31 Years NEET Previous Year Questions: Plant Kingdom - 1 Free MCQ Practice

In the life cycle of bryophytes, the gametophyte is the dominant phase. The correct sequence is:
B. The gametophyte first attaches to the substratum.
E. The male sex organs (antheridia) release antherozoids into water.
A. Antherozoids swim and fuse with the egg in archegonia to form a zygote.
D. The zygote develops into a sporophyte.
C. The sporophyte undergoes reduction division (meiosis) to produce haploid spores.

The life cycle of pteridophytes includes alternation of generations. The correct sequence is:
B. Meiosis in spore mother cells – forms haploid spores
A. Prothallus stage – spores germinate into gametophyte (prothallus)
D. Formation of archegonia and antheridia in gametophyte – gametophyte develops sex organs
E. Transfer of antherozoids to archegonia in presence of water – fertilisation requires water for sperm movement
C. Fertilisation – results in diploid zygote developing into sporophyte

A. Pteridophyte: Salvinia (IV)
Correct. Salvinia is an aquatic fern, hence a pteridophyte.
B. Bryophyte: Polystichum (III)
Correct.  Polytrichum is a moss.
C. Angiosperm: Salvia (I)
Correct. Salvia is a flowering plant (angiosperm).
D. Gymnosperm: Ginkgo (II)
Correct. Ginkgo is a well-known gymnosperm.

Gemmae are small, multicellular, green, disc-like structures found in bryophytes (e.g., Marchantia). They are produced in gemma cups and serve the purpose of asexual reproduction. When detached from the parent plant, they develop into new individuals, genetically identical to the parent.

Gymnosperms are seed-producing plants that do not form flowers or fruits. Their seeds are naked, meaning they are not enclosed within fruits, but are exposed on the surface of cone scales or other structures. This is a key distinguishing feature from angiosperms, which have seeds enclosed within fruits.

A. Microscopic angiosperm → Wolffia (IV): Wolffia is a genus of tiny floating aquatic plants known as the smallest flowering plants. Hence, it is the microscopic angiosperm.
B. Tallest gymnosperm → Sequoia (III): The Sequoia (often referred to as the Giant Sequoia or Redwoods) is the tallest gymnosperm, known for its height.
C. Thalloid bryophyte → Marchantia (II): Marchantia is a type of thalloid bryophyte, meaning its plant body is undifferentiated into roots, stems, and leaves (a thallus).
D. Heterosporous pteridophyte → Salvinia (I): Salvinia is a heterosporous pteridophyte, meaning it produces two types of spores (microspores and megaspores) for reproduction.
Therefore, the correct matching is:
A-IV (Wolffia)
B-III (Sequoia)
C-II (Marchantia)
D-I (Salvinia)
Thus, the correct answer is (B) A-IV, B-III, C-II, D-I.

Ans: (c)
Let's analyze each statement:

• Statement A: Asexual reproduction occurs usually by biflagellate zoospores: This statement is true for Phaeophyceae (brown algae). Asexual reproduction in these algae generally involves the release of biflagellate zoospores that swim away and eventually settle and grow into new individuals.
• Statement B: Sexual reproduction is by oogamous method only:  This statement is partially true. While sexual reproduction in Phaeophyceae often is oogamous (involving a large non-motile egg and a smaller motile sperm), there are instances where isogamy (both gametes are motile and similar in size) occurs, though it is less common. Thus, the statement might be misleading as it implies that oogamy is the only method of sexual reproduction.
• Statement C: Stored food is in the form of carbohydrates which is either mannitol or laminarin: This statement is correct. In brown algae, the primary carbohydrates stored are mannitol and laminarin. These serve as crucial energy storage compounds.
• Statement D: The major pigments found are chlorophyll a, c and carotenoids and xanthophyll:  This statement is true. The brown algae have chlorophyll a, c, various carotenoids, and xanthophylls like fucoxanthin which give them their distinctive brown color.
• Statement E: Vegetative cells have a cellulosic wall, usually covered on the outside by a gelatinous coating of algin: This statement is true. Brown algae have cell walls made of cellulose and are often covered by a layer of alginates, which can form a gelatinous coating. This helps in providing structural support and protection against dessication and mechanical damage.

Given these analyses:
A, C, D, and E are true.
B is not exclusively true as it suggests that oogamy is the only form of sexual reproduction.
Thus, the correct option is:
Option C: A, C, D and E only

Gymnosperms are seed-producing plants that do not have flowers or fruits. The examples listed in option (a) - Cedrus, Pinus, Sequoia - are all gymnosperms. Cedrus and Pinus are types of conifers (cone-bearing trees), and Sequoia is known for being the tallest tree and is also a gymnosperm.
Let’s review the other options:
(b) Angiosperms: Wolffia, Eucalyptus, Sequoia:
Wolffia and Eucalyptus are angiosperms, but Sequoia is a gymnosperm, not an angiosperm. This makes option (b) incorrect.
(c) Bryophytes: Polytrichum, Polysiphonia, Sphagnum:
Polytrichum and Sphagnum are bryophytes (non-vascular plants), but Polysiphonia is a type of red algae, not a bryophyte. Therefore, this option is incorrect.
(d) Pteridophytes: Equisetum, Ginkgo, Adiantum:
Equisetum and Adiantum are pteridophytes (ferns), but Ginkgo is a gymnosperm, not a pteridophyte. So, this option is also incorrect.
Therefore, the correct match is (a) Gymnosperms: Cedrus, Pinus, Sequoia.

Assertion (A): "In gymnosperms, the pollen grains are released from the microsporangium and carried by air currents."
This is True. In gymnosperms, the pollen grains are released from the microsporangium (pollen sacs) and are carried by wind (air currents) to reach the female cones for fertilization.
Reason (R): "Air currents carry the pollen grains to the mouth of the archegonia where the male gametes are discharged and pollen tube is not formed."
This is False. In gymnosperms, the pollen grains do not reach the mouth of the archegonia (female reproductive organ). Instead, the pollen grains land on the ovule, where a pollen tube is formed to carry the male gametes (sperm) to the egg cell for fertilization. Hence, the statement that "pollen tube is not formed" is incorrect.
Therefore, the correct answer is (d) (A) is True, (R) is False.

Selaginella and Salvinia are heterosporous pteridophytes. They produces two different kind of spores.
Psilotum, Lycopodium and Equisetum are homosporous pteridophytes.

The life cycle of mosses consists of two stages: the gametophyte stage and the sporophyte stage.

• Assertion A states : "The first stage of the gametophyte in the life cycle of moss is the protonema stage." This statement is correct. After a spore germinates, it forms a mass of green, branched, one-cell-thick filaments known as the protonema, which is indeed the first stage of the gametophyte generation in mosses.
• Reason R states : "Protonema develops directly from spores produced in the capsule." This statement is also correct. The spores are produced in a capsule, which is the sporophyte part of the moss life cycle. When these spores are released and germinate, they grow into the protonema.

Not only are both statements correct, but Reason R provides a correct explanation for Assertion A.
Therefore, the answer is: Option A : Both A and R are correct and R is the correct explanation of A.

• Pteropsida (A) corresponds to Adiantum (III): Pteropsida includes ferns, and Adiantum is a type of fern.
• Lycopsida (B) corresponds to Selaginella (IV): Lycopsida is a class of club mosses, and Selaginella is a type of club moss.
• Psilopsida (C) corresponds to Psilotum (I): Psilopsida is a group of primitive vascular plants, and Psilotum is an example.
• Sphenopsida (D) corresponds to Equisetum (II): Sphenopsida includes horsetails, and Equisetum is a type of horsetail.

Thus, the correct answer is (d) (A-III) (B-IV) (C-I) (D-II).

• Fucoxanthin is a type of carotenoid pigment that is primarily found in the class Phaeophyceae (brown algae). It gives these algae their characteristic brown or olive color and plays a role in capturing light energy for photosynthesis.
• Phycoerythrin is a phycobilin pigment found in Rhodophyceae (red algae). It imparts a red or pink color to these algae and is important for capturing light in the red and blue wavelengths, which helps red algae to thrive in deeper waters where light penetration is limited.

Summary:

• Phaeophyceae (Brown algae) possess fucoxanthin as their primary pigment, which gives them their brownish color.
• Rhodophyceae (Red algae) possess phycoerythrin, which gives them their red or pink color.

Thus, the correct match is (b) Phaeophyceae and Rhodophyceae.

Chlamydomonas is a unicellular alga. Cycas is a gymnosperm. Selaginella is a heterosporous pteridophyte and Sphagnum is a moss.

Alga shown in the diagram is Chara. It is a member of Chlorophyceae. Food is stored in the form of starch.
Chara is monoecious plant showing oogonium and antheridium on the same plant body.

• Spirogyra is an alga. It shows haplontic life-cycle.
• Fern is pteridophyte. The dominant phase of life-cycle is diploid sporophyte. Its gametophyte is called prothallus.
• Funaria is a bryophyte. Its gametophyte is a leafy stage.
• Cycas is a gymnosperm. The main plant body in gymnosperm is sporophyte. They have highly reduced gametophyte stage.

Ulothrix is a member of Chlorophyceae (green algae), with reserve food material, starch. Mannitol is stored food material of Phaeophyceae (brown algae).

Hydrocolloids are water holding substances for e.g. carrageen obtained from red algae (Rhodophyceae).

Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous.

Hence, the correct option is B.

NCERT Reference: Page no. 37 of topic “3.3 PTERIDOPHYTES” of chapter 3 of NCERT.

• Strobilus is a structure present on many land plant species consisting of sporangia bearing structure densely aggregated along a stem. Equisetum produces strobili.
• Marchantia, pteris and salvinia do not produce strobilus.

Hence, the correct option is B.

NCERT Reference: Page no. 36 of topic “3.3 PTERIDOPHYTES” of chapter 3 of NCERT.

• In Pteridophytes, megaspore is retained for some time in female gametophytes. However, permanent retention is required for seed formation and hence seed is not formed.
• That's why Pteridophytes are said to be precursors of seed habit.

Hence, the correct option is D.

NCERT Reference: Page no. 36 of topic “3.3 PTERIDOPHYTES” of chapter 3.

• Pinus has mutualistic association with fungus in the form of mycorrhizae.
• The fungi help the plant in the absorption of essential nutrients from the soil and the plant provides fungi with high energy-yielding carbohydrates.

Hence, the correct option is C.

NCERT Reference: Page no. 38 of topic “3.4 GYMNOSPERMS” of chapter 3 of NCERT.

• Gymnosperms have naked ovule.
• Selaginella and Salvinia both produce two kinds of spores, macro (large) and micro (small) hence, called heterosporous.
• Equisetum (horsetail, scouring rush) is a pteridophyte.
• Stems are branched in Cedrus but unbranched in Cycas.

Hence, the correct option is A.
NCERT Reference: Page no. 38 of topic “3.4 GYMNOSPERMS” of chapter 3 of NCERT.

Ectocarpus possesses haplodiplontic whereas Fucus possesses diplontic life cycle.

Fig: Diploid life cycle: Fucus

Hence, the correct option is B.
NCERT Reference: Page no. 43 of chapter 3 of NCERT.

• The presence of thick cuticle, presence of sunken stomata, and needle-like leaves are xerophytic adaptations of conifers for tolerating extreme environmental conditions.

Hence, the correct option is C.

NCERT Reference: Page no. 38 of topic “3.4 GYMNOSPERMS” of chapter 3 of NCERT.

• Algin is obtained from Laminaria & Fucus – Brown algae while Carrageenan from Chondrus crispus – Red algae.
• Agar-agar is a gelling agent with unbranched polysaccharides and is used in microbiology as a solidifying agent of liquid culture mediums. It is extracted from the cell wall of red algae, mostly from Gelidium species and Gracilaria species.
• Laminaria and Sargassum are brown algae and are cultivated as a crop. 
• Algae are green photosynthetic organisms that release oxygen in the immediate vicinity through the process of photosynthesis. 

Hence, the correct option is B.

NCERT Reference: Page no. 32 of topic “3.1 ALGAE” of chapter 3 of NCERT.

• In bryophytes and pteridophytes, transport of male gametes requires water. 
• The male gametes, produced by reproductive structures called antheridia, are free-swimming sperm cells that need water to transport them to the female gametes, which are enclosed within structures called archegonia.
• Because of the need for water, bryophytes are especially common in wet habitats such as bogs, streambanks, and moist forests. However, they are not restricted to these habitats, and some mosses thrive in deserts, above the tree line, and in the Arctic tundra.

Fig: Bryophytes vs Pteridophytes

Hence, the correct option is D.

NCERT Reference: Topics “3.2 BRYOPHYTES” and “3.3 PTERIDOPHYTES” of chapter 3 of NCERT.

The tallest trees in the world are redwoods (Sequoia sempervirens), which tower above the ground in California. These trees can easily reach heights of 300 feet (91 meters).

Fig: Sequoia sempervirens

Hence, the correct option is C.
NCERT Reference: Page no. 38 of topic “3.4 GYMNOSPERMS” of chapter 3 of NCERT.

Pinus belongs to gymnosperms in which male and female gametophytes do not have an independent free-living existence.

They remain within the sporangia which are of two types:

• Microsporangia
• Megasporangia

Hence, the correct option is C.
NCERT Reference: Page no. 39 of topic “3.4 GYMNOSPERMS” of chapter 3 of NCERT.

• The thalli of lichens can adhere to the surface of the rock and absorb moisture from the atmosphere; therefore, these colonize the bare surfaces of rocks first. These lichens produce acids that corrode the rock and their thalli collect windblown soil particles among them that help in formation of a thin film of soil. 
• The adult plant body of bryophyte represents the gametophyte. A short-lived sporophyte occurs as a parasite on the gametophyte. In gymnosperms, a leafy green sporophyte generates cones containing male and female gametophytes; female cones are bigger than male cones and are located higher up in the tree. 
• The coralloid roots contain symbiotic cyanobacteria (blue-green algae), which fix nitrogen and, in association with root tissues, produce such beneficial amino acids as asparagine and citrulline. 

Hence, the correct option is B.

NCERT Reference: Topics “3.2 BRYOPHYTES” and “3.4 GYMNOSPERMS” of chapter 3 of NCERT.