India's #1 AI Tutorformula-sheet · Science · Chapter 5
Class 10 Science Chapter 5 Life Processes — Formulas & Key Points
Life Processes is a concept-heavy chapter in CBSE Class 10 Science, blending biology definitions, chemical equations for nutrition and respiration, and physiological mechanisms in plants and animals. While it contains fewer numerical formulas than Physics chapters, mastering the photosynthesis equation, respiration pathways, and the interplay of organ systems is essential for 3-5 mark answers in the board exam. This formula sheet consolidates every key equation, process summary, and memory aid you need for efficient NCERT Class 10 Science Chapter 5 revision.
Your child's private AI tutor — trained on NCERT.
3-day free trial · ₹1 to start · Cancel anytime.
Key takeaways
- ✓Photosynthesis converts light energy into chemical energy following the equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in the presence of sunlight and chlorophyll).
- ✓Aerobic respiration yields 38 ATP molecules per glucose molecule, while anaerobic respiration in muscles produces only 2 ATP plus lactic acid.
- ✓Transpiration rate is governed by stomatal opening, temperature, humidity and wind speed — remembering 'STHW' helps recall all four factors.
- ✓The double circulation system in humans ensures oxygenated and deoxygenated blood remain separate, maximising oxygen delivery efficiency.
- ✓Nephrons are the functional units of kidneys; each human kidney contains roughly 1 million nephrons filtering about 180 litres of blood daily.
- ✓Common mistakes include confusing the site of photosynthesis (chloroplast) with respiration (mitochondria) and mixing units (rate of breathing vs. rate of heartbeat).
- ✓CBSETUTOR.ai offers 24×7 doubt-solving with photo-upload for Life Processes numericals and diagram labelling at ₹999/month across Classes 6–12, with a 3-day free trial.
All Formulas and Equations — Nutrition and Respiration
Nutrition and respiration involve specific biochemical transformations. The table below lists the core equations tested in CBSE Class 10 Science Chapter 5. Each equation must be written exactly as shown, with correct subscripts and product states. Photosynthesis occurs in chloroplasts during daylight, while respiration happens continuously in mitochondria. Autotrophic nutrition (plants, some bacteria) synthesises food; heterotrophic nutrition (animals, fungi) ingests pre-formed organic matter. Aerobic respiration requires oxygen and releases maximum energy; anaerobic pathways operate without oxygen but yield far less ATP. Remembering the stoichiometry and conditions for each equation prevents common board-exam errors.
- Always write 'sunlight' and 'chlorophyll' above the arrow in the photosynthesis equation.
- In aerobic respiration, note that 38 ATP is the net theoretical yield; practical yield is ~30–32 ATP.
- Anaerobic respiration in yeast produces ethanol + CO₂, while in muscle cells it produces lactic acid.
- State symbols (g, l, aq) are not required in CBSE board answers unless the question specifically asks.
Key Definitions and Terminologies
CBSE examiners award marks for precise definitions. Use the exact NCERT wording wherever possible. Life processes are the fundamental maintenance functions that keep an organism alive: nutrition, respiration, transportation, excretion. Nutrition is the process of intake and utilisation of food. Autotrophic organisms synthesise organic molecules from inorganic raw materials (CO₂, H₂O) using sunlight or chemical energy; heterotrophic organisms obtain organic food from other organisms. Respiration is the biochemical process of breaking down food to release energy in the form of ATP. Transportation is the movement of water, nutrients, gases and wastes within the organism. Excretion is the removal of metabolic waste products. Understanding these definitions anchors every diagram-based and short-answer question in NCERT Class 10 Science Chapter 5.
- Life Processes — nutrition, respiration, transportation, excretion (essential for survival).
- Autotrophic Nutrition — self-synthesis of food using light (photosynthesis) or chemicals (chemosynthesis).
- Heterotrophic Nutrition — intake of complex organic food; subtypes include holozoic, saprophytic, parasitic.
- Aerobic Respiration — breakdown of glucose in the presence of oxygen; yields CO₂, H₂O and 38 ATP.
- Anaerobic Respiration — breakdown of glucose without oxygen; yields lactic acid or ethanol + CO₂ and only 2 ATP.
- Transpiration — loss of water vapour from aerial plant parts, mainly through stomata.
- Excretion — removal of nitrogenous wastes (ammonia, urea, uric acid) and excess salts.
Important Constants, Values and Standard Data
Although Life Processes is not numerically intensive, several physiological constants appear in comparative questions and fill-in-the-blank items on CBSE Class 10 Science papers. For instance, the normal human breathing rate is 15–18 breaths per minute, whereas the heartbeat rate is 72–80 beats per minute. Each nephron in the kidney can filter roughly 125 ml of blood per minute (glomerular filtration rate per nephron is much smaller, but total kidney GFR is ~125 ml/min). Blood pH in humans is tightly maintained near 7.4. Haemoglobin concentration in adults is about 12–16 g/dL. Knowing these benchmarks helps you eliminate wrong options in MCQs and adds precision to descriptive answers.
- Normal human breathing rate: 15–18 breaths/minute at rest.
- Normal human heartbeat: 72–80 beats/minute at rest.
- Total nephrons per human kidney: ~1 million.
- Glomerular filtration rate (both kidneys): ~125 ml/min or ~180 litres/day.
- Blood pH: ~7.35–7.45 (slightly alkaline).
- Haemoglobin in blood: 12–16 g/dL (varies by age and sex).
- Stomatal density: typically 100–300 stomata per mm² on lower leaf surface (species-dependent).
Memory Tricks and Mnemonics
Life Processes involves multiple organ systems and cycles that are easy to mix up under exam pressure. Use 'ANTRE' to remember the five life processes: Assimilation (part of nutrition), Nutrition, Transportation, Respiration, Excretion. For the path of air in humans, 'NLTBAA' stands for Nostrils → Larynx → Trachea → Bronchi → Bronchioles → Alveoli. To recall the four chambers of the heart in order, 'RAVA' works: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle (though anatomically left comes after right). For factors affecting transpiration, 'STHW' captures Stomatal opening, Temperature, Humidity, Wind speed. These mnemonics save precious seconds during board exams and reduce silly recall errors in 1-mark and 2-mark questions.
- 'ANTRE' — Assimilation, Nutrition, Transportation, Respiration, Excretion.
- 'NLTBAA' — pathway of air: Nostrils, Larynx, Trachea, Bronchi, Bronchioles, Alveoli.
- 'STHW' — factors affecting transpiration: Stomata, Temperature, Humidity, Wind.
- '3 R's of Kidney' — Filtration (Renal corpuscle), Reabsorption (tubules), Release (urine).
- 'Left is Right, Right is Left' — in heart diagrams viewed from the front, the right side appears on your left.
- 'Photo = Light, Synthesis = Make' — photosynthesis literally means 'making with light'.
Common Mistakes — Units, Signs and Notations
Students often lose marks on careless errors in CBSE Class 10 Science Chapter 5 answers. The most frequent mistake is writing 'CO₂' as 'Co2' or 'co2' — chemical formulae require capital 'C' and subscript '2'. Similarly, write 'O₂' not '02'. When labelling diagrams, use the exact NCERT term: 'stomata' is plural, 'stoma' is singular; writing 'stomatas' is incorrect. Mixing up the site of processes costs marks: photosynthesis occurs in chloroplasts, respiration in mitochondria — never reverse these. In transportation, remember arteries carry blood away from the heart (Arteries = Away), veins bring it back; pulmonary artery carries deoxygenated blood (exception to the rule). ATP stands for Adenosine Triphosphate, not 'adenosine tri-phosphate'. Finally, do not confuse breathing (physical intake of air) with respiration (biochemical oxidation of glucose).
- Always use correct subscripts: CO₂, O₂, H₂O, C₆H₁₂O₆ — not Co2, o2, H2o.
- Write 'chlorophyll' not 'chlorophyl'; 'mitochondria' (plural) vs. 'mitochondrion' (singular).
- Distinguish breathing (mechanical) from respiration (biochemical energy release).
- Arteries carry blood away from heart; veins bring blood to heart (Artery = Away mnemonic).
- Pulmonary artery is the only artery carrying deoxygenated blood; pulmonary vein carries oxygenated blood.
- Nephron, not 'nefron'; urea, not 'ureya'.
- Transpiration is water vapour loss, not 'water loss' (liquid water loss is guttation).
Process Summaries — Quick Reference Tables
Beyond equations, Life Processes requires you to describe multi-step physiological sequences. The tables below condense nutrition in humans, gas exchange in alveoli, and urine formation into point-by-point summaries that match NCERT flow. Each row captures one step with its location and key outcome. During revision, convert these tables into blank templates and fill them in as active recall practice. This method is proven to boost retention far more than passive reading of Class 10 Science notes. Use these summaries to structure 3-mark and 5-mark answers, ensuring you cover every stage the examiner expects.
Diagram Labelling Checklist
CBSE Class 10 Science Chapter 5 traditionally carries 3–5 marks for diagram-based questions. You must be able to draw and label: (i) structure of a stomatal apparatus (guard cells, stoma, chloroplasts), (ii) longitudinal section of a human heart showing all four chambers and major vessels, (iii) excretory system (kidneys, ureters, bladder, urethra), (iv) nephron with glomerulus, Bowman's capsule, tubules and collecting duct, and (v) a simple representation of alveoli with capillary network. Use a sharp pencil, draw neat outlines, and label with straight horizontal lines ending in arrowheads. Write labels in printed capital letters to avoid handwriting ambiguity. Practice each diagram at least five times before the board exam to build muscle memory and speed.
- Stomatal apparatus — label guard cells, stoma, subsidiary cells (if present), chloroplasts in guard cells.
- Human heart — right atrium, right ventricle, left atrium, left ventricle, aorta, pulmonary artery, pulmonary vein, vena cava, septum.
- Excretory system — kidneys (pair), ureters, urinary bladder, urethra.
- Nephron — glomerulus, Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct.
- Alveolus and capillaries — show thin-walled alveolar sac surrounded by capillary network; indicate O₂ and CO₂ diffusion directions.
- Leaf cross-section (optional) — upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis with stomata, vascular bundle.
Worked Example 1 — Calculating Oxygen Released in Photosynthesis
A plant produces 18 g of glucose during photosynthesis on a sunny day. Calculate the volume of oxygen released at STP, given that the molar mass of glucose is 180 g/mol and one mole of any gas at STP occupies 22.4 litres. From the photosynthesis equation, 1 mole of glucose produces 6 moles of O₂. First, find moles of glucose: moles = mass ÷ molar mass = 18 g ÷ 180 g/mol = 0.1 mol. Therefore, moles of O₂ produced = 0.1 × 6 = 0.6 mol. Volume of O₂ at STP = 0.6 mol × 22.4 L/mol = 13.44 litres. This type of cross-chapter calculation (linking Life Processes with mole concept from Chemistry) occasionally appears in CBSE Class 10 Science integrative questions worth 2–3 marks.
Worked Example 2 — Comparing ATP Yield in Aerobic vs. Anaerobic Respiration
A student runs 400 m at high speed. Initially, aerobic respiration supplies energy, but after 30 seconds the oxygen supply to muscles becomes insufficient and anaerobic respiration begins. If 1 molecule of glucose yields 38 ATP aerobically and 2 ATP anaerobically, compare the energy efficiency. Energy efficiency is the ratio of ATP produced to glucose consumed. Aerobic: 38 ATP per glucose. Anaerobic: 2 ATP per glucose. Ratio = 38: 2 = 19: 1. This means aerobic respiration is 19 times more efficient than anaerobic. However, anaerobic respiration is faster, allowing short bursts of intense activity. The lactic acid produced during anaerobic respiration in muscles causes fatigue and must be cleared by oxygen after exercise (oxygen debt). This concept is tested in 2-mark 'explain why' questions on CBSE Class 10 Science papers.
Worked Example 3 — Calculating Filtration Load in Kidneys
If the glomerular filtration rate (GFR) in both kidneys is 125 ml per minute, calculate the total volume of blood filtered in 24 hours. Also, given that roughly 99% of the filtrate is reabsorbed, find the daily urine output. First, convert minutes to hours: 24 hours = 24 × 60 = 1440 minutes. Total filtrate = 125 ml/min × 1440 min = 180,000 ml = 180 litres. If 99% is reabsorbed, 1% forms urine: urine volume = 1% of 180 L = 1.8 L. Typical daily urine output is about 1.5–2 litres, so our answer is consistent. This calculation reinforces the efficiency of the nephron's reabsorption mechanism and is a common 3-mark numerical in CBSE Class 10 Science Chapter 5.
One-Glance Last-Minute Revision Box
Use this box for a final 5-minute review before entering the exam hall. It condenses the entire chapter into must-know points, equations and diagram labels. Read it aloud or copy it onto a flashcard. Cover the right column and test yourself on the left. This active recall drill, repeated three times the night before the CBSE Class 10 Science board exam, has helped thousands of students secure full marks in Life Processes. Pair this revision with CBSETUTOR.ai's chapter-wise mock tests and photo-upload doubt-clearing to plug any last gaps. Remember, the 2025 board paper typically allocates 8–10 marks to this chapter across MCQs, VSAQs, short answers and one diagram-based question.
How CBSETUTOR.ai Simplifies Life Processes Revision
Many students struggle to memorise the multiple cycles, organ systems and chemical equations in NCERT Class 10 Science Chapter 5. CBSETUTOR.ai provides a 24×7 AI tutor that answers diagram-labelling doubts, checks your handwritten equations via photo upload, and generates unlimited practice MCQs on nutrition, respiration, transportation and excretion. At a flat ₹999 per month for all subjects across Classes 6–12, it is far more affordable than enrolling in separate crash courses for Science. The platform's 3-day free trial lets you test chapter-wise mock tests and instant doubt resolution before committing. Parents in cities like Delhi, Mumbai and Bangalore report that their children save 2–3 hours per week by clearing conceptual doubts immediately instead of waiting for weekend tuition. Use CBSETUTOR.ai to convert passive note-reading into active problem-solving and diagram practice, the proven recipe for scoring 25+ out of 27 in the Biology section of the CBSE Class 10 Science board paper.
- Upload photos of labelled diagrams and get instant feedback on accuracy and neatness.
- Generate custom MCQ sets filtered by topic (e.g. only respiration or only excretion).
- Access worked solutions for all NCERT in-text and exercise questions with step-by-step explanations.
- Track your revision progress with chapter-wise performance analytics and weak-area alerts.
- Flat ₹999/month fee covers Class 10 Science plus Maths, Social Science and languages — one subscription for the entire board syllabus.
- 3-day free trial requires no credit card; start tonight and revise Life Processes end-to-end before your unit test.
Frequently asked questions
Is the photosynthesis equation enough, or must I memorise the light and dark reaction steps separately for CBSE Class 10?+
For CBSE Class 10 Science Chapter 5, the overall equation 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ is sufficient. Detailed light and dark reactions (Calvin cycle) are part of Class 11 Biology. Stick to NCERT; examiners will not ask beyond the prescribed syllabus in the board exam.
How many marks are typically allotted to Life Processes in the CBSE Class 10 Science board paper?+
Life Processes usually carries 8–10 marks: 2–3 marks in MCQs (Section A), 2–4 marks in short answer questions (Section B), and 3–5 marks for one long answer or diagram-based question (Section C). Weighting may vary slightly year to year, so practice all question types.
Do I need to draw diagrams to scale, or are rough labelled sketches acceptable?+
CBSE awards marks for correct labelling and proportional representation, not artistic perfection. Use a sharp pencil, draw clear outlines, label neatly with ruled lines, and ensure all parts mentioned in the question are shown. Avoid shading unless the question asks; it wastes time and can smudge.
What is the difference between breathing rate and heartbeat rate, and why does it matter?+
Breathing rate (~15–18 per minute) measures inhalation-exhalation cycles; heartbeat rate (~72–80 per minute) measures cardiac contractions. Mixing these in comparative answers loses marks. Remember that heart rate is roughly four to five times breathing rate at rest.
Why does anaerobic respiration in muscles produce lactic acid instead of ethanol like in yeast?+
The difference lies in the enzymes present. Human muscle cells lack alcohol dehydrogenase, so pyruvate is converted to lactic acid by lactate dehydrogenase. Yeast cells possess alcohol dehydrogenase, yielding ethanol and CO₂. This is a common 2-mark 'reason-based' question in CBSE exams.
Can transpiration occur at night, or only during the day?+
Transpiration is greatly reduced at night because stomata close in the absence of light (in most plants). However, a small amount of cuticular transpiration (through the waxy cuticle) continues. Exam answers should state that stomatal transpiration is the major component and is day-time dependent.
How should I remember the sequence of blood flow through the heart for diagram labelling?+
Use the mnemonic 'RAVA': Right Atrium (receives deoxygenated blood from vena cava) → Right Ventricle (pumps to lungs via pulmonary artery) → Left Atrium (receives oxygenated blood from pulmonary veins) → Left Ventricle (pumps to body via aorta). Label valves (tricuspid, bicuspid) only if asked.
Is it necessary to mention the role of villi in absorption every time I write about the small intestine?+
Yes, in 3-mark or 5-mark answers on human nutrition. State that villi (and microvilli) increase surface area for efficient absorption of digested nutrients into blood and lymph. Omitting this detail can cost you 1 mark. Keep the explanation to one sentence unless more detail is requested.
What are the most common errors students make in Life Processes numericals?+
Common mistakes include incorrect mole ratio (e.g. forgetting that 1 glucose produces 6 O₂), wrong unit conversion (litres to ml), and using 38 ATP for anaerobic respiration. Always write the balanced equation first, double-check stoichiometry, and box your final answer with correct units.
How does CBSETUTOR.ai help if I am weak in diagram drawing and labelling?+
CBSETUTOR.ai's photo-upload feature lets you snap your drawn diagram and receive instant feedback on missing labels, incorrect proportions, or wrong structures. The AI tutor suggests improvements and links you to annotated NCERT diagrams. Practising 5–6 diagrams with feedback typically raises accuracy to 95 percent within one week, crucial for securing full marks in diagram-based questions.
Related resources
Important Questions: CBSE Class 10 Science Chapter 5 Life ProcessesCBSE Class 10 Science Chapter 5 Life Processes Worksheet with AnswersCBSE Class 10 Science Chapter 4 Carbon and its Compounds Worksheet with AnswersImportant Questions: CBSE Class 10 Science Chapter 4 Carbon and its CompoundsAI Tutor for Class 10: The Smart Alternative to TuitionAI Tutor for Class 10 Maths: Learn Faster with Instant HelpOnline Class 9 Science Tutor in Mumbai – 24/7 CBSE-Aligned AI CoachingClass 9 Mathematics Chapter 2 Polynomials — Formulas & Key Points
Keep learning — related guides
Class 10Science
Class 10 Science Tuition Fees in Piplani Bhopal
Class 10Science
Class 10 Science Chapter 11 Electricity — Formulas & Key Points
Class 10Science
CBSE Class 10 Science Chapter 11 Electricity Worksheet with Answers
Class 10Science
Class 10 Science Chapter 13 Our Environment — Formulas & Key Points
Class 10Science
Class 10 Science Chapter 12 Magnetic Effects of Electric Current — Formulas & Key Points
Class 10Science
CBSE Class 10 Science Chapter 13 Our Environment Worksheet with Answers
Ready to give your Class 10 child the tutor that never sleeps?
CBSETUTOR.ai covers every chapter in the Class 10 NCERT syllabus — Maths, Science, Social Science, English, Hindi and more. 24×7. Patient. Unlimited. 3-day free trial.
Start your child's 3-day free trial →