Untitled Quiz

Study Notes

Prokaryotic cells are simple, unicellular organisms lacking a nucleus and membrane-bound organelles, primarily containing DNA in the nucleoid region.
Eukaryotic cells possess a nucleus enclosed by a membrane and have various other organelles that are also membrane-bound.
Both prokaryotes and eukaryotes can possess genetic information despite the lack of a defined nucleus in prokaryotes.
Bacteria, often viewed negatively, play essential roles in ecosystems and human health.

Specialized cells undergo differentiation to perform specific functions within multicellular organisms.
Key types of specialized animal cells include epithelial, connective, muscle, and nerve cells.

Plant cells also differentiate to carry out specialized functions, adapting to unique roles within plant tissues.

Epithelial tissue serves as linings for organs and cavities, characterized by closely packed cells with tight junctions.
Distinct arrangements of epithelial cells include:
- Cuboidal: For secretion.
- Simple Columnar: Brick-shaped for secretion and absorption.
- Simple Squamous: Plate-like for material exchange via diffusion.
- Stratified Squamous: Multilayered for protection, regenerates quickly.
- Pseudo-Stratified Columnar: Appears layered, lines the respiratory tract, may contain cilia for mucus sweeping.

Muscle tissues are made of long cells (muscle fibers) that allow for movement and contractibility, facilitating bodily functions.

Cells can adapt through structural changes such as:
- Cilia: Can be motile for movement or non-motile (sensory).
- Flagella: Whip-like structures for propulsion.
- Microvilli: Small projections enhancing surface area for increased absorption.
- Pseudopodia: Temporary extensions for movement and engulfing substances (phagocytosis).