The Epidermal Tissue System: Epidermis, Stomata and Appendages
The epidermal tissue system is the outermost covering of the whole plant body — the first line of defence between living tissue and a demanding environment. It is built from three cooperating components:
- Epidermal cells — elongated, compactly arranged, usually single-layered and parenchymatous
- Stomata — pores that regulate transpiration and gaseous exchange
- Epidermal appendages — root hairs and trichomes
This quiz tests your grasp of the waxy cuticle and why roots lack it, the bean-shaped versus dumb-bell-shaped guard cells of grasses, the stomatal apparatus, and the structural distinction between unicellular root hairs and usually multicellular trichomes.
How to attempt
Read each question carefully, choose the single best option, and study the explanation after answering. All questions are answerable from the lesson material alone.
Q1. Which of the following correctly lists the components of the epidermal tissue system?
The epidermal tissue system comprises epidermal cells, stomata and the epidermal appendages — the trichomes and hairs. The other options describe the ground tissue system or vascular tissues.
Q2. The epidermis is best described as which layer of the plant body?
The epidermis is the outermost layer of the primary plant body, forming a continuous protective sheet over the whole plant body.
Q3. Epidermal cells are typically:
Epidermal cells are elongated and compactly arranged, forming a continuous layer. They are parenchymatous, with a small amount of cytoplasm lining the cell wall and a large vacuole.
Q4. The epidermis is usually:
The lesson states that the epidermis is usually single-layered, made of elongated, compactly arranged cells forming a continuous layer.
Q5. The waxy thick layer often covering the outside of the epidermis is called the:
The outside of the epidermis is often covered with a waxy thick layer called the cuticle, which prevents the loss of water.
Q6. The primary function of the cuticle is to:
The cuticle is a waxy layer that prevents the loss of water from the epidermal surface. Absorption of water and minerals is the job of root hairs.
Q7. In which part of the plant is the cuticle absent?
The lesson explicitly states that the cuticle is absent in roots, which is consistent with the absorptive role of the root surface.
Q8. Stomata are structures present in the epidermis of leaves that mainly:
Stomata regulate the process of transpiration and gaseous exchange. They are present in the epidermis of leaves.
Q9. Each stoma is composed of two bean-shaped cells known as:
Each stoma is composed of two bean-shaped cells known as guard cells, which enclose the stomatal pore.
Q10. In grasses, the guard cells are typically:
In grasses the guard cells are dumb-bell shaped, whereas the typical stoma has bean-shaped guard cells.
Q11. With respect to the stomatal pore, the walls of the guard cells are:
The outer walls of guard cells (away from the stomatal pore) are thin, while the inner walls (towards the stomatal pore) are highly thickened.
Q12. Which feature of guard cells enables them to regulate the opening and closing of stomata?
Guard cells possess chloroplasts and regulate the opening and closing of stomata. They are living cells with walls.
Q13. A few epidermal cells in the vicinity of the guard cells that become specialised in shape and size are called:
Epidermal cells near the guard cells that become specialised in their shape and size are known as subsidiary cells.
Q14. The stomatal aperture, the guard cells and the surrounding subsidiary cells are together called the:
The stomatal aperture, guard cells and the surrounding subsidiary cells are together called the stomatal apparatus.
Q15. Root hairs are best described as:
Root hairs are unicellular elongations of the epidermal cells and help absorb water and minerals from the soil. Trichomes, by contrast, are usually multicellular.