What are the different types of vesicles?
Posted September 20, 2023
There are five main types of vesicles. Each has its own distinct function.
- Secretory vesicles: Secretory vesicles contain materials such as hormones to be transported between cells or waste products to be excreted from the cell. They play a pivotal role in moving molecules out of the cell and are important for the healthy functioning of tissues and organs. Examples of secretory vesicles include synaptic vesicles and vesicles in endocrine tissues.
- Transport vesicles: Transport vesicles are responsible for moving materials such as proteins and other molecules, within the cell itself, from one part of the cell to another. All cells require proteins to function properly. These proteins are synthesized in the ribosomes and then packaged into transported vesicles to be moved to the Golgi apparatus for further refining and sorting. The Golgi apparatus identifies specific types of proteins in the transport vesicles and guides them to where they are needed. For example, the Golgi apparatus is capable of identifying proteins that are antibodies in transport vesicles. When antibodies are needed to fight a pathogen, the Golgi apparatus packages the antibodies into secretory vesicles and releases them outside the cell to destroy the pathogen.
- Vacuoles: Vacuoles are vesicles that are only found in plant cells. They are large and composed mostly of water. Plant cells have a single vacuole in the center of the cell. The main functions of the vacuole is to control osmotic pressure and store nutrients. This helps to avoid the bursting of the cell due to the osmotic pressure.
- Lysosomes: Lysosomes are cellular vesicles that contain digestive enzymes. They are only found in animal cells. Lysosomes play a key role in helping cells break down food particles and eliminate superfluous cellular materials. Lysosomes also function as part of the cell’s recycling system and help initiate cell death. Lysosomes get activated and release their enzymes when a cell needs to recycle large molecules or when the cell absorbs a harmful pathogen. The enzyme breaks down the big molecules into smaller molecules recycling valuable biomolecules for the cells to re-use and eliminating superfluous, dysfunctional molecules.
- Peroxisomes: Peroxisomes are vesicles that are responsible for using oxygen to digest excess nutrients and break down toxic substances present in the cell. They are commonly found in the kidney and liver cells, two main sites where harmful substances are degraded before being eliminated. Peroxisomes may vary in size and shape, depending on the requirements of the cell they serve. For example, if there’s a lot of alcohol to be broken down, peroxisomes may increase in number and size to be more effective against the larger quantity.