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.