Question

Identify the types of cell junctions that help to stop the leakage of the substances across a tissue and facilitation of communication with neighbouring cells via rapid transfer of ions and molecules.

• A. Gap junctions and Adhering junctions, respectively
• B. Adhering junctions and Tight junctions, respectively.
• C. Tight junctions and Gap junctions, respectively
• D. Adhering junctions and Gap junctions, respectively

Answer 1

The correct option is C

Tight junctions and Gap junctions, respectively

The correct option is C:

Explanation of the correct option:

1. Tight connections form a watertight closure between two cells, preventing chemicals from flowing through a tissue.
2. Claudins, a type of protein found in tight junctions, are responsible for binding two cells together.
3. Gap junctions are only found in animal cells, and their function is similar to that of plant plasmodesmata.
4. Gap junctions are recognised for using protein channels to connect different types of cells. They connect the cytoplasm of neighbouring cells, allowing ions, tiny molecules, and big molecules to flow freely.
5. These junctions are located between cells that are in close proximity to one another.

Explanation of the incorrect option:

Option A:

1. Gap junctions are recognised for using protein channels to connect different types of cells. They connect the cytoplasm of neighbouring cells, allowing ions, tiny molecules, and big molecules to flow freely.
2. Adhering junctions are those that are used to maintain nearby cells together by cementing them together. Calcium is constantly required for adherence.

Option B:

1. Adhering junctions are those that are used to maintain nearby cells together by cementing them together. Calcium is constantly required for adherence.
2. Tight connections form a watertight closure between two cells, preventing chemicals from flowing through a tissue.

Option D:

1. Adhering junctions are those that are used to maintain nearby cells together by cementing them together. Calcium is constantly required for adherence.
2. Gap junctions are recognised for using protein channels to connect different types of cells. They connect the cytoplasm of neighbouring cells, allowing ions, tiny molecules, and big molecules to flow freely.

Final answer: Cell junctions that help to stop the leakage of the substances across a tissue and facilitation of communication with neighbouring cells via rapid transfer of ions and molecules are Tight junctions and Gap junctions, respectively.