Photosynthesis

Photosynthesis is the process by which plants produce oxygen. All life on Earth depends on photosynthesis because without it, we would not have oxygen.

Plants take in carbon dioxide from the air around them and water from the ground and use these elements to make oxygen.

Plants have organelles in their cells called chloroplasts that store the energy of sunlight. In the chloroplasts is a pigment called chlorophyll, which absorbs the red and blue light waves, thus giving plants their distinctive green color (RGB minus R&B = G).

Photosynthesis takes place in two phases: light-dependent and light-independent. The light taken in by the chloroplasts is converted into chemicals called ATP (Adenosine triphosphate) and NADPH (Nicotinamide adenine dinucleotide phosphate). The light-independent reaction, the Calvin Cycle, converts the energy from the ATP and NADPH and the carbon dioxide into glucose for the plant to use.

What is carbon fixation?

Carbon fixation is another term for the Calvin Cycle. In this cycle, carbon dioxide enters the leaves of the plants. Then, it is fixed onto an existing 5 carbon sugar by an enzyme called Ribulose-1,5-bisphosphate carboxylase/oxygenase or RuBisCO. This 6-carbon sugar becomes unstable and splits into two three carbon sugars. After two more 5-carbon sugars are fixed and split, ADP and NADH donate energy to the six three-carbon sugars, five of which reassemble into three 5-carbon sugars. One 3-carbon sugar goes into storage. It takes six turns of this cycle to produce one glucose molecule.

Carbon fixation is important because this is how plants get glucose, which is their food.

Factors Affecting the Rate of Photosynthesis

The factors affecting the rate of photosynthesis are light levels, carbon dioxide levels, and temperature.

As light and carbon dioxide levels increase, the rate of photosynthesis increases, but at a certain point, it stops increasing and stays the same no matter how much more light or carbon dioxide is added to the plant's environment.

However, when the temperature of the plant's environment increases, the rate also increases until a certain point where the rate decreases as the temperature increases.

Why is Photosynthesis Important?

Photosynthesis is important because without it, we would have no oxygen, and we wouldn't be able to survive.