Photosynthesis is a process of
producing glucose by plant using the energy from sunlight, carbon dioxide and
water. Here, light energy is converted into chemical energy. During
photosynthesis process oxygen is released which absolutely need to breathe and stay
alive. Typically, using chlorophyll, photosynthesis process is
happened in the chloroplasts. Chlorophyll is the green pigment of
photosynthesis. In the early evolutionary history of life, first
photosynthetic organisms were developed wherein hydrogen or hydrogen sulfide
was the source of electrons instead of water. Globally, photosynthesis can
capture huge amount of energy. It is approximately six times higher than our
existing power consumption. Photosynthetic organisms can also convert huge
amount of carbon into biomass per year.
Basically,
photosynthesis happens in plant leaves. The upper and lower epidermis, the
mesophyll, the vascular bundles and the stomates are parts of a typical leaf. Epidermis
are the outer layer of cells surrounding the body of an organism like a plant
leaf or our skin. No chloroplasts exists in the upper and lower epidermal
cells, thus no photosynthesis create there. Primarily, they provide protection
for the rest of the leaf. In the lower epidermis, stomates holes are created in
order to exchange air. Here, carbon dioxide enters and oxygen exits. Vascular
bundles of leaf transport required water and nutrients around the plant. The
mesophyll cells contain chloroplasts wherein photosynthesis
creates.Chloroplasts are photosynthetic organelle in plant.
Parts of a chloroplast
includes outer and inner membranes, inter membrane space, stroma and thylakoids
stacked in grain. Stroma is the the fluid within chloroplasts. Thylakoid is
one of the sacs within a chloroplast. Membranes of the thylakoid contains
chlorophyll. Absorbing red and blue light, it appears to us as green color. It
makes red and blue colors visually unavailable to our eyes. Because, green
light is not absorbed in chlorophyll. So, finally it appears as green
color to our eyes. However, it is the energy from the absorbed red and blue
light. It is used to do photosynthesis. As plants cannot absorb green light, it
cannot be used to do photosynthesis.
In the thylakoid membrane, light reaction occurs
and converts light energy into chemical energy. In the light reaction,
chlorophyll and few other pigments like beta-carotene are associated. Each of
these distinguished color pigments can absorb quite distinguished color of
light and transfers its energy into the central chlorophyll molecule in order
to do photosynthesis.
Energy collected through
the light reaction is stored by forming a chemical called ATP (adenosine
triphosphate). ATP is a compound wherein cells store energy. It contains
nucleotide adenine bonded to ribosomes and three phosphate groups. Dark
reaction happens in the stroma within the chloroplast and converts carbon
dioxide into glucose.