Differences and Similarities between Photosynthesis and Respiration

Photosynthesis and respiration are two fundamental processes that occur in living organisms. Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight into chemical energy in the form of glucose. Respiration is the process by which all living cells release energy from glucose and convert it into a form that cells can use for their activities. Although these processes may seem opposite, they share some similarities. Both involve the transfer of electrons, use enzymes to facilitate reactions, and occur in organelles (chloroplasts and mitochondria). Understanding the differences and similarities between these processes is crucial to understanding the bioenergetics of life. Differences and Similarities between Photosynthesis and Respiration.

Difference between photosynthesis and respiration

ParameterPhotosynthesisRespiration 
OccurrenceOnly occurs in phototrophs (all green plants, algae and some bacteria).Occurs in all living organism. 
By-product The by- product are oxygen, glucose and water.The by-products include carbon dioxide, water, and energy (ATP).
Reactants The reactants in the photosynthetic process include carbon dioxide, water, and light energy.The reactants of respiration are glucose and oxygen.
Location Photosynthesis takes place in chloroplasts.Respiration takes place in mitochondria.
Reactions Photosynthesis is an endothermic reaction as it requires energy.When energy is released during respiration, it is an exergonic process.
FunctionPhotosynthesis produce food and captures the energy.Respiration takes in oxygen and release out carbon dioxide. 
SunlightIt requires the presence of sunlight.It does not require the presence of sunlight and continues to occur day and night.
Co2 and water Absorb carbon dioxide and water. Release carbon dioxide and water. 
Chemical reaction The chemical reaction of photosynthesis is 6CO2 + 6H2O → C6H12O6+ 6O2.The chemical reaction of cellular Respiration is C6H12O6+ 6O→ 6CO2 + 6H2O.
Electrons carriersNADPH carries electrons in photosynthesis.NADH and FADHcarries electrons in cell respiration.
Proton movementProton are pumped into thylakoid space of chloroplast.Proton are pumped into inner membrane space of the mitochondria.
Differences and Similarities between Photosynthesis and Respiration

Relationship between Photosynthesis and Respiration

The products of one system are the reactants of the other because of the way that photosynthesis and cellular respiration are related. In order to create glucose and oxygen, photosynthesis uses the energy from sunlight, water, and carbon dioxide. Oxygen and glucose are used in cellular respiration to create carbon dioxide and water.

The cycle of cellular respiration and photosynthesis is essential for the life of humans, animals, and plants.  Humans and other animals breathe in oxygen that plants make during photosynthesis so that the blood may carry it to the cells where it is used for respiration. Plants absorb the carbon dioxide that is emitted from the body during breathing and uses it to help their growth and development. This never-ending cycle is what keeps life on earth going.

Differences and Similarities between Photosynthesis and Respiration
Fig: Relationship between photosynthesis and respiration

Plants and other photosynthetic organisms create energy through the process of photosynthesis, whereas cellular respiration converts the energy into a usable form.  These two processes have certain commonalities despite the differences between them. For instance, ATP, the unit of energy, is produced and used by both processes.

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Similarities Between Photosynthesis and Respiration

  • Energy is produced during both the photosynthesis and respiration processes.
  • Both photosynthesis and respiration produce and makes use of ATP.
  • Glycogen-3- phosphate is formed in both processes i.e., glycolysis in respiration and Calvin cycle in photosynthesis.
  • Both utilize electron transport change to produce ATP.
  • Both processes can observe emergent properties in multiple steps.
  • Both respiration and photosynthesis utilize cycle where starting materials is generated after molecules leaves the cycle.
  • Both processes involve exchange of gases.

Differences and Similarities between Photosynthesis and Respiration

Sarmila K C

Welcome to The Science Notes! I'm Sarmila K C, a science writer with a background in Food Technology. My mission is to simplify complex scientific topics and make them accessible to everyone. I cover the various topics of science and explain them with clear, accurate information.

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