Cellular Respiration: How Cells Release Energy from Sugar

0:00Every cell needs energy. How does a cell get energy from the sugar in food?

0:06Here is an animal cell. Inside are tiny structures called mitochondria; this is one mitochondrion.

0:15Releasing energy from sugar is called cellular respiration. Most of it happens in mitochondria.

0:22The first input is glucose, a sugar. Animals get it from food; plants make it by photosynthesis.

0:31The second input is oxygen, from the air you breathe, carried to the cell by your blood.

0:37In a series of steps, glucose is broken down using oxygen, and energy is released.

0:43The reaction makes two products: carbon dioxide and water.

0:49Part of the energy is stored in ATP, a small molecule that powers the cell's work.

0:56The rest is given off as heat, which helps keep your body warm.

1:00As a word equation: glucose plus oxygen gives carbon dioxide plus water plus energy.

1:09In symbols: one glucose and six oxygen molecules give six carbon dioxide and six water molecules.

1:18Respiration is not breathing. Breathing moves air in and out of your lungs.

1:24Respiration is the reaction in your cells that releases energy from glucose.

1:30Plant cells have mitochondria too, so plants respire, just like animals.

1:35In sunlight, plants also make glucose by photosynthesis, but they respire all the time, day and night.

1:44Cells use oxygen to release energy from glucose, giving carbon dioxide and water.