Plant Nutrition
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📘 Study MCQs
Q1. The components of food that are essential for an organism (Plant or animal) are called: NCERT
• Nutrients
• Vitamins only
• Minerals only
• Roughage
Answer: Nutrients
Nutrients are the components in food such as carbohydrates, proteins, fats, vitamins, and minerals that living organisms need to survive and grow .
Q2. The mode of nutrition in which organisms make their own food is called: NCERT
• Heterotrophic nutrition
• Autotrophic nutrition
• Parasitic nutrition
• Saprotrophic nutrition
Answer: Autotrophic nutrition
Autotrophic nutrition (auto = self, trophos = nourishment) is the mode where organisms like green plants synthesize their own food from simple inorganic substances .
Q3. Organisms that depend on other organisms for food are called: NCERT
• Autotrophs
• Producers
• Heterotrophs
• Parasites
Answer: Heterotrophs
Heterotrophs (heteros = other) are organisms that cannot produce their own food and obtain readymade food from plants or animals .
Q4. Plants are called autotrophs because they: Science
• Grow very fast
• Have green leaves
• Can produce their own food
• Absorb minerals from soil
Answer: Can produce their own food
Plants are autotrophs because they have the unique ability to synthesize their own food using sunlight, carbon dioxide, and water through photosynthesis .
Q5. The process by which plants make their food is called: NCERT
• Respiration
• Transpiration
• Photosynthesis
• Digestion
Answer: Photosynthesis
Photosynthesis (photo = light, synthesis = to combine) is the process where plants use sunlight energy to produce food from carbon dioxide and water .
Q6. The green pigment present in leaves is called: NCERT
• Haemoglobin
• Chlorophyll
• Carotene
• Xanthophyll
Answer: Chlorophyll
Chlorophyll is the green pigment found in chloroplasts that helps leaves capture energy from sunlight for photosynthesis .
Q7. The tiny pores on the surface of leaves are called: NCERT
• Lenticels
• Cuticle
• Stomata
• Veins
Answer: Stomata
Stomata (singular: stoma) are tiny pores present on the leaf surface that allow exchange of gases like carbon dioxide and oxygen .
Q8. The cells that surround stomata and regulate their opening are called: NCERT
• Epidermal cells
• Palisade cells
• Guard cells
• Root hair cells
Answer: Guard cells
Guard cells are kidney-shaped cells surrounding each stoma that control its opening and closing through changes in their shape .
Q9. The ultimate source of energy for all living organisms is the: Science
• Moon
• Sun
• Soil
• Air
Answer: Sun
The sun provides the solar energy that plants capture during photosynthesis. All living organisms ultimately depend on this energy for survival .
Q10. Plants absorb water and minerals from the soil through their: NCERT
• Leaves
• Stems
• Flowers
• Roots
Answer: Roots
Roots absorb water and dissolved minerals from the soil. These are then transported to other plant parts through vessels .
Q11. During photosynthesis, plants take in carbon dioxide and release: NCERT
• Nitrogen
• Oxygen
• Hydrogen
• Carbon monoxide
Answer: Oxygen
Oxygen is the byproduct of photosynthesis. Plants release oxygen into the atmosphere, which is used by animals for respiration .
Q12. Photosynthesis takes place in which part of the plant? NCERT
• Roots only
• Flowers only
• Green parts (mostly leaves)
• Fruits only
Answer: Green parts (mostly leaves)
Photosynthesis occurs in green parts of plants, especially leaves, because they contain chlorophyll. Green stems and branches also perform photosynthesis .
Q13. The food synthesized by plants during photosynthesis is primarily: Science
• Protein
• Fat
• Carbohydrates (glucose)
• Vitamin
Answer: Carbohydrates (glucose)
Plants produce carbohydrates (glucose) during photosynthesis. This glucose is later converted into starch for storage .
Q14. Guard cells contain chlorophyll to: Science
• Give color to the leaf
• Perform photosynthesis
• Protect the leaf
• Absorb water
Answer: Perform photosynthesis
Unlike other epidermal cells, guard cells contain chloroplasts with chlorophyll, allowing them to perform photosynthesis and produce energy for opening/closing stomata .
Q15. Which gas is absorbed from the atmosphere by plants through stomata for photosynthesis? NCERT
• Oxygen
• Nitrogen
• Carbon dioxide
• Hydrogen
Answer: Carbon dioxide
Plants absorb carbon dioxide from the air through stomata. This carbon dioxide is essential for synthesizing food during photosynthesis .
Q16. The mode of nutrition in which organisms obtain food from dead and decaying matter is called: NCERT
• Parasitic nutrition
• Saprotrophic nutrition
• Symbiotic nutrition
• Autotrophic nutrition
Answer: Saprotrophic nutrition
Saprotrophic nutrition involves taking nutrients in solution form from dead and decaying organic matter. Fungi and some bacteria follow this mode .
Q17. Fungi like mushrooms are examples of: NCERT
• Autotrophs
• Parasites
• Saprotrophs
• Producers
Answer: Saprotrophs
Mushrooms are saprotrophs. They secrete digestive juices on dead matter and absorb nutrients from it .
Q18. The relationship where two organisms live together and share nutrients is called: NCERT
• Parasitism
• Saprotrophism
• Predation
• Symbiosis
Answer: Symbiosis
Symbiosis is a mutually beneficial association where two organisms live together and share shelter and nutrients, like lichen and mycorrhiza .
Q19. The bacteria that can convert atmospheric nitrogen into soluble form and live in roots of legumes is: NCERT
• Rhizobium
• Nitrobacter
• Azotobacter
• E. coli
Answer: Rhizobium
Rhizobium bacteria live in roots of leguminous plants and convert atmospheric nitrogen into usable form. The plant provides shelter to the bacteria .
Q20. Cuscuta (dodder) is an example of a: NCERT
• Autotroph
• Saprotroph
• Parasite
• Producer
Answer: Parasite
Cuscuta is a parasitic plant. It lacks chlorophyll and derives its nutrition by growing on and taking food from a host plant .
Q21. Insectivorous plants like pitcher plant trap insects because they grow in soil deficient in: Science
• Water
• Sunlight
• Nitrogen
• Carbon dioxide
Answer: Nitrogen
Insectivorous plants grow in nitrogen-deficient soil. They trap and digest insects to obtain nitrogen for their protein requirements .
Q22. Plants which lack chlorophyll cannot perform: Science
• Respiration
• Transpiration
• Photosynthesis
• Reproduction
Answer: Photosynthesis
Chlorophyll is essential for capturing light energy. Plants without chlorophyll cannot carry out photosynthesis and depend on other modes of nutrition .
Q23. The food synthesized by plants is stored as: Science
• Glucose
• Starch
• Fructose
• Sucrose
Answer: Starch
The glucose produced during photosynthesis is converted into starch and stored in various plant parts like leaves, roots, stems, and seeds .
Q24. During photosynthesis, light energy is converted into: Science
• Kinetic energy
• Heat energy
• Chemical energy
• Electrical energy
Answer: Chemical energy
Plants convert solar energy (light energy) into chemical energy stored in the bonds of glucose molecules .
Q25. The opening and closing of stomata is regulated by: NCERT
• Temperature
• Water availability
• Guard cells
• Wind speed
Answer: Guard cells
Guard cells control stomatal opening by absorbing or losing water through osmosis, causing them to swell or shrink .
Q26. Plants get carbon dioxide for photosynthesis from the: NCERT
• Soil
• Water
• Air
• Fertilizers
Answer: Air
Carbon dioxide is present in the air (about 0.03-0.04%). Plants absorb it through their stomata directly from the atmosphere .
Q27. The network of pipes that transport water and minerals to leaves are called: NCERT
• Nerves
• Veins
• Vessels
• Pores
Answer: Vessels
Vessels run like pipes throughout the root, stem, branches, and leaves, forming a continuous path for water and minerals to flow to the leaf .
Q28. Leaves are called the food factories of plants because they: Science
• Store maximum food
• Look green
• Manufacture food through photosynthesis
• Are flat and broad
Answer: Manufacture food through photosynthesis
Leaves contain chlorophyll and all necessary structures to carry out photosynthesis, producing food for the entire plant .
Q29. What would happen if a plant’s leaves are coated with oil on both surfaces? Science
• It will grow faster
• Photosynthesis will stop
• It will produce more flowers
• It will absorb more water
Answer: Photosynthesis will stop
Coating leaves with oil blocks stomata, preventing carbon dioxide from entering the leaf. Without carbon dioxide, photosynthesis cannot occur.
Q30. The broad and flat part of the leaf that absorbs sunlight is called the: NCERT
• Petiole
• Lamina (leaf blade)
• Midrib
• Veins
Answer: Lamina (leaf blade)
The lamina or leaf blade is broad and flat, providing a large surface area to absorb maximum sunlight for photosynthesis .
Q31. Heterotrophic nutrition is found in: NCERT
• Green plants only
• Animals and non-green plants
• Only animals
• Algae only
Answer: Animals and non-green plants
Animals, fungi, and non-green plants lack chlorophyll and cannot produce their own food, so they follow heterotrophic nutrition .
Q32. The raw materials for photosynthesis are: NCERT
• Oxygen and glucose
• Carbon dioxide, water, sunlight, and chlorophyll
• Proteins and fats
• Nitrogen and minerals
Answer: Carbon dioxide, water, sunlight, and chlorophyll
These four elements are essential. Carbon dioxide and water are the raw materials, while sunlight provides energy and chlorophyll traps it .
Q33. Plants that feed on insects are called: Science
• Parasitic plants
• Saprotrophic plants
• Insectivorous plants
• Symbiotic plants
Answer: Insectivorous plants
Insectivorous plants like pitcher plant and Venus flytrap trap and digest insects to obtain nitrogen, though they can also perform photosynthesis .
Q34. In the photosynthesis equation, the reactants are carbon dioxide and water, and the products are: Science
• Glucose and oxygen
• Starch and carbon dioxide
• Protein and water
• Fats and minerals
Answer: Glucose and oxygen
The balanced equation for photosynthesis is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (with sunlight and chlorophyll) .
Q35. If a plant is kept in a dark room for several days, it will eventually die because: Science
• It cannot absorb water
• It cannot perform photosynthesis without light
• The roots stop growing
• It loses too much water
Answer: It cannot perform photosynthesis without light
Light is essential for photosynthesis. Without light, plants cannot produce food and will eventually starve and die.
Q36. The process of photosynthesis occurs mainly in which layer of the leaf? Science
• Upper epidermis
• Lower epidermis
• Mesophyll
• Cuticle
Answer: Mesophyll
The mesophyll is the middle layer of leaf tissue containing chloroplast-rich cells where most photosynthesis takes place .
Q37. Why do plants in deserts often have green stems? Science
• To store more water
• To attract insects
• To perform photosynthesis in place of leaves
• To protect from animals
Answer: To perform photosynthesis in place of leaves
Desert plants have reduced or spine-like leaves to minimize water loss. Their green stems contain chlorophyll and carry out photosynthesis .
Q38. The process of taking in food and utilizing it is called: NCERT
• Digestion
• Nutrition
• Excretion
• Respiration
Answer: Nutrition
Nutrition is the complete process of obtaining food and utilizing it for growth, repair, and energy requirements .
Q39. Guard cells swell to open stomata when they: Science
• Lose water
• Absorb water and become turgid
• Stop photosynthesis
• Divide rapidly
Answer: Absorb water and become turgid
Guard cells absorb water by osmosis, becoming turgid. This causes them to curve apart, opening the stoma for gas exchange .
Q40. Lichen is an example of which relationship? NCERT
• Parasitic
• Saprotrophic
• Symbiotic
• Insectivorous
Answer: Symbiotic
Lichen consists of an alga and a fungus living together. The alga produces food, while the fungus provides shelter and absorbs water .
Q41. Nitrogen is essential for plants to synthesize: Science
• Carbohydrates
• Fats
• Proteins
• Starch
Answer: Proteins
Nitrogen is a major component of amino acids, which are the building blocks of proteins. It is also needed for nucleic acids and chlorophyll .
Q42. Which part of the plant is not directly involved in photosynthesis? NCERT
• Leaf
• Green stem
• Root
• Sepals (if green)
Answer: Root
Roots lack chlorophyll and are underground, so they cannot perform photosynthesis. Their function is absorption and anchorage .
Q43. The process by which plants lose water vapor through stomata is called: Science
• Photosynthesis
• Transpiration
• Respiration
• Guttation
Answer: Transpiration
Transpiration is the loss of water vapor from plant leaves through stomata. It helps in cooling and creating suction for water absorption .
Q44. The midrib and veins in a leaf help in: NCERT
• Making food
• Transporting substances and providing strength
• Opening stomata
• Absorbing light
Answer: Transporting substances and providing strength
The midrib and veins contain vascular tissues (xylem and phloem) that transport water, minerals, and food. They also provide structural support .
Q45. In the absence of carbon dioxide, photosynthesis: Science
• Increases
• Continues normally
• Stops completely
• Produces more oxygen
Answer: Stops completely
Carbon dioxide is one of the essential raw materials for photosynthesis. Without it, the process cannot occur at all.
Q46. A plant appears green because chlorophyll: Science
• Absorbs green light
• Reflects green light
• Produces green pigment
• Converts light into green color
Answer: Reflects green light
Chlorophyll absorbs red and blue light most efficiently but reflects green light, which is why plants appear green to our eyes.
Q47. Farmers add fertilizers to soil to provide: Science
• More water
• Nitrogen and other nutrients
• More air
• More space for roots
Answer: Nitrogen and other nutrients
Fertilizers replenish nutrients in the soil, especially nitrogen, phosphorus, and potassium, which are essential for plant growth and depleted after harvesting .
Q48. Stomata are usually more numerous on the: Science
• Upper surface of leaf
• Lower surface of leaf
• Stem
• Roots
Answer: Lower surface of leaf
Stomata are typically found more on the lower epidermis to reduce water loss from direct sunlight and heat .
Q49. Which of the following is NOT required for photosynthesis? NCERT
• Sunlight
• Chlorophyll
• Oxygen
• Carbon dioxide
Answer: Oxygen
Oxygen is a byproduct of photosynthesis, not a requirement. The process requires carbon dioxide, water, sunlight, and chlorophyll.
Q50. The chloroplasts inside plant cells contain chlorophyll and are the sites where: Science
• Water is absorbed
• Photosynthesis occurs
• Oxygen is absorbed
• Food is stored
Answer: Photosynthesis occurs
Chloroplasts are the organelles in plant cells where photosynthesis actually takes place. They contain chlorophyll and the enzymes needed for the process .