You're asking about cellular structures that help with movement, either of the cell itself or of substances across its surface. Here's a breakdown of the key players:

1. Projections for Cell Movement:

* Cilia: These are short, hair-like projections that beat rhythmically. They are common in lining of respiratory tract (moving mucus), oviducts (moving egg cells), and some protozoa.

* Flagella: These are longer, whip-like projections, usually present in single numbers or small groups. They are used for locomotion, notably in sperm cells and some bacteria.

2. Projections for Substance Movement:

* Microvilli: These are tiny, finger-like extensions of the plasma membrane. They increase surface area, enhancing absorption of nutrients, like in the small intestine.

* Pseudopodia: These are temporary, flowing extensions of the cell membrane. They are used by amoebas and some white blood cells for movement and engulfing food (phagocytosis).

Key Points:

* Cytoskeleton: This internal network of protein fibers (microtubules and microfilaments) provides structural support and is crucial for the functioning of cilia, flagella, and pseudopodia.

* Motor proteins: These proteins, like dynein and kinesin, use energy from ATP to move along cytoskeletal elements, enabling movement of cilia, flagella, and even vesicles within the cell.

Let me know if you'd like more detail on any of these structures or the mechanisms of their movement!