• Biology,  Botony

    MCQ ON PLANT REPRODUCTION

    1. Formation of gametophyte directly from sporophyte without meiosis is (a) apospory (b) apogamy (c) parthenogenesis (d) amphimixis. Answer and Explanation: 1. (a): Formation of gametophyte directly from sporophyte without meiosis and spore formation is apospory. The gametophyte has a diploid number of chromosomes such gametophyte may form viable gametes which fuse to form tetraploid sporophyte. Apogamy is the development of sporophyte directly from gametophytic tissue without fusion of gametes. Amphimixis is normal sexual reproduction. Parthenogenesis is the development of an embryo from an egg without fertilization. 2. Parthenogenesis is (a) development of an embryo without fertilization (b) development of fruit without fertilization (c) development of fruit without hormones (d) development of…

  • Q & A

    Q & A ON REPRODUCTION IN ORGANISMS

    Q1. What is life span? Ans: Life span is the period from birth to natural death of an organism. Q2. Define clone. Ans: The individuals that are morphologically and genetically similar to the parent are called clone. Q3. Mention the different means/ methods of asexual reproduction with example. Ans:  Cell division – Protista, Monera Binary fission – Amoeba, Paramecium Budding – Yeast Zoospores (microscopic motile endogenous spores) – aquatic fungi, chlamydomonas Conidia (microscopic immotile exogenous spores)- pencillium External buds – hydra Internal buds like gemmules – sponges (spongilla) Q4.Unicellular organisms are immortal. Justify. Ans: Single celled organisms like amoeba & bacteria reproduce by cell division and there is no natural…

  • Q & A

    Q & A OF ANATOMY OF FLOWERING PLANTS

    Q1) Name the associated structure of companion cell. Ans: Sieve tube cell Q2) Name an enucleated plant cell. Ans: Sieve tube cell Q3) Name the conductory elements of xylem. Ans: Tracheary elements- Tracheids and Vessels (tracheae)  Q4) What is periderm? Ans: Phellogen, Phellum and Phelloderm are collectively called as Periderm Q5) What is annual ring? Ans: Springwood and autumn wood that appear as alternate concentric rings constitute an annual ring.  Q6) Name the meristem which is responsible for growth in diameter of the cortex. Ans: Cork Cambium Q7) What is intrafascicular cambium? Ans: Cells of cambium present between primary xylem and primary phloem. Q8) What is interfascicular cambium? Ans: The…

  • Botony

    ANATOMY OF DICOTYLEDONOUS AND MONOCOTYLEDONOUS PLANTS

    For a better understanding of tissue organisation of roots, stems and leaves, it is convenient to study the transverse sections of the mature zones of these organs. Dicotyledonous Root Look at Figure, it shows the transverse section of the sunflower root. The internal tissue organisation is as follows: The outermost layer is epiblema. Many of the cells of epiblema protrude in the form of unicellular root hairs. The cortex consists of several layers of thin-walled parenchyma cells with intercellular spaces. The innermost layer of the cortex is called endodermis. It comprises a single layer of barrel-shaped cells without any intercellular spaces. The tangential, as well as radial walls of the…

  • Botony

    THE TISSUE SYSTEM- ANATOMY OF FLOWERING PLANTS

    We were discussing types of tissues based on the types of cells present. Let us now consider how tissues vary depending on their location in the plant body. Their structure and function would also be dependent on location. On the basis of their structure and location, there are three types of tissue systems. These are the epidermal tissue system, the ground or fundamental tissue system and the vascular or conducting tissue system. Epidermal Tissue System The epidermal tissue system forms the outer-most covering of the whole plant body and comprises epidermal cells, stomata and the epidermal appendages – the trichomes and hairs. The epidermis is the outermost layer of the…

  • Botony

    THE TISSUES- ANATOMY OF FLOWERING PLANT

    A tissue is a group of cells having a common origin and usually performing a common function. A plant is made up of different kinds of tissues. Tissues are classified into two main groups, namely, meristematic and permanent tissues based on whether the cells being formed are capable of dividing or not. Meristematic Tissues Growth in plants is largely restricted to specialised regions of active cell division called meristems (Gk. meristos: divided). Plants have different kinds of meristems. The meristems which occur at the tips of roots and shoots and produce primary tissues are called apical meristems (Figure). Apical meristem: Shoot Apical meristem: Root Root apical meristem occupies the tip…

  • Biology,  Botony

    LEAF (PHYLLOPODIUM)

    The leaf is a lateral generally flattened structure borne on the stem. The leaves develop from the nodes. Their main function is photosynthesis and food making, axillary buds are found in its axil. All the leaves of a plant are known as phyllome. Axillary bud later develops into a branch. Leaves originated from shoot apical meristem and are arranged in acropetal order. Leaf is divided into 3 main parts : Leaf base (Hypopodium) – Leaves are attached to stem by leaf base. In some plants, leaf base becomes swollen and is called pulvinus which is responsible for sleep movement e.g., Cassia, mimosa, bean. In some plants, leaf base expands into…

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