Photosynthesis vs. Cellular Respiration (Similarities And Differences)

Living organisms are the largest and most complex life forms on Earth. They carry out chemical reactions to create energy, which they need to survive. Biological processes like photosynthesis and cellular respiration are crucial for the survival of these organisms.

Photosynthesis is the process by which cells use light energy to convert CO₂ into glucose, a type of sugar. Cellular respiration is the process by which cells use carbohydrates, oxygen, and other nutrients to produce energy.

These processes are vital for the survival of living organisms, and each one plays a unique role in sustaining life. They’re pretty similar in some aspects, along with a few differences.

The main difference between photosynthesis and cellular respiration is that photosynthesis uses light to convert solar energy into chemical energy, while cellular respiration uses glucose to produce energy.

Let’s discuss these complicated processes in detail.

What Is Photosynthesis?

Photosynthesis is one of the most critical processes on Earth because it helps produce your favorite foods.

It’s the process of using sunlight to create organic molecules from simple inorganic molecules. The process requires pigment-containing cells known as phytoliths to absorb light energy and turn it into chemical energy that plants can use to make food.

In broad terms, photosynthesis helps us convert carbon dioxide (CO2) and water into living things like trees and flowers.

Photosynthesis involves three basic steps: light absorption, conversion of light energy into chemical energy, and plant growth/manufacturing of food.

• First, the plant’s cells “see” sunlight in the form of photons and use that energy to convert CO₂ and water into carbohydrates (which are the building blocks of proteins).
• Secondarily converted products include oxygen gas and carbon dioxide—two gases essential for human survival.
• And finally, these gases are used by plants to manufacture new glucose-containing molecules that nourish them.

What Is Cellular Respiration?

Cellular respiration is the process by which cells use energy to create glucose from sugar. Glucose is then used by cells to create ATP, which is a key energy molecule.

Cellular respiration occurs in several steps:

• The first step is the breakdown of glucose into pyruvate and carbon dioxide.
• Pyruvate is then converted into oxaloacetate by the Pyruvate Carboxylase enzyme.
• Oxaloacetate is then converted into acetyl-CoA by the Acetyl-CoA Carboxylase enzyme.
• Acetyl-CoA is then used to produce ATP from glucose.

Differences Between Photosynthesis And Cellular Respiration

Photosynthesis and cellular respiration are two very different processes in cells.

Photosynthesis is the process by which plants and some other organisms produce energy from light by using carbon dioxide and water to create glucose.

Cellular respiration is the process by which the cells use energy to convert food into molecules that the cells can use for energy.

There’re a few key differences between photosynthesis and cellular respiration.

• One significant difference between photosynthesis and cellular respiration is that photosynthesis occurs mainly in plants, especially their green parts, like leaves.
• In contrast, cellular respiration occurs in all living organisms in all cells in the body.
• In photosynthesis, carbon dioxide is used as one of the reactants, while in cellular respiration, oxygen is used as one of the reactants.
• Cellular respiration is more efficient, producing more energy than photosynthesis.
• Photosynthesis makes food, while cellular respiration breaks down that food into energy.
• Photosynthesis can only occur in the presence of sunlight; in contrast, cellular respiration does not require sunlight to produce energy.

Here is a table of comparison between photosynthesis and cellular respiration.

Photosynthesis	Cellular Respiration
It occurs in the chloroplast present in the leaves of plants.	It occurs in the mitochondria of cells.
Its end product is glucose.	Its end product is ATP.
It needs sunlight.	It doesn’t need sunlight.
It requires carbon dioxide along with water as a reactant.	It requires glucose along with oxygen as a reactant.

Similarities Between Photosynthesis And Cellular Respiration

Photosynthesis and cellular respiration are two processes involved in the working machinery of living organisms. They involve the conversion of energy into mass, each with unique features.

• One fundamental similarity between photosynthesis and cellular respiration involves steps in a reaction chamber. In photosynthesis, light energy is absorbed by plant cells and used to produce energy-rich molecules called organic matter. Cellular respiration converts glucose into ATP, which fuels other cell activities.
• Both involve converting light energy into chemical energy, which is then used to create new molecules.
• Additionally, both processes rely on chains of linked reaction steps.
• Both processes require a Photosystem II enzyme to carry out their tasks.
• Moreover, both processes require an electron shuttle chain to transfer electrons from reduced nicotinamide adenine dinucleotide (NAD+) to oxygen. 

Here is a video clip comparing the process of photosynthesis and cellular respiration.

What Is The Importance Of Photosynthesis?

Photosynthesis is one of the earth’s most vital processes. Without it, it’s impossible to live. Without photosynthesis, the Earth would be a frozen wasteland; instead, its plants are constantly creating food to support all the life that occupies it.

Photosynthesis provides oxygen, which helps us breathe and prevents diseases like cancer from forming. It also produces glucose from carbon dioxide and water that’s essential for human and animal survival.

What Is The Importance Of Cellular Respiration?

Cellular respiration is the process by which energy is extracted from food and converted into ATP, the primary energy molecule in cells.

Cellular respiration provides the chemical energy that fuels all cellular activities, such as growth, reproduction, and healing. Without cellular respiration, organisms would quickly die due to a lack of energy.

The role of cellular respiration in human health is significant. Cellular respiration helps produce energy vital for cell functioning and average tissue growth.

It also synthesizes key vitamins and minerals, including vitamin B12 and iron. Inadequate cellular respiration can lead to fatigue, poor concentration, and muscle weakness.

So, individuals need to make sure they get enough protein and carbs during their everyday diet so that their cells can properly break down these nutrients for cellular respiration purposes.

What Is The Main Product Of Photosynthesis?

The main product of photosynthesis is glucose (C₆H₁₂O₆), along with side products like oxygen.

Final Thoughts

• Photosynthesis is the process of converting light energy into chemical energy in plants and some photosynthetic prokaryotic cells.
• Cellular respiration is the metabolic process by which cells convert glucose, water, and other nutrients into adenosine triphosphate (ATP), the energy source for most bodily functions.
• There are many similarities between the two processes and a few key differences.
• Both photosynthesis and cellular respiration involve converting energy from light into chemical bonds.
• Photosynthesis occurs in photo-assimilating chloroplasts, while cellular respiration occurs within cells alongside mitochondria.
• Photosynthesis is much more common in plants, while cellular respiration is more common in animals.
• The similarity between photosynthesis and cellular respiration is that both processes require water to happen.

Other Articles

• Difference Between Atoms And Molecules (How Many Atoms Are Required To Make A Molecule?)
• PCA VS ICA (Know the Difference)
• What Is The Difference Between Biology And Chemistry?
• What’s The Difference Between A Mole Fraction And PPM? How Do You Convert Them? (Explained)