The mechanism of photosynthesis involves two important
reactions- the Light/Hill/Photochemical Reaction and the Dark/Bio-synthetic
Reactions.
The chlorophyll electrons become excited by the light
energy. In an intact chloroplast with thy-akoid membranes, ATP is generated by
an electron flow along the cytochrome transport system. Since the electrons are
being transported to other "carrier" molecules, their energy is used
to generate ATP or energy. and no reddish glow is emitted. Leaves generally
appear green because wavelengths of light from the red and blue regions of the
visible spectrum are necessary to excite the chloroplast electrons, and unused
green light is reflected. Thus, we perceive trees, shrubs and grasses as green.
During the fall months , the leaves when chlorophyll production ceases in deciduous trees
and shrubs turn golden yellow or red due to the presence of other
pigments, such as yellow and orange carotenoids and bright red anthocyanins.
Another important ingredient for photosynthesis is also produced during the
light reactions. During these light-dependent reactions of photosynthesis, a
chemical called N A D P picks up two hydrogen atoms from water molecules forming
NADPH2, a powerful reducing agent that is used to convert carbon dioxide into
glucose during the dark reactions of photosynthesis (also called the Calvin
Cycle) then on to ATP. When the two atoms of hydrogen join with N A D P, oxygen is liberated, and
this is the source of oxygen gas in our atmosphere. ATP and NADPH2from the
light reactions are used in the dark reactions of photosynthesis that take
place in the stoma or region of the chloroplast.
Bottom line: Energy of Light photon (E
= h v) equates to the energy and v the frequency of light needed for production of O2 + ATP + NADPH2(used in the
dark reactions) and other bio materials needed for plants to grow (additional ATP and assorted compounds).
reactions- the Light/Hill/Photochemical Reaction and the Dark/Bio-synthetic
Reactions.
The chlorophyll electrons become excited by the light
energy. In an intact chloroplast with thy-akoid membranes, ATP is generated by
an electron flow along the cytochrome transport system. Since the electrons are
being transported to other "carrier" molecules, their energy is used
to generate ATP or energy. and no reddish glow is emitted. Leaves generally
appear green because wavelengths of light from the red and blue regions of the
visible spectrum are necessary to excite the chloroplast electrons, and unused
green light is reflected. Thus, we perceive trees, shrubs and grasses as green.
During the fall months , the leaves when chlorophyll production ceases in deciduous trees
and shrubs turn golden yellow or red due to the presence of other
pigments, such as yellow and orange carotenoids and bright red anthocyanins.
Another important ingredient for photosynthesis is also produced during the
light reactions. During these light-dependent reactions of photosynthesis, a
chemical called N A D P picks up two hydrogen atoms from water molecules forming
NADPH2, a powerful reducing agent that is used to convert carbon dioxide into
glucose during the dark reactions of photosynthesis (also called the Calvin
Cycle) then on to ATP. When the two atoms of hydrogen join with N A D P, oxygen is liberated, and
this is the source of oxygen gas in our atmosphere. ATP and NADPH2from the
light reactions are used in the dark reactions of photosynthesis that take
place in the stoma or region of the chloroplast.
Bottom line: Energy of Light photon (E
= h v) equates to the energy and v the frequency of light needed for production of O2 + ATP + NADPH2(used in the
dark reactions) and other bio materials needed for plants to grow (additional ATP and assorted compounds).
