The key difference between respiration and photosynthesis is that respiration is a biochemical process that utilizes oxygen and converts food into energy while photosynthesis is a process that produces carbohydrates and releases oxygen into the atmosphere.
Respiration and photosynthesis are two of the most important processes of life. These two fascinating processes are different from each other in many ways as discussed in this article. Primarily, one of these processes converts the unusable energy into food while the other process makes a serviceable form of energy from that stored food. In addition, carbon dioxide is involved in both these processes, but at different places.
CONTENTS
1. Overview and Key Difference
2. What is Respiration
3. What is Photosynthesis
4. Similarities Between Respiration and Photosynthesis
5. Side by Side Comparison – Respiration vs Photosynthesis in Tabular Form
6. Summary
What is Respiration?
Respiration is a biochemical process that converts food into energy with oxygen, and it takes place inside the cells of all living beings. In respiration, the biochemical energy of food transforms into adenosine triphosphate (ATP) and carbon dioxide as a result of the utilization of oxygen. Carbon dioxide is the waste product and the main product ATP is the usable form of energy of organisms. In fact, it is the energy currency of living organisms. Therefore, respiration is the main way of obtaining energy, which is vital to maintain all the biological processes. Hence, it could be stated that respiration produces energy by burning the foods inside cells. Sugars (glucose), amino acids, and fatty acids are amongst the highly used respiratory substrates in respiration.
Figure 01: Respiration
It is important to notice that the respiration process is either aerobic or anaerobic depending on the involvement of oxygen in the process. Aerobic respiration process uses oxygen as the final electron acceptor while anaerobic respiration takes place in the absence of oxygen and makes use of other chemicals such as sulphur compounds to generate energy.
The entire process of aerobic respiration involves four major steps: glycolysis, citric acid cycle (Krebs cycle), oxidative decarboxylation of pyruvate, and oxidative phosphorylation. At the end of the aerobic respiration, it produces a net amount of 38 ATP molecules from one glucose molecule (C6H12O6).
What is Photosynthesis?
Photosynthesis is the biochemical process that converts the energy of sunlight into organic compounds using carbon dioxide. Carbon dioxide (CO2) reacts with water (H2O) in the presence of sunlight to form glucose (C6H12O6) and oxygen (O2).
Photosynthesis occurs in the chloroplast of the cells of plants, green algae, and cyanobacteria. Most importantly, photosynthesis maintains the global CO2 level at a low level and improves the O2 level of the atmosphere. However, the recent anthropogenic activities have detrimental effects on the photosynthetic purification of CO2 in the atmosphere.
Figure 02: Photosynthesis
The green colour of the chlorophyll in the chloroplast is responsible for capturing sunlight at the desired level for the process of activation of electrons. There are two major steps in photosynthesis: light reaction and dark reaction. The light reaction involves Z-scheme and water photolysis while the dark reaction involves Calvin cycle and carbon concentrating mechanisms. The efficiency of the entire process of the photosynthesis varies around 3 – 6%. However, it depends mainly on the level of carbon dioxide in the atmosphere, light intensity, and temperature.
What are the Similarities Between Respiration and Photosynthesis?
- Respiration and photosynthesis are two important biochemical processes occurring in living organisms.
- Carbon dioxide, oxygen, glucose and water play major roles in both processes.
- Also, they occur at the cellular level.
- Moreover, both processes are globally important in order to maintain CO2 and O2 levels.
What is the Difference Between Respiration and Photosynthesis?
Respiration and photosynthesis are two extremely important biochemical processes occurring in living organisms. The key difference between respiration and photosynthesis is that respiration burns food and produces energy while photosynthesis produces foods by capturing the sunlight. Furthermore, respiration occurs in all living organisms but photosynthesis occurs only in plants, algae and cyanobacteria.
Moreover, a further difference between respiration and photosynthesis is the place where it occurs. Respiration occurs in the mitochondria while photosynthesis occurs in the chloroplasts. Additionally, respiration utilizes oxygen and releases carbon dioxide. In contrast, photosynthesis utilizes carbon dioxide and releases oxygen. Therefore, this is also a significant difference between respiration and photosynthesis.
Summary – Respiration vs Photosynthesis
Respiration is a catabolic process that burns food in order to produce ATP. In contrast, photosynthesis is an anabolic process that produces foods. Also, respiration occurs in all living organisms. But, photosynthesis takes place only in photoautotrophs such as plants, algae and cyanobacteria. In eukaryotes, respiration takes place in mitochondria while photosynthesis takes place in chloroplasts. Most importantly, photosynthesis releases oxygen and maintains the carbon dioxide level in the atmosphere. Thus, this summarizes the difference between respiration and photosynthesis.
Reference:
1. Vidyasagar, Aparna. “What Is Photosynthesis?” LiveScience, Purch, 15 Oct. 2018, Available here.
2. “Introduction to Cellular Respiration and Redox.” Khan Academy, Khan Academy, Available here.
Image Courtesy:
1. “2503 Cellular Respiration” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Simple photosynthesis overview” By Daniel Mayer (mav) – original imageVector version by Yerpo – Own work (CC BY-SA-4.0) via Commons Wikimedia