NEET Biology Plant Kingdom MCQs Set 17

Answer: (b) Rhodophyceae

Explanation:
1. Red algae (Rhodophyceae) store food as floridean starch, which resembles amylopectin and glycogen.
2. Green algae store true starch and brown algae store laminarin and mannitol.

Teacher's Note:
1. Match each algal class with its reserve food: green with starch, brown with laminarin and mannitol, red with floridean starch.

Answer: (a) Laminaria

Explanation:
1. Laminaria (a kelp) concentrates iodine and is a source of iodine.
2. Iodine is needed to make thyroxine in the thyroid gland.

Teacher's Note:
1. Brown algae such as Laminaria and Fucus are rich in iodine. Gelidium is the agar source.

Answer: (c) Bryophytes

Explanation:
1. Bryophytes were the first plants to colonise land, though they still need water for fertilization.
2. That is why they are called the amphibians of the plant kingdom.

Teacher's Note:
1. Order of appearance on land: bryophytes, pteridophytes, gymnosperms, angiosperms.

Answer: (a) Spore mother cell

Explanation:
1. The spore mother cell is part of the diploid sporophyte and divides by meiosis.
2. Gametes and spores (meiospores) are haploid.

Teacher's Note:
1. In bryophytes only the zygote, sporophyte and spore mother cells are diploid. Spores and the whole gametophyte are haploid.

Answer: (b) Western Himalayas

Explanation:
1. The Western Himalayas have a very rich liverwort flora.
2. This is a factual point about distribution in India.

Teacher's Note:
1. Western Himalayas for liverworts, a favourite one-line fact for NEET.

Answer: (c) Venter

Explanation:
1. The archegonium has a swollen base called the venter, which contains the egg and the ventral canal cell.
2. The neck lies above it and contains neck canal cells.

Teacher's Note:
1. Venter is the swollen base that holds the egg.

Answer: (b) Dioecious gametophytes

Explanation:
1. Heterosporous plants make small microspores and large megaspores.
2. Microspores give male gametophytes and megaspores give female gametophytes, so the gametophytes are dioecious.

Teacher's Note:
1. Heterospory means two spore sizes and separate male and female gametophytes.

Answer: (b) Sporophyte

Explanation:
1. In pteridophytes the dominant plant is the diploid sporophyte, differentiated into root, stem and leaves.
2. The gametophyte (prothallus) is small and short-lived.

Teacher's Note:
1. Dominant body: gametophyte in bryophytes, sporophyte in all higher groups.

Answer: (b) Chlorophyll a and d, floridean starch

Explanation:
1. Red algae contain chlorophyll a and d, phycoerythrin and store floridean starch.
2. Fucoxanthin and mannitol belong to brown algae.

Teacher's Note:
1. Red algae completely lack flagella. They store floridean starch.

Answer: (a) Dictyota

Explanation:
1. Laminarin and mannitol are the reserve foods of brown algae, and Dictyota is a brown alga.
2. Volvox and Chlamydomonas store starch and Polysiphonia stores floridean starch.

Teacher's Note:
1. Laminarin is a polysaccharide reserve in brown algae.

Answer: (c) Spirulina

Explanation:
1. Spirulina (a cyanobacterium) is rich in protein, vitamins and minerals and is used by space travellers.
2. Gracilaria is a source of agar.

Teacher's Note:
1. Chlorella and Spirulina are used as food supplements in space.

Answer: (a) Sargassum

Explanation:
1. Sargassum is a brown alga (Phaeophyceae).
2. Volvox, Ulothrix and Chara are green algae.

Teacher's Note:
1. Brown algae examples: Ectocarpus, Dictyota, Laminaria, Sargassum, Fucus.

Answer: (a) fragmentation of thalli and gemma formation

Explanation:
1. Liverworts reproduce asexually by fragmentation of the thallus and by gemmae formed in gemma cups.
2. Spores are haploid and are produced by the sexual cycle, and zoospores are not formed.

Teacher's Note:
1. Gemmae are green, multicellular buds that grow into new thalli.

Answer: (c) archegoniophore, gemma cup, rhizoids

Explanation:
1. The female branch that carries archegonia is the archegoniophore, and the male one is the antheridiophore.
2. Gemmae develop in gemma cups on the upper surface and the rhizoids anchor the thallus below.

Teacher's Note:
1. Marchantia is dioecious. Female thallus has archegoniophores, male thallus has antheridiophores.

Answer: (c) mosses and liverworts

Explanation:
1. Bryophytes are divided into liverworts and mosses.
2. Ferns are pteridophytes.

Teacher's Note:
1. Two classes of bryophytes are Hepaticopsida and Musci.

Answer: (c) prothallus

Explanation:
1. The spore is haploid and gives the free-living gametophyte called the prothallus.
2. The sporophyte develops later from the zygote.

Teacher's Note:
1. Spore leads to gametophyte, zygote leads to sporophyte.

Answer: (c) Selaginella and Salvinia

Explanation:
1. Selaginella and Salvinia produce two kinds of spores, microspores and megaspores.
2. The other genera listed are homosporous.

Teacher's Note:
1. Heterosporous pteridophytes: Selaginella, Salvinia, Marsilea, Azolla.

Answer: (d) all of these

Explanation:
1. Conifer leaves are needle-like, have a thick cuticle and sunken stomata.
2. All three reduce water loss and give resistance to wind and temperature extremes.

Teacher's Note:
1. Think of Pinus needles as a xerophytic adaptation.

Answer: (d) Both (a) and (c)

Explanation:
1. Pinus and Cedrus (conifers) have branched stems.
2. Cycas has an unbranched columnar stem.

Teacher's Note:
1. Cycas is unbranched. Conifers are branched.

Answer: (c) egg (n), secondary nucleus (2n)

Explanation:
1. One sperm fuses with the egg to form the diploid zygote (syngamy).
2. The other sperm fuses with the diploid secondary nucleus to form the triploid primary endosperm nucleus (triple fusion).

Teacher's Note:
1. Two fusions, syngamy and triple fusion, make double fertilization.

Answer: (a) laminarin or mannitol

Explanation:
1. Brown algae store food as complex carbohydrates called laminarin and as mannitol.
2. Algin is a wall component, not a reserve.

Teacher's Note:
1. Do not confuse algin (wall) with laminarin (reserve food).

Answer: (a) zoospores

Explanation:
1. Red algae have no flagellated stage at all, so no zoospores.
2. They make non-motile spores and non-motile gametes.

Teacher's Note:
1. Red algae are entirely without flagella.

Answer: (a) haploid

Explanation:
1. The dominant plant body is the gametophyte, which is haploid.
2. The diploid sporophyte is small and dependent.

Teacher's Note:
1. Bryophyte body equals haploid gametophyte.

Answer: (b) thalloid

Explanation:
1. Liverworts have a flat, dorsiventral thallus.
2. They have rhizoids, not true roots, and live in moist places.

Teacher's Note:
1. Mosses are leafy, liverworts are thalloid or leafy.

Answer: (a) strobili or cones

Explanation:
1. Sporophylls grouped into compact structures are called strobili or cones.
2. They occur in Selaginella and Equisetum.

Teacher's Note:
1. Cone equals strobilus equals a group of sporophylls.

Answer: (c) four classes

Explanation:
1. The four classes are Psilopsida, Lycopsida, Sphenopsida and Pteropsida.
2. Examples are Psilotum, Selaginella, Equisetum and Pteris.

Teacher's Note:
1. Memorise the four classes with one example each.