Loomrakud

Loomrakud, or animal cells, are the eukaryotic cells that form the tissues and organs of animals. They are typically flexible in shape and vary widely in size, reflecting their diverse roles in physiology, development, and tissue maintenance.

A loomrakud consists of a plasma membrane enclosing a cytoplasm that contains most cellular components. The nucleus houses the genetic material and is surrounded by a nuclear envelope. Energy production is carried out mainly by mitochondria. Protein synthesis occurs on ribosomes, with rough endoplasmic reticulum and the Golgi apparatus coordinating the processing and trafficking of proteins. Other organelles include lysosomes and peroxisomes, which participate in digestion and metabolism, as well as vesicles and an extensive cytoskeleton made of microfilaments, intermediate filaments, and microtubules that give shape and enable movement and intracellular transport. In many animal cells, a centrosome containing a pair of centrioles serves as the microtubule organizing center.

Loomrakud differ from plant and fungal cells in lacking a rigid cell wall and chloroplasts. The absence of a rigid wall allows greater flexibility in cell shape and tissue organization, while the presence of specialized cell junctions—such as tight junctions, desmosomes, and gap junctions—facilitates adhesion and communication between cells within tissues.

Diversity among loomrakud is tied to cellular specialization. Examples include epithelial cells that line surfaces, neurons that transmit signals, muscle cells that contract, and blood cells that perform transport and immune functions. In multicellular organisms, loomrakud cooperate through tissues and organs to sustain growth, development, and homeostasis. They are foundational to cell biology and are routinely cultured in laboratories for research and medical applications.