Endoplasmic reticulum facts for kids

An electron microscope picture showing the rough endoplasmic reticulum (RER) around the cell's control center, the nucleus. The small dark circles are mitochondria, which are like tiny power plants.

This picture shows different parts inside a cell: * 1 The nucleus, which is the cell's control center. * 2 A nuclear pore, a tiny hole in the nucleus's outer layer. * 3 The Rough endoplasmic reticulum (RER). * 4 The Smooth endoplasmic reticulum (SER). * 5 A Ribosome on the rough ER, where proteins are made. * 6 Proteins that are being moved. * 7 A transport vesicle, a small bubble that carries things. * 8 The Golgi apparatus, which sorts and packages proteins. * 9 The cis face of the Golgi apparatus (the "receiving" side). * 10 The trans face of the Golgi apparatus (the "shipping" side). * 11 Cisternae, the flattened sacs that make up the Golgi apparatus.

The endoplasmic reticulum (often called ER) is a super important part inside eukaryote cells. Think of it like a busy highway system or a factory within the cell. Its main job is to move molecules to specific places. These molecules don't just float around freely in the cell's liquid, called the cytoplasm. The ER makes sure they get where they need to go. You'll find the ER in cells that have a nucleus, like plant and animal cells, but not in simpler cells like bacteria.

There are two main types of endoplasmic reticulum:

Rough ER: The Protein Factory

The rough endoplasmic reticulum (RER) gets its name because it looks "rough" under a microscope. This is because it's covered with tiny dots called ribosomes. Ribosomes are like small machines that build proteins. The RER is very important for making proteins that will either be sent out of the cell or used in other parts of the cell's membrane. Once proteins are made on the RER, they are folded correctly and prepared for their journey.

Smooth ER: The Multi-Tasker

The smooth endoplasmic reticulum (SER) looks smooth because it doesn't have ribosomes on its surface. The SER has many different jobs. It helps make important substances like fats and steroids. It also plays a role in keeping the cell's outer layer, the plasma membrane, healthy. Plus, it acts as a pathway for molecules to move through the cell.

Sarcoplasmic Reticulum: Muscle's Special ER

There's a special type of ER called the sarcoplasmic reticulum (SR). You'll only find this in muscle cells. The SR is super important for how muscles work. It stores and releases calcium ions. When a muscle cell gets a signal to contract, the SR quickly releases its stored calcium. This calcium then helps the muscle fibers slide past each other, making the muscle contract.

How We Discovered the ER

Scientists first saw the delicate, lace-like membranes of the endoplasmic reticulum in 1945. They used a powerful tool called an electron microscope to get a close-up look inside cells. This discovery helped us understand much more about how cells are organized and how they work.

Images for kids

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  3D rendering of endoplasmic reticulum

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  A 2-minute animation showing how a protein destined for the secretory pathway is synthesized and secreted into the rough endoplasmic reticulum, which appears at the upper right approximately halfway through the animation.

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  Electron micrograph showing smooth ER (arrow) in mouse tissue, at 110,510× magnification.

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  Ca2+-antagonized transport into the endoplasmic reticulum (CaATiER) model

See also

In Spanish: Retículo endoplasmático para niños