Photosynthesis

Carbon Dioxide + Water --------) Glucose + Oxygen

Photosynthesis is an endothermic reaction. This is because the products of photosynthesis have more energy than the reactants.

Photosynthesis occurs in chloroplasts, which contains a green substance called chlorophyll that traps energy transferred by light. 

Factors that affect phtotsynthesis:

• Carbon Dioxide Concentration - There are fewer molecules in each cubic cm of air higher up than lower down. The more carbon dioxide there is, the larger the rate of photosynthesis.
• Temperature - The reactions in photosynthesis are catalysed by enzymes that work better at warmer temperatures.
• Light Intensity - As light intensity increases, so does the rate of photosynthesis.

The flow of gas in and out of a leaf is an example of gas exchange.

Transpiration - The flow of water into a root, up the xylem and out of the leaves.

• Keeps the leaves cool (water evapourates off the leaves).
• Makes water available.

Factors which increase transpiration:

• Wind - Moves water molecules away from stomata.
• Low humidity.
• Higher Temperatures - Particles move faster.
• Greater light intensity - Makes the stomata wider.

Translocation - The transport of sugars (mainly sucrose) and other compounds in the phloem tissue of a plant.

Plants make sucrose from the glucose and starch made from photosynthesis.

Sucrose is translocated in the sieve tubes of the phloem tissue.