16.2.1 Meristematic Tissues and Growth (Q&A)

Short Answer Questions

1. What are meristematic tissues?
   Answer
   Meristematic tissues are regions in a plant where cells actively divide, enabling growth.
2. What are the characteristics of meristem cells?
   Answer
   They have a dense cytoplasm, large nucleus, thin cell walls, and are actively dividing.
3. Where are apical meristems found?
   Answer
   At the tips of shoots and roots.
4. What type of growth is the apical meristem responsible for?
   Answer
   Primary growth, which increases the length of the plant.
5. What is the role of the lateral meristem?
   Answer
   It is responsible for secondary growth, increasing the girth or width of the plant.
6. What does the vascular cambium produce?
   Answer
   Secondary xylem and secondary phloem.
7. What type of cells does the cork cambium produce?
   Answer
   Cork cells (phellem), which form the outer protective layer of bark.
8. What is primary growth?
   Answer
   Primary growth is the increase in the length of a plant, occurring at the apical meristems.
9. What are the three zones of cell growth in the apical meristem?
   Answer
   Zone of cell division, zone of cell elongation, and zone of cell differentiation.
10. What happens in the zone of cell division?
    Answer
    Mitosis occurs, increasing the number of cells.
11. What is secondary growth?
    Answer
    Secondary growth is the increase in the thickness or girth of a plant.
12. Where does secondary growth occur?
    Answer
    In the lateral meristems, such as the vascular cambium and cork cambium.
13. What is the main component of wood?
    Answer
    Secondary xylem.
14. What is the function of cork cells?
    Answer
    Cork cells provide protection against water loss and mechanical damage.
15. What substance in cork cell walls provides protection?
    Answer
    Suberin.
16. What tissues are formed during primary growth?
    Answer
    Epidermis, cortex, primary xylem, and primary phloem.
17. What type of plants undergo secondary growth?
    Answer
    Dicots and gymnosperms.
18. What is the role of the vascular cambium in secondary growth?
    Answer
    It produces secondary xylem and secondary phloem.
19. What differentiates primary growth from secondary growth?
    Answer
    Primary growth increases length, while secondary growth increases girth.
20. What is the bark composed of?
    Answer
    Cork cells, cork cambium, and phelloderm.

Explanation Questions

1. How does the apical meristem contribute to plant growth?
   Answer
   The apical meristem is responsible for primary growth, increasing the length of the plant through cell division, elongation, and differentiation.
2. What is the significance of secondary growth in woody plants?
   Answer
   Secondary growth increases the thickness of stems and roots, providing structural support and protection.
3. How does the vascular cambium differ from the cork cambium?
   Answer
   The vascular cambium produces secondary xylem and phloem, while the cork cambium produces cork cells for protection.
4. What is the role of the zone of cell elongation in primary growth?
   Answer
   Cells absorb water and expand in size, contributing to the lengthening of roots and shoots.
5. Why does secondary growth not occur in most monocots?
   Answer
   Monocots lack lateral meristems like the vascular and cork cambium, which are essential for secondary growth.
6. How does suberin in cork cells protect the plant?
   Answer
   Suberin makes cell walls waterproof and protects against mechanical damage.
7. What happens in the zone of cell differentiation?
   Answer
   Cells mature and specialise into tissues like epidermis, xylem, and phloem, taking on specific functions.
8. How does the cork cambium contribute to the formation of bark?
   Answer
   The cork cambium produces cork cells and phelloderm, forming the protective bark layer.
9. What is the difference between primary xylem and secondary xylem?
   Answer
   Primary xylem forms during primary growth, while secondary xylem forms during secondary growth and is a major component of wood.
10. How do the zones of cell growth ensure structured plant development?
    Answer
    The zones of cell division, elongation, and differentiation create an organised process for growth and specialisation of plant tissues.