Dýrafrumur

Dýrafrumur are the basic units of life in the animal kingdom. They are eukaryotic cells, meaning they possess a membrane-bound nucleus and other organelles. Unlike plant cells, animal cells lack a rigid cell wall, which allows for greater flexibility and movement. They also do not have chloroplasts, as animals obtain their energy by consuming other organisms.

A key characteristic of animal cells is the presence of a plasma membrane, a selectively permeable barrier that controls the passage of substances into and out of the cell. Within the cytoplasm, various organelles perform specific functions. The nucleus contains the cell's genetic material, DNA, and controls cellular activities. Mitochondria are responsible for cellular respiration, generating energy in the form of ATP. The endoplasmic reticulum and Golgi apparatus are involved in protein synthesis and modification, while lysosomes contain enzymes that break down waste materials. Centrioles, typically found near the nucleus, play a role in cell division. Animal cells also have ribosomes, which synthesize proteins. The size and shape of animal cells can vary greatly depending on their function, ranging from the small, irregular shapes of white blood cells to the long, filamentous structure of nerve cells. This diversity reflects the specialized roles these cells play in the complex organization of an animal's body.