1. The mode of nutrition in green plants is ___________.
A) Heterotrophic
B) Autotrophic
C) Parasitic
D) Saprophytic
Answer: B
Explanation: Green plants use chlorophyll and sunlight to make food (photosynthesis).
2. Autotrophic nutrition involves___________.
A) Direct absorption of food
B) Photosynthesis or chemosynthesis
C) Feeding on dead matter
D) Dependence on host
Answer: B
Explanation: Autotrophic nutrition is a process where organisms (autotrophs) synthesize their own food from simple inorganic substances like carbon dioxide and water.
3. The primary source of energy for photosynthesis is___________.
A) ATP
B) Sunlight
C) Glucose
D) Water
Answer: B
Explanation: Sunlight is the ultimate and primary source of energy for photosynthesis. This light energy is captured by photosynthetic pigments and converted into chemical energy to drive the entire process.
4. Essential pigment for photosynthesis___________.
A) Carotene
B) Xanthophyll
C) Chlorophyll
D) Anthocyanin
Answer: C
Explanation: Chlorophyll is considered the essential (or primary) pigment for photosynthesis because it is the only pigment capable of directly converting light energy into chemical energy.
5. The green color of plants is due to___________.
A) Xanthophyll
B) Carotenoids
C) Chlorophyll
D) Starch
Answer: C
Explanation: The green color of plants is primarily due to chlorophyll, the main pigment found in the chloroplasts of plant cells. This pigment is vital for photosynthesis because it absorbs light energy from the sun.
6. Photosynthesis occurs in___________.
A) Mitochondria
B) Chloroplasts
C) Ribosomes
D) Nucleus
Answer: B
Explanation: Chloroplasts contain the pigment chlorophyll, which captures light energy to power the production of food.
7. Which is the first stable product of photosynthesis in C3 plants?
A) Pyruvate
B) Phosphoglycerate (PGA)
C) Oxaloacetate
D) Malate
Answer: B
Explanation: In C3 plants, the first stable product of the dark reaction (the Calvin Cycle) is 3-phosphoglyceric acid, commonly abbreviated as 3-PGA. Because this compound contains three carbon atoms, the pathway is named the C3 cycle.
8. In C4 plants, first stable product of photosynthesis is___________.
A) Pyruvate
B) Oxaloacetate
C) PGA
D) Malate
Answer: B
Explanation: In C4 plants (such as maize, sugarcane, and sorghum), the first stable product of carbon fixation is oxaloacetic acid (OAA). Because this molecule contains four carbon atoms, the pathway is named the C4 cycle (also known as the Hatch-Slack pathway).
9. Raw materials for photosynthesis are___________.
A) CO₂ + H₂O
B) O₂ + H₂O
C) Starch + O₂
D) Proteins + H₂O
Answer: A
Explanation: Photosynthesis is the process by which green plants manufacture their own food. To do this, they require specific “ingredients” or raw materials from their environment.
10. The gas released during photosynthesis is___________.
A) CO₂
B) O₂
C) H₂
D) N₂
Answer: B
Explanation: During the process of photosynthesis, plants release oxygen gas ($O_2$) as a byproduct. This gas is vital for the survival of almost all aerobic organisms on Earth, including humans.
11. CO₂ enters plant leaves through___________.
A) Cuticle
B) Lenticels
C) Stomata
D) Epidermis
Answer: C
Explanation: Carbon dioxide ($CO_2$) enters plant leaves primarily through stomata (singular: stoma). These are microscopic pores located mostly on the underside of leaves, acting as the “mouths” of the plant for gas exchange.
12. Which law of limiting factor applies to photosynthesis?
A) Blackman’s Law
B) Mendel’s Law
C) Hardy-Weinberg Law
D) Boyle’s Law
Answer: A
Explanation: Blackman’s Law of Limiting Factors states that when a physiological process (like photosynthesis) is influenced by multiple factors, its rate is determined by the factor that is in the shortest supply (the “slowest” factor).
13. Site of light reaction of photosynthesis___________.
A) Stroma
B) Thylakoid membrane
C) Mitochondria
D) Ribosome
Answer: B
Explanation: The light reactions (also known as light-dependent reactions) are the first stage of photosynthesis. They occur specifically within the thylakoid membranes of the chloroplast, where light-absorbing pigments like chlorophyll are located.
14. Site of dark reaction of photosynthesis___________.
A) Stroma
B) Thylakoid
C) Cytoplasm
D) Nucleus
Answer: A
Explanation: The dark reaction (also known as the light-independent reaction or the Calvin Cycle) is the second phase of photosynthesis. It takes place in the stroma, which is the colorless, protein-rich fluid that fills the space inside the chloroplast, surrounding the thylakoid stacks.
15. End products of photosynthesis are___________.
A) Glucose + O₂
B) Starch + CO₂
C) Proteins + H₂O
D) Glucose + N₂
Answer: A
Explanation: The end products of photosynthesis are glucose (a simple sugar/carbohydrate) and oxygen gas. During this process, plants convert solar energy into chemical energy stored in the bonds of glucose, while releasing oxygen as a vital byproduct.
16. Photosynthesis equation was first given by___________.
A) Calvin
B) Van Niel
C) Blackman
D) Mayer
Answer: B
Explanation: Van Niel’s work with purple and green sulfur bacteria led him to realize that photosynthesis is a light-dependent redox reaction.
17. In photosynthesis, water acts as___________.
A) Electron donor
B) Electron acceptor
C) Energy carrier
D) Pigment
Answer: A
Explanation: In the light-dependent reactions of photosynthesis, water H2O serves as the primary electron donor. This role is critical for maintaining the flow of energy that ultimately produces food for the plant.
18. Which light is most effective in photosynthesis?
A) Green
B) Yellow
C) Red and blue
D) Infrared
Answer: C
Explanation: While plants look green to our eyes, they actually use red and blue light most efficiently to power photosynthesis. This is because the primary pigment, chlorophyll, absorbs these specific wavelengths of light while reflecting others.
19. Photosynthetic unit is___________.
A) PSI
B) PSII
C) Quantasome
D) Chloroplast
Answer: C
Explanation: A quantasome is considered the functional unit of photosynthesis. It is a tiny particle found on the thylakoid membrane that contains the necessary pigments and components to perform the initial photochemical act of capturing light.
20. Calvin cycle was discovered by___________.
A) Blackman
B) Calvin
C) Mayer
D) Hill
Answer: B
Explanation: The Calvin cycle (also known as the C3 cycle or the “dark reaction”) was discovered by the American biochemist Melvin Calvin, along with Andrew Benson and James Bassham, in the late 1940s.
21. The Hill reaction shows that oxygen is evolved from___________.
A) CO₂
B) H₂O
C) Glucose
D) Sunlight
Answer: B
Explanation: The Hill reaction, discovered by Robert Hill in 1937, was a landmark experiment that proved oxygen released during photosynthesis comes from the splitting of water,not from carbon dioxide as previously thought.
22. CAM plants fix CO₂ at night using___________.
A) PEP carboxylase
B) Rubisco
C) ATP synthase
D) Malate dehydrogenase
Answer: A
Explanation: PEP carboxylase (also known as PEPCase) is the enzyme that initially fixes CO₂ in CAM plants during the night.
23. Which plants minimize photorespiration?
A) C3 plants
B) C4 plants
C) CAM plants only
D) Both C4 and CAM
Answer: D
Explanation: Both C4 and CAM plants have evolved specialized mechanisms to minimize photorespiration, a wasteful process where the enzyme RuBisCO binds with Oxygen,instead of Carbon Dioxide.
24. Dark reaction is called so because___________.
A) It occurs at night only
B) It does not require light directly
C) It occurs in absence of chloroplast
D) It needs darkness
Answer: B
Explanation: The name “dark reaction” is actually a bit of a misnomer in modern biology. It doesn’t mean the reaction requires darkness or that it only happens at night; it simply means that the chemical steps themselves do not use photons (light energy) to proceed.
25. End product of light reaction is___________.
A) ATP + NADPH
B) Glucose
C) Pyruvate
D) CO₂
Answer: A
Explanation: The light-dependent reactions (or simply the light reactions) are the first phase of photosynthesis. Their primary goal is to convert solar energy into chemical energy that can be used later to build sugar.
26. Plants that cannot prepare their own food and depend on others are___________.
A) Autotrophic
B) Heterotrophic
C) Symbiotic
D) Epiphytic
Answer: B
Explanation: Heterotrophic plants depend on other organisms for nutrition.
27. The parasitic mode of nutrition is seen in___________.
A) Cuscuta
B) Maize
C) Mango
D) Sunflower
Answer: A
Explanation: Cuscuta is a total stem parasite lacking chlorophyll.
28. A plant that depends partly on itself and partly on host is___________.
A) Total parasite
B) Partial parasite
C) Saprophyte
D) Symbiont
Answer: B
Explanation: Partial parasites like mistletoe photosynthesize but take water/minerals from host.
29. Which of the following is a total root parasite?
A) Orobanche
B) Viscum
C) Loranthus
D) Striga
Answer: A
Explanation: Orobanche completely depends on host roots for food and water.
30. Mistletoe (Viscum) is an example of___________.
A) Total parasite
B) Partial stem parasite
C) Total root parasite
D) Saprophyte
Answer: B
Explanation: Mistletoe contains chlorophyll but absorbs water/minerals from host.
31. Saprophytic plants obtain food from___________.
A) Living hosts
B) Dead and decaying matter
C) Symbiotic fungi
D) Photosynthesis
Answer: B
Explanation: Saprophytic plants (or more accurately, mycoheterotrophs) obtain their nutrients from dead organic material. Since they lack chlorophyll, they cannot perform photosynthesis and must rely on a unique “recycling” method for survival.
32. Example of saprophytic plant is___________.
A) Monotropa
B) Cuscuta
C) Loranthus
D) Viscum
Answer: A
Explanation: Saprophytic plants (or more accurately, mycoheterotrophs) obtain their nutrients from dead organic material. Since they lack chlorophyll, they cannot perform photosynthesis and must rely on a unique “recycling” method for survival.
33. Symbiotic nutrition is seen in___________.
A) Monotropa
B) Lichens
C) Cuscuta
D) Orobanche
Answer: B
Explanation: Symbiosis occurs between algae and fungi.
34. Algal partner in lichens provides___________.
A) Minerals
B) Water
C) Carbohydrates (food)
D) Support
Answer: C
Explanation: Lichens are a fascinating example of a symbiotic relationship (specifically mutualism) between a fungus (the mycobiont) and a photosynthetic partner (the photobiont), which is usually a green alga or a cyanobacterium.
35. Fungal partner in lichens provides___________.
A) Food
B) Water and minerals
C) Chlorophyll
D) Oxygen
Answer: B
Explanation: A lichen is a single life form that is actually a symbiotic partnership between two (or sometimes more) different organisms.
36. Mode of nutrition in Rhizobium is___________.
A) Autotrophic
B) Parasitic
C) Symbiotic
D) Saprophytic
Answer: C
Explanation: Rhizobium forms symbiosis with legume roots to fix nitrogen.
37. Haustoria are structures found in___________.
A) Saprophytes
B) Parasites
C) Symbionts
D) Autotrophs
Answer: B
Explanation: Specialized absorbing roots in parasites penetrate host tissues.
38. A mycoheterotrophic plant that is achlorophyllous is___________.
A) Monotropa
B) Sunflower
C) Mango
D) Wheat
Answer: A
Explanation: Monotropa uniflora, commonly known as the Ghost Pipe or Indian Pipe, is a unique plant that breaks the typical rules of botany.
39. Symbiotic association of fungi and roots of higher plants is called___________.
A) Lichen
B) Mycorrhiza
C) Root nodule
D) Haustoria
Answer: B
Explanation: The term comes from the Greek words “mykes” (fungus) and “rhiza” (root).
This association is a classic example of mutualism, where both the fungus and the plant benefit from each other’s presence.
40. Example of obligate parasite in plants___________.
A) Cuscuta
B) Monotropa
C) Lichens
D) Mango
Answer: A
Explanation: An obligate parasite (also known as a holoparasite) is an organism that cannot complete its life cycle without a host. In the case of Cuscuta, it is a total stem parasite that is completely dependent on its host for survival.
41. Example of facultative parasite___________.
A) Orobanche
B) Monotropa
C) Viscum
D) Mistletoe
Answer: C
Explanation: It can photosynthesize but also depends on host.
42. Insectivorous plants mainly trap insects to obtain___________.
A) Carbohydrates
B) Nitrogen
C) Water
D) Oxygen
Answer: B
Explanation: They are autotrophic but supplement nitrogen via insect digestion.
43. A symbiotic plant relationship where both partners benefit is called___________.
A) Parasitism
B) Mutualism
C) Commensalism
D) Saprophytism
Answer: B
Explanation: mutualism is a type of symbiotic relationship where both organisms involved receive a benefit. It is often referred to as a “win-win” interaction.
44. Which of the following is a hemiparasite (partial parasite)?
A) Viscum
B) Cuscuta
C) Orobanche
D) Monotropa
Answer: A
Explanation: Viscum (commonly known as Mistletoe) is a hemiparasite (or partial parasite). This means it is a “half-parasite” that still performs some of its own work but steals the rest from a host.
45. The nutrition mode in orchids is___________.
A) Autotrophic
B) Saprophytic
C) Epiphytic (with mycorrhizal association)
D) Parasitic
Answer: C
Explanation: Orchids are a diverse family of plants, but the majority of tropical orchids grow as epiphytes (plants that grow on trees for support). Their nutrition is highly specialized because they live in nutrient-poor environments above the ground.
46. Which of the following is a non-green mycoheterotroph?
A) Mushroom
B) Monotropa
C) Cuscuta
D) Mango
Answer: B
Explanation: Monotropa uniflora (commonly known as the Ghost Pipe or Indian Pipe) is the classic example of a non-green mycoheterotroph.
47. Example of root parasite in monocots___________.
A) Striga
B) Cuscuta
C) Loranthus
D) Monotropa
Answer: A
Explanation: Striga, commonly known as Witchweed, is a notorious root parasite that primarily targets monocotyledonous crops in the grass family (Poaceae), such as maize, sorghum, millet, rice, and sugarcane.
48. Loranthus is a___________.
A) Total root parasite
B) Partial stem parasite
C) Saprophyte
D) Symbiont
Answer: B
Explanation: Presence of Chlorophyll: Loranthus has green, leathery leaves. This allows the plant to perform photosynthesis and manufacture its own organic food (carbohydrates).
49. Symbiotic nitrogen fixation in leguminous plants is carried out by___________.
A) Azotobacter
B) Rhizobium
C) Clostridium
D) Nitrosomonas
Answer: B
Explanation: Rhizobium is a soil-dwelling bacterium that forms a famous symbiotic relationship with plants in the legume family (such as peas, beans, clover, and alfalfa).
50. Which heterotrophic plants lack chlorophyll completely?
A) Cuscuta, Orobanche, Monotropa
B) Viscum, Loranthus
C) Mango, Pea
D) Wheat, Rice
Answer: A
Explanation: These three plants are examples of holoparasites or mycoheterotrophs that have completely lost their chlorophyll. Because they cannot perform photosynthesis, they do not have the green color common to most plants.
51. Insectivorous plants are generally found in soils deficient in___________.
A) Water
B) Nitrogen
C) Carbon dioxide
D) Oxygen
Answer: B
Explanation: Insectivorous plants supplement nitrogen by digesting insects.
52. Pitcher plant (Nepenthes) is___________.
A) Saprophytic
B) Insectivorous
C) Symbiotic
D) Epiphytic
Answer: B
Explanation: Its modified leaf forms a pitcher to trap insects.
53. The leaf modification in pitcher plant is___________.
A) Phyllode
B) Pitcher (leaf lamina modified)
C) Spine
D) Tendril
Answer: B
Explanation: In the pitcher plant (such as Nepenthes), different parts of the leaf are highly specialized to perform specific roles for catching insects. The “pitcher” itself is a dramatic transformation of the leaf lamina (the flat, green blade of a typical leaf).
54. Venus flytrap (Dionaea muscipula) traps insects by___________.
A) Sticky secretion
B) Snap mechanism of leaf lobes
C) Pitcher with fluid
D) Tentacles with glue
Answer: B
Explanation: The Venus flytrap (Dionaea muscipula) is famous for its “active” trapping mechanism, which is one of the fastest movements in the plant kingdom.
55. Drosera (sundew) traps insects by___________.
A) Snap traps
B) Sticky glandular hairs
C) Pitfall trap
D) Suction trap
Answer: B
Explanation: Drosera, commonly known as the Sundew, uses a “flypaper” trapping mechanism. Its name comes from the glistening drops of mucilage on its leaves, which look like morning dew in the sunlight.
56. Utricularia (bladderwort) captures insects by___________.
A) Snap mechanism
B) Pitfall trap
C) Suction bladders
D) Sticky hairs
Answer: C
Explanation: Utricularia, commonly known as Bladderwort, possesses what is considered the most sophisticated and fastest trapping mechanism in the plant kingdom. It uses a highly specialized vacuum-driven suction trap.
57. Aldrovanda is a/an___________.
A) Aquatic insectivorous plant
B) Parasitic plant
C) Saprophyte
D) Symbiont
Answer: A
Explanation: Aldrovanda vesiculosa, commonly known as the Waterwheel plant, is a fascinating rootless, free-floating aquatic plant.
58. Pinguicula (butterwort) traps insects using___________.
A) Snap lobes
B) Pitcher
C) Sticky leaves
D) Suction bladder
Answer: C
Explanation: Pinguicula, commonly known as Butterwort, is a genus of carnivorous plants that uses a “flypaper” trapping mechanism. The name “Butterwort” comes from the greasy, buttery feel of its leaves, which is caused by the sticky secretions they produce.
59. Primary purpose of insect-trapping in insectivorous plants is___________.
A) Photosynthesis
B) Nitrogen supplementation
C) Pollination
D) Protection
Answer: B
Explanation: While insectivorous (carnivorous) plants are green and perform photosynthesis to create energy (sugars), they “eat” insects to solve a specific nutritional problem.
60. Mycorrhiza is a symbiotic association between___________.
A) Algae and fungi
B) Fungi and roots of higher plants
C) Bacteria and fungi
D) Two plant roots
Answer: B
Explanation: the word Mycorrhiza literally translates to “fungus-root.” This relationship is a classic example of mutualism, where both the plant and the fungus help each other survive.
61. Mycorrhizal association helps plants mainly in___________.
A) Nitrogen fixation
B) Phosphorus absorption
C) Oxygen transport
D) Carbon assimilation
Answer: B
Explanation: While mycorrhizal fungi help with the uptake of various micronutrients and water, their most critical and well-known role is the mobilization and transport of phosphorus to the plant.
62. Example of plant with mycorrhiza___________.
A) Pinus
B) Mustard
C) Wheat
D) Maize
Answer: A
Explanation: While many plants form mycorrhizal associations, members of the family Pinaceae (like Pinus, Fir, and Spruce) are famous for their obligatory relationship with Ectomycorrhizae
63. Lichens are indicators of___________.
A) Air pollution (SO₂)
B) Water pollution
C) Soil fertility
D) Mineral deficiency
Answer: A
Explanation: Lichens are among the most sensitive bioindicators in nature. They are often called “nature’s air quality monitors” because their presence, absence, or health directly reflects the cleanliness of the surrounding air.
64. In lichens, fungal partner is called___________.
A) Phycobiont
B) Mycobiont
C) Symbiont
D) Autotroph
Answer: B
Explanation: This term refers specifically to the fungal partner in the symbiotic association of a lichen. The prefix “myco-” relates to fungi.The fungus provides the structure, protection, and absorbs water and minerals for the organism.
65. In lichens, algal partner is called___________.
A) Phycobiont
B) Mycobiont
C) Symbiont
D) Epiphyte
Answer: A
Explanation: The algal partner in a lichen is called the phycobiont.The term is derived from “phyco,” which relates to algae.
66. The association of algae and fungi in lichens is an example of___________.
A) Mutualism
B) Commensalism
C) Parasitism
D) Saprophytism
Answer: A
Explanation: the relationship between the algae (phycobiont) and the fungi (mycobiont) in a lichen is primarily classified as mutualism because both partners benefit significantly from living together.
67. The nutrition mode in Rafflesia is___________.
A) Autotrophic
B) Saprophytic
C) Total root parasitic
D) Partial stem parasitic
Answer: C
Explanation: Rafflesia (known for having the largest individual flower in the world) is a holoparasite—a total parasite that has completely lost the ability to photosynthesize.
68. The nutrition mode in Santalum (sandalwood tree) is___________.
A) Autotrophic only
B) Partial root parasitic
C) Total stem parasitic
D) Saprophytic
Answer: B
Explanation: Santalum album, commonly known as the Sandalwood tree, is a hemiparasite (partial parasite). This means that while it is a green tree capable of making its own food, it still relies on other plants for specific resources.
69. Example of insectivorous aquatic plant___________.
A) Utricularia
B) Drosera
C) Nepenthes
D) Dionaea
Answer: A
Explanation: Utricularia (commonly known as Bladderwort) is the only one in this list that is primarily aquatic.
70. Mycorrhizal fungi increase plant resistance against___________.
A) Drought
B) Pathogens
C) Soil salinity
D) All of these
Answer: D
Explanation: While the most famous role of mycorrhizal fungi is phosphorus absorption, they act as a “biological shield” that significantly enhances a plant’s ability to survive various environmental stresses.
71. Dodder (Cuscuta) is a___________.
A) Total stem parasite
B) Partial root parasite
C) Symbiont
D) Saprophyte
Answer: A
Explanation: Cuscuta, commonly known as Dodder or Amarbel, is one of the most well-known examples of a holoparasite (total parasite).Unlike the Sandalwood tree or the Mistletoe, it has no green leaves and cannot perform photosynthesis.
72. Saprophytic mode of nutrition in fungi involves ___________.
A) Photosynthesis
B) Extracellular digestion of organic matter
C) Symbiotic nitrogen fixation
D) Trap mechanism
Answer: B
Explanation: Saprophytic fungi (like mushrooms, bread mold, and yeast) are the nature’s primary decomposers. Because they cannot move to find food or make their own through photosynthesis, they have evolved a unique “absorptive” way of eating.
73. Some orchids depend on fungi for nutrients. This relation is___________.
A) Parasitism
B) Mutualism (mycorrhiza)
C) Saprophytism
D) Predation
Answer: B
Explanation: This is a specific type of symbiotic relationship known as Orchid Mycorrhiza. While it is technically a form of mutualism, it is one of the most unique and complex examples in the plant kingdom because the “balance of power” shifts throughout the orchid’s life.
74. Coralloid roots of Cycas show symbiosis with___________.
A) Blue-green algae (Anabaena)
B) Rhizobium
C) Mycorrhizal fungi
D) Actinomycetes
Answer: A
Explanation: Cycas is a gymnosperm that produces two types of roots: normal taproots and specialized Coralloid roots. These roots get their name because they are dichotomously branched and resemble sea corals.
75. Insectivorous plants are mostly found in___________.
A) Nitrogen-rich soils
B) Marshy, nitrogen-poor soils
C) Desert soils
D) Sandy coastal soils
Answer: B
Explanation: Insectivorous plants have evolved their unique hunting abilities as an adaptation to survive in “difficult” neighborhoods where most other plants would starve.
76. Plants that derive water and minerals from host but make their own food are___________.
A) Total parasites
B) Partial parasites
C) Saprophytes
D) Autotrophs
Answer: B
Explanation: Examples include Viscum and Loranthus.
77. The mode of nutrition in fungi is___________.
A) Autotrophic
B) Saprophytic or parasitic
C) Holozoic
D) Symbiotic only
Answer: B
Explanation: The majority of fungi are saprophytes. They live on dead and decaying organic matter such as fallen leaves, animal remains, or rotting wood.
78. Insectivorous plants supplement their nutrition mainly for___________.
A) Carbohydrates
B) Proteins
C) Nitrogen and minerals
D) Oxygen
Answer: C
Explanation: While insectivorous plants are green and produce their own “food” (carbohydrates) through photosynthesis, they live in environments where the soil is extremely deficient in life-sustaining nutrients.
79. Which plant is called the “corpse flower” and is a parasitic plant?
A) Rafflesia
B) Nepenthes
C) Drosera
D) Monotropa
Answer: A
Explanation: It is a total root parasite with the world’s largest flower.
80. Which heterotrophic plant is also known as the “Indian pipe”?
A) Orobanche
B) Monotropa
C) Striga
D) Viscum
Answer: B
Explanation: A saprophytic/mycoheterotrophic plant growing in dark forest soils.
81. Nitrogen-fixing cyanobacteria associated with Cycas roots are___________.
A) Nostoc and Anabaena
B) Rhizobium
C) Azotobacter
D) Clostridium
Answer: A
Explanation: In Cycas, specialized roots called coralloid roots host these nitrogen-fixing cyanobacteria (also known as blue-green algae).
82. Which of the following is a root parasite in cereals?
A) Striga
B) Orobanche
C) Cuscuta
D) Monotropa
Answer: A
Explanation: Striga, commonly known as Witchweed, is a devastating root parasite that primarily targets cereal crops such as maize, sorghum, millet, rice, and sugarcane, especially in tropical and subtropical regions.
83. Epiphytic orchids absorb water through___________.
A) Haustoria
B) Velamen tissue in aerial roots
C) Root nodules
D) Symbiotic fungi only
Answer: B
Explanation: Epiphytic orchids, which grow on other plants without taking nutrients from them, have developed a specialized structure to survive high above the ground where there is no soil.
84. Which of the following is a non-green parasitic angiosperm?
A) Loranthus
B) Viscum
C) Cuscuta
D) Orchid
Answer: C
Explanation: To be a non-green parasitic angiosperm, a plant must be a holoparasite. This means it lacks chlorophyll and cannot perform photosynthesis, making it 100% dependent on its host for both water and organic food (sugars).
85. Which mode of nutrition is shown by lichens?
A) Parasitic
B) Symbiotic mutualism
C) Epiphytic
D) Saprophytic
Answer: B
Explanation: Lichens are not a single organism, but a composite life form consisting of two or more distinct partners living in a tight, mutually beneficial relationship.
86. Which among the following is a carnivorous plant with snap trap?
A) Nepenthes
B) Drosera
C) Dionaea (Venus flytrap)
D) Utricularia
Answer: C
Explanation: The snap trap is a rapid, active movement unique to a very small number of plants, most famously the Venus flytrap.
87. Sandalwood tree (Santalum album) is___________.
A) Total stem parasite
B) Partial root parasite
C) Saprophyte
D) Epiphyte
Answer: B
Explanation: Although the sandalwood tree is a large, green tree with leaves, it cannot complete its life cycle successfully without connecting to the roots of other nearby plants.
88. The “Indian telegraph plant” (Desmodium) shows___________.
A) Saprophytic nutrition
B) Insectivory
C) Movement of lateral leaflets
D) Parasitism
Answer: C
Explanation: A special adaptation, not related to photosynthesis directly.
89. Which plant uses sticky leaves to trap insects?
A) Nepenthes
B) Drosera
C) Dionaea
D) Pinguicula
Answer: D
Explanation: Pinguicula (Butterwort) is also a flypaper trap, but its leaves are flat and greasy (like butter), with tiny invisible sticky glands rather than long tentacles.
90. Symbiotic nitrogen fixation occurs in___________.
A) Mustard
B) Pea
C) Rice
D) Wheat
Answer: B
Explanation: Root nodules with Rhizobium.
91. Which mode of nutrition is exhibited by Azolla (fern) with Anabaena?
A) Parasitic
B) Symbiotic
C) Saprophytic
D) Carnivorous
Answer: B
Explanation: The relationship between the water fern Azolla and the cyanobacteria Anabaena azollae is one of the most efficient and famous examples of mutualistic symbiosis in the plant kingdom.
92. Example of a total root parasite in dicots___________.
A) Striga
B) Orobanche
C) Viscum
D) Monotropa
Answer: B
Explanation: Orobanche, commonly known as Broomrape, is a classic example of a total root parasite (holoparasite) that primarily targets dicot
93. Which plant family has many members that are insectivorous?
A) Orchidaceae
B) Droseraceae
C) Poaceae
D) Fabaceae
Answer: B
Explanation: the Droseraceae family is the most well-known in introductory biology because it contains some of the most iconic “active” insect-trapping genera.
94. The absorptive organ in parasitic plants is___________.
A) Haustoria
B) Velamen
C) Root hair
D) Rhizoid
Answer: A
Explanation: In parasitic plants, the specialized organ that penetrates the host’s tissue to absorb water, minerals, and nutrients is called a haustorium (plural: haustoria).
95. Example of facultative symbiosis is___________.
A) Rhizobium in legumes
B) Algae and fungi in lichens
C) Striga in cereals
D) Monotropa in forests
Answer: A
Explanation: A facultative symbiosis is a relationship where the partners can live together for mutual benefit but are also capable of surviving independently in the environment.
96. Which plant is a partial stem parasite?
A) Loranthus
B) Orobanche
C) Cuscuta
D) Monotropa
Answer: A
Explanation: A partial stem parasite (also known as a hemiparasite) is a plant that contains chlorophyll and can perform photosynthesis but depends on its host for water and essential minerals.
97. Carnivorous plants are generally found in soils___________.
A) Poor in nitrogen
B) Poor in water
C) Poor in carbon dioxide
D) Rich in nitrogen
Answer: A
Explanation: Carnivorous plants (also known as insectivorous plants) are usually found in habitats like bogs, fens, and marshes. These areas have waterlogged soils that are highly acidic and low in available nutrients, particularly nitrogen.
98. Albugo (causing white rust) obtains food by___________.
A) Autotrophy
B) Parasitism
C) Saprophytism
D) Symbiosis
Answer: B
Explanation: Albugo (specifically Albugo candida) is an obligate plant pathogen that causes a disease known as white rust (or white blisters) on cruciferous plants like mustard, radish, and cabbage.
99. The velamen tissue in orchids helps in___________.
A) Photosynthesis
B) Absorption of atmospheric moisture
C) Food conduction
D) Seed dispersal
Answer: B
Explanation: The velamen is a specialized, multi-layered epidermis found on the aerial roots of epiphytic orchids (orchids that grow on trees rather than in soil).
100. The best example of plant–fungus symbiosis enhancing mineral uptake is___________.
A) Mycorrhiza
B) Root hairs
C) Root nodules
D) Haustoria
Answer: A
Explanation: Mycorrhiza (literally meaning “fungus-root”) is the most prominent example of a mutualistic symbiotic relationship between a fungus and the roots of a higher plant, specifically designed to enhance nutrient and mineral absorption.