Chloroplasts in the cells of elodea and other plants perform photosynthesis, converting sunlight into biochemical energy stored as carbohydrates. Both plants and the animals that consume them require carbohydrates to fuel cellular activity.
Chloroplasts are organelles that form from undifferentiated plastids in plant leaf cells triggered by the presence of light, and they reproduce in a process similar to binary fission. An envelope composed of a double membrane separated by an inter-membrane space surrounds the chloroplast.
The light phase of photosynthesis, which converts sunlight into energy transport chemicals, occurs in a system of membranes pigmented with chlorophyll. This thylakoid network consists of light-gathering sheets called stroma lamellae connecting to light-processing sacs stacked into structures called grana. The grana stabilize the thylakoid structure while the stroma lamellae ensure it remains flexible enough to respond to available light.
The dark phase of photosynthesis occurs in a high-pH fluid called the stroma, and does not require light. Enzymes in the stroma convert unstable energized outcomes of the light phase into oxygen and glucose.
Elodea leaf cells engage in cytoplasmic streaming, which moves chloroplasts into areas of light in response to illumination gradients.
Nanotechnology is the next frontier for photosynthesis research. Scientists at the Massachusetts Institute of Technology introduced carbon nanotubes into chloroplasts, increasing the amount of light used.