Types of nutrition

• Plants follow autotrophic nutrition

• Inorganic substances: carbon dioxide, water, minerals, carbohydrates, lipids, proteins, vitamins

• Organic substances: Bread, Vegetables, Fruits

Photosynthesis

• Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light.

• Photosynthesis(light manufacture)

• Sunlight and chlorophyll are need for chemical process to take place

• Carbon dioxide + Water ———> Glucose + Oxygen

• 6CO2 + 6H2O ———> C6H12O6 + 6O2

• Chlorophyll is a green pigment in plants which helps in photosynthesis

• Chloroplasts are the organelles in which photosynthesis takes place

Leaves

• Leaves is a factory for making carbohydrates

• Leaf structure:

  • The top coat is called the lamina

  • joined to the plant by Petiole or leaf stalk

  • vascular bundles, veins in leaf

  

  • stomata: exchange of gases, transpiration

  • waxy substance cuticle

  • mesophyll contain chloroplasts

  • palisade layer performs photosynthesis

  • xylem vessel for carrying water

  • phloem tubes carry sucrose and other substances

• Leaf Adaptations:

  • adapted to obtain carbon dioxide, water, and sunlight

  • Carbon Dioxide:

    • spongy mesophyll cells need carbon dioxide

    • enters through stomata by diffusion

    • diffuses to all the cells in the plant through air spaces between mesophyll cells

  • Water:

    • obtained from soil and absorbed by root hairs

    • carried to the leaf through the xylem

    • to the mesophyll cell by osmosis

  • Sunlight:

    • the flat surface absorbs light

    • spongy mesophyll cells and palisade cells need sunlight

    • the thinness allows light to penetrate

Uses of Glucose

• Uses of Energy:

  • energy is released from glucose

• Stored as Starch:

  • glucose is stored as starch in the leaf

  • glucose is reactive and would dissolve in water around the plant cell

  • when dissolved it could cause damage from the concentration