Glucose is a sugar with the molecular formula C6H12O6.
The name "glucose" (/ˈɡluːkoʊs/) comes from the Greek word
γλευκος, meaning "sweet wine".
Glucose is made during photosynthesis
from water and carbon dioxide, using energy from sunlight.
The reverse of the photosynthesis reaction,
which releases this energy,
is a very important source of power for cellular respiration.
Glucose is stored as a polymer,
in plants as starch and in animals as glycogen.