• Chemical reactions?that take place inside living cells are described as?metabolic reactions
• Metabolic reactions produce waste products, some of which may be?toxic
• These toxic products must be?eliminated?from the body
• Excretion is the?removal of toxic materials and substances?from organisms

Excretion in animals

• Waste products excreted by?animals?include:
  • Carbon dioxide?from?respiration
  • Water?from?respiration?and other chemical reactions
  • Urea?which contains?nitrogen?resulting from the breakdown of?proteins

   

Excretion in humans, the waste products and organs involved

Excretion in plants

• Waste products excreted by?plants?include:
  • Oxygen?from?photosynthesis
  • Carbon dioxide?from?respiration
  • Water?from?respiration?and other chemical reactions

   

Excretion in plants, the waste products and the difference between day and night