RECAP THE CONCEPTS


Functions of various parts of plants

  • Plants have leaves that contain chlorophyll to trap sunlight and make food (photosynthesis).

  • Roots absorb water and minerals from the soil and hold the plant securely to the soil.

  • Stems transport water, minerals and food around the plant. Stems hold leaves up so that the leaves can trap more sunlight.

  • Flowers develop into fruits containing seeds.


Plant transport system

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  • Consists of phloem (food-carrying tubes) and xylem (water-carrying tubes).

  • The xylem tubes transport water and minerals upwards, from the roots to all other parts of the plant.

  • Phloem tubes transport food mainly downwards, from the leaves to all other parts of the plant.

  • If a cut is made on the stem with the food-carrying tubes removed, a bulge will develop above the cut. Food from the leaves is unable to be transported to parts below the cut, such as the roots.

  • Plants does not transport gases. Most of the living cells of plants are located near the surface. Gaseous exchange occurs directly with the surrounding air.


Plant respiratory system

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  • Plants exchange gases with their surroundings through stomata on the leaves.

  • When there is light, plants carry out photosynthesis to make their own food.
    During photosynthesis, carbon dioxide is taken in and oxygen is given out.

  • Plants carry out respiration all the time in order to release energy for life processes.
    Oxygen is taken in for respiration, while carbon dioxide is given out.

  • Transpiration occurs all the time. Plants lose water as water vapour through the stomata.

  • Generally, the stomata are mostly found on the underside of leaves. The underside does not face the Sun directly and has a lower temperature. This lowers the rate of evaporation and reduces water loss through transpiration.


Practice: Mastering Keywords

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