Plant Kingdom: Class 11 Biology Q&A · Page 3
59 free answers on Plant Kingdom (Biology) for Class 11 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- BiologyClass 11All
a) Draw a well-labelled diagram of Funaria representing gametophyte and sporophyte. (b) Explain sexual reproduction in brown algae.
(a) Funaria structure: Gametophyte: Leafy shoot with rhizoids, main axis, and leaves Sporophyte: Capsule, seta (emerging from gametophyte) (b) Sexual reproduction in brown algae: Exhibits isogamous, anisogamous, or oogamous patterns Gametes are typically pyriform (pear-shaped) with two
- BiologyClass 11All
Explain the haplo-diplontic condition in bryophytes and pteridophytes.
Haplo-diplontic life cycle features both multicellular haploid and diploid phases: In Bryophytes: Dominant phase: Independent, photosynthetic gametophyte (haploid) Sporophyte: Dependent on gametophyte for nutrition; consists of foot, seta, and capsule In Pteridophytes: Dominant phase: Independent, vascularized <s
- BiologyClass 11All
Represent schematically the type of life cycle pattern exhibited by most algae.
Most algae exhibit a haplontic life cycle: Haploid Gametophyte (n) → Gametes (n) → Syngamy → Zygote (2n) → Meiosis → Haploid Spores (n) → Gametophyte (n) Key features: Dominant phase is haploid Only the zygote is diploid Meiosis occurs immediately after fertilization (zygotic meiosis)
- BiologyClass 11All
Define microsporangiate and macrosporangiate.
Microsporangiate strobili (male cones): Bear microsporophylls with microsporangia producing microspores (pollen) Macrosporangiate strobili (female cones): Bear megasporophylls with megasporangia (ovules) producing megaspores
- BiologyClass 11All
What is the storage food in different classes of algae?
Class Storage Product Chlorophyceae Starch Phaeophyceae Laminarin, Mannitol Rhodophyceae <p
- BiologyClass 11All
Draw a well-labelled diagram of Fucus.
Fucus exhibits typical brown algae morphology with: Holdfast: Anchoring structure Stipe: Stem-like portion Frond: Photosynthetic blade with midrib Air bladders: Gas-filled structures providing buoyancy
- BiologyClass 11All
Give two general characteristics of angiosperms.
Reproductive structures: Produce flowers containing specialized reproductive organs; seeds develop within fruits (mature ovaries) Habitat diversity: Exhibit remarkable ecological adaptability, occupying virtually all terrestrial and many aquatic habitats
- BiologyClass 11All
Name the algae from which agar is obtained. Give two uses of agar.
Source algae: Gelidium and Gracilaria (red algae) Uses of agar: Microbiological culture medium: Provides solid substrate for bacterial and fungal cultivation Food industry: Gelling agent in ice creams, jellies, and confectionery
- BiologyClass 11All
Give two general characteristics of Rhodophyceae.
Pigmentation: Possess r-phycoerythrin (red pigment) that masks chlorophyll, enabling photosynthesis at greater depths where red wavelengths penetrate Habitat: Predominantly marine, with greater diversity in warmer tropical and subtropical waters
- BiologyClass 11All
In pteridophytes how are haploid spores produced?
In the dominant diploid sporophyte, specialized leaves called sporophylls bear sporangia. Within sporangia, diploid spore mother cells undergo meiosis, producing haploid spores that disperse and germinate into gametophytes.
- BiologyClass 11All
What is nucellus in gymnosperms?
The nucellus is the megasporangium tissue that comprises the central portion of the ovule. A single megaspore mother cell differentiates from nucellar cells and undergoes meiosis to produce megaspores, which develop into the female gametophyte.
- BiologyClass 11All
Discuss the flagellar number and position of insertion in different classes of algae.
Class Flagellar Number Position of Insertion Chlorophyceae (Green algae) 2–8, equal length Apical (at cell apex) Phaeophyceae (B
- BiologyClass 11All
What is alternation of generation?
Alternation of generation describes life cycles where multicellular haploid gametophyte and diploid sporophyte phases alternate regularly. The gametophyte produces gametes via mitosis; gamete fusion forms a zygote that develops into a sporophyte. The sporophyte produces spores via meiosis, which develop into gametophytes, completing the cycle.
- BiologyClass 11All
Explain how sexual reproduction occurs in gymnosperms.
Gymnosperm sexual reproduction involves: Pollination: Wind-dispersed pollen grains reach the ovule's micropyle Pollen tube formation: The pollen grain germinates, forming a tube that grows through nucellus tissue Fertilization: The pollen tube delivers male gametes to archegonia within the megagametophyte Syngamy: Male gamete fuses with egg cell, forming a diploid zygote</s
- BiologyClass 11All
Mention the "division" of plant group that is known as non-vascular amphibians of the plant kingdom. Why are they called so?
Bryophytes are termed the "amphibians of the plant kingdom" because: Lack of vascular tissue (xylem and phloem) limits their size and distribution Dependence on water for sexual reproduction—flagellated sperm require external moisture to swim to the egg Terrestrial habitat with aquatic reproduction, paralleling amphibian life history
- BiologyClass 11All
Explain how mosses reproduce sexually.
Sexual reproduction in mosses follows this sequence: Antheridia release biflagellated antherozoids into water Antherozoids swim chemotactically toward archegonia Fertilization occurs when an antherozoid fuses with the egg cell The resulting zygote develops into a multicellular sporophyte consisting of: Foot (absorbs nutr
- BiologyClass 11All
Explain how liverworts reproduce asexually.
Liverworts employ two primary asexual reproductive mechanisms: Fragmentation: The thallus breaks into fragments; each fragment regenerates into a complete individual through mitotic cell division Gemma formation: Specialized multicellular propagules develop in gemma cups, detach, and germinate into new gametophytes under favorable conditions
- BiologyClass 11All
What are microphylls?
Microphylls are small, simple leaves with a single, unbranched vascular strand (vein), characteristic of certain pteridophytes such as Selaginella and Lycopodium. They contrast with megaphylls, which have complex branching venation.
- BiologyClass 11All
What is the function of holdfast in brown algae?
The holdfast is a root-like anchoring structure that attaches brown algae (Phaeophyceae) to substrata such as rocks, preventing dislodgement by water currents and waves. Unlike true roots, holdfasts do not absorb nutrients.