Which of the following statements about pollen grains is INCORRECT?
Answer: C
Mature pollen grains are bicellular (or sometimes tricellular), not unicellular. They contain vegetative and generative cells.
Q.2Hard
In apomixis, seeds are produced without:
Answer: B
Apomixis is asexual reproduction through seeds, occurring without meiosis and fertilization, producing clones of the parent.
Q.3Hard
The phenomenon where a single plant produces both male and female flowers is called:
Answer: B
Monoecious plants have both male and female flowers on the same plant (e.g., maize, coconut). Dioecious plants have them on different plants.
Q.4Hard
Which stage of meiosis in microsporogenesis ensures genetic variation in pollen grains?
Answer: B
Anaphase I involves separation of homologous chromosomes, which along with crossing over in Prophase I ensures genetic variation in resulting microspores.
Q.5Hard
Identify the correct sequence in the development of male gametophyte:
Answer: B
The correct sequence is: Microsporocyte undergoes meiosis to form microspores, which undergo mitosis to form mature pollen grain (male gametophyte).
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Q.6Hard
The endothecium in the anther wall is important for:
Answer: B
The endothecium contains fibrous thickenings on cell walls that help in anther dehiscence by creating tension during drying, aiding pollen dispersal.
Q.7Hard
The phenomenon where pollen grains retain viability after being kept in dry conditions for extended periods is called:
Answer: A
Pollen dormancy refers to the reduced metabolic activity of pollen that allows it to maintain viability over extended storage periods in dry, cool conditions.
Q.8Hard
In a typical angiosperm flower, after dehiscence, the mature pollen is released at which stage?
Answer: B
Most angiosperms release pollen at the binucleate stage (containing generative and vegetative nuclei). Some release at the trinucleate stage after generative nucleus division.
Q.9Hard
In orchids, the lack of endosperm development is compensated by:
Answer: B
Many orchids have seeds without endosperm (lacking nutritious reserve tissue). They require mycorrhizal fungal associations to obtain nutrients from the soil for germination and growth.
Q.10Hard
The phenomenon of pollen dimorphism is observed in which type of flowers?
Answer: B
Pollen dimorphism is associated with heterostyly, where plants like Primula produce different-sized pollen grains corresponding to different floral forms to promote cross-pollination.
Q.11Hard
Which of the following represents the correct ploidy level progression during the life cycle of a typical angiosperm?
Answer: B
Angiosperm life cycle: diploid sporophyte (2n) → haploid spores (n) → haploid gametophyte (n) → diploid zygote (2n) after fertilization, and triploid endosperm (3n) after double fertilization.
Q.12Hard
In apomixis, the formation of seeds without meiosis and fertilization occurs through which mechanisms?
Answer: B
Apomixis includes apospory (diploid egg from vegetative cells), apomeiosis (unreduced spore formation), and parthenogenesis (unfertilized egg development), all bypassing meiosis and fertilization.
