Photosynthesis is the process by which plant cells,
algae, and some bacteria, capture light energy and change
it to chemical energy. Almost all of the world?s energy is
provided through photosynthesis. The equation for
photosynthesis is CO 2 + 2H 2 A + light energy—> (CH 2 ) +
H2 0 + H2 A .
Photosynthesis is in two stages : a series of
reactions that need light and certain temperatures and a
series of reactions that don?t need light but need certain
temperatures. The rate of the light reaction, can be sped
up by increasing the amount of light (with some limits). In
the dark reaction, their rate can be increased by
increasing the temperature (with some limits), but not
changing the amount of light. The first step in
photosynthesis is absorbing light by pigments. The
Chlorophyll captures light energy (violet and red) and
transforms it into chemical energy. The chemicals involved
with photosynthesis are organized into units of the
chloroplasts called thylakoids. Light is absorbed by
pigments, raising their electrons to higher energy levels.
The energy is the put into the chlorophyll through a
reaction center.
Now here are some of the creators of ideas of
photosynthesis. If it weren?t for people who did such
things as discovering oxygen, finding chemical reactions in
plants, and discovering biology as a science, we would know
very little about photosynthesis or any kind of science at
all.
Jan Baptista van Helmont (1580-1644) was a Belgian
physician and chemist. Helmont was the first scientist to
tell the difference between gases and air. He invented an
early type of biochemistry, named iatrochemistry. Helmont
thought that the main elements of the universe were air and
water.
Melvin Calvin is an American chemist and Nobel prize
winner. Calvin studied photosynthesis and plants that
produce fuel oil. Calvin started his experiments in
photosynthesis during the 1940?s. He used carbon-14 to
detect chemical reaction chains produced by plants in
converting carbon dioxide and water into oxygen and
carbohydrates.
Joseph Priestley is a British chemist, who isolated and
described several gases, including oxygen. In 1774,
Priestley discovered oxygen and described its role in
combustion and in respiration. Priestley didn?t understand
how important his discovery was. If Priestly hadn?t made
the discovery, the theories of photosynthesis may never had
been realized. Priestly also discovered ammonia, nitrous
oxide, sulfur dioxide, and carbon monoxide. He opposed the
new theories of Antoine Lavoisier, who named oxygen, and
described it correctly.
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