Problem 22 - Objective Biology for NEET

Question

What is the function of Adhering junction? (a) Cementing to keep neighbouring cells together (b) Give rigidity to tissue (c) Stop leaking substance across the tissue (d) All of these

Step-by-Step Solution

Answer

The correct answer is: (d) All of these.

Step 1: Understanding Adhering Junctions

Adhering junctions are cell structures with the ability to connect and hold the neighboring cells together, they can provide rigidity to tissues or prevent leakage of substances across the tissue. Understanding this properly is vital to provide the accurate answer for the given multiple-choice question.

Step 2: Comparing the Answer Options

Option (a) mentions keeping cells together, which is a recognized role of adhering junctions. Option (b) notes providing rigidity to tissues, another recognized role of adhering junctions. Option (c) incorporates preventing leakage of substances across tissues, which is also a known function. By comparing all these functions with the known functions of adhering junctions, it can be concluded that all these options are, in fact, roles of adhering junctions.

Step 3: Determining the Correct Answer

Because all options (a), (b), and (c) are valid functions of adhering junctions, the correct answer to the given question is option (d) which contains all of these.

Key Concepts

Adhering Junctions in Cells

Adhering junctions are integral components of cellular architecture, playing a critical role in maintaining the structure and integrity of tissues. Composed of proteins such as cadherins and catenins, these junctions serve to anchor cells to one another, acting much like cement in construction. This cell-to-cell adhesion is facilitated by the interaction of these proteins with the actin cytoskeleton within the cell, enabling the junctions to withstand mechanical stress.

For students learning about cell biology, it's essential to understand that these junctions are not merely static elements. They dynamically facilitate communication and signal transduction between cells, thus influencing cellular behavior and tissue development. While studying adhering junctions, students should focus on the importance of these junctions in enabling tissues to function as a cohesive unit, allowing them to work together to perform complex biological processes.

Cellular Adhesion in Tissues

The concept of cellular adhesion extends beyond the mere physical connection between cells; it underpins tissue formation and maintenance. Think of each cell as an individual block in a larger structure—without a robust bonding mechanism, the structure would fall apart. This is where cellular adhesion molecules (CAMs) come into play. These molecules, which include the cadherins involved in adhering junctions, contribute to a myriad of critical biological roles such as tissue repair, embryonic development, and immune response.

Students should view cellular adhesion as a dynamic process regulated by both cellular signaling and the mechanical forces exerted on tissues. It's the balance between adhesion and detachment that allows for processes like wound healing and cell migration. When exploring this topic, an appreciation for the complexity and regulation of cellular adhesion will provide a more comprehensive understanding of how tissues maintain their structure and respond to various stimuli.

Cell Junctions and Tissue Rigidity

Cell junctions, particularly adhering junctions, endow tissues with rigidity and shape. The rigidity of a tissue is crucial for maintaining its shape and function, and for providing protection to the body's delicate internal organs. For example, the rigidity of skin tissue is a consequence of an array of cell junctions working in tandem to resist deformation.

To grasp the interplay between cell junctions and tissue rigidity, students should consider the mechanical aspects of how cells interact. Cell junctions can be envisioned as springs that connect cells, absorbing tension and compression to maintain the overall structural integrity of the tissue. This understanding of cell junctions can also be applied to pathological conditions where tissue rigidity is altered, such as in scarring or fibrosis. Emphasizing the mechanical nature of cell junctions in maintaining tissue rigidity offers a tangible way for students to conceptually link cellular structures with their physiological functions.