Class 9 Biology Chapter 14: Breathing & Exchange of Gases MCQ with Answers
Breathing and Exchange of Gases is a critical chapter in CBSE Class 9 Biology that explains how organisms respire and exchange oxygen and carbon dioxide with their environment. This chapter covers aerobic and anaerobic respiration, the human respiratory system, and gas exchange in plants and animals. Our carefully curated Multiple Choice Questions (MCQs) help you master this topic with confidence. These questions align with NCERT Class 9 Biology Chapter 14 and are designed to strengthen your conceptual clarity before board exams. Whether you're preparing for school tests or competitive entrance exams, practising these MCQs will boost your confidence and improve your score.
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Understanding Breathing vs. Respiration in NCERT Class 9 Biology
Breathing is the physical process of inhaling and exhaling air, while respiration is the chemical breakdown of glucose to release energy. In NCERT Chapter 14, students learn that aerobic respiration requires oxygen and produces CO₂ and water, releasing 686 calories per mole of glucose. Anaerobic respiration occurs without oxygen in muscle cells during intense exercise, producing lactic acid. Understanding this distinction is essential for answering MCQs accurately and scoring well in board examinations.
The Human Respiratory System: Structure & Function
The human respiratory system includes the nose, pharynx, larynx, trachea, bronchi, and lungs. According to NCERT Class 9, the trachea divides into two bronchi, which further divide into bronchioles and alveoli. Alveoli are tiny air sacs where gas exchange occurs. The diaphragm is a muscle below the lungs that contracts during inhalation, increasing lung volume. MCQs often test students' knowledge of these structures and their roles in the breathing process.
Gas Exchange Mechanism: How Oxygen Enters & CO₂ Leaves
Gas exchange occurs across the thin walls of alveoli through diffusion. Oxygen moves from the alveoli into the blood, binding to haemoglobin in red blood cells, while carbon dioxide diffuses from the blood into the alveoli for exhalation. NCERT Chapter 14 emphasizes that this process is passive and depends on concentration gradients. Understanding this mechanism helps students answer questions about partial pressures of gases and oxygen transport in blood.
Aerobic vs. Anaerobic Respiration: Key Differences Explained
Aerobic respiration occurs in the mitochondria and involves the complete oxidation of glucose in three stages: glycolysis, Krebs cycle, and electron transport chain, producing 38 ATP molecules. Anaerobic respiration, covered in NCERT Class 9, produces only 2 ATP and occurs in the cytoplasm without oxygen, resulting in lactic acid or ethanol. MCQs frequently compare these processes, asking about ATP yield, products, and conditions where each occurs. This comparison is crucial for conceptual understanding.
Respiration in Plants: Stomata, Lenticels & Gas Exchange
Plants respire through stomata (in leaves) and lenticels (in stems and roots). NCERT Chapter 14 explains that stomata are pores bounded by guard cells that open during the day for photosynthesis and gas exchange. Plants also undergo both aerobic and anaerobic respiration, though aerobic respiration is dominant. MCQs test knowledge about the role of guard cells, factors affecting stomatal opening, and how plant respiration differs from animal respiration.
Capacity of Lungs: Tidal Volume, Vital Capacity & More
Lung capacity measurements include tidal volume (normal breathing), vital capacity (maximum air that can be expelled), and residual volume (air remaining after exhalation). NCERT Class 9 introduces these concepts to help students understand respiratory efficiency. Tidal volume is typically 500 mL in adults, while vital capacity ranges from 3,500–4,600 mL. MCQs often include numerical problems based on these values, making it essential to memorize and understand these measurements.
CBSETUTOR.ai: Your AI Tutor for Class 9 Biology Mastery
CBSETUTOR.ai is India's most trusted AI tutor for CBSE Classes 6–12, used by lakhs of families across the country for comprehensive exam preparation. Our platform offers chapter-wise MCQs with instant feedback, video explanations in Hindi and English, and personalized learning paths aligned with NCERT 2024–25 curriculum. With 24x7 availability, CBSETUTOR.ai helps you practise Breathing & Exchange of Gases until you achieve mastery, boosting confidence before unit and board exams.
Common MCQ Patterns & Question Types to Expect
CBSE MCQs on this chapter typically include: (1) definition-based questions on respiration types, (2) structural identification of respiratory organs, (3) numerical calculations of ATP or lung volumes, (4) comparative questions (aerobic vs. anaerobic), and (5) application-based scenarios. NCERT Chapter 14 MCQs also test understanding of gas exchange mechanisms and factors affecting respiration like temperature and oxygen availability. Practising diverse question types strengthens your exam readiness.
Tips to Ace Breathing & Exchange of Gases MCQs
First, read NCERT Chapter 14 thoroughly and underline key points about aerobic respiration, anaerobic respiration, and gas exchange. Create a mind map linking structures like alveoli, bronchi, and diaphragm to their functions. Practise MCQs daily, reviewing incorrect answers to identify knowledge gaps. Focus on numerical problems involving ATP yield and lung volumes. Finally, use CBSETUTOR.ai's AI-powered explanations to clarify doubts instantly and track your progress.
Exam Strategy: Time Management for MCQ Success
In board exams, MCQ sections demand speed and accuracy. Allocate 1–1.5 minutes per question, reading the stem and all options carefully. Eliminate obviously incorrect options to improve accuracy. If stuck, skip and return later rather than guessing randomly. NCERT-based questions are usually straightforward; focus on understanding concepts rather than rote learning. Use CBSETUTOR.ai's timed practice quizzes to develop exam-level speed and confidence in real exam conditions.
Frequently asked questions
What is the main difference between breathing and respiration in Class 9 Biology?+
Breathing is the physical process of inhaling and exhaling air, while respiration is the biochemical process of breaking down glucose to release energy. Respiration includes both aerobic (with oxygen) and anaerobic (without oxygen) pathways, as covered in NCERT Chapter 14.
How much ATP is produced in aerobic respiration according to NCERT?+
NCERT Class 9 states that aerobic respiration produces approximately 38 ATP molecules per glucose molecule through glycolysis, Krebs cycle, and electron transport chain. This is significantly more than the 2 ATP produced in anaerobic respiration.
Is CBSETUTOR.ai available for Hindi-medium students preparing for Class 9 Biology?+
Yes, CBSETUTOR.ai supports both Hindi and English-medium students with bilingual MCQ questions, video explanations, and study materials. Our platform ensures Hindi-medium learners can prepare effectively for CBSE exams in their preferred language.
Can I access CBSETUTOR.ai's MCQ practice for free before subscribing?+
CBSETUTOR.ai offers a free trial period allowing students to access sample MCQs, chapter summaries, and foundational content. Full access to complete practice sets, video solutions, and personalized progress tracking is available with a premium subscription.
What are stomata and why are they important for plant respiration?+
Stomata are tiny pores in plant leaves bounded by guard cells that regulate gas exchange. According to NCERT Chapter 14, stomata allow oxygen and carbon dioxide to enter and exit, enabling both photosynthesis and respiration in plants. They open during the day and close at night.
How should I prepare for Breathing & Exchange of Gases MCQs effectively?+
Read NCERT Chapter 14 carefully, create concept maps, memorize key terms and values (like tidal volume = 500 mL), practise MCQs daily on CBSETUTOR.ai, and review incorrect answers. Focus on understanding mechanisms rather than rote learning for lasting retention and higher exam scores.
What is anaerobic respiration and where does it occur in the body?+
Anaerobic respiration occurs without oxygen in muscle cells during intense exercise, producing lactic acid and only 2 ATP per glucose. NCERT Class 9 explains that this causes muscle fatigue and soreness, while aerobic respiration in mitochondria is the primary energy source during normal activities.
Does CBSETUTOR.ai provide explanations in Hindi for Class 9 Biology chapters?+
Yes, CBSETUTOR.ai offers comprehensive Hindi explanations for all CBSE Class 9 Biology chapters, including video lectures, MCQ solutions, and concept clarifications. Students can switch languages based on preference, making it accessible for both Hindi and English-medium learners.
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