Ridha Fathima

🔹 1. Types of Cells (in humans)

Muscle cells 💪 – help in movement

Nerve cells (neurons) 🧠 – carry messages

Blood cells 🩸 – red blood cells carry oxygen, white fight germs

Skin cells 🧴 – protect the body

Bone cells 🦴 – give support

🔹 2. Reproduction of Cells

Cells make more cells by cell division. Two main ways:

Mitosis – one cell divides into two identical cells (growth & repair).

Meiosis – makes sex cells (sperm and egg) for reproduction.

🔹 3. Where it Happens

Cell division (reproduction) happens inside the nucleus of the cell, where DNA is copied and shared.

🔹 4. Energy House of the Cell

The Mitochondria 🔋 is called the “powerhouse of the cell” because it makes energy from food.

🔹 5. Parts of a Cell (main ones)

Cell membrane – outer cover, protects cell

Cytoplasm – jelly-like fluid inside

Nucleus – control center, has DNA

Mitochondria – makes energy

Ribosomes – make proteins

Endoplasmic Reticulum – transports materials

Golgi body – packs and sends materials

🔹 6. Layers of a Cell

In a human cell, mainly two layers:

Cell membrane (outer layer)

Cytoplasm (inner jelly-like part holding organelles)

(Plants also have a cell wall, but humans don’t.

🔹 7. Outer Cover of the Cell

The Cell Membrane 🧩 is the outer cover. It controls what enters and leaves the cell, like a security guard.

Small definition

Types: muscle, nerve, blood, skin, bone…

Reproduction: mitosis & meiosis (in nucleus)

Energy house: mitochondria

Parts: nucleus, cytoplasm, membrane, etc.

Layers: membrane + cytoplasm

Outer cover: cell membrane