Plant Nutrition
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Q1. The components of food that are essential for an organism (Plant or animal) are called:
Nutrients are the components of food that are essential for the growth, development, and functioning of an organism. They include carbohydrates, proteins, fats, vitamins, minerals, and water. Vitamins and minerals are only two types of nutrients, and roughage is a type of dietary fiber, not a nutrient itself. So the correct term is nutrients.
Q2. The mode of nutrition in which organisms make their own food is called:
Autotrophic nutrition is the mode of nutrition in which organisms (like green plants) make their own food using simple inorganic substances like carbon dioxide and water, with the help of sunlight and chlorophyll. Heterotrophic nutrition is when organisms depend on others for food. Parasitic and saprotrophic are types of heterotrophic nutrition.
Q3. Organisms that depend on other organisms for food are called:
Heterotrophs are organisms that cannot make their own food and depend on other organisms (plants or animals) for food. All animals, fungi, and many bacteria are heterotrophs. Autotrophs and producers make their own food. Parasites are a type of heterotrophs that live on or inside a host.
Q4. Plants are called autotrophs because they:
Plants are called autotrophs because they can produce their own food through the process of photosynthesis. They use carbon dioxide, water, and sunlight to synthesize food. Having green leaves, growing fast, or absorbing minerals are not the reasons they are called autotrophs—the ability to make their own food is the key reason.
Q5. The process by which plants make their food is called:
Photosynthesis is the process by which green plants use sunlight, carbon dioxide, and water to produce glucose (food) and oxygen. Respiration is the process of releasing energy from food, transpiration is water loss from leaves, and digestion is the breakdown of food. Photosynthesis is the correct term for food-making in plants.
Q6. The green pigment present in leaves is called:
Chlorophyll is the green pigment present in leaves that traps sunlight for photosynthesis. Haemoglobin is the red pigment in blood, carotene is an orange pigment, and xanthophyll is a yellow pigment. Chlorophyll is the primary pigment responsible for the green color of leaves and for absorbing light energy.
Q7. The tiny pores on the surface of leaves are called:
Stomata are tiny pores present on the surface of leaves through which gases (carbon dioxide and oxygen) enter and leave the plant. Lenticels are pores on stems, the cuticle is the waxy outer layer, and veins are the vascular bundles in leaves. Stomata are the correct structures for gas exchange.
Q8. The cells that surround stomata and regulate their opening are called:
Guard cells are the specialized cells that surround the stomata and control their opening and closing. They swell with water to open the stomata and shrink to close them. Epidermal cells are the outer layer of cells, palisade cells are involved in photosynthesis, and root hair cells absorb water.
Q9. The ultimate source of energy for all living organisms is the:
The Sun is the ultimate source of energy for all living organisms. Plants capture solar energy through photosynthesis, and animals get energy by eating plants or other animals. The Moon, soil, and air are not sources of energy—they are part of the environment. Sunlight drives the entire food chain.
Q10. Plants absorb water and minerals from the soil through their:
Plants absorb water and minerals from the soil through their roots. Root hairs increase the surface area for absorption. Leaves are for photosynthesis and gas exchange, stems transport substances, and flowers are for reproduction. The roots are the organs for absorption.
Q11. During photosynthesis, plants take in carbon dioxide and release:
During photosynthesis, plants take in carbon dioxide and water and release oxygen as a byproduct. The oxygen released comes from the splitting of water molecules. Nitrogen, hydrogen, and carbon monoxide are not released during photosynthesis.
Q12. Photosynthesis takes place in which part of the plant?
Photosynthesis takes place in the green parts of plants, especially the leaves, because they contain chlorophyll. The green stems of some plants also perform photosynthesis. Roots, flowers, and fruits do not usually perform photosynthesis as they lack chlorophyll.
Q13. The food synthesized by plants during photosynthesis is primarily:
The primary food synthesized by plants during photosynthesis is glucose, which is a carbohydrate. This glucose is later converted into starch for storage. Proteins, fats, and vitamins are not the primary products of photosynthesis; they are synthesized through other processes.
Q14. Guard cells contain chlorophyll to:
Guard cells contain chlorophyll, which allows them to perform photosynthesis. This helps them generate energy to actively pump ions, which regulates water movement and stomatal opening/closing. The green color of leaves is mainly from other cells, and protection and water absorption are done by other structures.
Q15. Which gas is absorbed from the atmosphere by plants through stomata for photosynthesis?
Plants absorb carbon dioxide from the atmosphere through stomata for photosynthesis. Oxygen is released during photosynthesis, nitrogen is not directly absorbed for this process, and hydrogen is not a gas absorbed from the air. Carbon dioxide is the raw material needed for photosynthesis.
Q16. The mode of nutrition in which organisms obtain food from dead and decaying matter is called:
Saprotrophic nutrition is the mode of nutrition in which organisms obtain food from dead and decaying organic matter by secreting digestive enzymes and absorbing nutrients. Parasitic nutrition involves living on a host, symbiotic nutrition is a mutual relationship, and autotrophic nutrition is self-feeding. Fungi and many bacteria are saprotrophs.
Q17. Fungi like mushrooms are examples of:
Fungi like mushrooms are saprotrophs because they obtain their nutrition from dead and decaying organic matter. They secrete enzymes to break down complex organic matter and absorb the nutrients. They are not autotrophs (they don’t make their own food), not parasites (they don’t live on living hosts), and not producers.
Q18. The relationship where two organisms live together and share nutrients is called:
Symbiosis is the relationship where two organisms live together and share nutrients. This can be mutualistic (both benefit), commensalistic (one benefits, the other is unaffected), or parasitic (one benefits, the other is harmed). Parasitism is a type of symbiotic relationship where one benefits at the cost of the other. Saprotrophism and predation are different.
Q19. The bacteria that can convert atmospheric nitrogen into soluble form and live in roots of legumes is:
Rhizobium is the bacterium that lives in the root nodules of leguminous plants (like peas, beans, and clover) and converts atmospheric nitrogen into soluble forms that plants can use. Nitrobacter is involved in nitrification, Azotobacter is a free-living nitrogen-fixer, and E. coli is found in the human intestine.
Q20. Cuscuta (dodder) is an example of a:
Cuscuta (dodder) is a parasitic plant that lacks chlorophyll and depends on a host plant for nutrition. It grows on other plants and absorbs water and nutrients through its specialized structures. It is not an autotroph, saprotroph, or producer. It is a classic example of a parasitic plant.
Q21. Insectivorous plants like pitcher plant trap insects because they grow in soil deficient in:
Insectivorous plants like pitcher plants, Venus flytraps, and sundews grow in soil that is deficient in nitrogen. They trap and digest insects to obtain nitrogen, which is essential for protein synthesis. They still perform photosynthesis for energy, but they need insects for nitrogen. Water, sunlight, and carbon dioxide are not the primary deficiencies.
Q22. Plants which lack chlorophyll cannot perform:
Chlorophyll is essential for photosynthesis because it traps sunlight energy. Plants that lack chlorophyll cannot perform photosynthesis. They may still respire, transpire, and reproduce, but they must obtain food through other means (like parasitism or saprotrophism). Photosynthesis is the process that requires chlorophyll.
Q23. The food synthesized by plants is stored as:
The food synthesized by plants during photosynthesis is glucose, but this glucose is often converted into starch for storage. Starch is a polysaccharide that plants store in various parts like roots, stems, and seeds. Glucose, fructose, and sucrose are simpler sugars, but starch is the primary storage form.
Q24. During photosynthesis, light energy is converted into:
During photosynthesis, light energy from the sun is converted into chemical energy stored in the bonds of glucose molecules. This chemical energy is then used by plants and other organisms for various life processes. It is not converted into kinetic, heat, or electrical energy directly.
Q25. The opening and closing of stomata is regulated by:
The opening and closing of stomata are regulated by guard cells. When guard cells absorb water, they become turgid and swell, opening the stomata. When they lose water, they become flaccid, closing the stomata. Temperature, water availability, and wind speed are external factors that influence stomatal movement, but the guard cells are the regulators.
Q26. Plants get carbon dioxide for photosynthesis from the:
Plants get carbon dioxide for photosynthesis from the air (atmosphere) through stomata. Carbon dioxide is a gas present in the air. Soil and water provide minerals and water, and fertilizers provide nutrients. Carbon dioxide is absorbed from the air, not from the soil, water, or fertilizers.
Q27. The network of pipes that transport water and minerals to leaves are called:
Veins in plants are the network of pipes (vascular bundles) that transport water, minerals, and food throughout the plant. They contain xylem (for water and minerals) and phloem (for food). Nerves are in animals, vessels are the individual tubes, and pores are openings like stomata. Veins are the visible network in leaves.
Q28. Leaves are called the food factories of plants because they:
Leaves are called the food factories of plants because they are the main sites where photosynthesis takes place, manufacturing food for the plant. While they may store some food and are flat and green, the key reason is that they produce food through photosynthesis.
Q29. What would happen if a plant’s leaves are coated with oil on both surfaces?
If a plant’s leaves are coated with oil on both surfaces, the stomata will be blocked, preventing gas exchange. Carbon dioxide cannot enter, and oxygen cannot leave. Without carbon dioxide, photosynthesis cannot occur, so photosynthesis will stop. Growth and flowering would cease due to lack of food.
Q30. The broad and flat part of the leaf that absorbs sunlight is called the:
The broad and flat part of the leaf is called the lamina or leaf blade. It is the main photosynthetic part of the leaf that absorbs sunlight. The petiole is the stalk that attaches the leaf to the stem, the midrib is the central vein, and the veins are the network of vascular bundles.
Q31. Heterotrophic nutrition is found in:
Heterotrophic nutrition is found in animals and non-green plants (like fungi, parasites, and some bacteria). Green plants and algae are autotrophs because they make their own food. Animals cannot make their own food, and non-green plants also depend on others for food. So heterotrophic nutrition is found in both animals and non-green plants.
Q32. The raw materials for photosynthesis are:
The raw materials for photosynthesis are carbon dioxide (from air), water (from soil), sunlight (from the sun), and chlorophyll (the green pigment). These are essential for the process. Oxygen and glucose are products of photosynthesis, not raw materials. Proteins, fats, nitrogen, and minerals are not directly used in photosynthesis.
Q33. Plants that feed on insects are called:
Plants that trap and digest insects are called insectivorous plants. They grow in nitrogen-deficient soil and obtain nitrogen from insects. Examples include pitcher plants and Venus flytraps. Parasitic plants depend on hosts, saprotrophic plants feed on dead matter, and symbiotic plants have mutual relationships.
Q34. In the photosynthesis equation, the reactants are carbon dioxide and water, and the products are:
The photosynthesis equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. The reactants are carbon dioxide and water, and the products are glucose (food) and oxygen. Starch is formed from glucose, but the immediate product is glucose. Proteins, fats, and minerals are not products of photosynthesis.
Q35. If a plant is kept in a dark room for several days, it will eventually die because:
Light is essential for photosynthesis. If a plant is kept in a dark room, it cannot perform photosynthesis, so it cannot produce food. Eventually, the plant will use up its stored food and die. Water absorption and root growth may continue for a while, but without food, the plant cannot survive. It will die due to lack of photosynthesis.
Q36. The process of photosynthesis occurs mainly in which layer of the leaf?
The mesophyll layer of the leaf is where most photosynthesis occurs. It contains palisade and spongy cells that are rich in chloroplasts. The upper and lower epidermis protect the leaf, and the cuticle is the waxy outer layer. The mesophyll is the primary photosynthetic tissue.
Q37. Why do plants in deserts often have green stems?
Desert plants often have green stems that perform photosynthesis in place of leaves. This adaptation reduces water loss because leaves have stomata that lose water. The green stems contain chlorophyll and can carry out photosynthesis. The other options are not the primary reason.
Q38. The process of taking in food and utilizing it is called:
Nutrition is the process of taking in food and utilizing it for growth, energy, and maintenance. Digestion is the breakdown of food, excretion is the removal of waste, and respiration is the release of energy. Nutrition encompasses the entire process of obtaining and using food.
Q39. Guard cells swell to open stomata when they:
Guard cells open stomata when they absorb water and become turgid (swollen). This causes them to bend and create an opening. When they lose water, they become flaccid and close the stomata. This regulates gas exchange and water loss in plants.
Q40. Lichen is an example of which relationship?
Lichen is a symbiotic relationship between algae and fungi. The algae perform photosynthesis and provide food for the fungus, and the fungus provides shelter, water, and minerals for the algae. Both partners benefit from this relationship. It is not parasitic, saprotrophic, or insectivorous.
Q41. Nitrogen is essential for plants to synthesize:
Nitrogen is essential for plants to synthesize proteins, which are needed for growth and development. Nitrogen is a key component of amino acids, the building blocks of proteins. Carbohydrates, fats, and starch do not contain nitrogen. Plants absorb nitrogen in the form of nitrates from the soil.
Q42. Which part of the plant is not directly involved in photosynthesis?
Roots are not directly involved in photosynthesis because they do not contain chlorophyll and are underground. Leaves, green stems, and green sepals can all perform photosynthesis. Roots absorb water and minerals but cannot make food through photosynthesis.
Q43. The process by which plants lose water vapor through stomata is called:
Transpiration is the process by which plants lose water vapor through stomata. This helps in cooling the plant and creating a pull for water absorption. Photosynthesis is food-making, respiration is energy release, and guttation is water loss as liquid droplets. Transpiration is the correct term.
Q44. The midrib and veins in a leaf help in:
The midrib and veins in a leaf contain vascular bundles (xylem and phloem) that transport water, minerals, and food. They also provide structural support and strength to the leaf. They do not directly make food, open stomata, or absorb light; those are functions of other parts.
Q45. In the absence of carbon dioxide, photosynthesis:
Carbon dioxide is an essential raw material for photosynthesis. In its absence, photosynthesis cannot occur. The plant cannot make food without carbon dioxide. It would stop completely, regardless of the presence of sunlight and water.
Q46. A plant appears green because chlorophyll:
Chlorophyll absorbs light in the blue and red regions of the spectrum and reflects green light. This reflected green light is what makes plants appear green to our eyes. It does not absorb green light; it reflects it. It does not produce green pigment (it is the pigment) or convert light into green color.
Q47. Farmers add fertilizers to soil to provide:
Farmers add fertilizers to soil to provide essential nutrients like nitrogen, phosphorus, and potassium, which are needed for plant growth. Fertilizers supplement the soil’s natural nutrient supply. Water, air, and space are managed through other methods like irrigation, tillage, and planting distance.
Q48. Stomata are usually more numerous on the:
In most plants, stomata are more numerous on the lower (under) surface of the leaf. This adaptation helps reduce water loss while allowing gas exchange, as the lower surface is less exposed to direct sunlight and wind. Some plants have stomata on both surfaces, but the lower surface typically has more.
Q49. Which of the following is NOT required for photosynthesis?
Oxygen is not required for photosynthesis; it is a byproduct. The requirements for photosynthesis are sunlight, chlorophyll, carbon dioxide, and water. Oxygen is released during photosynthesis, not used. So oxygen is the only option that is NOT required.
Q50. The chloroplasts inside plant cells contain chlorophyll and are the sites where:
Chloroplasts are the organelles inside plant cells where photosynthesis occurs. They contain chlorophyll, which traps sunlight energy, and the chemical reactions of photosynthesis take place within them. Water is absorbed by roots, oxygen is released (not absorbed), and food is stored in various parts like roots, stems, and seeds. The chloroplasts are the sites of photosynthesis.