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Difference Between Photosynthesis and Respiration

Last updated date: 17th Apr 2024
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An Introduction to Photosynthesis and Respiration

Photosynthesis and respiration are two vital processes that occur in living organisms, driving the flow of energy within ecosystems and this helps to explain photosynthesis and respiration. Photosynthesis, typically carried out by plants and certain microorganisms, is a complex anabolic process that converts sunlight, carbon dioxide, and water into glucose and oxygen. It is the foundation of life on Earth, capturing solar energy and storing it in the form of chemical energy. Respiration, on the other hand, is a catabolic process that takes place in all living cells, including plants and animals. It breaks down glucose to release stored energy, utilizing oxygen and producing carbon dioxide as a byproduct. While photosynthesis builds up energy resources, respiration breaks them down to fuel cellular activities.

What is Photosynthesis and Respiration?

Photosynthesis: Photosynthesis is the biological process by which plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose (a form of chemical energy) and oxygen. Photosynthesis is responsible for approximately 70% of the oxygen in Earth's atmosphere, while respiration consumes oxygen and produces carbon dioxide.

Respiration: Respiration, on the other hand, is the metabolic process that occurs in all living cells, including plants, animals, and microorganisms. It involves the breakdown of glucose or other organic molecules in the presence of oxygen to release energy. Respiration is not solely an energy-releasing process. It also plays a role in the breakdown and recycling of cellular components and molecules.

Characteristics of Photosynthesis and Respiration


Function: Photosynthesis is an anabolic process that converts light energy into chemical energy stored in glucose, which serves as a source of energy and building blocks for the organism.

Oxygen Production: Photosynthesis is responsible for producing oxygen as a byproduct, contributing to the oxygen levels in the atmosphere.


Occurrence: Respiration occurs in all living cells, including plants, animals, and microorganisms.

Dependence: Respiration is dependent on oxygen and requires its presence for the complete breakdown of glucose to produce ATP.

Difference Between Photosynthesis and Respiration





Energy Conversion

Sunlight into Chemical Energy

Chemical Energy into ATP



Glucose, Oxygen

Carbon Dioxide, Water, ATP



Oxygen Production

Generates oxygen as a byproduct

Consumes oxygen, produces carbon dioxide


Location in Organism

Mainly in leaves and green parts

Occurs in all cells of an organism



Independent of Respiration

Requires oxygen produced by photosynthesis


Photosynthesis and respiration are contrasting processes in living organisms. Photosynthesis is an anabolic process occurring in plants, algae, and some bacteria, converting sunlight, carbon dioxide, and water into glucose and oxygen, storing energy and producing oxygen. Respiration is a catabolic process occurring in all living cells, breaking down glucose to release energy, utilizing oxygen, and producing carbon dioxide. Photosynthesis builds energy resources and produces oxygen, while respiration breaks down resources, releases energy, and produces carbon dioxide. Together, they maintain the energy flow and balance in ecosystems, sustaining life on Earth.

FAQs on Difference Between Photosynthesis and Respiration

1. What is the overall significance of photosynthesis and respiration?

Photosynthesis is crucial for providing oxygen, regulating atmospheric carbon dioxide levels, and acting as the primary source of energy and nutrients for ecosystems. Respiration releases the stored energy from glucose, fueling cellular processes and maintaining life functions in organisms. Together, photosynthesis and respiration create a balance in the flow of energy and matter, sustaining life on Earth and maintaining the delicate equilibrium of atmospheric gases and nutrient cycles. They are fundamental processes that support the survival and functioning of diverse organisms and ecosystems.

2. Can photosynthesis and respiration occur simultaneously in a plant?

Yes, photosynthesis and respiration can occur simultaneously in plants during the day. However, photosynthesis dominates in the presence of sunlight, producing more energy than the energy consumed by respiration. At night, when there is no sunlight, respiration continues as the primary energy-generating process.It's important to note that during the night, when there is no sunlight available, photosynthesis ceases, but respiration continues. In this case, respiration becomes the primary process for releasing energy from stored glucose, maintaining cellular functions until photosynthesis can resume with the return of daylight.

3. Are there any organisms that can survive without photosynthesis or respiration?

No, all organisms require either photosynthesis or respiration (or both) to survive. Photosynthetic organisms rely on photosynthesis to produce energy-rich molecules, while non-photosynthetic organisms depend on consuming organic matter produced by photosynthetic organisms and utilizing respiration for energy release. Both photosynthesis and respiration are essential processes for the majority of organisms, providing energy, oxygen, and nutrients necessary for survival and sustaining ecosystems.