Biology: Fragmentation and Akinetes
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Questions and Answers

What is the characteristic feature of autospores?

  • They are similar to the parent cell in all respects except size (correct)
  • They have flagella
  • They have a cell wall distinct from the parent wall
  • They are produced by meiotic division

    • Which type of spores are produced by the division of the protoplast in three planes?

  • Zoospores
  • Endospores (correct)
  • Exospores
  • Aplanospores

    • What is the main difference between aplanospores and autospores?

  • Presence or absence of a cell wall
  • Size and structure (correct)
  • Method of production
  • Presence or absence of flagella

    • Which of the following is NOT a characteristic of zoospores?

    <p>They are non-motile</p> Signup and view all the answers

    What is the mechanism of exospore formation?

    <p>Rupturing of the cell wall apically</p> Signup and view all the answers

    What is the main difference between spores produced by meiotic division and mitotic division?

    <p>Method of production</p> Signup and view all the answers

    What is the main function of akinetes in algae?

    <p>To provide a means of perennation and multiplication</p> Signup and view all the answers

    How do akinetes separate from the parent cell?

    <p>By the decay or drying up of the vegetative cell</p> Signup and view all the answers

    What is the characteristic of aplanospores?

    <p>They are non-flagellated</p> Signup and view all the answers

    What is the term for the process of akinete formation in algae?

    <p>Akinetogenesis</p> Signup and view all the answers

    Which of the following spores is not mentioned in the text?

    <p>Cyanospores</p> Signup and view all the answers

    What is the characteristic of zoospores?

    <p>They are flagellated and contain a chromatophore</p> Signup and view all the answers

    In which type of cell can asexual spores be formed?

    <p>In any vegetative cell or in specially differentiated cells called sporangia</p> Signup and view all the answers

    What is the purpose of asexual reproduction in algae?

    <p>To multiply the algae under favourable conditions</p> Signup and view all the answers

    What is the characteristic of isogamous type of sexual reproduction?

    <p>Male and female gametes are morphologically similar but differ physiologically</p> Signup and view all the answers

    What is the main difference between anisogamous and oogamous types of sexual reproduction?

    <p>The motility of male and female gametes</p> Signup and view all the answers

    Which type of sexual reproduction is considered to be the most advanced?

    <p>Oogamous</p> Signup and view all the answers

    What is the characteristic of heterogamous type of sexual reproduction?

    <p>Male and female gametes differ in size and physiology</p> Signup and view all the answers

    What is the term for the male reproductive body in Rhodophyceae?

    <p>Spermatangium</p> Signup and view all the answers

    Which type of sexual reproduction is common in unicellular algae?

    <p>Isogamous</p> Signup and view all the answers

    What is the characteristic of oogamous type of sexual reproduction?

    <p>Female gametes are motile and larger in size</p> Signup and view all the answers

    What is the term for the female reproductive body in Rhodophyceae?

    <p>Oogonium</p> Signup and view all the answers

    Study Notes

    Fragmentation

    • Fragmentation is a process where each fragment grows into a new individual under favorable conditions
    • It involves the repeated division and subsequent separation of component cells

    Akinetes

    • Akinetes are single-celled, resting fragments specially modified for perennation and multiplication
    • They are formed either singly or in chains in the vegetative filament
    • The entire protoplast of the vegetative cell loses water, contracts, and becomes rounded or oval in form
    • The parent cell wall becomes thickened and highly resistant
    • Akinetes enable the species to tide over unfavorable periods for growth
    • Each akinete grows into a new filament under suitable conditions

    Asexual Reproduction

    • Asexual reproduction is the commonest method of multiplication among algae under favorable conditions
    • It may take place repeatedly during the season
    • It involves the formation of specialized cells, including zoospores, aplanospores, autospores, hypnospores, carpospores, tetraspores, endospores, and exospores
    • Zoospores are the most important kind of asexual spore, provided with one or more flagella and a chromatophore, nucleus, and eye spot
    • Aplanospores are non-flagellated

    Sexual Reproduction

    • Sexual reproduction can be categorized into two types: isogamous and heterogamous

    Isogamous

    • Isogamy is a type of sexual reproduction common among unicellular algae
    • Both male and female gametes are morphologically similar but differ physiologically
    • It is considered a primitive nature

    Heterogamous

    • Heterogamy is a more advanced type of sexual reproduction
    • Both male and female gametes differ morphologically and physiologically
    • Male gametes are usually smaller in size
    • Heterogamy can be further divided into anisogamous and oogamous types
    Anisogamous
    • Both fusing gametes are motile, but male gametes are smaller in size and more active (e.g., Pandorina and Chlamydomonas)
    Oogamous
    • It is considered the most advanced type of sexual reproduction
    • Male gametes are motile and found in large numbers, whereas female gametes are non-motile and larger in size
    • It is common among higher algae

    Life Cycles in Algae

    • There are three different types of life cycles, depending on when meiosis occurs, the type of cells produced, and if there is more than one free-living stage present in the life cycle

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    Description

    This quiz covers the process of fragmentation, a method of asexual reproduction in organisms, and akinetes, a type of modified cell that helps in perennation and multiplication.

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