The female gametophyte in angiosperms is typically represented by the _______ stage.
Answer: B
The mature embryo sac with 7 cells (3 antipodal cells, 2 synergids, 1 egg cell, 2 polar nuclei) represents the female gametophyte in angiosperms.
Q.42Medium
Which of the following statements about alternation of generations is correct?
Answer: A
Bryophytes display clear alternation of generations with the gametophyte being the dominant, independent phase while the sporophyte is small and dependent.
Q.43Medium
A botanist observes a plant with jointed stems, scale-like leaves, and spores produced in strobili. This plant likely belongs to which division?
Answer: B
Equisetophytes (horsetails) are characterized by jointed stems with silica deposition, reduced scale-like leaves in whorls, and spores in terminal strobili.
Q.44Medium
The vascular tissue in ferns differs from that in gymnosperms primarily in which aspect?
Answer: B
Both ferns and gymnosperms lack vessels in xylem and have sieve cells instead of sieve tubes in phloem, but ferns typically have scattered vascular bundles.
Q.45Medium
Which of the following is NOT a characteristic of angiosperms compared to gymnosperms?
Answer: C
Angiosperms can be monocots (one cotyledon) or dicots (two cotyledons), so not all angiosperms have two cotyledons.
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Q.46Medium
In liverworts, the gemma cup structure primarily serves the function of:
Answer: B
Gemma cups in liverworts produce small vegetative bodies (gemmae) that are dispersed for asexual reproduction, allowing rapid colonization.
Q.47Medium
The prothallus in pteridophytes is homologous to which structure in bryophytes?
Answer: B
The prothallus (gametophyte) in pteridophytes is homologous to the gametophytic generation in bryophytes as both are haploid structures producing gametes.
Q.48Medium
The integument in an ovule develops from:
Answer: B
The integument develops from the chalaza end of the nucellus and grows upward to cover the nucellus, leaving only the micropyle opening for pollen entry.
Q.49Medium
A research team identifies a plant with the following features: free-living sporophyte, independent gametophyte, presence of sporangia on leaf undersurface, and no seeds. This plant belongs to:
Answer: B
These characteristics are typical of pteridophytes/ferns: independent sporophyte and gametophyte, sporangia on fern fronds, and reproduction through spores without seeds.
Q.50Medium
The archegonium in bryophytes and pteridophytes is significant because it:
Answer: B
The archegonium is a flask-shaped female reproductive organ that protects the egg cell and provides a passage (neck canal) for sperm entry, requiring moisture for fertilization.
Q.51Medium
In bryophytes, the dominant generation is gametophytic, while in pteridophytes it shifts to sporophytic dominance. Which of the following best explains the evolutionary advantage of this transition?
Answer: D
The shift from gametophytic to sporophytic dominance in pteridophytes is advantageous because: (1) Sporophytes with indeterminate growth can produce more spores, increasing reproductive success, and (2) Spores with thick protective walls (sporopollenin) can survive in drier environments, reducing dependence on moisture. This represents a major evolutionary transition.
Q.52Medium
The tissue present between the upper and lower epidermis of a dicot leaf is:
Answer: B
Mesophyll tissue consists of palisade and spongy parenchyma and is located between the two epidermal layers.
Q.53Medium
In a dicot root, the vascular bundle arrangement is:
Answer: B
Dicot roots show radial arrangement of vascular bundles with xylem rays alternating with phloem strands.
Q.54Medium
The endodermis in roots is characterized by the presence of:
Answer: A
Casparian strips are bands of suberin deposited on the radial and transverse walls of endodermal cells, preventing lateral water movement.
Q.55Medium
Which of the following is NOT a function of the epidermis?
Answer: B
The epidermis is primarily protective and regulatory; photosynthesis is the function of mesophyll cells in the leaf.
Q.56Medium
The pericycle is primarily involved in:
Answer: B
The pericycle, a layer of parenchyma cells inside the endodermis, initiates the formation of lateral roots.
Q.57Medium
Secondary growth in plants results in the formation of:
Answer: B
Secondary growth, mediated by vascular cambium, produces secondary xylem (wood) and secondary phloem (inner bark).
Q.58Medium
In a three-year-old dicot stem, the annual rings are formed due to:
Answer: A
Annual rings result from the difference in growth rate between spring wood (lighter) and autumn wood (darker) formed by secondary xylem.
Q.59Medium
The tissue that forms a protective layer in older stems and replaces the epidermis is:
Answer: B
Periderm, consisting of cork, cork cambium, and phelloderm, replaces the epidermis in older stems.
Q.60Medium
In dicot roots, the xylem is typically arranged in a pattern described as
Answer: B
Dicot roots typically show tetrarch arrangement (4 xylem groups), while monocot roots show polyarch arrangement. Triarch is less common in roots.
