CBSE Class 11 Biology – Anatomy of Flowering Plants | Short Answer Questions (NCERT Based)

📘 Course & Examination Details

• Course: CBSE Class 11 Biology
• Unit: Unit II – Structural Organisation in Animals and Plants
• Chapter: Chapter 6 – Anatomy of Flowering Plants
• Question Type: Short Answer Type (60–80 words)
• Total Questions: 50
• Exam Relevance:
  • CBSE Class 11 Annual Examination
  • School Unit Tests & Term Exams
  • NCERT-based Conceptual Assessment

🌱 Section A: Plant Tissues (Q1–Q15)

Q1. Explain meristematic tissue and its main characteristics.

Answer:
Meristematic tissue consists of actively dividing living cells responsible for plant growth. These cells are small, thin-walled, rich in cytoplasm, and possess a prominent nucleus. They lack intercellular spaces and vacuoles. Meristems retain the capacity for continuous division, enabling increase in length and girth of plant organs.

Q2. Describe apical meristem and its functions.

Answer:
Apical meristem is located at the tips of roots and shoots. It brings about primary growth by increasing the length of plant organs. Cells produced by apical meristem differentiate into primary tissues such as epidermis, cortex, and vascular tissues, forming the basic structure of roots and shoots.

Q3. What is intercalary meristem? Mention its role.

Answer:
Intercalary meristem is found between mature tissues, usually at the base of internodes or leaves, especially in grasses. It is responsible for rapid elongation and regrowth of plant parts after grazing or cutting, helping plants recover quickly.

Q4. Define permanent tissues and state their types.

Answer:
Permanent tissues are derived from meristematic tissues and have lost the ability to divide. They perform specific functions. Permanent tissues are classified into simple permanent tissues, complex permanent tissues, and special tissues based on structure and function.

Q5. Describe parenchyma tissue and its functions.

Answer:
Parenchyma is a simple permanent tissue composed of living, thin-walled cells with intercellular spaces. It functions in storage of food, photosynthesis when chlorophyll is present, gaseous exchange, and buoyancy in aquatic plants due to large air spaces.

Q6. Explain collenchyma tissue.

Answer:
Collenchyma consists of living elongated cells with unevenly thickened corners. It provides mechanical support and flexibility to growing plant parts such as stems and petioles. Collenchyma allows bending without breaking and is commonly found below the epidermis of dicot stems.

Q7. What is sclerenchyma? Mention its significance.

Answer:
Sclerenchyma is a simple permanent tissue made of dead cells with thick, lignified walls. It provides mechanical strength and rigidity to plant parts. Sclerenchyma occurs as fibres and sclereids, helping plants withstand mechanical stress.

Q8. Describe complex permanent tissues.

Answer:
Complex permanent tissues are composed of different types of cells working together for a common function. Xylem and phloem are complex tissues responsible for transport of water, minerals, and food within the plant body.

Q9. Explain the structure and function of xylem.

Answer:
Xylem is a complex tissue composed of tracheids, vessels, xylem fibres, and xylem parenchyma. It conducts water and minerals from roots to aerial parts and provides mechanical support due to lignified cell walls.

Q10. Describe the components of phloem.

Answer:
Phloem consists of sieve tube elements, companion cells, phloem parenchyma, and phloem fibres. It transports organic food materials from leaves to other parts of the plant. Except phloem fibres, all components are living.

Q11. Differentiate between xylem and phloem briefly.

Answer:
Xylem mainly conducts water and minerals and is composed mostly of dead cells. Phloem transports food and consists mainly of living cells. Xylem flow is upward, while phloem transport can occur in both directions.

Q12. What is ground tissue system?

Answer:
Ground tissue system includes all tissues except epidermal and vascular tissues. It mainly consists of parenchyma cells and is involved in storage, photosynthesis, and support. Cortex, pith, and mesophyll are parts of ground tissue.

Q13. Explain the role of lateral meristem.

Answer:
Lateral meristem is responsible for secondary growth in plants. It increases the girth of stems and roots by producing secondary tissues. Vascular cambium and cork cambium are examples of lateral meristems.

Q14. Why are meristematic cells always living?

Answer:
Meristematic cells are living because they continuously divide to form new cells. They have active cytoplasm, large nucleus, and high metabolic activity, which are essential for growth and tissue formation.

Q15. What are simple permanent tissues?

Answer:
Simple permanent tissues consist of only one type of cell performing similar functions. They include parenchyma, collenchyma, and sclerenchyma, which are involved in storage, support, and mechanical strength.

🌿 Section B: Internal Structure of Root (Q16–Q25)

Q16. Describe the internal structure of a dicot root.

Answer:
Dicot root shows epiblema, cortex, endodermis with Casparian strips, pericycle, radial vascular bundles, and small pith. Xylem and phloem are arranged alternately, and xylem is exarch, allowing efficient conduction.

Q17. Explain the role of endodermis in roots.

Answer:
Endodermis is the innermost layer of cortex containing Casparian strips. It regulates the movement of water and minerals into the vascular tissues, ensuring selective absorption and preventing backflow.

Q18. What is pericycle? State its function.

Answer:
Pericycle is a layer of cells located just inside the endodermis. It gives rise to lateral roots and contributes to secondary growth in dicot roots.

Q19. Describe monocot root structure.

Answer:
Monocot roots have epiblema, cortex, endodermis, pericycle, radial vascular bundles with many xylem groups, and a large central pith. Secondary growth is absent due to lack of cambium.

Q20. What is radial vascular bundle?

Answer:
In radial vascular bundles, xylem and phloem are arranged alternately on different radii, a characteristic feature of roots that helps efficient transport of water and nutrients.

Q21. Explain exarch xylem arrangement.

Answer:
Exarch xylem refers to xylem arrangement where protoxylem lies towards the periphery and metaxylem towards the centre. This arrangement is typical of roots.

Q22. Differentiate between dicot and monocot roots.

Answer:
Dicot roots have fewer xylem bundles and small pith, while monocot roots have many xylem bundles and large pith. Secondary growth occurs in dicot roots but is absent in monocot roots.

Q23. What is the function of cortex in root?

Answer:
Cortex stores food materials and helps in the movement of water from epidermis to vascular tissues. It also provides mechanical support.

Q24. Why is secondary growth absent in monocot roots?

Answer:
Secondary growth is absent in monocot roots due to absence of vascular cambium, which is essential for secondary tissue formation.

Q25. What is pith in roots?

Answer:
Pith is the central region of root composed of parenchyma cells. It stores food and is well developed in monocot roots but reduced in dicot roots.

🌿 Section C: Stem, Leaf & Secondary Growth (Q26–Q50)

Q26. Describe the internal structure of a dicot stem.

Answer:
A dicot stem consists of epidermis, hypodermis made of collenchyma, cortex, endodermis called starch sheath, pericycle, vascular bundles arranged in a ring, and central pith. Vascular bundles are conjoint, collateral, and open, with cambium present between xylem and phloem, allowing secondary growth.

Q27. Explain the role of hypodermis in dicot stem.

Answer:
The hypodermis of dicot stem is composed of collenchyma cells. It provides mechanical support and flexibility to the stem, enabling it to withstand bending stresses without breaking, especially during growth.

Q28. What are vascular bundles? Mention their type in dicot stem.

Answer:
Vascular bundles are conducting tissues consisting of xylem and phloem. In dicot stems, they are conjoint, collateral, and open, arranged in a ring, with cambium present for secondary growth.

Q29. Why is the dicot stem capable of secondary growth?

Answer:
Dicot stem shows secondary growth because its vascular bundles are open, containing vascular cambium. This cambium actively divides to form secondary xylem and secondary phloem, increasing the girth of the stem.

Q30. Describe the internal structure of a monocot stem.

Answer:
A monocot stem has an epidermis, sclerenchymatous hypodermis, ground tissue without clear cortex and pith differentiation, and numerous vascular bundles scattered throughout. Vascular bundles are conjoint, collateral, and closed, lacking cambium, so secondary growth is absent.

Q31. Differentiate between dicot stem and monocot stem.

Answer:
Dicot stem has vascular bundles arranged in a ring and shows secondary growth due to presence of cambium. Monocot stem has scattered, closed vascular bundles and lacks secondary growth. Cortex and pith are distinct in dicot stem but not in monocot stem.

Q32. What is endodermis in stem? Why is it called starch sheath?

Answer:
Endodermis is the innermost layer of cortex in dicot stem. It is called starch sheath because its cells are rich in starch grains, storing reserve food material.

Q33. Explain the function of pericycle in stem.

Answer:
In dicot stem, pericycle is usually composed of sclerenchyma. It provides mechanical strength and support to the stem and helps protect vascular tissues.

Q34. What is pith and state its function in stem.

Answer:
Pith is the central region of the stem composed mainly of parenchyma cells. It functions in storage of food materials and provides internal support to the stem.

Q35. What is ground tissue system in stem?

Answer:
Ground tissue system includes all tissues except epidermal and vascular tissues. In stem, it consists of cortex, endodermis, pericycle, and pith, mainly involved in storage and support.

Q36. Describe the anatomy of a dorsiventral leaf.

Answer:
A dorsiventral leaf has distinct upper and lower surfaces. It consists of upper epidermis, palisade mesophyll for photosynthesis, spongy mesophyll for gaseous exchange, vascular bundles, and lower epidermis with stomata.

Q37. What is palisade parenchyma?

Answer:
Palisade parenchyma consists of elongated, chlorophyll-rich cells arranged vertically below the upper epidermis. It is the main photosynthetic tissue of a dorsiventral leaf.

Q38. Explain spongy parenchyma.

Answer:
Spongy parenchyma is composed of loosely arranged cells with large intercellular spaces. It facilitates gaseous exchange and also performs photosynthesis to a lesser extent.

Q39. Describe the anatomy of an isobilateral leaf.

Answer:
An isobilateral leaf has similar upper and lower surfaces. Mesophyll is not differentiated into palisade and spongy tissues. Bulliform cells are present, helping in leaf rolling, and stomata occur on both surfaces.

Q40. What are bulliform cells and state their function.

Answer:
Bulliform cells are large, thin-walled epidermal cells found in monocot leaves. They help in rolling and unrolling of leaves during water stress, reducing water loss.

Q41. Define secondary growth.

Answer:
Secondary growth is the increase in girth or thickness of stems and roots due to activity of lateral meristems such as vascular cambium and cork cambium.

Q42. Explain the role of vascular cambium in secondary growth.

Answer:
Vascular cambium forms a continuous ring and produces secondary xylem towards the inner side and secondary phloem towards the outer side, increasing stem thickness.

Q43. What is cork cambium? Mention its function.

Answer:
Cork cambium or phellogen is a lateral meristem that produces cork cells outward and secondary cortex inward, forming the protective periderm during secondary growth.

Q44. What is periderm?

Answer:
Periderm is a protective tissue formed during secondary growth. It consists of cork, cork cambium, and secondary cortex, replacing the epidermis in older stems.

Q45. Explain formation of annual rings.

Answer:
Annual rings are formed due to seasonal activity of vascular cambium. Rapid growth in spring produces spring wood, while slower growth in winter produces autumn wood, forming visible rings.

Q46. What is sapwood?

Answer:
Sapwood is the outer, light-coloured, active part of secondary xylem. It conducts water and minerals and contains living cells.

Q47. What is heartwood?

Answer:
Heartwood is the inner, dark-coloured, inactive part of secondary xylem. It does not conduct water but provides mechanical strength to the plant.

Q48. Why does heartwood appear darker than sapwood?

Answer:
Heartwood appears darker due to accumulation of tannins, resins, oils, gums, and other waste substances within its cells.

Q49. Why is secondary growth absent in monocot stems?

Answer:
Secondary growth is absent in monocot stems because their vascular bundles are closed and lack vascular cambium, which is essential for secondary tissue formation.

Q50. Why are labelled diagrams important in this chapter?

Answer:
Labelled diagrams help understand tissue arrangement and internal structure clearly. CBSE frequently asks diagram-based questions from this chapter, making them important for scoring marks.