10 Difference Between Cellular Respiration And Photosynthesis (With Diagram)

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Learn the differences between cellular respiration and photosynthesis. The basis of comparison include: Description, Place of Occurrence, Main Purpose, By-Products, Electron Transport Chain, Stages and so on.

Key Difference

Description

Photosynthesis is a chemical process that takes place in the presence of light, light energy from the sun is used to produce ATP (energy) and other molecules known as NADPH.  Photosynthesis occurs in the chlorophyll containing plant cells. Chlorophyll absorbs the light energy and utilizes it to produce carbohydrates from carbon dioxide and water. These carbohydrates produced by the plants as a source of immediate energy for growth, reproduction and absorption of nutrients. Through the process, oxygen is produced and released into the atmosphere.

Cellular respiration is the process of oxidizing food molecules or breaking down chemical bonds of glucose into carbon dioxide and water. The energy released in the process is trapped in the form of ATP and used by different energy consuming activities of the cell.

Place of Occurrence

Photosynthesis takes place in the plant leaves containing the chlorophyll pigment. Cellular respiration on the other hand, takes place in the cytoplasm and mitochondria of the cell.

Main Purpose

The main purpose of photosynthesis is to capture and conversion of light energy from the sun into chemical energy and storing it in the bonds of glucose. On the contrary, the main purpose of cellular respiration is to release the chemical energy stored in form of glucose to produce ATP for the cell.

The Process

Photosynthesis makes use of sunlight to produce food (glucose molecules). Cellular respiration on the other hand, makes use of the glucose molecules to produce energy-storing ATP molecules.

By-Products

Photosynthesis uses water, sunlight and carbon dioxide from the atmosphere to create glucose molecules and release oxygen as a by-product. Cellular respiration on the other hand, uses glucose molecules and oxygen to produce ATP molecules and carbon dioxide as the by-product.

Electron Transport Chain

In photosynthesis, the electron transport chain occurs at the beginning of the process, however, in cellular respiration, the electron transport chain occurs at the end of the process.

Occurrence in Organisms

Photosynthesis occurs only in plants, algae and some bacteria whereas cellular respiration takes place in all types of living organisms.

What it Entails

Photosynthesis involves conversion of one type of energy into another that is light energy into chemical energy while cellular respiration involves using that chemical energy and breaking it down to release energy.

Necessary Conditions

Photosynthesis happens only when there is sunlight whereas cellular respiration occurs at all times, it does not depend on sunlight for it to happen.

Stages

Photosynthesis takes place in two stages; the stages include the light dependent reaction (light cycle) and light independent reaction (Calvin cycle). 

  1. In Light dependent reactions (light cycle), light energy and water are used to produce ATP and NADPH.
  2. In Calvin Cycle (light independent reactions), carbon dioxide and the energy from ATP and NADPH are used to produce glucose.

Cellular respiration takes place in four stages; the stages include Glycolysis, Pyruvate Oxidation, Kreb’s Cycle and Electron Transport Chain.

  1. Glycolysis stage, glucose is combined with ATP to produce pyruvate molecules, NADH and more ATP.
  2. Pyruvate Oxidation stage, pyruvate molecules are broken down into 2-carbon molecules and carbon dioxide is produced.
  3. Kreb’s Cycle stage, the 2-carbon molecules combine with 4-carbon molecules to form 6-carbon citrate molecules used to generate NADH, CO2 and ATP.
  4. Electron Transport Chain, energy stored in NADH and FADH2 during the kreb’s cycle is used to generate ATP, Water, NAD+ and FAD.

Also Read: Difference Between Normal Respiration And Photorespiration

Difference Between Cellular Respiration And Photosynthesis In Tabular Form

BASIS OF COMPARISON PHOTOSYNTHESIS CELLULAR RESPIRATION
Description Photosynthesis is a chemical process that takes place in the presence of light, light energy from the sun is used to produce ATP (energy) and other molecules known as NADPH.  Photosynthesis occurs in the chlorophyll containing plant cells. Chlorophyll absorbs the light energy and utilizes it to produce carbohydrates from carbon dioxide and water. Cellular respiration is the process of oxidizing food molecules or breaking down chemical bonds of glucose into carbon dioxide and water. The energy released in the process is trapped in the form of ATP and used by different energy consuming activities of the cell.  
Place of Occurrence Photosynthesis takes place in the plant leaves containing the chlorophyll pigment. Cellular respiration takes place in the cytoplasm and mitochondria of the cell.  
Main Purpose The main purpose of photosynthesis is to capture and conversion of light energy from the sun into chemical energy and storing it in the bonds of glucose. The main purpose of cellular respiration is to release the chemical energy stored in form of glucose to produce ATP for the cell.  
The Process Photosynthesis makes use of sunlight to produce food (glucose molecules). Cellular respiration on the other hand, makes use of the glucose molecules to produce energy-storing ATP molecules.  
By-Product Photosynthesis uses water, sunlight and carbon dioxide from the atmosphere to create glucose molecules and release oxygen as a by-product. Cellular respiration on the other hand, uses glucose molecules and oxygen to produce ATP molecules and carbon dioxide as the by-product.  
Electron Transport Chain In photosynthesis, the electron transport chain occurs at the beginning of the process. In cellular respiration, the electron transport chain occurs at the end of the process.  
Occurrence in Organisms Photosynthesis occurs only in plants, algae and some bacteria.   Cellular respiration takes place in all types of living organisms.  
What it Entails Photosynthesis involves conversion of one type of energy into another that is light energy into chemical energy. Cellular respiration involves using that chemical energy and breaking it down to release energy.  
Necessary Condition Photosynthesis happens only when there is sunlight.   Cellular respiration occurs at all times, it does not depend on sunlight for it to happen.  
Stages Photosynthesis takes place in two stages; the stages include: the light dependent reaction (light cycle) and light independent reaction (Calvin cycle).    Cellular respiration takes place in four stages; the stages include: Glycolysis, Pyruvate Oxidation, Kreb’s Cycle  Electron Transport Chain.  

What are the Similarities between Photosynthesis and Cellular Respiration?

  1. ATP is produced in both processes.
  2. Both photosynthesis and cellular respiration involve the conversion of energy from one form to another through a series of biochemical reactions.
  3. All living things must either use photosynthesis or cellular respiration.
  4. Both cellular respiration and photosynthesis depend on each other.
  5. Both photosynthesis and cellular respiration involve cycles of reactions.
  6. Both cellular respiration and photosynthesis use the coenzymes such as NAD and NADP.
  7. Both processes involve electron transport chain.
  8. Occur in the interior space of organelles.

Summary

  • Photosynthesis captures energy while cellular respiration releases energy.
  • ATP is the main purpose for cellular respiration whereas for photosynthesis, ATP is only needed in order to create glucose.
  • Photosynthesis produces food whereas cellular reaction breaks down food.
  • Photosynthesis occurs in the chloroplast of plants, whereas cellular respiration occurs in mitochondria.