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Respiration and Transportation in Organisms - Aerobic and Anaerobic Respiration

Grade 7CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Cellular Respiration: The process of breakdown of food in the cell with the release of energy is called cellular respiration. It takes place in the cells of all organisms.

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Aerobic Respiration: When the breakdown of glucose occurs with the use of oxygen (O2O_2), it is called aerobic respiration. It produces carbon dioxide (CO2CO_2), water (H2OH_2O), and a significant amount of energy.

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Anaerobic Respiration: Breakdown of food that occurs without the use of oxygen is called anaerobic respiration. This process is common in organisms like yeast and in human muscle cells during heavy exercise.

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Anaerobic Respiration in Yeast: Yeasts are single-celled organisms that respire anaerobically. In this process, glucose is converted into alcohol (ethanol, C2H5OHC_2H_5OH) and carbon dioxide (CO2CO_2).

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Anaerobic Respiration in Muscles: During heavy exercise, the supply of oxygen (O2O_2) to our muscle cells may be insufficient. To meet the high energy demand, muscles respire anaerobically, producing lactic acid (C3H6O3C_3H_6O_3) instead of CO2CO_2.

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Muscle Cramps: The accumulation of lactic acid (C3H6O3C_3H_6O_3) in the muscles causes muscle cramps. Relief is obtained by a hot water bath or massage, which improves blood circulation and increases the supply of oxygen to the cells.

📐Formulae

Glucose+Oxygen→Carbon dioxide+Water+EnergyGlucose + Oxygen \rightarrow Carbon\ dioxide + Water + Energy

C6H12O6+6O2→6CO2+6H2O+EnergyC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + Energy

Glucose→absence of oxygenin yeastAlcohol+Carbon dioxide+EnergyGlucose \xrightarrow[absence\ of\ oxygen]{in\ yeast} Alcohol + Carbon\ dioxide + Energy

Glucose→absence of oxygenin muscle cellsLactic acid+EnergyGlucose \xrightarrow[absence\ of\ oxygen]{in\ muscle\ cells} Lactic\ acid + Energy

💡Examples

Problem 1:

Why do athletes often suffer from muscle cramps during a heavy sprinting session?

Solution:

During sprinting, the demand for energy is high but the supply of O2O_2 to produce energy is limited. Consequently, anaerobic respiration takes place in the muscle cells: Glucose→Lactic acid+EnergyGlucose \rightarrow Lactic\ acid + Energy.

Explanation:

The partial breakdown of glucose produces lactic acid (C3H6O3C_3H_6O_3). The accumulation of this acid in the muscle tissues leads to cramps.

Problem 2:

How is the process of anaerobic respiration in yeast utilized in the food industry?

Solution:

Yeasts undergo anaerobic respiration to produce CO2CO_2 and C2H5OHC_2H_5OH (alcohol). The equation is: Glucose→Alcohol+CO2+EnergyGlucose \rightarrow Alcohol + CO_2 + Energy.

Explanation:

The CO2CO_2 released makes the dough rise in bread-making, giving it a fluffy texture, while the alcohol produced is essential in the wine and beer industries.