What is the Difference Between Transport Vesicles and Secretory Vesicles

The key difference between transport vesicles and secretory vesicles is that transport vesicles facilitate the movement of molecules within the cells while secretory vesicles excrete molecules out of the cell.

A vesicle is a small structure within the biological cell. It consists of fluid enclosed by a lipid bilayer. The membrane enclosing the vesicle is also a lamellar phase that is similar to that of the plasma membrane. The space inside the vesicle can be chemically different from the cytosol. This space can perform various metabolic activities such as transport and store molecules. There are different types of vesicles in the biological cells: transport vesicles, secretory vesicles, vacuoles, lysosomes, peroxisomes, and extracellular vesicles.

CONTENTS

1. Overview and Key Difference
2. What are Transport Vesicles  
3. What are Secretory Vesicles
4. Similarities – Transport Vesicles and Secretory Vesicles
5. Transport Vesicles vs Secretory Vesicles in Tabular Form
6. Summary – Transport Vesicles vs Secretory Vesicles

What are Transport Vesicles?

Transport vesicles move molecules within the cells. For example, they can move molecules like proteins from the rough endoplasmic reticulum to the Golgi apparatus. Membrane-bound and secreted proteins are usually made on ribosomes found in the rough endoplasmic reticulum. Most of these proteins mature in the Golgi apparatus before moving to their final destination, which may be lysosomes, peroxisomes, or outside of the cell. These proteins travel within the cell inside of the transport vesicles.

The Golgi apparatus identifies specific types of transport vesicles, then directs them to where they are needed. Some proteins in the transporter vesicles could be proteins such as antibodies. Golgi apparatus would package them into secretory vesicles to be released outside of the cell to fight pathogens. Because of the above reason, some scientists refer Golgi apparatus as the cell’s “post office.” Transport vesicles represent not only the carrier for the exchange of soluble material between the cell compartments but also constitute an effective way of continuously rebuilding cellular membranes through vesicle-membrane fusions and fissions.

What are Secretory Vesicles?

Secretory vesicles excrete molecules out of the cell. Normally, secretory vesicles contain materials that are to be excreted from the cell. The cells have many reasons to excrete materials. One reason is to dispose of waste. Another reason is associated with the function of the cell. In larger organisms, some cells are specialized to produce certain chemicals. These chemicals are stored in secretory vesicles and released when needed. There are two types of secretory vesicles: synaptic vesicles and vesicles in endocrine tissues.

Synaptic vesicles are located at presynaptic terminals in the neurons and store neurotransmitters. In animal endocrine tissues, they have vesicles that contain hormones that are to be released into the bloodstream. Furthermore, secretory vesicles hold enzymes that are used to make the cell walls of plants, protists, fungi, bacteria, and archaea, as well as the extracellular matrix of animal cells.

What are the Similarities Between Transport Vesicles and Secretory Vesicles?

• Transport vesicles and secretory vesicles are two types of vesicles in the cell.
• Both vesicles have small structures.
• Both vesicles consist of fluid enclosed by a lipid bilayer.
• These vesicles play important functions in organisms.
• They work together in case of pathogen elimination.

What is the Difference Between Transport Vesicles and Secretory Vesicles?

Transport vesicles move molecules within the cells, while secretory vesicles excrete molecules out of the cell. Thus, this is the key difference between transport vesicles and secretory vesicles. Furthermore, transport vesicles work within the cell, while secretory vesicles work outside the cell.

The below infographic presents the differences between transport vesicles and secretory vesicles in tabular form for side by side comparison.

Summary – Transport Vesicles vs Secretory Vesicles

Transport vesicles and secretory vesicles are the two main types of vesicles in the cell. Transport vesicles move molecules within the cells, while secretory vesicles excrete molecules out of the cell. So, this summarizes the difference between transport vesicles and secretory vesicles.

Reference:

1. “Transport Vesicle.” An Overview | ScienceDirect Topics.
2. “Secretory Vesicles.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Brefeldin A Inhibition of Intracellular Vesicle Transport” By Ahop28 – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Outer membrane vesicle secretion from gram-negative microbes – mechanism proposed (Original work of R C YashRoy)” By Rakeshyashroy – Own work (CC BY-SA 4.0) via Commons Wikimedia