Class 11 Biology Ch 5 Morphology and Anatomy introduces us to the external and internal structure of flowering plants. This chapter explains how roots, stems, leaves, flowers, and tissues are organized in a plant’s body. Understanding plant morphology and anatomy helps us identify plants, understand their functions, and relate structure to function in the plant world. It forms a strong base for topics in botany and future exams like NEET and boards.

Class 11 Biology Ch 5 Morphology and Anatomy – Intext Questions

Page 78 – Intext Questions

Q1. Define the term inflorescence. What are the different types of inflorescence?
Answer:
Inflorescence is the arrangement of flowers on the floral axis (main stem or peduncle). It describes how flowers are grouped on the plant. There are two main types:

  • Racemose inflorescence: The main axis continues to grow and flowers are arranged in an acropetal order (older at base, younger at top).
  • Cymose inflorescence: The main axis terminates in a flower and further growth occurs from lateral branches. Flowers are arranged in basipetal order (younger at base, older at top).

Q2. Define aestivation. What are its types?
Answer:
Aestivation is the arrangement of sepals or petals in a flower bud before it opens. It is useful for classification of plants.
The main types are:

  • Valvate: Sepals or petals touch each other without overlapping.
  • Twisted: Each petal overlaps the next one in a regular pattern.
  • Imbricate: There is no definite overlapping pattern; some petals overlap while others are overlapped.
  • Vexillary: Found in pea flowers; the largest petal (standard) overlaps the two lateral petals (wings), which in turn overlap the two smallest (keel).

Q3. Differentiate between actinomorphic and zygomorphic flowers.
Answer:

  • Actinomorphic flowers are radially symmetrical. You can cut them into two equal halves from any plane passing through the center. Example: Mustard, Datura.
  • Zygomorphic flowers are bilaterally symmetrical. They can only be divided into equal halves in one plane. Example: Pea, Bean.

Q4. What is a placentation? Name different types of placentation found in flowering plants.
Answer:
Placentation is the arrangement of ovules within the ovary. It helps in plant classification. The main types are:

  • Marginal: Ovules are arranged along the margin of a single carpel. Example: Pea
  • Axile: Ovules are attached to a central axis. Example: Tomato
  • Parietal: Ovules are attached to the inner walls. Example: Mustard
  • Free central: Ovules are on a central column without septa. Example: Dianthus
  • Basal: A single ovule at the base. Example: Sunflower

Q5. What is the importance of anatomical features in the classification of plants?
Answer:
Anatomical features like arrangement of vascular bundles, types of tissues, and stomata are helpful in understanding the internal structure of plants. These characters are used in classification because:

  • They remain constant regardless of environmental conditions.
  • They help in distinguishing between monocots and dicots.
  • They also provide evolutionary relationships among different plant groups.

Exercise Questions

Q1. What is meant by modification of root? What type of modification of root is found in:
(a) Banyan tree (b) Turnip (c) Mangrove trees
Answer:
Modification of roots means a change in root structure to perform functions other than absorption and anchorage, like storage, support, or breathing.

  • (a) Banyan tree: It has prop roots. These are aerial roots that grow from branches and hang down to provide support.
  • (b) Turnip: It has a taproots modified for storage. The root becomes swollen with stored food.
  • (c) Mangrove trees: These have pneumatophores (breathing roots) which grow upward and help in gaseous exchange in waterlogged soil.

Q2. Justify the following statements on the basis of external features:
(a) Underground parts of a plant are not always roots.
(b) Flower is a modified shoot.
Answer:

  • (a) Some underground parts look like roots but are actually modified stems, like rhizomes (ginger), bulbs (onion), tubers (potato), or corms (colocasia). They have nodes, internodes, and scale leaves—features of stems, not roots.
  • (b) A flower develops from a floral bud, which is a modified shoot. It has nodes and internodes, and floral parts like sepals, petals, stamens, and carpels are modified leaves. So, the flower is a condensed reproductive shoot.

Q3. How is a pinnately compound leaf different from a palmately compound leaf?
Answer:

  • Pinnately compound leaf: Leaflets are arranged on both sides of a central axis (rachis), like in neem.
  • Palmately compound leaf: All leaflets arise from the tip of the petiole, like in silk cotton.

Q4. Explain with suitable examples the different types of phyllotaxy.
Answer:
Phyllotaxy is the arrangement of leaves on a stem or branch. There are 3 main types:

  • Alternate: One leaf per node on alternate sides. Example: mustard
  • Opposite: Two leaves at each node, opposite each other. Example: guava
  • Whorled: More than two leaves arise at a single node. Example: Alstonia

Q5. Define the following terms:
(a) aestivation (b) placentation (c) actinomorphic (d) zygomorphic (e) superior ovary (f) perigynous flower (g) epipetalous stamen
Answer:

  • (a) Aestivation: Arrangement of sepals or petals in a flower bud.
  • (b) Placentation: Arrangement of ovules inside the ovary.
  • (c) Actinomorphic: A flower that can be divided into two equal halves from any plane.
  • (d) Zygomorphic: A flower that can be divided into two equal halves only through one plane.
  • (e) Superior ovary: Ovary lies above other floral parts.
  • (f) Perigynous flower: Ovary is half-inferior; floral parts are at the same level around it.
  • (g) Epipetalous stamen: Stamens are attached to petals. Example: brinjal

Q6. Differentiate between the following:
(a) Racemose and cymose inflorescence
(b) Fibrous root and adventitious root
(c) Apocarpous and syncarpous ovary
Answer:

  • (a) Racemose vs. Cymose inflorescence:
    • Racemose: Main axis grows continuously; flowers arranged in acropetal order.
    • Cymose: Main axis ends in a flower; growth continues through branches; basipetal arrangement.
  • (b) Fibrous root vs. Adventitious root:
    • Fibrous: Arise in clusters from the base of the stem, like in wheat.
    • Adventitious: Arise from parts other than the radicle (like stem or leaves), like in money plant.
  • (c) Apocarpous vs. Syncarpous ovary:
    • Apocarpous: Carpels are free. Example: lotus
    • Syncarpous: Carpels are fused. Example: mustard

Q7. Draw the labeled diagram of:
(i) gram seed
(ii) V.S. of maize seed
Answer:
You can draw them based on NCERT textbook figures.

  • (i) Gram seed: Shows seed coat, embryo, cotyledons, and radicle.
  • (ii) V.S. of maize seed: Shows single cotyledon (scutellum), coleoptile, coleorhiza, plumule, and radicle.

Class-wise Solutions

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For additional reference and to access the official NCERT Class 10 Maths textbook, visit the NCERT website. This will help you understand the concepts covered in Class 10 Math Ch 1 Real Numbers Ex 1.1 more effectively.

🔗 Visit NCERT Official Website: NCERT Class 10 Maths Book