Rakkude

Rakkude is the Estonian word for cells; rakkude is the genitive plural form used when referring to “of cells” or describing cell-related concepts in Estonian. In biology, cells are the basic units of life and the fundamental building blocks of all organisms. They can function independently, as in single-celled organisms, or form tissues and organs in multicellular organisms.

Biologists categorize cells into two broad types: prokaryotic and eukaryotic. Prokaryotic cells, found in bacteria and archaea, typically lack a defined nucleus and membrane-bound organelles. Eukaryotic cells, which make up plants, animals, fungi, and protists, possess a nucleus that houses genetic material and a variety of organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. Cells vary in size but commonly range from about 0.2 micrometers in prokaryotes to 10–100 micrometers in many eukaryotic cells.

Core components of cells include the cell membrane, cytoplasm, and genetic material (DNA). Eukaryotic cells contain organelles that carry out specialized functions; prokaryotes perform many of these functions within the cytoplasm and membrane. Key processes include metabolism, growth, response to stimuli, and replication. Reproduction occurs via binary fission in prokaryotes or mitosis (and often meiosis) in eukaryotes.

In multicellular organisms, cells specialize and organize into tissues, which form organs and systems. The study of rakkude encompasses cell biology, genetics, physiology, and pathology, providing insight into development, health, and disease.