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CBSE Class 7 Science Chapter 6 Respiration in Organisms Worksheet with Answers

Respiration in Organisms is a core chapter in CBSE Class 7 Science that explains how living beings obtain energy from food. This printable worksheet aligns with the NCERT Class 7 Science curriculum and covers cellular respiration, aerobic versus anaerobic pathways, the human breathing mechanism, and how plants, insects, fish, and earthworms respire. Perfect for self-assessment, homework, or exam revision, this resource offers structured practice with detailed answers.

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Key takeaways

✓Cellular respiration releases energy from glucose in all living cells; aerobic respiration requires oxygen while anaerobic does not
✓Breathing (inhalation and exhalation) is the mechanical process that supplies oxygen for cellular respiration in animals
✓Plants respire through stomata and lenticels; oxygen and carbon dioxide exchange occurs in leaves, stems, and roots throughout the day and night
✓Earthworms respire through moist skin, insects use spiracles and tracheae, and fish use gills to extract dissolved oxygen from water
✓Anaerobic respiration in yeast produces ethanol and carbon dioxide (fermentation), while in muscle cells it produces lactic acid during intense exercise
✓The diaphragm and rib muscles expand the chest cavity during inhalation, creating lower pressure that draws air into the lungs
✓All organisms respire continuously to release energy for life processes, but only some organisms breathe using specialised respiratory organs

Chapter 6 Respiration in Organisms: Quick Recap

Respiration is a biochemical process that occurs in every living cell to release energy stored in glucose. It is NOT the same as breathing. Breathing is the physical act of inhaling oxygen and exhaling carbon dioxide, whereas cellular respiration is the chemical breakdown of food inside cells. Aerobic respiration requires oxygen and produces carbon dioxide, water, and a large amount of energy (ATP). The word equation is: Glucose + Oxygen → Carbon dioxide + Water + Energy. Anaerobic respiration happens without oxygen, producing less energy and different by-products like lactic acid in muscles or ethanol in yeast. Different organisms have evolved unique respiratory structures: humans use lungs and a diaphragm, fish use gills, insects rely on spiracles and a network of tracheae, earthworms exchange gases through moist skin, and plants use stomata in leaves and lenticels in stems. Understanding these mechanisms helps students appreciate the diversity of life and the universal need for energy.

Cellular respiration: energy release from glucose inside cells
Aerobic respiration: requires oxygen, yields high energy (approx. 38 ATP molecules per glucose)
Anaerobic respiration: no oxygen needed, yields low energy (2 ATP), produces lactic acid or ethanol
Breathing mechanism in humans: diaphragm contracts (moves down) during inhalation, relaxes during exhalation
Respiration in plants: occurs 24×7 through stomata (leaves) and lenticels (woody stems)
Fish gills extract dissolved oxygen from water; insects use spiracles with tracheal tubes

Worksheet Details: Difficulty Level and Time Allocation

This worksheet is designed at a Medium difficulty level, suitable for regular practice and exam preparation for CBSE Class 7 students. It contains a balanced mix of recall-based questions (MCQs, fill-in-the-blanks), application-based short answers, and higher-order thinking questions that test conceptual understanding. The worksheet is divided into six sections plus a detailed answer key. Students should attempt this worksheet in examination conditions to gauge their grasp of Chapter 6 Respiration in Organisms from NCERT Class 7 Science. Suggested time allocation: Section A (MCQs) – 12 minutes; Section B (Fill-in-the-blanks) – 8 minutes; Section C (True/False) – 6 minutes; Section D (Short answers) – 20 minutes; Section E (Long answers & HOTS) – 18 minutes; Case study – 6 minutes. Total recommended time is 60-70 minutes. Teachers can use this as a class test, and parents can print it for weekend revision. Mark distribution mirrors typical CBSE question patterns to familiarise students with exam formats.

Difficulty: Medium (aligned with CBSE Class 7 term-end expectations)
Total questions: 35+ across all sections
Suggested duration: 60-70 minutes under exam conditions
Sections cover knowledge recall, comprehension, application, and analysis
Answer key includes brief explanations for self-assessment
Printable A4 format; students should write answers in a separate notebook

Section A: Multiple Choice Questions (1 mark each)

This section tests foundational knowledge of respiration concepts as per NCERT Class 7 Science Chapter 6. Each MCQ has four options; students must choose the most accurate answer. These questions cover definitions, organ systems, by-products of respiration, and comparisons between aerobic and anaerobic pathways. MCQs are a staple in CBSE exams and help reinforce key terms and facts. Students should read each question carefully, eliminate obviously wrong choices, and select the best fit. Time management is crucial: aim to spend no more than 1.5-2 minutes per question.

Section B: Fill in the Blanks (1 mark each)

Fill-in-the-blank questions require students to recall precise scientific terms and concepts from NCERT Class 7 Science Chapter 6. This section reinforces vocabulary related to respiration, organ names, chemical equations, and organism-specific adaptations. Students must write the exact term that completes each sentence meaningfully. Spelling accuracy is important. These questions assess memory and understanding of definitions and processes. Encourage students to read the entire sentence first to understand context before filling the blank.

Section C: True or False (1 mark each)

True/False questions sharpen critical thinking by asking students to evaluate statements about respiration. Each statement must be marked as True or False. Students should base their answers strictly on NCERT Class 7 Science content. If a statement is false, it can be helpful (though not mandatory here) for students to mentally correct it, reinforcing accurate understanding. This section covers common misconceptions such as confusing breathing with respiration or believing plants do not respire at night.

Section D: Short Answer Questions (2-3 marks each)

Short-answer questions demand concise, accurate explanations in 30-50 words. Students should define terms, differentiate concepts, or describe processes clearly. These questions test comprehension and the ability to express scientific ideas in simple language. Marks are awarded for correctness, clarity, and completeness. Students should avoid unnecessary details but include key points. For example, when differentiating aerobic and anaerobic respiration, mention presence/absence of oxygen, energy yield, and by-products. Use diagrams or labelled sketches where asked; neat presentation matters. This section builds writing skills essential for CBSE board exams in higher classes.

Section E: Long Answer and HOTS Questions (5 marks each)

Long-answer questions require detailed explanations, often with diagrams, examples, or step-by-step reasoning. Each answer should be around 80-120 words and structured into clear points or short paragraphs. Higher-Order Thinking Skills (HOTS) questions test application, analysis, and evaluation. For instance, explaining the mechanism of breathing in humans involves describing diaphragm and rib movement, pressure changes, and air flow. HOTS questions may ask students to predict outcomes (e.g., what happens if stomata are blocked?) or compare adaptations. These questions prepare students for case-based and application-oriented questions in CBSE exams. Encourage the use of scientific terminology from NCERT Class 7 Science and logical sequencing of ideas.

Section F: Case-Study Based Question (4 marks)

Case-study questions present a real-life or experimental scenario followed by 3-4 sub-questions. This format, increasingly common in CBSE exams, assesses comprehension, data interpretation, and application skills. Students must read the passage carefully, extract relevant information, and answer each sub-question precisely. Marks are distributed across sub-parts. Case studies in Chapter 6 may describe experiments (like showing CO₂ release in germinating seeds), observations in nature (respiration in different habitats), or everyday phenomena (yeast fermentation in baking). Such questions bridge theory and practical application, helping students see science in context.

Complete Answer Key with Explanations

The answer key below provides correct answers and brief explanations for every question in this worksheet. Students should attempt all questions independently before checking answers. For MCQs and objective questions, compare your response with the key. For descriptive answers, check if you have covered the main points listed. Use the explanations to understand mistakes and clarify doubts. Parents and teachers can use this key for quick evaluation. If a student consistently struggles with a particular question type, revisit the NCERT Class 7 Science textbook Chapter 6 or refer to NCERT solutions for detailed explanations. For personalised doubt-clearing and step-by-step help, platforms like CBSETUTOR.ai offer 24×7 AI tutoring where students can upload photos of questions and receive instant, curriculum-aligned guidance at just ₹999/month for all classes 6-12, with a 3-day free trial.

Section A answers: Correct option with reasoning
Section B answers: Exact term expected, with context
Section C answers: True/False with brief justification
Section D answers: Key points for 2-3 mark allocation
Section E answers: Detailed points and diagrams where needed
Case-study answers: Direct responses linked to the scenario

How to Use This Worksheet Effectively for Class 7 Science Revision

To maximise learning, students should first revise NCERT Class 7 Science Chapter 6 Respiration in Organisms from the textbook, reading definitions, diagrams, and activity descriptions carefully. Next, attempt this worksheet in one sitting under timed conditions without referring to notes. Write answers neatly in a notebook or on blank sheets. After completion, check answers using the answer key and mark each response honestly. Identify weak areas — for example, if most errors are in anaerobic respiration or breathing mechanism, revisit those sections in the NCERT book. Reattempt incorrect questions after understanding the concepts. Parents can support by timing the session and discussing answers. Teachers can modify the worksheet by adding or removing questions to suit classroom needs. Regular practice with such worksheets builds confidence, improves recall, and trains students to manage time during exams. For topics that remain unclear even after self-study, consider using digital learning aids or tutor support.

Revise NCERT Chapter 6 thoroughly before attempting the worksheet
Attempt all sections in one sitting, timing yourself (60-70 minutes)
Write answers in complete sentences for short and long questions
Self-assess using the answer key; note topics with repeated mistakes
Reattempt wrong questions after understanding concepts
Discuss challenging HOTS or case-study questions with teachers or peers
Use this worksheet weekly during exam preparation for best results

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Even with the best worksheets, students sometimes need personalised help to clarify doubts instantly. CBSETUTOR.ai offers an AI-powered tutor available 24×7 that understands the CBSE curriculum inside-out. Students can snap a photo of any question from their NCERT Class 7 Science textbook, worksheet, or exam paper and upload it to the platform. Within seconds, the AI provides step-by-step solutions, explanations, and tips tailored to CBSE marking schemes. Whether the doubt is about the difference between aerobic and anaerobic respiration, labelling a diagram of the human respiratory system, or solving a tricky case-study question, CBSETUTOR.ai delivers clear, syllabus-aligned answers in Indian English. The platform covers all classes from 6 to 12 at a flat ₹999 per month — one price regardless of class or number of subjects. Parents appreciate the transparency and affordability compared to expensive coaching centres. A 3-day free trial lets families test the service risk-free. For Class 7 students juggling Science, Maths, Social Science, and languages, having an always-available AI tutor removes the anxiety of waiting for the next tuition class and empowers independent learning.

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Frequently asked questions

What is the difference between breathing and respiration in Class 7 Science Chapter 6?+

Breathing is the physical process of inhaling oxygen-rich air and exhaling carbon dioxide through lungs or other respiratory organs. Respiration is the biochemical process inside cells where glucose breaks down to release energy. Breathing supplies oxygen needed for cellular respiration.

Why do we get muscle cramps after heavy exercise, according to NCERT Class 7 Science?+

During intense exercise, muscles do not receive enough oxygen for aerobic respiration. They switch to anaerobic respiration, which produces lactic acid as a by-product. Accumulation of lactic acid in muscle tissues causes cramps and temporary pain until oxygen supply is restored.

How do plants respire if they do not have lungs, as taught in Class 7 Science?+

Plants respire through tiny pores called stomata on leaves and lenticels on stems. Oxygen enters and carbon dioxide exits through these openings. Each plant cell carries out cellular respiration continuously, breaking down glucose to release energy required for growth and other life processes.

What are spiracles and tracheae in insects, mentioned in Respiration in Organisms chapter?+

Spiracles are small openings on the body surface of insects. They lead to a network of fine tubes called tracheae that carry air directly to body cells. This system allows insects to exchange gases without lungs or a circulatory system transporting oxygen.

Is this worksheet enough for scoring full marks in CBSE Class 7 Science Chapter 6 exam?+

This worksheet covers all key concepts and question types from Respiration in Organisms. However, students should also solve NCERT in-text and end-of-chapter questions, review diagrams, and practise additional worksheets. Regular revision and understanding concepts (not rote learning) ensure full marks in exams.

How much time should a Class 7 student take to complete this Respiration worksheet?+

The suggested time is 60-70 minutes under exam conditions. Students should allocate roughly 12 minutes for MCQs, 8 for fill-in-the-blanks, 6 for true/false, 20 for short answers, 18 for long answers, and 6 for the case study. Practising within time limits builds speed and confidence.

Can I download and print this CBSE Class 7 Science Chapter 6 worksheet?+

Yes, this worksheet is designed to be printer-friendly. Copy the questions into a document, format for A4 size, and print. Students should write answers in a separate notebook. Teachers can photocopy and distribute in class; parents can print for weekend practice at home.

What is anaerobic respiration in yeast, and why is it important?+

Anaerobic respiration in yeast breaks down glucose without oxygen, producing ethanol and carbon dioxide as by-products. This process, called fermentation, is used commercially in baking (CO₂ makes bread rise) and brewing (ethanol in alcoholic beverages). It releases less energy compared to aerobic respiration.

Where can I find detailed solutions and extra practice for Class 7 Science Chapter 6?+

Refer to NCERT solutions books, CBSE sample papers, and online platforms like CBSETUTOR.ai. CBSETUTOR.ai offers instant, photo-based doubt solving and unlimited practice questions for ₹999/month across all classes 6-12, with a 3-day free trial to start learning immediately.

Do plants respire at night when photosynthesis stops, as asked in Class 7 Science?+

Yes, plants respire continuously both day and night. Photosynthesis (which produces oxygen) occurs only in light, but respiration (which consumes oxygen and releases energy) happens 24×7 in all living plant cells to support growth, repair, and metabolic activities.

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