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.
The characteristics of this leaf that make it adapted for its function are:
- The upper epidermis is transparent to let as much light through for photosynthesis.
- 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.
- Xylem is nearby, so a lot of water can be transported to the cells for photosynthesis.
- Phloem is nearby, so the glucose produced can be transported to the rest of the plant more quickly.
- The mesophyll layer has a large surface area for gaseous exchange.
- 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:
- For respiration to release energy.
- To create cell walls by converting glucose to cellulose.
- To make amino acids for protein synthesis.
- To store in seeds to help the seeds grow.
- To convert to starch, which is insoluble. This makes starch a good way to store glucose.