Final answer:
RuBisCO is a holoenzyme composed of two types of subunits, including 8 large and 8 small, for a total of 16 subunits. This enzyme is crucial in the photosynthesis process, enabling carbon fixation in plants.
Step-by-step explanation:
The ribulose bisphosphate carboxylase (RuBisCO) is a holoenzyme consisting of two types of subunits for a total of 16 subunits. Specifically, it is made of 8 large subunits (L) and 8 small subunits (S).
RuBisCO is the enzyme responsible for initiating the process of carbon fixation in the Calvin cycle. This enzyme is essential in the transformation of inorganic carbon dioxide to organic compounds in plants. The large subunit is encoded by the rbcL gene in the chloroplast DNA, while the small subunit is encoded by a family of rbcS genes in the nuclear DNA. As the most abundant enzyme on earth, RuBisCO has a crucial role in the process of photosynthesis, allowing for the production of the sugars that drive plant growth and development. The distinctive composition of the enzyme, with its 16 subunits, constitutes the protein complex that facilitates the conversion of CO₂ to an energy-rich form that can be utilized by the plant and, by extension, other forms of life that depend on plants for sustenance.