Question

What forms the barrier of the tight junctions that seals off the space between adjacent cells?

Answer 1

Tight junctions are formed by proteins, predominantly claudins and occludins, which create a watertight seal between adjacent animal cells to prevent materials from leaking between them, and are found in epithelial tissues.

Step-by-step explanation:

Tight Junctions in Animal Cells

The barrier of tight junctions that seals off the space between adjacent cells is formed by proteins. Specifically, claudins and occludins are the dominant proteins that hold the cells tightly against each other, creating a watertight seal. This prevents materials, such as fluids and particles, from leaking between the cells. Tight junctions are crucial in maintaining the integrity of tissues by ensuring that extracellular fluids cannot pass freely between cells. These junctions are commonly found in epithelial tissue which lines internal organs and cavities.

For instance, the tight junctions of the epithelial cells lining the urinary bladder are vital as they prevent urine from leaking into the extracellular space. Similarly, tight junctions in the gut are important in preventing the leakage of food substances between cells into the body, although these can be regulated to allow certain substances to pass through under specific circumstances.

Answer 2

Tight junctions are made up of proteins called claudins and occludins, which hold cells together to form a watertight seal, preventing leakage between cells in tissues lining internal cavities.

Step-by-step explanation:

What Forms the Barrier of Tight Junctions?

Tight junctions form watertight seals that prevent materials from leaking between adjacent animal cells, thereby maintaining distinct internal environments.

These junctions are particularly important in epithelial tissues that line internal organs and cavities. The barrier of tight junctions is made up of proteins—predominantly two proteins called claudins and occludins.

These proteins hold the cells tightly against one another, creating a waterproof barrier between cells. For instance, such tight junctions are found lining the urinary bladder to prevent urine from leaking into the extracellular space and lining the gut to regulate the passage of substances into the body.