Key features of eukaryotes:
1. Nucleus: Eukaryotic cells have a true nucleus, a double-membrane-bound organelle that houses and protects the cell's genetic material. The nucleus contains chromosomes made up of DNA, the blueprint for the organism's traits and development.
2. Membrane-Bound Organelles: Unlike prokaryotes, eukaryotic cells have various membrane-bound organelles that compartmentalize functions and reactions within the cell. These include organelles like mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes. Each organelle has specialized roles, enabling complex cellular processes.
3. Cellular Complexity: Compared to prokaryotes, eukaryotic cells are structurally and functionally more complex. They have a cytoskeleton, a network of protein filaments and microtubules that provides structural support, shape, and the ability for cellular movement and division.
4. Mitosis and Meiosis: Eukaryotes undergo mitosis, a process of cell division that ensures equal distribution of genetic material to daughter cells during growth and asexual reproduction. Additionally, eukaryotes have the capability of meiosis, a specialized form of cell division that produces gametes (sex cells like eggs and sperm) with half the number of chromosomes, facilitating sexual reproduction and genetic variation.
5. Endomembrane System: The internal compartments and membrane-bound organelles of eukaryotic cells are interconnected through the endomembrane system. This network allows for selective transport of materials within the cell and contributes to critical functions like protein synthesis, secretion, and waste removal.
6. Multicellularity: Many eukaryotic organisms are multicellular, meaning they are composed of multiple cells working together to form specialized tissues, organs, and systems. This complexity allows for a diverse range of ecological niches and adaptations.
In summary, eukaryotes are organisms characterized by the presence of a nucleus and membrane-bound organelles. Their cellular complexity and advanced features enable them to carry out sophisticated functions, adapt to various environments, and exhibit a remarkable diversity of life forms on Earth.