Biology Seed Structure and Function Quiz
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Questions and Answers

What structure surrounds the embryo in a seed?

  • Testa
  • Endosperm (correct)
  • Seed coat
  • Cotyledon

    • What are cotyledons?

  • The first leaves of the developing embryo (correct)
  • The main stem of the plant
  • The roots of the plant
  • The male reproductive cells

    • The testa is the innermost layer of a seed.

    False

    What is the primary function of the endosperm in a seed?

    <p>To provide nourishment to the developing embryo.</p> Signup and view all the answers

    Fertilization involves the fusion of the male nucleus with the female nucleus.

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

    What is fertilization?

    <p>The fusion of the male nucleus with that of the egg.</p> Signup and view all the answers

    The seed is composed of the embryo and the ________.

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

    Match the following seed components with their descriptions:

    <p>Embryo = The developing plant within the seed Endosperm = Nourishing tissue surrounding the embryo Testa = Protective outer layer of the seed Cotyledon = First leaves that emerge from a germinating seed</p> Signup and view all the answers

    The ____ are the first leaves of the developing embryo.

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

    Match the following terms with their descriptions:

    <p>Embryo = A developing plant that arises from fertilization Cotyledon = The first leaves of a seedling Fertilization = The process of nucleus fusion Male nucleus = The reproductive cell from the male parent</p> Signup and view all the answers

    What is formed from the union of one sperm with the egg cell?

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

    The endosperm is formed from the union of a sperm with the egg cell.

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

    What is the first part to emerge from the developing seed?

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

    In double fertilization, one sperm fertilizes the egg cell to form the embryo, while the other sperm fuses with ______ nuclei to form the endosperm.

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

    What is the primary function of the seed coat?

    <p>To protect the kernel tissues</p> Signup and view all the answers

    The term 'Orthoplocous' refers to a type of seed coat.

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

    What are the two primary types of embryo mentioned?

    <p>Radical bents and Cotyledons</p> Signup and view all the answers

    A seed is formed of one or two seed _____ that protect the kernel.

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

    What is the primary structure of simple aleurone grains?

    <p>Amorphous mass of protein enveloped by a protein membrane</p> Signup and view all the answers

    All aleurone grains consist of a crystalloid structure.

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

    What is the characteristic of aleurone grains found in leguminous seeds?

    <p>Simple structure with an amorphous mass of protein</p> Signup and view all the answers

    Aleurone grains can be either simple in structure or consist of __________.

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

    Match the following structures with their descriptions:

    <p>Simple aleurone grains = Amorphous mass of protein Crystalloid aleurone grains = Crystalline structure</p> Signup and view all the answers

    What does the raphe connect in a seed?

    <p>The hilum to the chalaza</p> Signup and view all the answers

    The raphe is located at the top of the seed near the flower.

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

    What is the role of the raphe in a seed?

    <p>It connects the hilum to the chalaza.</p> Signup and view all the answers

    The raphe is a line running from the _____ to the chalaza.

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

    Signup and view all the answers

    Study Notes

    Course Information

    • Course Title: Pharmacognosy II
    • Course Code: PG303
    • University: Egyptian Chinese University

    Course Assessment

    • Periodic exam: 20 marks
    • Practical exam: 40 marks
    • Oral exam: 15 marks
    • Final exam: 75 marks

    Week 1: Introduction to Seeds

    • Seeds are mature, fertilized ovules containing an embryo.
    • Ovules develop into seeds.
    • Pollination is the process of pollen landing on the stigma.
    • This leads to fertilization.
    • After fertilization, the ovary swells and develops into the fruit, which encloses the seed.
    • Images of various seeds were presented.

    Introduction to Seeds (Definition)

    • Seeds are plant parts that develop from fertilized ovules.
    • They contain an embryo, which has the potential to develop into a new plant.

    Parts of a Pea Flower & Pea Pod

    • Parts of a pea flower were labeled: stigma, ovary wall, ovule, fruit wall, and seed.
    • Components of a pea pod were labelled: stigma, ovary wall, ovule, fruit wall, and seed.

    Pollination and Fertilization of a Flower

    • Pollination occurs when pollen lands on the stigma of a carpel.
    • A pollen tube grows down the style of the carpel to the ovary, carrying the sperm cells.
    • Fertilization involves the fusion of the sperm with the egg cell and the central cell.

    Function of Seeds

    • Seeds ensure the continuation and distribution of plants.
    • Seeds facilitate transportation.

    Structure of the Ovule

    • Integuments form the seed coat (testa) that protect the embryo.
    • Micropyle: opening for pollen tube entry.
    • Nucellus: tissue for nutrition.
    • Endosperm: nutritive tissue.
    • Embryo sac: contains the egg cell.
    • Chalaza: basal part of the nucellus.
    • Funicle: stalk that attaches the ovule to placenta.

    Structure of the Ovule (continued)

    • Testa: protective seed coat.
    • Micropyle: a small opening for pollen tube entry.
    • Nucellus: tissue containing stored food.
    • Perisperm: nutritive tissue, sometimes developed from nucellus.
    • Endosperm: nutritive tissue, derived from fusion of sperm and central cell.
    • Embryo sac: contains egg cell and other cells.
    • Embryo: developed from fertilized egg cell.

    After Fertilization of the Ovule

    • Integuments: develop into the seed coat (testa).
    • Nucellus: may develop into perisperm.
    • Endosperm: develops to provide nutrients for the developing embryo.

    Types of Seeds (Based on Endosperm)

    • Exalbuminous seeds: do not have endosperm, the embryo develops rapidly, and nutrients are stored in cotyledons.
    • Albuminous seeds: have endosperm, the embryo remains small, and the nucellus develops into perisperm to store additional nutrients.

    External Appearance of a Seed

    • Testa: seed coat (outer layer).
    • Hilum: scar where seed was attached to funicle.
    • Micropyle: small opening.
    • Position of radicle: location of the future root..

    Types of Ovules

    • Atropous: straight.
    • Anatropous: inverted.
    • Amphitropous: partly bent.
    • Campylotropous: bent upon itself.
    • Raphe: line on ovule, formed by the fusion of funicle with the integument.

    A Typical Seed

    • Testa: seed coat, originated from integument, protects the kernel.
    • Kernel: embryo and nutritive tissue –endosperm/perisperm, enclosed by testa.

    Types of Embryos

    • Various classifications of embryos were reviewed and illustrated.

    Types of Outgrowths

    • Arillus: from funicle/hilum; entire seed enveloping, e.g., Cardamom.
    • Arillode: from micropyle, covers part of seed, e.g., Nutmeg.
    • Caruncle: localized fleshy outgrowth from neighborhood of micropyle e.g., Ricinus.
    • Strophiole: local enlargement, e.g., Colchicum.
    • Wing: membranous extension, e.g., Strophanthus.
    • Tuft of hairs: on stem, Apocyanaceae family; awn-like hairs on stalk, Strophanthus genus.

    Testa Types (Texture)

    • Membranous
    • Leathery
    • Hard
    • Woody
    • Fleshy

    Testa Types (Shape)

    • Longitudinally striated
    • Smooth
    • Papillose
    • Pitted
    • Reticulate
    • Hairy
    • Rugged

    Microscopical Characters

    • Testa and outgrowths, if present.
    • Perisperm: parenchyma cells containing starch.
    • Endosperm: containing starch, protein, or fixed oils
    • Embryo
    • Cell contents: Starch, protein, Fixed oils

    The Testa:

    • Formed from one or two integuments.
    • Four basic layers: epidermis, hypodermis, sclerenchymatous layer, and nutritive/hyaline layer.
    • Pigment layer: contributes to the seed's color.

    Reserved Food Material

    • Carbohydrates (Starch, cellulose, hemicellulose)
    • Fixed oils and proteins (aleurone grains).

    Types of Aleurone Grains

    • Simple: Amorphous mass of protein enveloped in a protein membrane –e.g. legumes seeds.
    • Compound: Consist of crystalloid and globoid embedded within a protein matrix.

    Ground Substance, Crystalloids, and Globoids

    • Ground substance: amorphous matrix surrounding the grains.
    • Crystalloids: proteinoid matter crystals.
    • Globoids: rounded or ovoid shape, insoluble in water.

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    Pharmacognosy II PG303: Seed Structure and Morphology PDF

    Description

    Test your knowledge on seed structure and function with this quiz. Explore essential terms like cotyledons, endosperm, and the processes of fertilization. Perfect for biology students looking to solidify their understanding of plant reproductive systems.

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