Nutrition Science and Everyday Application - beta v 0.1

PHOTOSYNTHESIS AND METABOLISM 135
The importance of photosynthesis is not just that it can capture sunlight’s energy.
Photosynthesis is vital because it provides a way to capture the energy from solar radiation
(the “photo-” part) and store that energy in the carbon-carbon bonds of glucose (the “-
synthesis” part). Glucose is the main energy source that animals and humans use to power
the synthesis of adenosine triphosphate (ATP). ATP is the energy-containing molecule found
in the cells of all animals and humans. Energy from the foods we eat is captured in ATP and
used to fuel the workload of cells. 1
The energy stored in carbohydrate molecules from photosynthesis passes through the
food chain. Consider a predator, such as a wolf, preying on a deer. The wolf is at the end of
an energy path that went from atoms colliding on the surface of the sun, to visible light, to
photosynthesis, to vegetation, to the deer, and finally to the wolf. The wolf, by feeding on the
deer, receives a portion of the energy that originated in the photosynthetic vegetation that
the deer consumed.
Our food supply is also directly linked to photosynthesis. Major grocery stores in the
United States are organized into departments, such as dairy, meats, produce, bread, cereals,
and so forth. Each aisle contains hundreds, if not thousands, of different products for
customers to buy and consume. Although there is a large variety, each item ultimately can be
linked back to photosynthesis. Meat and dairy link because the animals were fed plant-based
foods. The breads, cereals, and pastas come largely from starchy grains, which are the seeds
of photosynthesis-dependent plants. What about desserts and drinks? All of these products
contain sugar—sucrose is a plant product, a carbohydrate molecule, which is also derived
from photosynthesis. Many items are less obviously derived from plants: virtually every spice
and flavoring in the spice aisle was produced by a plant as a leaf, root, bark, flower, fruit,