large, the organism is less likely to require specialised exchange surfaces and a transport system.

  
• Why can single-celled organisms rely on diffusion for transport?

  They have a relatively large surface area to volume ratio and low metabolic demands.
• Why can't multicellular organisms rely solely on diffusion?

  They have a small surface area to volume ratio, requiring adaptations for transport.
• How does increasing surface area benefit an organism?

  It allows the organism to take in more nutrients and expel waste products more efficiently.
• What are alveoli?


  Alveoli are small air sacs in the lungs.
• How are alveoli adapted for gas exchange?

  They are small, arranged in clusters, have thin walls, and are surrounded by capillaries.
• What factors affect the rate of diffusion?

  • Concentration gradient
  • Temperature
  • Surface area
  • Thickness of the membrane

  
• What components make up blood?

  Blood is made up of plasma, red blood cells, white blood cells, and platelets.
• What is the function of plasma in blood?

  Plasma carries components such as red blood cells, white blood cells, platelets, glucose, and hormones.
• What is the role of red blood cells?

  They carry oxygen molecules from the lungs to all the cells in the body.
• How does the biconcave disc shape of red blood cells benefit their function?

  It provides a large surface area for oxygen transport.
• Why do red blood cells have no nucleus?

  To allow more room to carry oxygen.
• What is the function of haemoglobin in red blood cells?

  Haemoglobin binds to oxygen and forms oxyhaemoglobin.
• What is the role of white blood cells?


  They are part of the immune system and defend against pathogens.
• What are the different types of white blood cells?

  1. Antibody-producing cells, 2. Phagocytes that engulf pathogens, 3. Cells that produce antitoxins.
• What is the function of platelets in blood?

  They help form blood clots at the site of a wound.
• How do platelets contribute to wound healing?

  They dry and harden to form a scab, allowing new skin to grow underneath.
• What are the three types of blood vessels?

  Arteries, veins, and capillaries.
• What is the function of arteries?


  They carry blood away from the heart.
• How do arteries withstand high pressure?

  They have strong muscle layers and elastic fibres in their walls.
• What is the function of veins?

  They carry blood towards the heart.
• How do veins ensure blood flows in the right direction?

  They have valves that prevent backflow of blood.