Cards (119)

    • What is the primary source of water vapour lost from a plant?
      Water drawn up from the roots
    • Where can chemical waste materials be stored in plants?
      In the dying tissues
    • What happens to chemical substances no longer needed by plant cells?
      They are broken down
    • How are waste substances removed from a plant when stored in dying tissues?
      When the dying tissue falls off
    • What causes the change in color of deciduous tree leaves in autumn?
      Chemical waste products
    • What type of reactions produce waste products in cells of organisms?
      Metabolic reactions
    • What is excretion?
      Removal of waste, toxic, excess substances
    • What metabolic wastes are produced by the human body?
      Carbon dioxide, water, and urea
    • What process produces carbon dioxide and water?
      Aerobic respiration
    • Where is urea produced in humans?
      The liver
    • What process produces urea in the liver?
      Breakdown of excess proteins
    • Besides urea, what other substances are excreted in excess?
      Medical drugs and dietary minerals
    • What is one potential negative effect of waste products building up?
      Toxicity
    • How does carbon dioxide affect pH?
      It lowers the pH
    • What happens when carbon dioxide dissolves in water?
      It forms an acidic solution
    • How does an acidic solution affect enzymes?
      Reduces their activity
    • What is the 'osmotic effect' of waste products?
      Body fluids become more concentrated
    • What does concentrated body fluids cause?
      Water to move out of cells
    • What is the effect of water moving out of cells?
      Prevents essential reactions
    • Why is limited storage space a problem for waste?
      Space needed for useful molecules
    • What is egestion?
      Expulsion of unabsorbed food as faeces
    • What is the route that egested material takes out of the body?
      Via the anus
    • What is the function of excretory organs?
      Removal of certain excretory products
    • Which organs excrete urea, water, and excess salts?
      The kidneys
    • What form do the kidneys excrete urea, water and salts in?
      In the urine
    • From what process does the urea excreted by the kidneys come?
      Breakdown of amino acids in liver
    • Which organs excrete carbon dioxide and water?
      The lungs
    • How does water leave the lungs?
      As vapour
    • Which organ excretes excess mineral ions and water?
      The skin
    • How does excretion occur at the skin's surface?
      Via sweating
    • Where are the kidneys located in the body?
      In the back of the abdomen
    • What are the two important functions of the kidneys?
      • Regulate water content of blood
      • Excrete toxic waste and excess substances
    • Why is regulating the water content of blood vital?
      Maintaining blood pressure and osmoregulation
    • What type of waste substances are removed by the kidney?
      • Urea
      • Salts
      • Water
    • What is osmoregulation?
      Maintaining water and salt concentrations
    • What kind of process is osmoregulation?
      An example of homeostasis
    • What are the two main components of cytoplasm and blood plasma?
      Largely composed of water
    • Why are maintaining water levels vital for the body?
      Prevent harmful changes to cells
    • How do body cells function if they lose or gain too much water?
      They do not function efficiently
    • What is the effect of too much water in the blood?
      Cells swell and may lyse
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