• The basic unit of useable energy cells need to
power their lives is known as ATP. ATP stands for:
Adenosine Tri-phosphate.
• ATP is organized in the cell mitochondria and
released to all parts of the cell. This molecule is
effectively the ‘currency’ or ‘money’ that is used
to power life.
• It is the bonds that hold the Adenosine, Ribose
(sugar) and Phosphate groups together that hold
the energy. When the molecule is broken apart
by cells, this energy is released and used.
• Photosynthesis is an ‘energy storing’ process.
Performed only by plants, it harnesses the energy
available in sunlight for the purpose of building
glucose, a basic sugar molecule organisms use as
food. The term comes from the two latin roots
‘photo’ always meaning light, and ‘synthesis’
which means to build.
• The essential factor plants have that animals do
not, allowing them to perform this function, is
the pigment chlorophyll.
• Chlorophyll acts like an energy trap, or a rechargeable battery. It collects the energy
available from sunlight and then uses that to
begin the chemical process that forms
2 Phases of Photosynthesis
• Light Reactions: The first phase of the process.
Water is split into oxygen and hydrogen. The
oxygen is given off as a waste product, the
hydrogen is used by the plant. This is a
complex process, but it takes place almost
Steps of light reaction
1. Chlorophyll is energized.
2. Energy created is stored in ATP.
3. Water molecule is split, hydrogen kept and
oxygen is given off into atmosphere as
4. Hydrogen is trapped by a NADP. Chloroplast
contain this coenzyme, which is a hydrogen
Steps of the Dark Reactions
1. Carbon dioxide is fixed by RDP (chloroplasts
contain ribulose diphosphate or RDP. This is a
5-carbon sugar molecule with two phosphate
groups. This is a carbon dioxide receptor.
2. PGA combines with hydrogen and forms
3. Glucose is formed.
• Photosynthesis is the bridge between the
organic (living) and inorganic (nonliving)world! This is the process in which nonliving building blocks are organized into a
carbon based substance that then powers life.