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Q1. Apart from carbohydrates, plants also synthesize:
Plants not only synthesize carbohydrates (glucose) through photosynthesis but also use these carbohydrates along with other elements to synthesize proteins and fats. Proteins are made from amino acids, which require nitrogen, and fats are made from glycerol and fatty acids derived from carbohydrates. Plants do not synthesize water (they absorb it), and minerals are absorbed, not synthesized.
Q2. Plants use carbohydrates along with nitrogen and other elements to synthesize:
Plants use carbohydrates (which provide carbon and energy) along with nitrogen and other elements like sulfur to synthesize proteins. Nitrogen is a key component of amino acids, which are the building blocks of proteins. Fats, starch, and cellulose are made from carbohydrates but do not require nitrogen directly.
Q3. The element essential for protein synthesis that plants obtain from soil is:
Nitrogen is essential for protein synthesis because it is a key component of amino acids. Plants obtain nitrogen from the soil in the form of nitrates or ammonium ions. Carbon, oxygen, and hydrogen are obtained from air and water, not primarily from soil for protein synthesis.
Q4. Fats and oils in plants are synthesized from:
Fats and oils in plants are synthesized from carbohydrates. Glucose produced during photosynthesis is converted into glycerol and fatty acids, which combine to form fats and oils. Proteins are made from amino acids, and minerals and vitamins are not precursors for fat synthesis.
Q5. Which part of a plant typically stores the most fats and oils?
Seeds typically store the most fats and oils in plants. These are stored as energy reserves to support germination and early growth. Examples include sunflower, groundnut, and mustard seeds. Leaves store mostly carbohydrates, roots store starch, and stems are less commonly storage sites for fats.
Q6. Plants that lack chlorophyll and obtain their nutrition from other organisms are called:
Plants that lack chlorophyll cannot perform photosynthesis and must obtain their nutrition from other organisms, making them heterotrophs. Autotrophs and producers make their own food, and green plants are typically autotrophs. Heterotrophs include parasites, saprotrophs, and insectivorous plants.
Q7. An organism that lives on or inside another living organism and derives food from it is called a:
A parasite is an organism that lives on or inside another living organism (the host) and derives its food from it, often harming the host. The host is the organism that is exploited, saprotrophs feed on dead matter, and symbionts have mutual relationships. The parasite is the organism that benefits at the host’s expense.
Q8. The organism from which a parasite derives its food is called the:
The organism from which a parasite derives its food is called the host. The host provides nutrients and shelter to the parasite, often being harmed in the process. A predator kills its prey, a saprophyte feeds on dead matter, and the host is the living organism that the parasite exploits.
Q9. Cuscuta (Amarbel) is an example of a:
Cuscuta (Amarbel) is a total parasitic plant. It lacks chlorophyll and obtains its food from the host plant through specialized structures called haustoria. It is not a saprophyte (which feeds on dead matter), not an autotroph (doesn’t make its own food), and not a symbiont (it harms the host).
Q10. Plants that feed on insects are called:
Plants that trap and feed on insects are called insectivorous plants. They do this to obtain nitrogen, which is deficient in the soil they grow in. Parasitic plants depend on hosts, saprophytic plants feed on dead matter, and symbiotic plants have mutual relationships. Insectivorous plants are the correct term.
Q11. The pitcher plant gets its name because:
The pitcher plant gets its name because its leaf is modified into a pitcher-like structure that traps insects. Insects are attracted by nectar and fall into the pitcher, where they are digested. It is not for storing water (though it may hold rainwater), but its primary purpose is trapping insects.
Q12. Why do insectivorous plants trap insects?
Insectivorous plants trap insects to obtain nitrogen, which is deficient in the soil they grow in. They still perform photosynthesis for carbohydrates and energy, but they need nitrogen for protein synthesis. Water, oxygen, and carbohydrates are not the primary reasons for trapping insects.
Q13. Which of the following is an insectivorous plant?
Venus flytrap is a well-known insectivorous plant that traps insects to obtain nitrogen. Cactus is a xerophyte, mango is an autotroph, and Cuscuta is a parasite. The Venus flytrap is the correct example of an insectivorous plant.
Q14. Organisms that obtain nutrition from dead and decaying matter are called:
Saprotrophs are organisms that obtain their nutrition from dead and decaying organic matter by secreting digestive enzymes and absorbing the nutrients. Parasites live on living hosts, predators kill prey, and hosts are the organisms that parasites exploit. Saprotrophs are the correct term for this mode of nutrition.
Q15. Which of the following is an example of a saprotroph?
Bread mold is a fungus that grows on dead organic matter like bread, making it a saprotroph. Mango trees are autotrophs, Cuscuta is a parasite, and tigers are heterotrophs that consume living prey. Bread mold is the correct example of a saprotroph.
Q16. The mode of nutrition in fungi is:
Most fungi obtain their nutrition from dead and decaying matter, making them saprotrophs. Some fungi are parasites, but the general mode of nutrition in fungi is saprotrophic. Autotrophs make their own food, insectivorous plants trap insects. Fungi are not autotrophs and are generally not insectivorous.
Q17. Saprotrophs secrete digestive juices on:
Saprotrophs secrete digestive juices on dead and decaying matter to break down complex organic substances into simpler forms that can be absorbed. They do not secrete on living organisms (parasites do), green plants (not needed), or rocks. Their nutrition depends on dead organic matter.
Q18. Mushrooms growing on a rotting log are examples of:
Mushrooms growing on a rotting log are saprotrophs because they feed on the dead organic matter of the log. They break down the wood and absorb nutrients. They are not parasites (they don’t harm living organisms), not autotrophs (they don’t perform photosynthesis), and not insectivorous. Mushrooms are classic examples of saprotrophs.
Q19. The association where two different organisms live together and mutually benefit each other is called:
Symbiosis is a close association between two different organisms in which both benefit from each other (mutualism). Parasitism benefits one at the expense of the other, saprotrophism is feeding on dead matter, and predation is one organism killing another for food. Symbiosis is the correct term for a mutually beneficial relationship.
Q20. Lichen is a symbiotic association between:
Lichen is a symbiotic association between an alga and a fungus. The alga provides food through photosynthesis, and the fungus provides shelter, water, and minerals. Fungus and root form mycorrhiza, bacteria and plants form nitrogen-fixing associations, and viruses are not part of lichens.
Q21. In lichen, what does the alga provide to the fungus?
In lichen, the alga provides food (carbohydrates) to the fungus through photosynthesis. The fungus provides water, minerals, and shelter to the alga. The alga is the photosynthetic partner that produces food for both. Shelter, water, and minerals are provided by the fungus.
Q22. In lichen, what does the fungus provide to the alga?
In lichen, the fungus provides water, minerals, and shelter to the alga. The fungus absorbs water and minerals from the environment and protects the alga from desiccation. Food is provided by the alga, and chlorophyll is present in the alga, not provided by the fungus. Carbon dioxide is obtained from the air.
Q23. Rhizobium bacteria live in the root nodules of:
Rhizobium bacteria live in the root nodules of leguminous plants such as peas, beans, and clover. They form a symbiotic relationship with these plants. Wheat and rice are not legumes, and Rhizobium does not live in all plants. Leguminous plants are the specific hosts for Rhizobium.
Q24. The relationship between Rhizobium and leguminous plants is an example of:
The relationship between Rhizobium and leguminous plants is an example of symbiosis (mutualism). The bacteria fix nitrogen for the plant, and the plant provides food and shelter to the bacteria. Parasitism would harm the host, saprotrophism involves dead matter, and insectivorous is about trapping insects.
Q25. Rhizobium bacteria convert atmospheric nitrogen into a form that plants can use. This process is called:
Nitrogen fixation is the process by which Rhizobium bacteria convert atmospheric nitrogen into soluble forms like nitrates that plants can use. Photosynthesis is food-making, transpiration is water loss, and respiration is energy release. Nitrogen fixation is the correct term for this process.
Q26. Plants cannot absorb atmospheric nitrogen directly because:
Plants cannot absorb atmospheric nitrogen (N₂) directly because it is in an unusable, inert form. They need nitrogen in the form of nitrates or ammonium ions, which are soluble in soil water. Nitrogen is abundant in the atmosphere, but it must be fixed into a usable form by bacteria like Rhizobium.
Q27. Continuous growing of crops in the same field makes the soil poor in:
Continuous growing of the same crop in the same field depletes the soil of specific nutrients, especially nitrogen. This leads to reduced soil fertility and lower yields. Water and air are not directly depleted, and sand content does not change. Nutrient depletion is the main problem with continuous monoculture.
Q28. Nutrients in the soil are replenished by adding:
Nutrients in the soil are replenished by adding fertilizers (chemical) and manure (organic). Water provides hydration but not nutrients, pesticides kill pests, and weeds compete with crops. Fertilizers and manure restore essential nutrients like nitrogen, phosphorus, and potassium.
Q29. Which bacteria present in root nodules help in nitrogen fixation?
Rhizobium is the bacteria present in the root nodules of leguminous plants that helps in nitrogen fixation. E. coli is found in the intestine, Lactobacillus is used in curd making, and Streptococcus is a pathogenic bacterium. Rhizobium is the correct nitrogen-fixing bacterium.
Q30. Farmers rotate crops by growing legumes in the field to:
Farmers grow legumes (like peas, beans) in rotation to replenish nitrogen in the soil. Legumes have Rhizobium bacteria in their root nodules that fix atmospheric nitrogen, enriching the soil. This is done to maintain soil fertility, not primarily for vegetables, water, or pest control (though it may help indirectly).
Q31. Parasitic plants absorb ready-made food from the host through special structures called:
Parasitic plants absorb ready-made food from the host through specialized structures called haustoria. These structures penetrate the host’s tissues and absorb nutrients. Root hairs are for absorption in normal plants, stomata are for gas exchange, and pneumatophores are breathing roots in mangroves.
Q32. Indian pipe (Monotropa) is a plant that lacks chlorophyll and gets food from dead matter. It is a:
Indian pipe (Monotropa) is a plant that lacks chlorophyll and obtains its food from dead organic matter, making it a saprophyte. It does not parasitize living plants, trap insects, or perform photosynthesis. It is a classic example of a saprophytic plant, though it is actually a myco-heterotroph (associated with fungi).
Q33. Which of the following is a partial parasite that performs photosynthesis but also derives water and minerals from the host?
Mistletoe is a partial parasite that contains chlorophyll and performs photosynthesis but derives water and minerals from the host plant. Cuscuta is a total parasite (no chlorophyll), mushroom is a saprotroph, and pitcher plant is insectivorous. Mistletoe is the correct example of a partial parasite.
Q34. The rotting dead matter on which saprotrophs grow is called:
The rotting dead matter on which saprotrophs grow is called the substrate. Saprotrophs feed on the substrate by secreting enzymes and absorbing nutrients. Humus is the organic component of soil, host is the organism a parasite lives on, and prey is the organism killed by a predator. Substrate is the correct term.
Q35. Enzymes secreted by saprotrophs help in:
Enzymes secreted by saprotrophs help in digesting complex organic matter (like cellulose, proteins) into simpler forms that can be absorbed. These enzymes are secreted externally (exoenzymes). Photosynthesis is not performed by saprotrophs, and reproduction and transpiration are different processes.
Q36. The mode of nutrition in animals and most non-green plants is:
Animals and most non-green plants (like fungi, parasites) are heterotrophs because they cannot make their own food and depend on other organisms for nutrition. Autotrophic organisms make their own food, photosynthetic is a type of autotrophy, and chemosynthetic is a rare mode used by some bacteria. Heterotrophic is the correct term for animals and non-green plants.
Q37. A symbiotic association in which both organisms are benefitted is called:
A symbiotic association in which both organisms are benefited is called mutualism (mutually beneficial symbiosis). Commensalism benefits one without affecting the other, parasitism benefits one at the expense of the other, and predation is killing for food. Mutualism is the correct term for a mutually beneficial relationship.
Q38. The element that is fixed by Rhizobium in leguminous plants is:
Rhizobium fixes nitrogen from the atmosphere into a usable form for plants. Oxygen, carbon, and hydrogen are not fixed by Rhizobium. Nitrogen is the key element that is converted from atmospheric N₂ into nitrates or ammonium ions, which plants can absorb.
Q39. Which of the following is NOT a method to replenish soil nutrients?
Continuous monoculture (growing the same crop repeatedly) depletes soil nutrients and is NOT a method to replenish them. Adding fertilizers, adding manure, and crop rotation are all methods to replenish soil nutrients. Continuous monoculture leads to nutrient depletion and reduced yields.
Q40. The practice of growing different crops alternately to replenish soil nutrients is called:
Crop rotation is the practice of growing different crops alternately in the same field to replenish soil nutrients. Multiple cropping is growing more than one crop in a year, intercropping is growing two crops simultaneously, and hybridization is breeding different varieties. Crop rotation is the correct term for alternating crops to maintain soil fertility.
Q41. Which nutrient is most commonly replenished by growing leguminous crops?
Growing leguminous crops replenishes nitrogen in the soil because they have Rhizobium bacteria that fix atmospheric nitrogen. Phosphorus, potassium, and calcium are also important, but nitrogen is the primary nutrient replenished by legumes. This is why farmers grow legumes in rotation with cereals.
Q42. Manure is better than fertilizers because it:
Manure is better than fertilizers because it is cheaper and improves soil structure, water-holding capacity, and microbial activity. Fertilizers act faster and are more concentrated, but they do not improve soil structure and can cause pollution. Manure releases nutrients slowly and is more sustainable.
Q43. The process of nitrogen fixation by Rhizobium occurs in:
Nitrogen fixation by Rhizobium occurs in the root nodules of leguminous plants. These nodules provide a suitable environment for the bacteria to convert atmospheric nitrogen into soluble forms. Leaves, stems, and flowers are not the sites of nitrogen fixation by Rhizobium.
Q44. A plant that partially depends on another plant for shelter and nutrition is called a:
A partial parasite depends on another plant for some nutrients (like water and minerals) but can perform photosynthesis for carbohydrates. Examples include mistletoe. A total parasite depends completely on the host (like Cuscuta). Saprophytes feed on dead matter, and autotrophs make their own food.
Q45. Which of the following contains chlorophyll but still depends on other plants?
Mistletoe contains chlorophyll and performs photosynthesis but still depends on other plants for water and minerals, making it a partial parasite. Cuscuta lacks chlorophyll, mushrooms are saprotrophs, and pitcher plants trap insects but are autotrophs for carbohydrates. Mistletoe is the correct answer.
Q46. Fungi like yeast which grow on dead sugary substances are examples of:
Yeast growing on dead sugary substances (like fruit juices) are saprotrophs because they obtain nutrition from dead organic matter. Parasites live on living hosts, autotrophs make their own food, and insectivores trap insects. Yeast is a saprotroph that ferments sugars.
Q47. The relationship between a shark and a remora fish (which attaches to shark and eats leftovers) is an example of:
The relationship between a shark and a remora fish is commensalism. The remora benefits by getting food and transport, while the shark is neither helped nor harmed. Parasitism would harm the host, symbiosis implies mutual benefit (mutualism), and saprotrophism is about dead matter. Commensalism is the correct term.
Q48. The root nodules of leguminous plants contain a pigment called:
The root nodules of leguminous plants contain a pigment called leghemoglobin, which regulates oxygen concentration for the nitrogen-fixing bacteria. Chlorophyll is for photosynthesis, haemoglobin is in animals, and carotene is a plant pigment. Leghemoglobin is specific to legume root nodules.
Q49. Which element is essential for making proteins and is often deficient in soil?
Nitrogen is essential for making proteins and is often deficient in soil because plants absorb it in large quantities and it is not always replenished naturally. Carbon, hydrogen, and oxygen are abundant from air and water. Nitrogen is the nutrient most commonly deficient, which is why fertilizers and legumes are used.
Q50. The ultimate source of nitrogen for plants is:
The ultimate source of nitrogen for plants is the atmosphere, which contains about 78% nitrogen gas (N₂). However, plants cannot use it directly; it must be fixed into a soluble form by bacteria like Rhizobium. Soil, fertilizers, and water are intermediate sources, but the atmosphere is the ultimate source.