Photosynthesis

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All About Photosynthesis

What is Phototsynthesis?

Photosynthesis is the process which plant cells use in order to change energy from the sun into chemical energy.

This is a picture of cotton plants. On the right is a picture of light energy.

Process

http://students.umf.maine.edu/~duplinj/webquest/Phtsyn1.gif

The process takes place in the chloroplast using chlorophyll, a green pigment which traps the sun's energy.

Step 1: The starting materials are carbon dioxide (6CO2), light energy, and water (6H2O). The plant absorbs these materials from the air and the soil.

Step 2: The CO2 and the H2O enter the chloroplast. Then, the chlorophyll captures the light energy which is used to make the starting materials (above) into new things.

Step 3: The "new things" I was saying about in Step 2 are sugars such as glucose (C6H12O6) and Oxygen (6O2). The oxygen is like a waste product for the plant so most of it is released into the air. Some of the glucose is kept for the energy it needs.

Where Can You Find Photosynthesis?

Photosynthesis is found mostly in plants. Plants are an example of autotroph. Autotroph organisims are organisms that can produce their own "food". Photosynthesis does not occur in only plants, but many species of Bacteria such as algae and cyanobacteria. The process can be a little bit different than plants, but they all contain chlorophyll. Many people think that the kingdom of "Fungi" use photosynthesis, but they do not. They may look similar to plants, but they are actually very different. Instead of getting their "food" from Co2, O2, and light energy, they get the nutrients from the soil.

History of Photosynthesis

The process of photosynthesis started around the same time when all Earth's creatures were microorganisms. Scientists hypothesize that was around 3.5 billion years ago. The first photosynthetic organisms probably used hydrogen or hydrogen sulfide instead of H2O. Then cyanobacteria appeared 3 billion years ago, an organism that will change the Earth forever. Cyanobacteria started producing oxygen and releasing them into the atmosphere. Without them, we wouldn't be here right now! The oxygen began forming new complex organisms and protists. Around 550 million years ago, some of those protists evolved into what we now call today plants and algae.

Glucose

The glucose used in plants is not suddenly used all at once. Glucose molecules create carbohydrates called starch by linking together. They store the starch and when they need energy, they break it down into glucose or other sugars. The glucose is very important because it can be energy for the plant, and it can supply food for other organisms that eat the plant.

This is a microscopic picture of glucose.