Tuesday, November 25, 2008

Photosynthesis


Photosynthesis




Part 1 : Introduction

* When you get hungry, what do you do? You might decide to raid the refrigerator or try to convince your mom to take you to a fast food restaurant. You do those things because you are a heterotroph (or consumer). Heterotrophs are organisms that need to get their energy from the foods they eat. Humans and animals are heterotrophs — so are parasites like fleas, ticks, and tapeworms!
Conifers, like other green plants, can't just reach in the fridge for a quick snack. They have to make their own food. Green plants are called autotrophs (or producer). Autotrophs use light energy from the sun to produce the food they need. To understand how this works, we need to learn about photosynthesis.



Bio4Kids



* Photosynthesis takes place in the chloroplasts in plant cells. Chloroplasts contain a green substance called chlorophyll. This absorbs the light energy needed to make photosynthesis happen. Plants can only photosynthesise in the light.





Chloroplast


Part 2 : The Process


* Photosynthesis is a process. It's a set of steps that happen in a certain order inside the cells of green plants. Let's think of photosynthesis as a recipe — the plant version of a making a batch of chocolate chip cookies!
Before you begin cooking, you need to be sure you have all of the ingredients. Then you can get started! It's the same with plants.


* There are many things that the plants need for Photosynthesis:
Carbon Dioxide
Water
Sun Light


1- The chlorophyll in the cell of the plant absorbs light from the sunlight.

2-The sun's energy splits the water molecules into hydrogen and oxygen.

3-The hydrogen joins with carbon dioxide to make sugar (Food)

4- The sugar is carried to other parts of plant.

Note that: The extra oxygen is released into the air



* With every process there is a result :
Oxygen
Glucose


* Without chlorophyll a plant would not be able to make the food it needs. Chlorophyll is a pigment found in green plants. It's what makes the needles of a TREE look green.
Chloroplasts are special parts of most green plant cells. They are where you find chlorophyll.
This is where the action of photosynthesis takes place.



Leaf