Plants use a protein called Rubisco to convert carbon dioxide into organic compounds, allowing them to “make” their own food through photosynthesis. A type of green algae called Chlamydomonas reinhardtii also employs this strategy, but does so with the help of a small cellular structure called the pyrenoid. This structure is a condensed ball of Rubisco units that is connected to a complex network of tubules, or tube-shaped membranes. These tubules act as a transport system for carbon dioxide, essentially allowing the algae to provide high levels of carbon dioxide directly to Rubisco, making the process much more efficient. The efficiency of the pyrenoid has huge implications for agriculture and climatology--in fact, it is responsible for approximately one-third of carbon fixation on the planet. Because of this, figuring out how the pyrenoid works and how to engineer it into crops is a major priority. To gain a better understanding of the structure on a molecular level, I have used advanced imaging techniques to visualize the proteins of the tubule network with nanometer-scale precision. In the process, I have found that different proteins are located in unique patterns within the network, which hint at the specialized roles that they may play in different aspects of pyrenoid formation and function.