Endoplasm

Endoplasm, also called entoplasm, is the inner, dense part of a cell's cytoplasm. It is different from the outer part called ectoplasm, found in cells like amoeba and other simple organisms called protists. The nucleus, which holds important information for the cell, is separated from the endoplasm by a special covering.

The endoplasm contains many important things such as water, building blocks for proteins, sugars, salts, fats, and special helper molecules called enzymes. It is where most of the cell's important activities happen, including making new cells. Because of this, the endoplasm is very important for keeping the cell alive and working.

Endoplasm is always moving and changing. Tiny packages called vesicles carry materials between different parts of the cell and the cell's outer layer. Some parts of the cell's support structure called the cytoskeleton are found in the endoplasm, but most are near the edges of the cell. The granules in the endoplasm float in a liquid called cytosol.

Granules

The term granule refers to a tiny particle inside the endoplasm, often a secretory vesicle. Granules are special because they are usually only found in the endoplasm, not in the outer part of the cell called the ectoplasm. These granules are enclosed by a special layer and can join with other parts of the cell. They help the cell store and control important substances like enzymes, hormones, and waste. When the cell needs these substances, the granules release them to help the cell function properly.

Cytosol component of endoplasm

The cytosol is the soft, jelly-like part of the endoplasm inside cells. It holds many things floating in it and acts like a gel instead of a liquid because everything inside is packed tightly together.

The cytosol is mostly water but also has many different molecules, tiny particles, and proteins. Its makeup changes depending on what the cell needs at the time. Unlike the whole cytoplasm, the cytosol is just the gel part of the cell and does not include all the big molecules the cell uses to work.

Locomotion of amoeba via endoplasmic changes

Amoebas move mainly by using something called pseudopodial locomotion, which means they stretch out parts called pseudopods, or "false feet." These pseudopods form when the outer part of the cell, called ectoplasm, changes from a gel-like substance to a more fluid one. This change helps push the cell's outer layer forward.

As the pseudopod stretches out, the fluid inside turns back into a gel, and the rest of the cell follows, moving the amoeba along. Researchers have found that tiny structures inside the cell, called microfilaments, may help with this process, but exactly how it works is still being studied.

Processes within the endoplasm

Cellular respiration

The mitochondria are very important for cells. These tiny parts of the cell break down sugars like glucose to make energy called ATP (adenosine triphosphate). This energy helps the cell build proteins and do other important jobs, like sending signals. The number of mitochondria in the cell changes depending on what the cell needs to do. Cells that need a lot of energy have many mitochondria. Glucose is broken down in three steps: glycolysis, the citric acid cycle, and the electron transport chain.

Protein synthesis

Protein building starts at the ribosome. Ribosomes read instructions from mRNA to make chains of amino acids called peptides. These chains often need more work before they can do their job. Ribosomes attached to the rough endoplasmic reticulum send their protein chains into the space inside the ER. There, the proteins are shaped and changed by adding small molecules. After this, they move to the Golgi apparatus, where they get more changes and are packed up to go to their final place in or out of the cell. Tiny bags called vesicles help move these proteins around.

Other metabolic activities

Besides these two big jobs, the endoplasm does many other important things. Lysosomes break down waste and harmful stuff using enzymes. The smooth endoplasmic reticulum makes hormones and fats, breaks down toxins, and helps control calcium levels. Even though the main control for cell division is in the nucleus, the centrosomes in the endoplasm help make structures needed for cell division. The endoplasm is where many activities happen to keep the cell healthy and balanced.