Has anyone ever bugged you about finishing your breakfast?  You may have been told that without food, you would not be able to learn in school or play sports.  You need that cereal, fruit, juice and milk to do important things.  Plants also need food to do plant work.  Plants do not eat food, though; they make their own food through the process called photosynthesis.  Both plants and animals break down their food in much the same way.


For plants, making food starts with the sun.  They use sunlight, water, and carbon dioxide to make sugars through photosynthesis.  Once plants have made the sugars, they can store them, then break them down and use them to do the things they need to stay alive.  Plants use these sugars to make energy they can use.  Energy is the ability to cause change.  With energy, living things can do the things they need to in order to stay alive.

You are my sunshine.


Plants have ways of changing energy from one kind to another.  They soak up the sun's light with green stuff inside their cells called chlorophyll.  This is what makes a leaf green.  Plants use the trapped heat from the sun to change water and the gas you breathe out into sugar.   We say plants capture the sun's light and use it to make sugars.  To capture means to take in or to grab.   Plants capture the sun's light just like your coat and fuzzy blanket trap warm air close to your skin in the winter.


Once plants make their sugars, they must turn them into energy.   This takes place inside a specific part of each cell.  Our cells work a lot like our bodies.  Think about the different parts of your body.  Your eyes, ears, heart and skin each have their own job to do.  In each cell, there are parts that have different jobs, too.   Both plant and animal cells need energy from sugar, so they both have special parts that make energy.


You can think of the parts that make energy as tiny power plants.  They bring together sugars and the air you breathe.  The cell's power plants that use oxygen and sugars to make energy are called mitochondria.  Your muscles are packed with these, because you need so much power to run, jump and play.  Plants also use these cell parts to make the power they need to grow and stay alive.

Nature's solar power plant.
מינוזיג, CC0, via Wikimedia Commons


All living things must turn food into fuel they can use to do work.  Plants start with the sugars they make.  Then they take in water and air.  They break these apart and move pieces around to let out energy.  When the plants are finished, water and the gas you breathe out are left over.  It's called cellular respiration when plant or animal cells turn sugars or other food into energy.  This process lets plants make new cells, move things around inside their cells, and move things in and out of their cells.

Hot, right out of the oven.


Animals need to find their own food, drink water, and breathe to make energy.   Plants can make their own food from a few everyday things, like light, the gas animals breathe out, and water.  Plants and animals may get food in different ways, but they break down their food in the same way.  Changing food into energy takes place inside the cells' mitochondria.  They are the cells' power plants.  They turn your cereal, fruit, juice and milk into the power to learn and play.