cell structure

Cells are the basic building blocks of all living organisms. They are tiny, typically microscopic units that contain various structures called organelles, each with specific functions. The cell membrane surrounds and protects the cell, allowing substances to enter and exit. The nucleus acts as the control center, housing genetic material (DNA) that directs cell activities. Other organelles, like mitochondria, produce energy, while ribosomes make proteins essential for growth and repair. Cells come in diverse shapes and sizes, reflecting their specific roles in the body, from muscle contraction to nerve signal transmission.