Final answer:
The contractile ring consists of microfilaments and proteins, playing a crucial role in cell division. The cytoskeleton's microfilaments, intermediate filaments, and microtubules each carry out specific functions in the cell, such as contraction, structural support, and cell motility. Tight junctions restrict intercellular movement, while gap junctions facilitate communication between adjacent cells.
Step-by-step explanation:
The contractile ring involved in cell division is composed of microfilaments and proteins. Specifically, these microfilaments are often actin filaments, which work alongside myosin proteins during cell contraction processes. The cytoskeleton within eukaryotic cells consists of three main types of filaments: microfilaments (actin filaments), intermediate filaments (e.g., keratin), and microtubules (composed of tubulin).
- Microfilaments and myosin are responsible for muscle cell contractions.
- Intermediate filaments like keratin provide structural support and resist tension.
- Microtubules maintain cell shape and are involved in a variety of cell motility functions.
Tight junctions are the type of junctions that prevent the movement of chemicals between two adjacent animal cells. The main components of myelin, which is the insulating layer around nerve fibers, are lipids and proteins. Meanwhile, gap junctions are special connections that allow for direct communication between the cytoplasm of two cells, permitting the transport of ions and small molecules.