Question

Identify the parts labeled P, Q and R in the diagram of a root hair cell shown.

A. P- Vacuole, Q- Nucleus, R- Cell wall
B. P- Protoplasm, Q- Nucleus, R- Cell membrane
C. P- Nucleus, Q- Vacuoles, R- Cell wall
D. P- Mitochondria, Q- Nucleus, R- Cell wall

Answer 1

Root hairs are structures that arise from the epidermal cells of the roots of a plant. Their long and thin structure makes them penetrate the soil very easily and their large surface area helps in the maximum absorption of water present in the soil.

Complete answer:
The internal structure of the root hair cell is roughly rectangular that extends to the right in a long thin tail. At the top corner of this tail, the nucleus is situated. The nucleus is situated at the extreme corner because of the presence of a large vacuole that helps in the maximum absorption of water. The entire root hair cell is covered by an outer layer of the cell wall that provides strength and protection against mechanical as well as osmotic stress to the cell.
Options (A), (B), and (D) are incorrect because in the above diagram the structure labeled as P at the extreme corner represents the nucleus of the root hair cell. The structure labeled as Q which is a large structure in the root hair cell covering most of its area represents the vacuole of the root hair cell, and the structure labeled as R represents the cell wall of the root hair cell that is an outer covering of the root hair cell.
Option (C) is correct because it represents the correct structures labeled as P, Q, and R i.e., nucleus, vacuole, and cell wall, respectively.
Hence, the correct option is (C).

Note:
Root hair cells possess large vacuole because it helps in the maximum water absorption as well as its storage until its transport does not take place. The water and minerals enter into the cytoplasm of root hair cells through the process of osmosis.