Problem 25 - Objective Biology for NEET

Question

The collenchyma tissue is characterized by (a) Elongated cells with thickness at the corners. (b) Isodiametric cells with deposits of cellulose and pectin at the corners. (c) Elongated cells with deposits of cellulose and pectin all over the wall. (d) Isodiametric cells with thickness all over the cell wall.

Step-by-Step Solution

Answer

The collenchyma tissue is best characterized by option (a) Elongated cells with thickness at the corners.

Step 1: Understand characteristics of collenchyma tissues

Collenchyma is one of the three types of ground, or fundamental, tissue in plants, along with parenchyma and sclerenchyma cells. Collenchyma cells are known for providing support to plants. These are elongated cells with unevenly thickened walls.

Step 2: Match characteristics of options with collenchyma tissues

Let's analyze the given options. (a) refers to elongated cells with thickness at the corners, which can be part of the characteristics of collenchyma but it does not mention about uneven thickening. (b) refers to isodiametric cells, these are not elongated so we can eliminate this option. (c) refers to elongated cells with deposits of cellulose and pectin all over the wall, although collenchyma cells are elongated this option implies an evenly deposition of substances all over the wall, which is not characteristic of collenchyma. (d) is not suitable as it refers to isodiametric cells and also an even thickness all over the cell.

Step 3: Select the most suitable option

By comparing the properties of collenchyma with the given options, it can be inferred that option (a) Elongated cells with thickness at the corners, best matches the characteristics of collenchyma. Although the option does not specifically state the uneven thickening, it is the closest match.

Key Concepts

Plant Tissue Types

Plants are composed of various types of tissues, which play multiple roles essential for their growth and development. Understanding plant tissue types is crucial as each serves a unique purpose within the plant body.

• Meristematic Tissue: These are the active tissues in plants where all types of plant cells are initially formed. They are found at the tips of roots and shoots and are responsible for plant growth.
• Dermal Tissue: This is the outermost layer of the plant, which protects it from the external environment. The main component of dermal tissue is the epidermis.
• Vascular Tissue: It conducts water, minerals, and nutrients throughout the plant. It is mainly made up of xylem and phloem.
• Ground Tissue: This includes parenchyma, collenchyma, and sclerenchyma cells, and is involved in photosynthesis, storage, and support.

Collenchyma is a type of ground tissue known for providing flexible support, particularly in regions of rapid growth and expansion.

Cell Structure and Function

At the core of collenchyma tissue is its cell structure, which allows it to perform its role within the plant efficiently. Understanding the cell structure helps elucidate the function of these specialized plant cells.

• Cell Shape: Collenchyma cells are typically elongated, which helps in providing structural support.
• Cell Wall: The cell walls of collenchyma cells are unevenly thickened, mainly due to deposits of cellulose and pectin. This unique property allows them to be flexible yet strong.
• Function: Their main function is to support young, growing parts of the plant without restricting growth due to their elasticity.

The uneven thickening is crucial as it allows the plant to withstand various mechanical stresses and be flexible enough to grow.

Ground Tissue in Plants

Ground tissue is a fundamental component of the plant's anatomy that serves several vital functions. It belongs to the three major types of plant tissues and plays a significant role in the plant's lifecycle.

Ground tissue is usually located between the dermal and vascular tissues and performs various functions:

• Photosynthesis: Parenchyma cells in the leaves contain chloroplasts which are essential for photosynthesis.
• Storage: They can store nutrients and water, providing resources when conditions are unfavorable for growth.
• Support: Collenchyma and sclerenchyma cells provide structural support and strength, especially where the plant needs extra resilience.

Collenchyma, as part of the ground tissue system, balances the need for flexibility with the necessity of support, enabling plants to grow and adapt to their environments.