The sun is the ultimate source of
energy for all living things. Without the sun, life as we know it would be
impossible. The light energy on which all life on earth depends is obtained by
the conversion of hydrogen into helium atoms inside the sun. Photosynthesis and
cellular respiration are reversible reactions and closely interrelated.
Light is a radiant form of energy
and can be thought of as consisting of many particles, or photons. The photon theory states that a photon carries a unit of
energy known as a quantum. The
energy that each photon carries together with the number of photons per unit
area per second determines the intensity of light.
Chloroplasts are the sites of
photosynthesis in plants. They are found mainly in mesophyll cells forming the
tissues in the a interior of the leaf. Chloroplast are disc-shaped and are
composed of two portions: the stroma and grana. Chlorophyll is the main pigment
of photosynthesis and is found in the thylakoid membrane. The color of a leaf
comes from chlorophyll, the green pigment in the chloroplast. Chlorophyll plays
an important role in the absorption of light energy during photosynthesis.
Their role is to catalyse the transference of radiant energy into chemical
energy in a molecular form.
Photosynthesis involves a series
of chemical reactions. Photosynthesis transfers electrons from
to
molecules forming sugar molecules
. This electron transfer is an example of
an oxidation-reaction process the
water oxidized (loses electrons) and the
is reduced (gains electrons). During
photosynthesis, light energy is captured and converted to the chemical energy
of sugars and other organic compounds;
and
are used and
is
released as a byproduct into the atmosphere. Photosynthesis involves a series
of chemical reactions. It consists of two main stages, the light phase and the
dark phase. In the light phase light
energy is converted into chemical energy in ATP. In the dark side, products of the light phase are used to combine carbon
dioxide.
-Zambak
