All questions of Respiration in Organisms for Class 7 Exam

Fish

An athlete breathes faster and deeper than usual after finishing a race because their body needs to intake more oxygen to compensate for the oxygen debt incurred during the intense physical activity. This helps in the removal of lactic acid and the replenishment of oxygen levels in the muscles.

B

• Frog: Frogs are amphibians that have the ability to breathe through their skin as well as through their lungs. Their skin is thin and moist, allowing for gas exchange to occur. This is especially important for frogs when they are underwater or in environments with low oxygen levels.

• Frogs have a specialized skin that is permeable to gases, allowing them to absorb oxygen and release carbon dioxide through their skin.


• When frogs are on land, they primarily use their lungs to breathe. However, when they are in water or in damp environments, they rely more on their skin for respiration.


• This dual breathing system allows frogs to adapt to different environments and survive in a variety of conditions.

• In conclusion, frogs are a unique example of animals that can breathe through their skin as well as through their lungs, showcasing their remarkable adaptation to varying habitats.

Understanding Aerobic Respiration
Aerobic respiration is the process by which cells break down food molecules in the presence of oxygen to release energy. This process is crucial for the survival of most living organisms, as it provides the energy required for various cellular activities.

Key Features of Aerobic Respiration:
- **Oxygen Requirement:**
Aerobic respiration occurs only in the presence of oxygen. This is a key differentiator from anaerobic respiration, which happens without oxygen.
- **Energy Production:**
The main purpose of aerobic respiration is to produce ATP (adenosine triphosphate), the energy currency of the cell. One glucose molecule can yield up to 36-38 ATP molecules during aerobic respiration.
- **Process Overview:**
The process involves several steps, mainly:
- **Glycolysis:** This occurs in the cytoplasm, where glucose is partially broken down into pyruvate, producing a small amount of ATP.
- **Krebs Cycle:** In the mitochondria, pyruvate is further broken down, releasing carbon dioxide and transferring energy to electron carriers.
- **Electron Transport Chain:** This final stage occurs in the inner mitochondrial membrane, where oxygen acts as the final electron acceptor, allowing ATP to be produced efficiently.

Importance of Aerobic Respiration:
- **Sustains Life:**
It provides the energy necessary for growth, repair, and maintenance of cells.
- **Waste Products:**
The by-products of aerobic respiration, primarily carbon dioxide and water, are less toxic compared to those produced during anaerobic respiration.
In summary, aerobic respiration is a vital process that utilizes oxygen to efficiently break down food and produce energy, sustaining life in various organisms.

Yeast Respiration and Alcohol Production
Anaerobic respiration in yeasts is known as fermentation, which produces alcohol as a byproduct. Here's a breakdown of the process:

Yeast Cells
- Yeasts are single-celled organisms that can respire anaerobically when oxygen is not present.
- They have the ability to convert sugars into energy without the need for oxygen through fermentation.

Anaerobic Respiration
- In the absence of oxygen, yeasts undergo anaerobic respiration to generate energy.
- This process involves breaking down sugars (such as glucose) into simpler compounds to release energy.

Alcohol Production
- During anaerobic respiration, yeasts produce alcohol (ethanol) and carbon dioxide as byproducts.
- The alcohol produced by yeasts is commonly used in the production of alcoholic beverages such as beer and wine.

Final Product
- The main product of anaerobic respiration in yeasts is alcohol, which is utilized in various industrial and culinary processes.
- This process is essential for the fermentation of sugars into alcohol, making yeasts valuable organisms in biotechnology and food production.