What Are Cells?

Every living thing, including you, is made of tiny units called cells! Cells are like little factories that carry out all the processes needed for life. Some organisms, like bacteria, are just one cell, but humans are made of trillions!

Types of Human Cells

• Muscle cells: Help you move your body.
• Nerve cells: Carry electrical signals so you can think, feel, and react.
• Blood cells: Transport oxygen and fight off invaders.
• Skin cells: Protect your insides from the outside world.

How Do Cells Work?

Each cell has parts called organelles, like:

• Nucleus: The control center where DNA lives.
• Mitochondria: The powerhouses that make energy.
• Cell membrane: The border that lets things in and out.

Real-World Connections

When you scrape your knee, skin cells work overtime to heal the wound. When you run, muscle cells use energy stored in mitochondria to power your movement.