How do cyanobacteria synthesize their requirements?

• A. Fermentation
• B. Chemosynthesis
• C. Photosynthesis
• D. Respiration

Answer: (C)

Cyanobacteria meet their energy and carbon needs through photosynthesis. They capture light energy and use it to drive a series of reactions that convert carbon dioxide and water into organic matter, building sugars that fuel growth. This process also releases oxygen because water is split to provide electrons for the reactions. Through this light-driven synthesis, cyanobacteria function as photoautotrophs, producing their own food from light. Fermentation would rely on breaking down existing sugars without light, chemosynthesis uses chemical energy from inorganic molecules rather than light, and respiration breaks down organic material for energy rather than creating new biomass from CO2 using light. So photosynthesis is the way cyanobacteria synthesize their requirements.