The main difference between amphiphilic and amphipathic molecules is that amphiphilic molecules have less distinct hydrophilic and hydrophobic regions, whereas amphipathic molecules have distinct separations between hydrophilic and hydrophobic regions.
Amphiphilic and amphipathic molecules are types of molecules that contain both hydrophobic and hydrophilic regions.
Key Areas Covered
1. What are Amphiphilic Molecules
– Definition, Features, Examples
2. What are Amphipathic Molecules
– Definition, Features, Examples
3. Similarities – Amphiphilic and Amphipathic Molecules
– Outline of Common Features
4. Difference Between Amphiphilic and Amphipathic Molecules
– Comparison of Key Differences
Key Terms
Amphiphilic Molecules, Amphipathic Molecules
What are Amphiphilic Molecules
Amphiphilic molecules are molecules that have a distinct separation between hydrophobic and hydrophilic regions. The hydrophilic portion of an amphiphilic molecule is usually a charged or a polar group, while the hydrophobic portion is a non-polar group such as a hydrocarbon chain. The two parts of the molecule are often connected by a linker that determines the overall structure and the properties of the molecule.
One of the properties of amphiphilic molecules is their ability to self-assemble into structures such as micelles, vesicles, and bilayers. In aqueous solutions, amphiphiles will aggregate to minimize their exposure to water, forming structures that allow hydrophobic groups to associate with one another while keeping the hydrophilic groups in contact with the surrounding water. This property is used in the creation of surfactants. It is also useful in making detergents and emulsions. Detergents are surfactants that we use to remove dirt and grease from surfaces, including fabrics and dishes. Meanwhile, emulsions are used in many products, including food, cosmetics, and pharmaceuticals.
Amphiphilic molecules also help in the transport of lipids and other molecules in the body. For example, lipoproteins are composed of amphiphilic lipids and proteins. Another important property of amphiphilic molecules is their ability to lower the surface tension of water.
What are Amphipathic Molecules
Amphipathic molecules are a type of molecule that contains both hydrophobic and hydrophilic regions that are distinct. Amphipathic molecules are important in many biological processes, such as in the formation of cell membranes, transport of lipids and proteins in the bloodstream, formation of micelles, and assembly of viruses and other infectious agents. As these molecules contain two different constituents, their parts may react in opposing ways. Its hydrophilic portion will react with polar molecules, so it can be dissolved using polar solvents such as water. In contrast, the hydrophobic portion will not react with polar molecules; rather, it repels them. Unlike the hydrophilic portion, the hydrophobic part will not dissociate into ions in the presence of water. Other polar molecules will not react with this portion, but certain non-polar organic solvents will.
One example of amphipathic molecules is lipids which form the building blocks of cell membranes. Lipids have a hydrophilic head group and a hydrophobic tail group. Lipids spontaneously self-organize into bilayers, with the hydrophobic tails facing inwards and the hydrophilic heads facing outwards towards the water in the aqueous environments.
Another example of amphipathic molecules is surfactants. They also have both hydrophilic and hydrophobic regions, which allows them to interact with both polar and non-polar compounds. Amphipathic molecules also involve in the formation of micelles and liposomes. They are found in the protein structure and function. Soap and cholesterol are two other examples of amphipathic molecules.
Similarities Between Amphiphilic and Amphipathic Molecules
- Amphiphilic and amphipathic molecules have both hydrophobic and hydrophilic regions.
- Both types of molecules play important roles in biological systems, such as in the structure and function of cell membranes, emulsions, and surfactants.
Difference Between Amphiphilic and Amphipathic Molecules
Definition
Amphiphilic molecules are molecules that have both hydrophobic and hydrophilic regions, which are typically separate from each other within the molecule, whereas amphipathic molecules are molecules that have both hydrophobic and hydrophilic regions integrated into the same molecule.
Separation of Regions
Amphiphilic molecules have less distinct hydrophilic and hydrophobic regions, whereas amphipathic molecules have a distinct separation between hydrophilic and hydrophobic regions.
Examples
Some examples of amphiphilic molecules are phospholipids, soap, emulsifiers, lipoproteins, surfactants, and cholesterol, while examples of amphipathic molecules include phospholipids, detergents, apolipoproteins, hemoglobin, and bile acids.
Conclusion
Amphiphilic and amphipathic molecules are both types of molecules that contain both hydrophobic and hydrophilic regions. The main difference between amphiphilic and amphipathic molecules is that amphiphilic molecules have less distinct hydrophilic and hydrophobic regions, whereas amphipathic molecules have a distinct separation between hydrophilic and hydrophobic regions.
Reference:
1. “Amphipathic.” Biology Dictionary.
2. “Amphiphilic Molecules.” Encyclopedia of Membranes.
Image Courtesy:
1. “The lipid and lipid bilayer” By Bradleyhintze – Own work (CC BY-SA 3.0) via Commons Wikimedia
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