Aerobic Respiration – Respiration with Oxygen
Aerobic Respiration requires oxygen and is defined as the chemical reaction that uses oxygen to break down nutrients to release a significant amount of energy in the form of ATP.
It involves the complete breakdown of nutrient molecules to release energy
It requires Oxygen
It produces Water and Carbon Dioxide
The equation for aerobic respiration is:
Glucose + Oxygen -> Carbon Dioxide + Water + Energy (ATP)
In chemical terms:
C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP)
This equation represents the overall process of aerobic respiration, where glucose (C6H12O6) and oxygen (O2) react to produce carbon dioxide (CO2), water (H2O), and energy in the form of ATP (adenosine triphosphate).
FLOWCHART
Aerobic respiration begins when oxygen molecules are taken in by cells from the surrounding environment, typically through breathing in animals or through pores in plant cells.
The food molecules, such as glucose, that cells acquire contain carbon, hydrogen, and oxygen atoms. These molecules serve as the fuel for aerobic respiration.
Inside the cell, enzymes facilitate the oxidation of food molecules. During oxidation, carbon atoms in the food molecules are converted into carbon dioxide (CO2), while hydrogen atoms are transformed into water (H2O).
As carbon and hydrogen atoms are oxidized, energy is released in the form of adenosine triphosphate (ATP), which is the primary energy currency of cells. This energy is crucial for powering various cellular processes, including muscle contraction, protein synthesis, and cell division.
ATP molecules generated during aerobic respiration are utilized by cells to perform work and maintain essential functions, ensuring the organism’s survival and growth.
Aerobic respiration begins with the intake of oxygen by cells from the surrounding environment.
Oxygen is acquired through breathing in animals or through pores in plant cells.
Food molecules, such as glucose, serve as the fuel for aerobic respiration.
Enzymes facilitate the oxidation of food molecules inside the cell.
During oxidation, carbon atoms in the food molecules are converted into carbon dioxide (CO2).
Hydrogen atoms are transformed into water (H2O) during this process.
Energy is released in the form of adenosine triphosphate (ATP) as carbon and hydrogen atoms are oxidized.
ATP is the primary energy currency of cells, crucial for powering various cellular processes.
These processes include muscle contraction, protein synthesis, and cell division.
ATP molecules generated during aerobic respiration are utilized by cells to perform work and maintain essential functions.
This ensures the organism’s survival and growth.
Flowchart
Oxygen intake by cells (Breathing in animals or pores in plant cells) —> Fuel molecules (e.g., glucose) for aerobic respiration —> Enzyme-facilitated oxidation of food molecules —>Conversion of carbon atoms into CO2 and hydrogen atoms into H2O —> release of energy in the form of ATP —> ATP powers cellular processes (muscle contraction, protein synthesis, cell division) —> Maintenance of essential functions for organism’s survival and growth.
Importance of Aerobic Respiration
It provides the energy needed for cellular activities and processes, including movement, growth, and reproduction.
It ensures efficient utilization of nutrients obtained from food, supporting overall health and metabolism.
It enables organisms to adapt to changing environmental conditions by regulating energy production based on oxygen availability.
Anaerobic Respiration – Respiration without Oxygen
Anaerobic respiration is a way for cells to get energy from food without using oxygen.
It produces less energy than aerobic respiration and often creates byproducts like lactic acid or ethanol.
Anaerobic respiration occurs in the absence of oxygen, where energy is still released from food molecules through chemical breakdown. While oxygen is not utilized in these reactions, carbon dioxide is often produced.
Anaerobic Respiration in Yeast
A common example is the fermentation process carried out by yeast.
Sugar is converted into carbon dioxide and alcohol, such as ethanol. This process is essential in various applications like ethanol production and bread-making.
The equation for anaerobic respiration in yeast, where glucose is converted into alcohol (such as ethanol) and carbon dioxide, releasing energy, is:
Glucose → Alcohol + Carbon Dioxide + Energy
In yeast, anaerobic respiration occurs in small steps and requires multiple enzymes.
However, it yields much less energy compared to aerobic respiration because the alcohol produced still contains a significant amount of energy that the yeast cannot utilize.
Anaerobic Respiration in Animals
In muscles, anaerobic respiration also occurs during intense exercise when oxygen cannot be delivered quickly enough for aerobic respiration.
Unlike yeast, muscle cells produce lactic acid instead of alcohol. This build-up of lactic acid contributes to muscle fatigue and soreness.
The equation for anaerobic respiration in muscles is:
Glucose → Lactic Acid
After vigorous exercise, the excess lactic acid is transported through the bloodstream to the liver, where some of it is metabolized aerobically. This process requires oxygen and produces carbon dioxide and water. The body continues to consume oxygen at a high rate until the excess lactic acid is broken down, a phenomenon known as Excess Post-exercise Oxygen Consumption (EPOC) or oxygen debt.
Oxygen debt is the extra oxygen consumed post-exercise to restore cellular processes, including metabolizing lactic acid and replenishing ATP stores. It reflects the body’s need to repay the oxygen deficit accumulated during anaerobic metabolism, ensuring metabolic balance and recovery. Oxygen debt is essential for returning muscles and bodily systems to their pre-exercise state after strenuous activity.
To facilitate lactic acid removal and replenish oxygen levels, the heart rate increases to ensure rapid circulation of blood, while deeper and faster breathing helps increase oxygen intake. This recovery process restores the body to its normal metabolic state, preventing muscular fatigue and promoting overall homeostasis.
