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Plant cells are cells that are in plants. Plant cells are like animal cells, but they have a cell wall and chloroplasts. Here's a labeled picture of a plant cell. You will see all the main parts of the cell. Listed below are definitions of those words. Read on to learn more about photosynthesis.
|Cell Membrane: A thin layer that surrounds the cell.|
|Cell Wall: A rigid layer that surrounds the cell membrane of a plant cell.|
|Chloroplast: (KLOR-o-plast) A cell structure in which photosynthesis takes place, and it contains the chloropyll.|
|Chlorophyll: (KLOR-a-fil) A green substance in plant cells that helps to make food.|
|Cytoplasm: (SIGH-ta-plaz-em) The jellylike liquid in cells where activities take place.|
|Nucleus: (NEW-kle-us) The dark structure inside the cell that controls the cell's activities and contains material such as DNA.|
|Photosynthesis: (foto-SIN-thi-sis) The process when plants use lights energy to make food.|
A very special process that takes place inside of the chloroplasts in plant cells is called photosynthesis (foto-SIN-thi-sis). Photo means "light" and synthesis means " putting things together." In photosynthesis, green plants actually make their own food. That is so cool! Imagine if we could make our own food. I wonder what we'd make? Personally, I would make pizza. Plants seem to have the right idea since they make sugar. This amazing process is responsible for everything we eat. That's because animals eat plants, and we eat the animals and the plants.
If you would like to see an actual photograph of a chloroplast viewed through the lens of an electron microscope, visit the Nanoworld Image Gallery (you'll need to register in order to view the gallery).
In photosynthesis, the chloropyll (KLOR-a-fil) takes in energy from sunlight. The energy comes in the form of a tiny bundle known as a photon. The photon hits a molecule of water inside the chlorophyll. The photon's energy splits the water molecule into hydrogen and oxygen. The hydrogen combines with carbon dioxide (which the plant has absorbed from the air) to make sugars or glucose. The oxygen is released back into the atmosphere to give us more air. Did you know that the largest suppliers of oxygen in the whole world are tiny plants known as photoplankton? They are found in the oceans and are really important to giving us the oxygen needed to keep life going on our planet.
Believe it or not, a plant uses only about one-sixth of the energy it gets from the sun to nourish itself. The rest of the energy is stored in the glucose until it is eaten by other animals or humans. What an amazing process!