PRELIMINARY STAGE
2013
Presbyterian Boys SHS
St Monicas
MfantsiMan Girls
QUESTION
Fibers and sclereids are types of which plant cells?
ANSWER: Sclerenchyma
EXPLANATION
Sclerenchyma cells have thick, often lignified walls providing structural support; fibres and sclereids are its two main types.
PRACTICE QUESTIONS
1. Are sclerenchyma cells living or dead at maturity?
ANSWER: Dead
2. What is the main function of sclerenchyma?
ANSWER: Mechanical support
3. What substance thickens sclerenchyma walls?
ANSWER: Lignin
4. What is the shape of sclerenchyma fibres?
ANSWER: Long and slender with tapered ends
5. What is the shape of sclereids?
ANSWER: Short and irregular (stone cells)
6. Where are sclereids found?
ANSWER: Nut shells and the gritty flesh of pears
7. Name a commercial plant fibre made of sclerenchyma.
ANSWER: Jute (or flax, hemp)
8. How do sclerenchyma walls differ from collenchyma walls?
ANSWER: Sclerenchyma walls are evenly thick and lignified
9. Where are fibres often found in stems?
ANSWER: Around the vascular bundles
10. What causes the gritty texture of a pear?
ANSWER: Clusters of sclereids
11. Name the openings in sclerenchyma walls that connect cells.
ANSWER: Pits
12. Name the two main types of sclerenchyma cell.
ANSWER: Fibres and sclereids