C3 plants

C3 plants are a type of photosynthetic plant that utilize the C3 carbon fixation pathway, the most common and widespread photosynthetic pathway in plants. This pathway is also known as the Calvin cycle, named after its discoverer, Melvin Calvin.

Overview

C3 plants are characterized by the creation of a three-carbon compound (3-phosphoglyceric acid) during the process of photosynthesis. This is in contrast to C4 plants and CAM plants, which create four-carbon and crassulacean acid metabolism compounds respectively.

Photosynthesis in C3 Plants

In C3 plants, the first step of photosynthesis involves the fixation of carbon dioxide by the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase). This enzyme combines carbon dioxide with ribulose-1,5-bisphosphate (RuBP) to form a six-carbon compound that immediately splits into two molecules of 3-phosphoglyceric acid.

Advantages and Disadvantages

C3 plants are more efficient in conditions of moderate light intensity and temperature, and high carbon dioxide concentration. However, they are less efficient than C4 and CAM plants under conditions of high light intensity, high temperature, and low carbon dioxide concentration. This is due to a process called photorespiration, in which RuBisCO incorporates oxygen instead of carbon dioxide, leading to a loss of carbon and energy.

Examples of C3 Plants

Examples of C3 plants include most trees and grasses, and all dicots such as soybeans, wheat, and rice. These plants are typically found in cooler, wetter areas.

See Also

• C4 plants
• CAM plants
• Photosynthesis
• Photorespiration
• RuBisCO