An Overview of Photosynthesis
This process occurs in all photosynthetic organisms including some bacteria, some protists and plants.
This is the most fundamental metabolic process required to support the capture of energy from sunlight
and storing the energy in the chemical bonds of glucose. This glucose then serves as a source of
chemical energy for all heterotrophic life forms. The other important function is to convert inorganic
carbon into organically available carbon.
The best chemical equation to represent this reaction is:
sunlight
6 CO2 + 12 H2O
chlorophyll
C6H12O6 + 6 H2O
This photosynthesis equation shows that water is both a reactant and different molecules of water are
products. This process occurs in a chloroplast which has many structural similarities to mitochondria.
Most chloroplasts are found in the mesophyll cells of a leaf.
The chloroplast has an outer and an inner membrane. Inside there are thylakoids which are stacked into
granum (singular is grana). This folding increases surface area for capturing more photons of light
energy. Also this membrane has an electron transport system and an ATP synthase enzyme. The space
inside is called the lumen and has a high concentration of H+. Granum are joined together by lamellae.
The liquid surrounding the granum is the stroma.
The overall processes with the reactants and products of photosynthesis are shown in this diagram.
The two main processes of photosynthesis are the light reactions and the Calvin Cycle.
1. LIGHT REACTIONS
The light reactions occur on the thylakoid membrane where photons of light energy excite electrons in
either photosystem I or photosystem II. The energy is used to photophosphorylate ADP + Pi  ATP. The
sunlight energy is also used to reduce NADP+ to NADPH.
2. CALVIN CYCLE
The ATP and NADPH are oxidized in the stroma and the released energy is used to join 3 CO2 to form a
trisaccharide called glyceraldehyde-3-phosphate (G3P). Two G3P are joined to form 1 glucose. These
reactions can only occur when there is a high concentration of ATP and NADPH. This means that shortly
after the sun sets these reactions stop.
An Overview of Photosynthesis
This process occurs in all photosynthetic organisms including some __________, some __________ and
__________. This is the most fundamental metabolic process required to support the capture of energy
from sunlight and _______________________________________________________. This glucose then
serves as a source of chemical energy for all heterotrophic life forms. The other important function is to
convert inorganic carbon into ____________________________________________.
The best chemical equation to represent this reaction is:
This photosynthesis equation shows that water is both a ___________________ and different molecules
of water are ________________. This process occurs in a ____________________________ which has
many structural similarities to mitochondria. Most chloroplasts are found in the _________________
cells of a leaf.
The chloroplast has an __________ and an __________________________. Inside there are
_______________________ which are stacked into _________________ (singular is grana). This folding
________________________________________ for capturing more photons of light energy. Also this
membrane has an ____________________________________________ and an ___________________
enzyme. The space inside is called the __________________ and has a high concentration of _________
Granum are joined together by lamellae. The liquid surrounding the granum is the
__________________.
The overall processes with the ______________ and ___________________________ of photosynthesis
are shown in this diagram.
The two main processes of photosynthesis are the light reactions and the Calvin Cycle.
1. LIGHT REACTIONS
The light reactions occur ____________________ membrane where photons of light energy excite
electrons in either ________________ or photosystem II. The energy is used to ____________________
ADP + Pi  ATP. The sunlight energy is also used to ________________________ NADP+ to _________.
2. CALVIN CYCLE
The ATP and NADPH are ____________________________ and the released energy is used to
______________________ to form a trisaccharide called glyceraldehyde-3-phosphate (G3P). Two G3P
are joined to form 1 glucose. These reactions can only occur when there is a ______________
concentration of ATP and NADPH. This means that shortly after the sun sets these reactions ________.