CBSE Class 10 Biology Revision Worksheet Set A - Free Printable

Problem Analysis:

The worksheet provided focuses on the concept of respiration in plants and includes multiple-choice questions related to the process of respiration, its energy storage mechanisms, and the end products of aerobic and anaerobic respiration. Let's solve each question step by step.

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Question 1:

The process of releasing energy from food is called...
- [A] digestion
- [B] nutrition
- [C] assimilation
- [D] respiration

#### Explanation:
- Digestion: This is the process of breaking down complex food molecules into simpler substances that can be absorbed by the body. It does not directly involve the release of energy.
- Nutrition: This refers to the intake of nutrients by an organism. It is a broader term and does not specifically describe the process of energy release.
- Assimilation: This is the process by which organisms incorporate absorbed nutrients into their own tissues. It is not related to energy release.
- Respiration: This is the biological process by which organisms break down organic molecules (such as glucose) to release energy, typically in the form of ATP. This is the correct answer.

#### Correct Answer:
[D] respiration

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Question 2:

The energy released during respiration is stored in...
- [A] ATP
- [B] mitochondria
- [C] lungs
- [D] cell nucleus

#### Explanation:
- ATP (Adenosine Triphosphate): This is the primary molecule used to store and transfer energy within cells. During respiration, the energy released from the breakdown of glucose is used to synthesize ATP.
- Mitochondria: These are the organelles where most of the respiration occurs, but they do not store energy; they are the sites where ATP is produced.
- Lungs: In animals, lungs are involved in gas exchange (oxygen and carbon dioxide), but they do not store energy.
- Cell Nucleus: This is the control center of the cell and contains genetic material. It is not involved in energy storage.

#### Correct Answer:
[A] ATP

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Question 3:

During anaerobic respiration, glucose molecules are broken down to ______ in animal muscle cells.
- [A] ethanol
- [B] lactic acid
- [C] ethylene
- [D] glycogen

#### Explanation:
- Ethanol: This is a product of anaerobic respiration in certain microorganisms (e.g., yeast) but not in animal muscle cells.
- Lactic acid: During anaerobic respiration in animal muscle cells, glucose is broken down into lactic acid. This process occurs when oxygen is limited, such as during intense exercise.
- Ethylene: This is a plant hormone and is not related to anaerobic respiration in animals.
- Glycogen: This is a storage form of glucose in animals, not a product of anaerobic respiration.

#### Correct Answer:
[B] lactic acid

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Question 4:

In plants, the end products of anaerobic respiration are CO₂ and...
- [A] ethanol
- [B] lactic acid
- [C] water
- [D] starch

#### Explanation:
- Ethanol: During anaerobic respiration in plants, glucose is broken down into ethanol and carbon dioxide (CO₂). This is a common pathway in plant cells under anaerobic conditions.
- Lactic acid: This is the product of anaerobic respiration in animal muscle cells, not in plants.
- Water: Water is a product of aerobic respiration, not anaerobic respiration.
- Starch: Starch is a storage form of glucose in plants, not a product of anaerobic respiration.

#### Correct Answer:
[A] ethanol

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Final Answers:

1. [D] respiration
2. [A] ATP
3. [B] lactic acid
4. [A] ethanol

Boxed Final Answer:
\[
\boxed{D, A, B, A}
\]