Problem 72 - Objective Biology for NEET

Question

Cells positioned away from root apical meristems, differentiate as (a) Epidermis (b) Root cap (c) Both (a) and (b) (d) None of these

Step-by-Step Solution

Answer

The correct answer is (c) Both (a) and (b)

Step 1: Understand the Root Apical Meristems role

Root Apical Meristems are responsible for an important part of plant's growth, they contain stem cells, which are undifferentiated or partially differentiated cells that can differentiate into various cell types. They are the ones driving the growth at the tips of plants.

Step 2: Recognize Derivative Cells

From these root apical meristems, cells differentiate into different types. The Epidermis, the outer layer of cells, covers the entire surface of the plant. And Root caps are at the tip of a plant root that protect the root meristem as it forces its way through the soil during primary root growth.

Step 3: Choose the Correct Answer

Given that both the Epidermis and the Root cap are cells that differentiate from cells on the Root apical meristem, the correct answer is (c) Both (a) and (b).

Key Concepts

Cell Differentiation

Cell differentiation is a fascinating process that allows plant cells to develop specific functions. It begins at root apical meristems, which house stem cells. These stem cells are unique because they are undifferentiated or only partially differentiated. This means they have the potential to become any type of cell needed by the plant. Their versatile nature fuels the plant's ability to grow and adapt to its environment.

During differentiation, these cells undergo changes to take on specialized roles. This process involves altering the structure and function of the cells. For instance, some cells become part of the epidermis, while others join the root cap. This specialization is essential for the plant’s development and survival. Because each type of cell has a unique function, the plant can efficiently carry out various roles, from protection to absorption.

Epidermis

The epidermis is the plant's outermost layer and acts like a protective skin. As cells differentiate from the root apical meristems, some become epidermal cells. These cells play a vital role in multiple aspects of a plant's life.

• Protection: The epidermis shields the inner tissues of the plant from physical damage and pathogens.
• Water Regulation: It helps in minimizing water loss by regulating the opening and closing of stomata, which are tiny pores located on the surface.
• Absorption: In roots, epidermal cells can develop into root hairs, increasing surface area for water and nutrient uptake.

These functions are crucial for maintaining the plant's health and enabling it to thrive in various environments. The structure and arrangement of epidermal cells ensure that the plant is well-protected and can maximize its intake of necessary resources.

Root Cap

The root cap is a specialized structure that protects the root apical meristem as it grows and pushes through the soil. Differentiated from the root apical meristems, these cells form a protective covering at the tip of the root.

• Protection: The root cap acts as a shield, safeguarding the delicate meristematic cells from abrasive soil particles.
• Perception: It plays a role in sensing gravity, helping the root to navigate and grow in the direction of gravity, a process known as gravitropism.
• Secretion: The root cap secretes mucilage. This sticky substance lubricates the root tip and facilitates easier movement through the soil.

Each of these roles highlights the importance of the root cap in ensuring the root system grows effectively. Not only does it protect the root tip, but it also aids the plant in orienting its roots to maximize resource absorption from the soil. This ability is crucial for the plant's overall growth and nutrient intake.