Anatomy of Flowering Plants — Class 11 Biology NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 11 Biology chapter "Anatomy of Flowering Plants" — 8 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 11 Biology chapter "Anatomy of Flowering Plants" — 8 important questions with detailed answers for CBSE bo…
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NCERT Solutions for Class 11 Biology — Anatomy of Flowering Plants. Step-by-step answers to all 8 textbook questions from this chapter, written for CBSE board preparation and free to use.
Anatomy of Flowering Plants — All 8 Questions Solved
Q1. Define tissue and classify plant tissues.
A tissue is a group of similar cells organized to perform a specific function. Plant tissues are classified into two main categories:
1. Meristematic tissue (growing tissue):
- Cells are actively dividing; undifferentiated and totipotent.
- No intercellular spaces; cells densely packed.
- Types: Apical meristem (root and shoot tips), intercalary meristem (grass internodes), lateral meristem (cambium, cork cambium).
2. Permanent tissue (non-growing tissue):
- Cells have stopped dividing; differentiated and mature.
- Classified into simple and complex tissues.
Simple tissues (homogeneous, made of one cell type): Parenchyma, collenchyma, sclerenchyma.
Complex tissues (heterogeneous, made of multiple cell types): Xylem, phloem.
Q2. Describe the structure and function of parenchyma with its subtypes.
Parenchyma is a simple permanent tissue composed of living, thin-walled cells. General characteristics:
- Polyhedral shape; loosely packed with intercellular spaces.
- Thin cellulose cell wall; large central vacuole.
- Metabolically active; retain capacity for mitosis.
Subtypes and functions:
1. Chlorenchyma (assimilatory parenchyma):
- Contains chloroplasts.
- Site of photosynthesis.
- Found in leaves and green stems.
2. Aerenchyma:
- Has prominent intercellular spaces.
- Provides buoyancy and aeration in aquatic plants.
- Example: Water lily, hyacinth.
3. Storage parenchyma:
- Stores starch, proteins, oils, or water.
- Found in seeds, fruits, tubers, roots.
4. Ground parenchyma:
- Fills spaces between vascular tissues; packing tissue.
- Supports other tissues.
Functions of parenchyma:
- Photosynthesis, storage, support, and transport.
- Wound healing and regeneration.
Q3. Compare collenchyma and sclerenchyma tissues.
Collenchyma and sclerenchyma are both support tissues but differ:
Collenchyma:
- Living cells with thick, unevenly thickened cellulose walls.
- Thickening concentrated at corners; areas between are thin.
- Flexible; allows growth and bending.
- Chloroplasts often present (photosynthetically active).
- Found in growing regions like petioles, veins, young stems.
- Provides mechanical support without restricting growth.
Sclerenchyma:
- Dead cells at maturity; thick, lignified secondary walls.
- Wall uniformly thick; lumen (cell cavity) very small.
- Hard and rigid; does not allow bending.
- No living contents; no cytoplasm or nucleus at maturity.
- Found in mature organs where growth has ceased.
- Provides maximum mechanical strength and protection.
- Types: Fibers (elongated) and sclereids (variable shape).
Comparison summary:
Collenchyma = living, flexible support (young tissues).
Sclerenchyma = dead, rigid support (mature tissues).
Q4. Describe the structure of primary xylem and its components.
Primary xylem is the first-formed vascular tissue; it is complex, heterogeneous tissue composed of multiple cell types:
Components:
1. Tracheary elements (water-conducting cells):
a) Tracheids: Elongated cells with tapered ends; thick, lignified secondary walls with bordered pits; found in gymnosperms and ferns; water transport only (no sieve function).
b) Vessel elements (vessels): Shorter, wider cells arranged end-to-end forming long tubes; thick lignified walls with perforations (completely open holes) between them; highly specialized for water transport; found in angiosperms.
2. Parenchyma (xylem parenchyma):
- Living cells; associated with tracheary elements.
- Stores starch and other substances.
- Aids in lateral transport of water and minerals.
3. Fibers (xylem fibers or tracheids in conifers):
- Sclerenchymatous cells providing mechanical support.
- Dead at maturity; thick lignified walls.
Function: Transport of water and minerals from roots to shoots; mechanical support.
Q5. Explain the structure of phloem tissue and name its components.
Phloem is a complex vascular tissue responsible for translocation (transport) of food and other substances. Components:
1. Sieve elements (food-conducting cells):
a) Sieve cells: Found in gymnosperms; elongated with tapered ends; sieve areas (small pores) on all walls.
b) Sieve tube members: Found in angiosperms; short, wide cells; highly specialized with sieve plates (perforated transverse walls) connecting adjacent cells end-to-end, forming continuous sieve tubes.
- Sieve tube members lose nucleus and ribosomes at maturity; remain alive.
- Cytoplasm reticulates (forms networks); maintain turgor.
2. Companion cells:
- Closely associated with sieve tube members in angiosperms.
- Living cells with large nucleus and many mitochondria.
- Provide metabolic energy for sieve tube members (which lack nuclei).
- Help load and unload sugars.
3. Phloem parenchyma:
- Living cells; stores starch and proteins.
- Aids in lateral transport.
4. Phloem fibers:
- Sclerenchymatous, dead cells providing mechanical support.
- Example: Bast fibers used commercially.
Function: Transport of photosynthetic products (mainly sucrose) and other organic compounds from leaves (source) to growing and storage tissues (sinks).
Q6. Describe the structure of a typical dicot root with the arrangement of tissues (5-mark answer).
A typical dicot root structure from outside to center:
1. Root hair zone (piliferous layer):
- Outermost layer; composed of epidermal cells.
- Root hairs are outgrowths of epidermal cells; absorb water and minerals.
- Very short-lived (few days to weeks).
2. Cortex:
- Multiple layers of parenchyma cells; loosely packed with intercellular spaces.
- Functions: Storage of food, lateral transport of water and minerals.
- Outer layer = exodermis (cork-like cells).
3. Endodermis:
- Innermost layer of cortex; single layer of tightly packed cells.
- Contains Casparian strip (band of suberin)—waterproof barrier on radial and transverse walls.
- Controls entry of water and minerals into xylem; acts as selective barrier.
4. Pericycle:
- Layer of parenchyma cells just inside endodermis.
- Origin of lateral (secondary) roots.
- In some plants, produces cambium and cork cambium in secondary growth.
5. Vascular cylinder (stele):
a) Xylem: Arranged in radial pattern (2, 3, or 4 arms); typically ridged; protoxylem toward periphery, metaxylem toward center.
b) Phloem: Alternating with xylem arms; located between xylem arms.
c) Conjunctive tissue: Parenchyma between xylem arms.
6. Pith (if present):
- Central region of parenchyma.
- Stores food; also helps in root conduction (in some species).
Note: In dicot roots, there is NO cambium initially (primary growth only); secondary growth begins when cambium forms from pericycle.
Q7. Describe the internal structure of a dicot stem with labeled tissue arrangement.
Internal structure of a typical dicot stem from outside inward:
1. Epidermis:
- Single outer layer of cells; protective.
- Covered by cuticle (waxy layer reducing water loss).
- Contains stomata for gas exchange; hairs for protection.
2. Cortex:
- Layer(s) of parenchyma cells below epidermis.
- Provides support and storage.
- Outermost layer may be collenchyma (hypodermis) for added strength.
3. Endodermis:
- Innermost layer of cortex; single layer.
- Starch-containing cells in some species.
- Acts as boundary between cortex and vascular tissues.
4. Pericycle:
- Layer of cells just inside endodermis; parenchymatous.
- Gives rise to lateral buds (adventitious) and lateral roots.
5. Vascular bundles:
- Arranged in a ring (eustele) in dicots.
- Each bundle (from outside to inside): Phloem - Cambium - Xylem.
a) Phloem: Transports food; outside the cambium.
b) Cambium: Layer of meristematic cells; produces secondary xylem (inside) and secondary phloem (outside) during secondary growth.
c) Xylem: Transports water and minerals; inside the cambium.
- Bundles separated by medullary rays (parenchyma cells running radially).
6. Pith:
- Central region composed of parenchyma cells.
- Stores food and water; provides support.
- May consist of spongy tissue with large intercellular spaces.
Key point: Presence of cambium allows secondary growth (increase in thickness) in dicot stems.
Q8. Compare the internal structure of dicot and monocot stems (5-mark answer).
Dicot stem vs. Monocot stem:
Dicot stem:
1. Vascular bundles: Arranged in a ring; clearly visible as a circular arrangement.
2. Arrangement of tissues in bundle: Phloem (outside) - Cambium (middle) - Xylem (inside).
3. Cambium: Present; meristematic layer produces secondary tissues.
4. Secondary growth: Occurs, increasing stem thickness year after year.
5. Pith: Large, well-developed central region.
6. Cortex: Distinct layers; clearly demarcated.
7. Examples: Sunflower, tomato, oak.
Monocot stem:
1. Vascular bundles: Scattered throughout the ground tissue; no definite ring pattern.
2. Arrangement of tissues in bundle: Phloem - Xylem (no distinct cambium between them); surrounded by bundle sheath (sclerenchyma).
3. Cambium: Absent; no meristematic layer for producing secondary tissues.
4. Secondary growth: Does NOT occur; stem diameter remains constant.
5. Pith: May be absent or small; often breaks down forming a hollow stem.
6. Cortex: Not clearly demarcated from ground tissue (no distinct endodermis).
7. Examples: Wheat, rice, maize, bamboo.
Summary table:
Feature | Dicot | Monocot
Vascular bundles | Ring of bundles | Scattered bundles
Cambium | Present | Absent
Secondary growth | Yes | No
Pith | Large | Small/absent
Cortex | Well-defined | Not distinct
Anatomy of Flowering Plants — Practice MCQs with Answers
Attempt these 20 multiple-choice questions after working through the solutions above. Each carries the correct option and the reasoning behind it, so a wrong answer tells you which idea to revisit.
MCQ 1. Which type of meristem is responsible for the increase in girth of a plant?
- A. Apical meristem
- B. Intercalary meristem
- C. Lateral meristem
- D. Primary meristem
Answer: C. Lateral meristem — Lateral meristems, such as vascular cambium and cork cambium, are responsible for increasing the diameter or girth of the plant body through secondary growth.
MCQ 2. Which of the following permanent tissues stores food and performs photosynthesis?
- A. Sclerenchyma
- B. Collenchyma
- C. Parenchyma
- D. Phloem
Answer: C. Parenchyma — Parenchyma cells are living, thin-walled, and involved in storage, photosynthesis (chlorenchyma), and secretion.
MCQ 3. Which component of xylem tissue is responsible for the radial conduction of water?
- A. Tracheids
- B. Vessels
- C. Xylem parenchyma
- D. Xylem fibres
Answer: C. Xylem parenchyma — Xylem parenchyma cells store food and assist in the radial conduction of water, while tracheids and vessels are primarily involved in axial water transport.
MCQ 4. What is a distinguishing feature of a monocot root compared to a dicot root?
- A. Presence of cambium
- B. Exarch vascular bundles
- C. Large and well-developed pith
- D. Few xylem bundles
Answer: C. Large and well-developed pith — Monocot roots typically have a large and well-developed pith, whereas dicot roots have a small or inconspicuous pith. Both have exarch vascular bundles.
MCQ 5. During secondary growth in dicot stems, the vascular cambium is formed from which of the following tissues?
- A. Pericycle and Medullary rays
- B. Primary xylem and Primary phloem
- C. Intrafascicular cambium and Interfascicular cambium
- D. Cortex and Endodermis
Answer: C. Intrafascicular cambium and Interfascicular cambium — The vascular cambium ring is formed by the activity of intrafascicular cambium (present within vascular bundles) and interfascicular cambium (formed from medullary rays between vascular bundles).
MCQ 6. Stomata are pores found on the epidermis of leaves, primarily responsible for:
- A. Food storage
- B. Water absorption
- C. Gaseous exchange
- D. Mechanical support
Answer: C. Gaseous exchange — Stomata regulate the exchange of gases (carbon dioxide and oxygen) and transpiration (water vapor release) between the plant and the atmosphere.
MCQ 7. In a dicot stem, vascular bundles are typically:
- A. Scattered and closed
- B. Radial and exarch
- C. Conjoint, collateral, and open
- D. Conjoint, collateral, and closed
Answer: C. Conjoint, collateral, and open — Dicot stems have vascular bundles arranged in a ring, which are conjoint (xylem and phloem together), collateral (phloem outside xylem), and open (with cambium between xylem and phloem).
MCQ 8. What constitutes the periderm of a dicot stem undergoing secondary growth?
- A. Phellogen and Phellem
- B. Phellogen, Phellem, and Phelloderm
- C. Phellem and Secondary cortex
- D. Cork cambium and Secondary phloem
Answer: B. Phellogen, Phellem, and Phelloderm — The periderm is a protective layer that replaces the epidermis during secondary growth and consists of the cork cambium (phellogen), cork (phellem), and secondary cortex (phelloderm).
MCQ 9. Which permanent tissue provides mechanical support to young stems and petioles of dicot plants?
- A. Sclerenchyma
- B. Collenchyma
- C. Parenchyma
- D. Tracheids
Answer: B. Collenchyma — Collenchyma provides flexible mechanical support to young stems and petioles due to the localized thickening of its cell walls.
MCQ 10. Companion cells are usually found associated with which of the following phloem elements?
- A. Sclereids
- B. Phloem parenchyma
- C. Sieve tube elements
- D. Phloem fibers
Answer: C. Sieve tube elements — Companion cells are specialized parenchyma cells that assist sieve tube elements in their function, as sieve tube elements lack a nucleus in mature state.
MCQ 11. What is the primary function of bulliform cells in monocot leaves?
- A. Photosynthesis
- B. Water storage
- C. Mechanical support
- D. Rolling up of leaves to reduce water loss
Answer: D. Rolling up of leaves to reduce water loss — Bulliform cells are large, empty, colourless cells in the epidermis of some monocot leaves that help in rolling up the leaf during water stress to reduce transpiration.
MCQ 12. When xylem and phloem are arranged in an alternate manner on different radii, the vascular bundles are said to be:
- A. Conjoint
- B. Collateral
- C. Radial
- D. Bicollateral
Answer: C. Radial — Radial vascular bundles, characteristic of roots, have xylem and phloem arranged separately on different radii.
MCQ 13. In a dicot root, the stele comprises:
- A. Endodermis, Pericycle, Vascular bundles, and Pith
- B. Pericycle, Vascular bundles, and Pith
- C. Endodermis, Cortex, and Vascular bundles
- D. Epidermis, Cortex, and Endodermis
Answer: B. Pericycle, Vascular bundles, and Pith — The stele is the central vascular cylinder of a plant root or stem, consisting of the pericycle, vascular bundles, and pith (if present).
MCQ 14. What causes the formation of distinct annual rings in temperate regions?
- A. Variations in light intensity throughout the year
- B. Seasonal activity of cork cambium
- C. Uneven activity of vascular cambium due to climatic variations
- D. Accumulation of food reserves in the stem
Answer: C. Uneven activity of vascular cambium due to climatic variations — The vascular cambium's activity is influenced by seasonal climatic changes, leading to the formation of 'early wood' (spring wood) and 'late wood' (autumn wood), which together form an annual ring.
MCQ 15. Epidermal outgrowths, such as hair, are called:
- A. Stomata
- B. Lenticels
- C. Trichomes
- D. Guard cells
Answer: C. Trichomes — Trichomes are epidermal hairs on the stem that can be branched or unbranched, soft or stiff, and may be secretory.
MCQ 16. Sclereids are a type of sclerenchymatous cells characterized by:
- A. Thin walls and large central lumen
- B. Thick, lignified, highly pitted walls and usually spherical
- C. Elongated with tapering ends
- D. Presence of chloroplasts
Answer: B. Thick, lignified, highly pitted walls and usually spherical — Sclereids are dead cells with thick, lignified, highly pitted walls, typically spherical, oval, or cylindrical, and provide mechanical support.
MCQ 17. Which of the following statements is TRUE regarding heartwood?
- A. It is the outer, lighter-coloured region of secondary xylem
- B. It is involved in the conduction of water and minerals
- C. It is more resistant to attack by microorganisms and insects
- D. It has living cells and accumulates organic substances
Answer: C. It is more resistant to attack by microorganisms and insects — Heartwood is the central, dark-coloured, non-conducting part of the secondary xylem, made durable and resistant to pests by the accumulation of tannins, resins, and other substances.
MCQ 18. Root apical meristem is present at the:
- A. Tips of roots only
- B. Tips of stems only
- C. Tips of roots and stems
- D. Axillary buds
Answer: A. Tips of roots only — The root apical meristem is located at the apex of the root, responsible for its growth in length.
MCQ 19. A prominent feature of the monocot stem is the presence of:
- A. A well-defined pith
- B. Vascular bundles arranged in a ring
- C. Sclerenchymatous hypodermis
- D. Open vascular bundles
Answer: C. Sclerenchymatous hypodermis — Monocot stems typically have a sclerenchymatous hypodermis, which provides mechanical strength, unlike the collenchymatous hypodermis in dicot stems.
MCQ 20. Lenticels are formed due to the activity of:
- A. Vascular cambium
- B. Apical meristem
- C. Cork cambium
- D. Intercalary meristem
Answer: C. Cork cambium — Lenticels are lens-shaped openings in the periderm formed by the cork cambium, facilitating gaseous exchange in woody stems.
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.