biology 1.4

• GELL PEGLEMENTS
• CHAPTER 1.4
• a mitotic
• d bee
• of the
• Chapter 1.4 Cell requirements

  Science Understanding
• Cells require


  • Energy
  • Nutrients
  • Removal of wastes
• Source of energy


  Autotrophs use light or chemical energy

  Heterotrophs use organic molecules
• Photosynthesis


  1. Light energy

  2. Carbon dioxide

  3. Water

  4. Glucose

  5. Oxygen
• Respiration


  1. Glucose

  2. Oxygen

  3. Carbon dioxide

  4. Water

  5. ATP
• Fermentation


  1. Glucose

  2. Alcohol or lactic acid

  3. Carbon dioxide
• Cells require energy for movement, synthesis and maintenance of a stable internal environment
• Energy can be transformed but not created or destroyed
• Cells must convert chemical energy into other useful forms of energy
• Cell movement


  • Sperm cells, mitosis, membrane transport, active transport
• Cell synthesis


  • Hormone production, DNA replication, protein manufacture
• Stable internal environment


  • Maintain temperature, concentrations of salts, ions, glucose, metabolic waste
• Autotrophs


  Organisms that can synthesize organic molecules from inorganic substances
• Heterotrophs


  Organisms that obtain organic molecules by feeding on other organisms
• Nutrients required by cells

  • Light
  • Carbon dioxide
  • Water
  • Nitrogen
  • Phosphorus
  • Magnesium
  • Sodium
  • Cobalt
  • Other trace elements
• Heterotrophic diet


  • Proteins
  • Carbohydrates
  • Fats and oils
  • Nucleic acids
  • Water
  • Mineral ions
  • Vitamins
• Waste products


  Substances produced by metabolic reactions that need to be removed as they can be toxic
• Excretion


  1. Carbon dioxide removal via respiratory system

  2. Urea removal via excretory system
• Faeces is not a metabolic waste