Plant Structure

 

Photosynthesis is the process used by plants to produce glucose. The equation for this process is:

 

CO2 + H2O   →sunlight→ glucose + O2

 

 The organ responsible for this process in plants are its leaves. The cross-section of a leaf is shown below.

 

leaf cross section diagram, beginner biology

The characteristics of this leaf that make it adapted for its function are:

 

  1. The upper epidermis is transparent to let as much light through for photosynthesis.
  2. The palisade leaf cells are packed with chloroplasts, so more photosynthesis can take place. They are also thin, so a lot of these cells can fit in a smaller area.
  3. Xylem is nearby, so a lot of water can be transported to the cells for photosynthesis.
  4. Phloem is nearby, so the glucose produced can be transported to the rest of the plant more quickly.
  5. The mesophyll layer has a large surface area for gaseous exchange.
  6. The guard cells on the lower epidermis control the opening and closing of the stomata. If the plant doesn’t have a lot of water or if the plant is in a dark environment, the guard cells close the stomata to reduce water loss through transpiration.

 

The glucose produced during photosynthesis are used in a variety of functions. These functions are:

 

  1. For respiration to release energy.
  2. To create cell walls by converting glucose to cellulose.
  3. To make amino acids for protein synthesis.
  4. To store in seeds to help the seeds grow.
  5. To convert to starch, which is insoluble. This makes starch a good way to store glucose.


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