nutrition

• nutrition is the process by which living organisms obtain or make food
• autotrophic nutrition occurs in green plants and some bacteria
• autotrophs use simple inorganic substances (carbon dioxide, water and minerals) to manufacture complex organic food substances (carbs, proteins, lipids)
• autotrophic nutrition requires a source of energy. the main type is photosynthesis which occurs in green plats and uses energy from the sunlight.
• heterotrophic nutrition occurs in animals, fungi and most bacteria.
• heterotrophs obtain ready made organic food from their environment
• three types of heterotrophic nutrition :

  holozoic

  saprophytic

  parasitic
• holozoic nutrition occurs in animals that obtain food by consuming other organisms, the complex organic food is ingested by the organism and then digested into simpler organic substances within the body of the organism
• saprophytic nutrition occurs in fungi and bacteria. Saprophytes obtain food from the dead remains of other organisms. they digest the complex organic food outside their bodies and absorb the the simpler organic substances produced
• parasitic nutrition occurs in some plants, animals, fungi and bacteria
• parasites obtain organic food from the body of another living organism called the host which is usually harmed during the process
• photosynthesis occurs in any plant structure that contains chlorophyll
• photosynthesis is catalysed by enzymes
• Photosynthesis takes place in the mesophyll cells of the lamina
• the lamina is attached to the plant stem by the petiole
• Environmental factors that affect the rate of photosynthesis :
• Environmental factors that affect the rate of photosynthesis :

  Light

  Temperature

  Water

  Carbon Dioxide
• Minerals are absorbed from the soil by plant roots in the form of ions