Problem 10 - Objective Biology for NEET

Question

The root region is arranged proximal to distal part in the following manner (a) Zone of cell elongation- Zone of cell maturation \(-\) Zone of cell division (b) Zone of cell division \(-\) Zone of cell elongation \(-\) Zone of cell maturation (c) Zone of cell maturation- Zone of cell elongation \(-\) Zone of cell division (d) Zone of cell maturation \(-\) Zone of cell division \(-\) Zone of cell elongation

Step-by-Step Solution

Answer

The correct order of root zones from proximal to distal part is Zone of cell division \(-\) Zone of cell elongation \(-\) Zone of cell maturation, so option (b) is the right answer.

Step 1: Understanding Plant Root Anatomy

A fundamental concept in botany is understanding the root's structure. Roots generally consist of three zones: The Zone of Cell Division, The Zone of Cell Elongation, and The Zone of Cell Maturation. They are arranged in the root from the proximal part (near the rest of the plant) towards the distal part (away from the rest of the plant).

Step 2: Ordering the Zones

Starting from the proximal part, the first zone encountered is the Zone of Cell Division. This is where the growth of the root actually begins and new cells are produced. The next zone is the Zone of Cell Elongation, where these new cells increase in size. Finally, the Zone of Cell Maturation is where cells differentiate into various types of cells such as epidermal cells, cortex, and vascular tissue. This is the typical order from proximal to distal part.

Step 3: Match the Arrangement with Options

Following the typical order of zones from proximal to distal part: Zone of cell division \(-\) Zone of cell elongation \(-\) Zone of cell maturation, we compare this order with the options provided in the question. The matching order is found in option (b). This is therefore the answer.

Key Concepts

Zone of Cell Division

In the anatomy of plant roots, the zone of cell division is where root growth begins. Located in the proximal part of the root, close to the root tip, this zone contains meristematic cells. Meristematic cells are unspecialized and can divide and develop into different types of cells.
This area is crucial because it is the site of new cell production.

• This process supports the root in extending further into the soil.
• The cells in this region are small and densely packed.
• Constantly dividing, the zone plays a vital role in the plant's ability to adapt and stabilize in its environment.

The significance of the zone of cell division cannot be understated as it thwarts root growth and expansion. Without this area, the plant would struggle to absorb nutrients efficiently.

Zone of Cell Elongation

Next to the zone of cell division is the zone of cell elongation. Here, the previously produced cells begin to increase in size.
This process allows the root to extend even further into the ground.

• The key activity here is cell enlargement, not division.
• Enzymes help loosen the cell walls, allowing cells to stretch.
• Water uptake aids the expansion as cells absorb more water and swell.

Through elongation, roots improve their penetration into different soil layers. This increased length helps the plant cover more ground to source water and nutrients efficiently. Hence, the zone of cell elongation plays a pivotal role in the plant’s sustenance and growth.

Zone of Cell Maturation

Finally, the zone of cell maturation is where the root cells differentiate into specialized types. This zone lies further away from the root tip compared to the previous zones. As such, differentiation allows the root to perform various functions required for plant growth.

• Cells become specialized into different tissue types, such as epidermal cells, cortex cells, and vascular cells.
• The root develops root hairs, which increase the surface area for water and nutrient absorption.
• This zone is essential for the stability and nutrient transport within the plant.

In summary, the zone of cell maturation is critical for completing the plant root's function. Differentiation into specialized cells ensures the plant can sustain its life processes effectively. Consequently, this zone finalizes the root’s development into a fully capable structure for the plant's needs.