NEET Biology Plant Kingdom MCQs Set 20

Answer: (a) Red algae

Explanation:
1. Phycoerythrin is the red pigment that dominates in red algae (Rhodophyceae), which gives them their colour.
2. Green algae are rich in chlorophylls, brown algae in fucoxanthin and blue-green algae also carry phycocyanin.

Teacher's Note:
1. Match pigment to class: red algae phycoerythrin, brown algae fucoxanthin.
2. Red algae can grow at great depths because of this pigment.

Answer: (b) Male and female gametophytes are free living

Explanation:
1. Gymnosperms are heterosporous, have naked seeds and mostly narrow needle-like leaves with a thick cuticle.
2. Their male and female gametophytes are highly reduced and remain dependent on the sporophyte, not free living.

Teacher's Note:
1. In seed plants the gametophytes are retained within the sporophyte.
2. Free-living gametophytes occur in bryophytes and pteridophytes.

Answer: (c) Angiosperms

Explanation:
1. In angiosperms the male and female gametophytes (pollen grain and embryo sac) are reduced and do not live independently.
2. In algae, bryophytes and pteridophytes the gametophyte is free living.

Teacher's Note:
1. Gametophyte dependence increases from bryophytes to seed plants.
2. Dominant sporophyte is the evolutionary trend.

Answer: (c) Amylopectin and glycogen

Explanation:
1. Floridean starch, the food reserve of red algae, is similar in structure to amylopectin and glycogen.
2. Laminarin is the reserve of brown algae, while mannitol and algin are other brown algal products.

Teacher's Note:
1. Red algae store floridean starch, brown algae store laminarin and mannitol.
2. Compare it with glycogen to remember its branched structure.

Answer: (a) Equisetum

Explanation:
1. Strobili or cones are compact reproductive structures found in Equisetum and in Selaginella and Lycopodium.
2. Salvinia, Pteris and Marchantia do not form cones.

Teacher's Note:
1. Equisetum, the horsetail, bears cones with sporangiophores.
2. Cones also occur in gymnosperms.

Answer: (c) Pteridophytes

Explanation:
1. Retention of the female gametophyte with the developing young embryo on the parent sporophyte for some time is first seen in some pteridophytes (Selaginella, Salvinia), a step towards the seed habit.
2. Bryophytes show only the zygote retained in the archegonium.

Teacher's Note:
1. This is a major evolutionary step towards the seed habit.
2. Heterospory and retention of megaspore go together.

Answer: (d) Both sieve tubes and companion cells

Explanation:
1. Phloem of gymnosperms has albuminous cells and sieve cells, but it lacks sieve tubes and companion cells, which are characteristic of angiosperms.

Teacher's Note:
1. Gymnosperm phloem has sieve cells with albuminous cells.
2. Angiosperm phloem has sieve tube elements with companion cells.

Answer: (c) Chlamydomonas

Explanation:
1. Zygotic meiosis is found in haplontic algae such as Chlamydomonas, where the zygote divides by meiosis to form haploid spores.
2. Fucus is diplontic, while Funaria and Marchantia show haplo-diplontic life cycles.

Teacher's Note:
1. In haplontic cycles meiosis occurs in the zygote.
2. Volvox, Spirogyra and Chlamydomonas are common examples.

Answer: (d) Algin is obtained from red algae, and carrageenan from brown algae. E NEET-II - 2016 153

Explanation:
1. Agar is obtained from Gelidium and Gracilaria, Laminaria and Sargassum are eaten, and algae add dissolved oxygen by photosynthesis.
2. Algin is obtained from brown algae and carrageen from red algae, so the last statement is reversed.

Teacher's Note:
1. Algin comes from brown algae, carrageen from red algae.
2. Memorise the economic products of each algal class.

Answer: (c) Sequoia is one of the tallest trees

Explanation:
1. Sequoia (giant redwood) is one of the tallest trees.
2. Gymnosperms are heterosporous only, Salvinia is a pteridophyte and gymnosperm leaves are well adapted to extremes of climate.

Teacher's Note:
1. Sequoia sempervirens grows over 100 m tall.
2. Gymnosperm leaves have thick cuticle and sunken stomata.

Answer: (a) upper oogonium and lower antheridium on the same plant

Explanation:
1. In Chara, which is monoecious, the oogonium (female) lies above the antheridium (male) on the same plant.

Teacher's Note:
1. Remember that the female structure is on top in Chara.
2. Chara is a green alga, but with a complex body.

Answer: (d) In Oomycetes female gamete is smaller and motile, while male gamete is larger and non-motile

Explanation:
1. Chlamydomonas shows both isogamy and anisogamy and Fucus is oogamous.
2. In oomycetes (and in oogamy generally) the female gamete is larger and non-motile while the male gamete is smaller and motile, so the last statement is wrong.

Teacher's Note:
1. In oogamy the egg is large and non-motile and the sperm is small and motile.
2. Isogametes look alike, anisogametes differ in size.

Answer: (d) Salvinia - Prothallus

Explanation:
1. Viroids have RNA, mustard has synergids in the embryo sac and Ginkgo, a gymnosperm, bears archegonia.
2. Salvinia is a heterosporous pteridophyte whose gametophytes remain reduced and develop inside the spores, so it does not form a free-living prothallus.
3. Hence the pair Salvinia-Prothallus is wrongly matched.

Teacher's Note:
1. Heterosporous plants produce endosporic, reduced gametophytes.
2. Free-living prothalli occur in homosporous ferns.

Answer: (a) Marchantia

Explanation:
1. Archegoniophores (female receptacles) are found in Marchantia, a liverwort.
2. Chara is an alga, and Adiantum and Funaria do not have archegoniophores.

Teacher's Note:
1. Marchantia has antheridiophores and archegoniophores on separate thalli.
2. It also reproduces asexually through gemma cups.