Plant Kingdom - 2 - Free MCQ Practice Test with solutions, NEET Biology

Green algae usually have a rigid cell wall made of cellulose.

The cell wall structure is important for the following reasons:

• Cellulose provides strength and support, helping the algae maintain its shape.
• The cell wall is typically composed of an inner layer of cellulose and an outer layer of pectose.
• This structure allows green algae to thrive in various aquatic environments.

Overall, the composition of the cell wall is crucial for the survival and functionality of green algae.

The given diagram is of Green  Algae -VOLVOX .In the given image, the incorrect feature about the class depicted is:

- C: Inner pectose and outer cellulose in cell wall

Explanation:
- The cell wall of organisms in this class typically consists of cellulose as the primary component, not pectose.
- Pectose is not a common constituent of the cell wall in this class of organisms.
- Cellulose provides structural support and rigidity to the cell wall, which is a defining characteristic of this class.

Species of Sphagnum, a type of moss, are significant for their ability to produce peat, which has been used as a source of fuel for many years.

Key points about Sphagnum:

• It is a moss known for its water retention capabilities.
• Peat formed from Sphagnum is used in gardening and as a fuel source.
• Sphagnum plays a crucial role in ecosystems, aiding in soil formation and moisture retention.

In Gymnosperms,The two kinds of spores are produced within sporangia that are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones.

The megaspores and microspores germinate and give rise to female and male gametophytes, respectively. The female gametophytes in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos take place within the female gametophytes. This event is a precursor to the seed habit considered an important step in evolution

Correct answer B. 

The plant body of liverworts is thalloid and dorsiventral whereas mosses have upright, slender axes bearing spirally arranged leaves.

Unlike bryophytes and pteridophytes, in gymnosperms the male and the female gametophytes do not have an independent free-living existence.

Solution: C  Asexual reproduction in liverworts occurs through fragmentation of thalli or gemmae formation, while sexual reproduction involves separate thalli producing male and female sex organs. The sporophyte includes a foot, seta, and capsule, where meiosis occurs to produce spores that develop into gametophytes.

Fusion between one large, non-motile (static) female gamete and a smaller, motile male gamete is termed as oogamous.

• Isogamous - C. Fusion of gametes that are similar in size and both flagellated or non-flagellated - i. Spirogyra or iv. Ulothrix
• Anisogamous - A. Fusion of gametes that are dissimilar in size - ii. Eudorina
• Oogamous - B. Fusion between a large, non-motile female gamete and a smaller, motile male gamete - iii. Volvox or v. Fucus

The plant shown above is cycas. This plant belongs to division cycadophyta and family cycadceae. It is diecious and native to India.

The sex organs in bryophytes are multicellular. The male sex organ is called antheridium. They produce biflagellate antherozoids. The female sex organ called archegonium is flask-shaped and produces a single egg.

Assertion Correctness: The assertion is correct as mosses, along with lichens, are among the initial organisms to colonize rocks due to their ecological importance.

Reason Correctness: The reason is also correct as mosses do form dense mats on the soil, which helps in reducing the impact of falling rain and preventing soil erosion.

Explanation of Reason as Correct Explanation of Assertion: While both the assertion and reason are true, the reason provided does not directly explain why mosses are the first organisms to colonize rocks. The reason focuses on the impact of mosses on soil erosion, which is related but not a direct explanation for their role as primary colonizers.

Correct option: C. Three statements are correct.

• Statement I - Correct. The gametophyte generation in liverworts, mosses and ferns is an independent, free-living phase (for example, the prothallus in ferns).

• Statement II - Correct. Gymnosperms are heterosporous, and certain ferns (for example, Salvinia, Marsilea) also produce distinct microspores and megaspores.

• Statement III - Correct. The listed genera reproduce by oogamy: Fucus shows oogamous reproduction with oogonia and antheridia; many species of Volvox form larger eggs and smaller motile male gametes (oogamy); and Albugo (an oomycete or water mould) produces oogonia and antheridia and is oogamous.

• Statement IV - Incorrect. The sporophyte of mosses is generally more elaborate (with a seta and capsule) than that of liverworts, so the claim that the liverwort sporophyte is more elaborate is false.

Therefore, three statements are true and option C is the correct choice.

Statement a is incorrect because gemmae are specialized reproductive structures primarily in bryophytes, not thallophytes.
Statement b is incorrect: Gemmae are multicellular, not unicellular.
Statement c is correct: Gemmae are formed in small receptacles called gemma cups located on the thalli.
Statement d is partially correct: A single gemma typically forms one new individual.
Statement e is correct: Gemmae are chlorophyllous and multicellular structures.
Statement f is incorrect: Gemmae germinate to form new individuals, but not necessarily a monoecious thallus in Marchantia.
Thus, the correct statements are c, d, and e.