Why Do Plants Need Photosynthesis & Cellular Respiration?

Plants conduct photosynthesis and cellular respiration to create, store and use energy.
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During photosynthesis, plants produce the substance they require to survive and store it until they need it. During cellular respiration, plants carry out chemical reactions to derive energy from the products of photosynthesis.

Photosynthesis

Plants transform light energy into chemical energy during photosynthesis.
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During photosynthesis, plants transform light energy into chemical energy that living organisms can use. Plants absorb water from the soil and carbon dioxide from the air to produce sugars. Plants also release oxygen as a by-product during photosynthesis.

Glycolysis

Plants convert glucose into pyruvic acid during glycolisis.
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During glycolysis, plants convert the simple sugar known as glucose into pyruvic acid and produce energy. This process occurs with or without oxygen in the cytoplasm of plant cells.

Cellular Respiration

During cellular respiration, plants use oxygen to further break down the products of glycolysis.
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During cellular respiration, plants use oxygen to further break down the products of glycolysis in the mitochondria of plant cells. This process releases more energy, carbon dioxide and water.