Understanding the Structure and Function of Cell Components
The network is composed of x 1 d protein fibers embedded in a structure of moisturizing gel and glycoproteins. It is abundant in connective tissues and may accumulate deposits. Function: Maintains attachment to the cell and gives consistency to tissues. It allows diffusion of substances in cell migration. Cell wall and cellulose: typical of plant cells, covered thick and rigid on the outer surface of the plasma membrane. This forms long fibrils of x x 1 unit cell matrix. Cellulose is a linear polymer of glucose that forms long chains. Around 70 parallel chains linked by intermolecular hydrogen bridges are grouped into microfibrils and are engulfed in a matrix of hemicellulose, pectin, and glycoproteins. Some cells also have additional deposits of lignin, suberin, and waxes. In the process of lignification and cutinization, layers of suberization occur in the cell wall. A) Lamina: Proteins average. B) Wall 1st: Cell deposited during the ever-growing engine. C) Wall 2nd: Starts thickening as cell growth progresses. The cell wall is rich in components and has various functions. Functions of the cell wall: It protects and shapes the cell and acts as a barrier to pathogenic agents. Specializations: The walls are thinnest in areas where the deposition of cellulose and matrix is abundant. Plasmodesmata: Fine ducts pass through the cell walls and interconnect the cytoplasm of adjacent cells, allowing exchange. L:2 -> The cytoplasm is formed as a gelatinous mass with a large number of organelles, most of which are membrane-bound. The gel is a highly organized complex network due to protein filaments. Cytosol: This is the aqueous part of the cytoplasm where organelles are embedded.
It contains proteins, lipids, carbohydrates, and mineral salts. It serves as the medium where many metabolic processes occur. Cytoskeleton: This is a complex chain of protein filaments extending throughout the cytoplasm. It participates in all structural cellular movements and organizes enzymatic reactions. A) Actin filaments: Formed by globular proteins, they are involved in cell locomotion and phagocytosis, as well as in the formation of the contractile ring that leads to the separation of daughter cells. They maintain the structure and reinforce microvilli. B) Intermediate filaments: These fibers serve a structural function. C) Microtubules: Scattered throughout the cytoplasm, they are hollow cylinders formed by tubulin dimers that organize into microtubules. Their function includes generating cilia and flagella and transporting cytoplasmic organelles, as well as organizing and maintaining the cytoskeleton. Cilia and flagella: Cilia and flagella have the same structural displacement and allow cells to move through extracellular liquid. Structure: 1) Axis or axoneme: Contains 2 central microtubules and doublets of microtubules (9 pairs) surrounding the plasma membrane. 2) Transition zone: Corresponds to the base of the cilium or flagellum. In this area, the central microtubules disappear and are replaced by the basal plate. 3) Basal plate: Located below the plasma membrane, it has the same structure as centrioles. Centrosome: Centrioles and basal bodies of cilia and flagella share the same structural exception. In plants, all eukaryotic cells have a pair of centrioles in the centrosome, which is considered the organizing center of microtubules. It is located next to the nucleus and contains 2 mutually perpendicular centrioles formed by existing duplication.