Activity 8: Background Information

Photosynthesis
Plants stay where they are and they cannot go anywhere to get food. They have to make their own “food” since they cannot get it from somewhere else. They use the energy from the Sun, the carbon from the carbon dioxide found in the atmosphere, and the water they absorbed through their roots to produce their own “food” in the form of starch or sugars. The process of doing this is called photosynthesis where carbon-carbon bonds are formed in the starch or sugars. Aside from the food that is produced, oxygen is also produced and is eventually released.

Respiration
With the sugars that they themselves made through photosynthesis, the plants now have a source of energy to do their own daily activities. They break the carbon-carbon bonds present in the sugars that they made and combine it with oxygen from the atmosphere to get energy, which is either used or lost, in the form of heat. This process releases carbon dioxide and water.

Organisms that cannot make their own food just do respiration and not photosynthesis. These living things get energy from the sugars that the plants made. They also get their energy by eating those that consume the plants. These organisms, just like the plants, break the carbon-carbon bonds to release the energy that they then can use and if not used is lost in the form of heat.

Carbon Cycle
The carbon that the plants took from the atmosphere in the form of carbon dioxide is changed into sugars when combined with water and light energy in the process of photosynthesis. With oxygen, the breakdown of carbon-carbon bonds present not only in the sugars that the plants made but also found in the bodies of those that accessed the sugars from the plants, results in the release of energy and with it carbon is returned to the atmosphere in the form of carbon dioxide. Together with the carbon dioxide, water is also released in the process of respiration.

Oxygen Cycle
Just like the carbon cycle, the oxygen cycle involves the processes of photosynthesis and respiration. In photosynthesis, carbon dioxide is used and oxygen is released. This oxygen is utilized in the process of respiration to release the energy stored in the sugars’ carbon-carbon bonds. With the breakdown of the carbon-carbon bonds, energy is released and carbon dioxide is formed. The plants use the carbon dioxide to form the carbon-carbon bonds and with it oxygen is released. Oxygen shuttles between photosynthesis and respiration.