Nutrition in Plants for Class 7: The Complete CBSE Guide (2026-27)

Nutrition in Plants Class 7 is Chapter 1 in the NCERT Science textbook for the 2026-27 academic session. The chapter defines nutrition as the process by which organisms obtain and utilize food for growth, energy, and repair. Plants, unlike animals, manufacture their own food through photosynthesis, classifying them as autotrophs. The NCERT framework divides the chapter into four core sections: Mode of Nutrition in Plants (autotrophic vs. heterotrophic), Photosynthesis (the food-making process), Other Modes of Nutrition (saprotrophs and parasites), and Symbiotic Relationships. The chapter typically spans 8-10 classroom periods and is assessed through 3-5 mark questions in term exams, including one mandatory diagram (usually a leaf cross-section or stomata). Understanding Nutrition in Plants Class 7 is essential because it introduces scientific vocabulary—chlorophyll, stomata, host, saprotroph—that recurs throughout secondary school biology.

Autotrophic nutrition is the hallmark of green plants, algae, and certain bacteria. The term 'autotroph' derives from Greek: auto (self) and trophe (nourishment). In Nutrition in Plants Class 7, students learn that autotrophs use simple inorganic substances—carbon dioxide from air and water from soil—to synthesize complex organic compounds (glucose) using sunlight as an energy source. This process, photosynthesis, occurs in chloroplasts, specialized organelles containing the green pigment chlorophyll. Chlorophyll absorbs light energy (primarily red and blue wavelengths) and reflects green, giving leaves their characteristic colour. The NCERT textbook emphasizes that photosynthesis is the primary source of food for nearly all life on Earth, as herbivores eat plants and carnivores eat herbivores. During CBSE exams, students are often asked to differentiate autotrophic from heterotrophic nutrition with two examples each.

Photosynthesis is represented by the chemical equation: 6CO₂ + 12H₂O + light energy → C₆H₁₂O₆ + 6O₂ + 6H₂O. This formula is critical for Nutrition in Plants Class 7 exams and must be memorized accurately. The equation shows that six molecules of carbon dioxide react with twelve molecules of water in the presence of light energy (and chlorophyll, which acts as a catalyst) to produce one molecule of glucose, six molecules of oxygen, and six molecules of water. The glucose (C₆H₁₂O₆) is a simple sugar that plants convert to starch for storage or sucrose for transport through phloem. Oxygen is released through stomata as a by-product, replenishing atmospheric oxygen that animals and humans breathe. Water appears on both sides: twelve molecules are consumed (split during the light reactions), and six are regenerated. CBSE examiners frequently ask students to balance this equation or identify the role of each component.

The NCERT Nutrition in Plants Class 7 chapter dedicates significant attention to leaf structure because leaves are the primary photosynthesis factories. A typical leaf has a broad, flat lamina (blade) to maximize sunlight capture, a midrib and veins containing xylem (water transport) and phloem (food transport), and two critical features: chlorophyll and stomata. Chlorophyll resides in chloroplasts within mesophyll cells, giving leaves their green colour and enabling light absorption. Stomata are tiny pores (usually on the lower epidermis) surrounded by two guard cells that regulate opening and closing. During the day, guard cells swell with water (become turgid), opening stomata to allow CO₂ entry and O₂ exit. At night, guard cells lose water (become flaccid), closing stomata to reduce water loss via transpiration. The NCERT textbook includes a diagram of stomatal structure, which is a favourite 3-mark question in CBSE exams—students must label guard cells, stomatal pore, and epidermal cells.

Heterotrophic nutrition is the mode of nutrition in which organisms cannot synthesize their own food and must obtain organic compounds from other organisms. The term 'heterotroph' combines hetero (other) and trophe (nourishment). In Nutrition in Plants Class 7, students learn three sub-types of heterotrophic nutrition relevant to plants and fungi: saprotrophic, parasitic, and symbiotic. Unlike autotrophs, heterotrophs lack chlorophyll (hence are non-green) and rely on external organic matter—either dead (saprotrophs), living (parasites), or mutual exchange (symbionts). Humans, animals, fungi, and even some non-green plants (like cuscuta) are heterotrophs. The NCERT textbook contrasts heterotrophic nutrition with autotrophic using a simple table that frequently appears in CBSE worksheets. Understanding heterotrophic modes is crucial because it explains decomposition (nutrient recycling), disease (parasitism), and beneficial partnerships (symbiosis) in ecosystems.

Saprotrophic (or saprophytic) nutrition is a mode of heterotrophic nutrition in which organisms feed on dead and decaying organic matter. The term 'saprotroph' derives from sapros (rotten) and trophe (nourishment). Common saprotrophs include fungi (mushrooms, bread mould, yeast), certain bacteria, and some protists. The NCERT Nutrition in Plants Class 7 chapter highlights mushrooms and bread mould (Rhizopus) as key examples. Saprotrophs secrete digestive enzymes onto dead material (leaves, wood, animal carcasses, food waste), breaking down complex organic molecules (proteins, cellulose, starch) into simpler compounds (amino acids, sugars) that they absorb. This external digestion is called extracellular digestion. By decomposing organic waste, saprotrophs recycle nutrients (carbon, nitrogen, phosphorus) back into the soil, making them available to plants—hence they are called 'nature's recyclers'. CBSE exams often ask students to explain the ecological role of saprotrophs or differentiate them from parasites.

Parasitic nutrition is a mode of heterotrophic nutrition in which an organism (the parasite) derives nutrition from a living organism (the host), usually harming the host in the process but not immediately killing it. In Nutrition in Plants Class 7, the NCERT textbook introduces cuscuta (Amarbel) as a classic parasitic plant and ticks/lice as animal parasites. Cuscuta is a leafless, yellow/orange vine lacking chlorophyll. It wraps around host plants (often shrubs or trees) and penetrates the host stem using specialized root-like structures called haustoria, which tap into the host's phloem to extract ready-made sugars and nutrients. The host plant experiences stunted growth and reduced yield. Other examples of parasitic plants include mistletoe (partial parasite, retains some chlorophyll) and Rafflesia (total parasite). Parasitic relationships are contrasted with saprotrophic (which use dead matter) and symbiotic (which benefit both organisms). CBSE questions often ask students to identify the parasite-host pair and explain the mechanism of nutrient extraction.

Symbiotic relationships (or symbiosis) are associations between two different organisms in which both partners benefit nutritionally. The term 'symbiosis' means 'living together'. In Nutrition in Plants Class 7, the NCERT textbook presents two key examples: lichens and the rhizobium-legume partnership. Lichens are composite organisms formed by a fungus and an alga living together. The alga (autotroph) performs photosynthesis, producing glucose that nourishes both itself and the fungus. The fungus provides shelter, moisture retention, and minerals absorbed from the substrate (rock or tree bark), benefiting the alga. Lichens grow in harsh environments (bare rocks, Arctic tundra) where neither organism could survive alone. The second example is the symbiotic relationship between rhizobium bacteria and leguminous plants (peas, beans, pulses). Rhizobium resides in root nodules of legumes, fixing atmospheric nitrogen (N₂) into ammonia (NH₃), which the plant uses to synthesize proteins. In return, the plant supplies the bacteria with carbohydrates from photosynthesis. This partnership enriches soil nitrogen, which is why farmers practice crop rotation with legumes.

While not a separate category in the NCERT Class 7 classification, insectivorous (carnivorous) plants are briefly mentioned as a special case of heterotrophic nutrition supplementing autotrophic nutrition. These plants grow in nitrogen-poor soils (bogs, marshes) and have evolved mechanisms to trap and digest insects to obtain nitrogen and other nutrients. The NCERT Nutrition in Plants Class 7 textbook specifically mentions the pitcher plant (Nepenthes). Pitcher plants have modified leaves forming a pitcher-shaped structure containing digestive enzymes. Insects attracted by nectar or colour fall into the pitcher, drown in the digestive fluid, and are broken down, releasing nitrogen compounds that the plant absorbs. Importantly, pitcher plants still perform photosynthesis (they are green and have chlorophyll), so they are not fully heterotrophic—they are autotrophs with a heterotrophic supplement. Other examples include the Venus flytrap and sundew, though these are not emphasized in the CBSE Class 7 syllabus.

The final section of Nutrition in Plants Class 7 addresses how soil nutrients—essential for plant growth—are replenished. Continuous cropping depletes soil nitrogen, phosphorus, and potassium (NPK). The NCERT textbook explains two natural replenishment mechanisms: decomposition by saprotrophs and biological nitrogen fixation by rhizobium. Saprotrophs (fungi and bacteria) break down dead plants, animals, and organic waste, releasing minerals back into soil. Rhizobium bacteria in legume nodules convert atmospheric nitrogen into ammonia, enriching the soil. Additionally, farmers add fertilizers (chemical sources of NPK) and manure (organic sources) to restore soil fertility. The chapter briefly mentions the importance of crop rotation and leaving fields fallow to allow nutrient recovery. Understanding nutrient cycles links Nutrition in Plants Class 7 to environmental science topics in higher classes (Classes 9-10 discuss biogeochemical cycles). CBSE exams may ask students to explain how saprotrophs and rhizobium contribute to soil fertility or why legumes are grown in rotation with cereals.

The NCERT Nutrition in Plants Class 7 chapter includes several hands-on experiments that reinforce theoretical concepts and are frequently referenced in CBSE practical exams or internal assessments. The starch test for photosynthesis is the most important: a potted plant is kept in darkness for 24-48 hours to destarch the leaves, then exposed to sunlight for 3-4 hours. A leaf is plucked, boiled in water (to kill cells and soften), then immersed in alcohol (to remove chlorophyll, turning the leaf white), and finally treated with iodine solution. Blue-black colour indicates starch presence, confirming photosynthesis. A variation involves partially covering a leaf with black paper, exposing only a portion to light—only the exposed area turns blue-black with iodine. The second experiment demonstrates stomatal structure: a thin peel from the lower leaf epidermis is mounted on a slide with a drop of water, covered with a coverslip, and observed under a microscope at 100x or 400x magnification. Students sketch stomata, labeling guard cells and the stomatal pore. The third experiment involves observing bread mould growth: a slice of bread is sprinkled with water, placed in a closed container, and left for 2-3 days in a warm place. Students observe fuzzy fungal growth and identify it as a saprotroph.

Nutrition in Plants Class 7 introduces scientific vocabulary, chemical equations, and diagram-based questions that many students find challenging, especially when preparing for term exams or competitive exams like NTSE and Olympiads. Parents looking for structured, 24×7 support turn to CBSETUTOR.ai—a specialized AI tutor that has ingested every NCERT textbook for Classes 6-12, including the complete Nutrition in Plants chapter with all diagrams, experiments, and NCERT in-text and end-of-chapter questions. Students can upload a photo of any worksheet question (e.g. 'Draw and label stomatal structure' or 'Differentiate autotrophic and heterotrophic nutrition'), and CBSETUTOR.ai provides step-by-step solutions using NCERT-aligned terminology. The platform explains the photosynthesis equation in simple language, offers mnemonic devices for remembering the differences between saprotrophs and parasites, and generates custom practice questions with varying difficulty levels. Unlike generic tutoring, CBSETUTOR.ai is tailored to the CBSE curriculum, ensuring that explanations match the exact definitions and examples students encounter in their textbooks and exams. Parents across India—from Bengaluru to Patna—use CBSETUTOR.ai at a flat rate of ₹999 per month (covering all subjects, Classes 6-12), with a 3-day free trial requiring no card details. It is particularly effective for Science chapters like Nutrition in Plants, where visual understanding (leaf structure, stomatal diagrams, lichen partnerships) and concept clarity (modes of nutrition) determine exam performance.

CBSE Class 7 Science exams allocate 3-5 marks to Nutrition in Plants, typically structured as one 3-mark diagram question and 1-2 short-answer questions (2 marks each). Common 3-mark questions include: 'Draw a labeled diagram of stomatal structure' (labels: guard cells, stomatal pore, epidermal cells); 'Explain the process of photosynthesis with a chemical equation' (balanced equation + brief description of role of chlorophyll and sunlight); 'Differentiate between saprotrophic and parasitic nutrition with examples'. Two-mark questions often ask definitions ('What is autotrophic nutrition?') or examples ('Name two saprotrophs and two parasites'). Diagram questions carry 1 mark for neatness, 1 mark for correct labels, and 1 mark for appropriate title. Students should practice drawing from the NCERT textbook: leaf cross-section showing chloroplasts, stomatal structure (guard cells and pore), lichen (showing algal and fungal components), and cuscuta on a host plant. One-mark MCQs or fill-in-the-blanks test vocabulary: chlorophyll, stomata, haustoria, symbiosis, rhizobium. A strategic approach is to memorize the photosynthesis equation verbatim, prepare a table comparing autotrophic and heterotrophic nutrition, and list 2-3 NCERT examples for each nutrition type. Time management is critical—allocate 5-6 minutes for a 3-mark question, ensuring legible handwriting and clear labeling in diagrams.