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What Is Exocytosis and Endocytosis in Biology

In this what is exocytosis and endocytosis in biology post we have briefly explained about exocytosis and endocytosis in biological cell membrane. Read on to learn more about exocytosis and endocytosis!!

Exocytosis and Endocytosis

Certain particles or molecules are too big to traverse the plasma membrane, or pass through a transporter. Cells use two different active transport mechanisms to move those macromolecules (large molecules) to and out of cells. 

Vesicles or other structures within the cytoplasm transport macromolecules or other large particles over the membrane. There are two kinds of vesicle transport: exocytosis and endocytosis (exocytosis and endocytosis process illustrated in the figure below). Both of these exocytosis and endocytosis processes that are active, which require energy.

Exocytosis and Endocytosis Process

Exocytosis and Endocytosis Process: Illustration of the two types of vesicle transport, exocytosis and endocytosis. Image Source: https://www.ck12.org/student/

What Is Exocytosis and Endocytosis in Biology

Endocytosis

Endocytosis captures an object or particle outside of the cell by engulfing it in the cell membrane. The membrane is folded over the substance until it is completely covered in the membrane. The membrane-bound sac or the vesicle is formed and can move the substance into the cell’s cytosol. There are two types of endocytosis.

Phagocytosis, also known as cell eating, occurs when dissolved substances enter the cell. A plasma membrane covers the solid and forms a phagocytic vesicle.

Pinocytosis, also known as cellular drinking, is in the process of folding plasma backward to form a channel, allowing dissolving substances to enter the cell, as shown in the image below. When the channel is shut, the liquid is enclosed by a pinocytic vessel.

Exocytosis and Endocytosis Process

Exocytosis

Exocytosis describes the process of vesicles joining with plasma membranes and dispersing their contents onto an outside cell, as seen in the figure following. Exocytosis is triggered when cells produce substances that can be exported, like proteins, or eliminate an unneeded product or toxin. Freshly produced plasma membrane substances and membrane lipids get transferred over the plasma membrane through exocytosis.

Take Away

Active transport is the energy-requiring process of pumping molecules and ions across membranes against a concentration gradient. Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell. Exocytosis describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell. Both endocytosis and exocytosis are active transport processes.

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