Final answer:
Intermediate filaments are components of the cytoskeleton with structural roles such as providing tensile strength and resisting mechanical stress. They play a part in maintaining cell shape and anchoring organelles and can connect cells at desmosomes, but are not composed of identical subunits across all eukaryotic cells. Option 1 is correct answer.
Step-by-step explanation:
Intermediate filaments are crucial components of the cytoskeleton that play a vital role in maintaining cell structure and integrity. These filaments are composed of several intertwined strands of fibrous proteins, usually including keratins, and they serve a purely structural function. Their diameter, which ranges between 8 to 10 nm, categorizes them between microfilaments and microtubules in size, hence the name 'intermediate'. They provide tensile strength to cells, allowing them to resist stretching and mechanical stress.
Intermediate filaments are known for their high tensile strength and ability to protect cells from mechanical stress by resisting stretching. This is essential, particularly in cells that are subjected to tension, like the epithelial cells in the skin. Additionally, intermediate filaments play a role in positioning organelles within the cell and are involved in cell-to-cell adhesion through structures such as desmosomes, linking cells together and providing further structural support.
However, these filaments are not uniform across all eukaryotic cells. They are composed of a variety of proteins that are cell-type specific. For example, keratins are found in epithelial cells, while other types are present in muscle cells, nerve cells, and more. This specificity contradicts the statement that intermediate filaments are constructed of identical subunits found in all eukaryotic cells.
Concerning the question's statements, the following options are consistent with the structure and function of intermediate filaments:
- Intermediate filaments can connect cells at cell-cell junctions called desmosomes.
- Intermediate filaments protect cells from mechanical stress because they have high tensile strength and resist stretching.
The correct options from the statements given are that intermediate filaments can connect cells at desmosomes and they protect cells from mechanical stress due to their high tensile strength.