The cytoskeleton of a cell is comprised of which of the following macromolecules?
A.
Nucleic acids
B.
Proteins
C.
Carbohydrates
D.
Lipids
The Correct Answer and Explanation is:
The correct answer is B. Proteins.
Explanation:
The cytoskeleton of a cell is an intricate network of protein fibers and tubules that provides structural support, shape, and organization to the cell. It is crucial for various cellular functions, including maintaining cell shape, enabling cellular movement, and facilitating intracellular transport.
The cytoskeleton is composed primarily of three types of protein structures:
- Microfilaments: These are thin, flexible fibers made of actin, a globular protein. Microfilaments are involved in various cellular processes, including cell motility, division, and shape changes. They play a significant role in muscle contraction and amoeboid movement.
- Intermediate Filaments: These fibers provide mechanical support to the cell and help maintain its shape. They are composed of a variety of proteins, including keratins, vimentin, and desmin, depending on the cell type. Intermediate filaments are more stable than microfilaments and microtubules and help anchor organelles in place.
- Microtubules: These are hollow tubes made of tubulin, another type of protein. Microtubules are involved in various essential functions, such as maintaining cell shape, enabling intracellular transport through motor proteins (like kinesin and dynein), and forming the mitotic spindle during cell division.
The cytoskeleton’s dynamic nature allows cells to adapt to changing conditions and respond to external signals. It also facilitates the organization of intracellular components and helps in cellular processes like endocytosis and exocytosis.
In contrast to proteins, the other macromolecules listed—nucleic acids, carbohydrates, and lipids—serve different functions within the cell. Nucleic acids (DNA and RNA) are involved in genetic information storage and transfer. Carbohydrates function primarily as energy sources and cell recognition molecules. Lipids are crucial for forming cellular membranes and storing energy but are not the primary components of the cytoskeleton.
Therefore, proteins are the essential macromolecules that constitute the cytoskeleton, enabling its diverse and critical functions in maintaining cell integrity and facilitating dynamic cellular processes.