hydrophilic

Examples of hydrophilic in the following topics:

• Hydrophilic and Hydrophobic Colloids

  • Hydrocolloids are stable suspensions of hydrophilic molecules; emulsions are suspensions of hydrophobic molecules that need stabilization.
  • A hydrophilic colloid, or hydrocolloid, is defined as a colloid system in which the colloid particles are hydrophilic polymers dispersed in water.

• Fluid Mosaic Model

  • Thus, the membrane surfaces that face the interior and exterior of the cell are hydrophilic.
  • This type of protein has a hydrophilic region or regions, and one or several mildly hydrophobic regions.
  • The glycocalyx is highly hydrophilic and attracts large amounts of water to the surface of the cell.
  • This phospholipid molecule is composed of a hydrophilic head and two hydrophobic tails.
  • The hydrophilic head group consists of a phosphate-containing group attached to a glycerol molecule.

• Salt Formation

  • Carboxylic acids and salts having alkyl chains longer than six carbons exhibit unusual behavior in water due to the presence of both hydrophilic (CO2) and hydrophobic (alkyl) regions in the same molecule.
  • Depending on the nature of the hydrophilic portion these compounds may form monolayers on the water surface or sphere-like clusters, called micelles, in solution.

• Functional Groups

  • Functional groups are usually classified as hydrophobic or hydrophilic depending on their charge or polarity.
  • Among the hydrophilic functional groups is the carboxyl group found in amino acids, some amino acid side chains, and the fatty acid heads that form triglycerides and phospholipids.
  • This carboxyl group ionizes to release hydrogen ions (H+) from the COOH group resulting in the negatively charged COO- group; this contributes to the hydrophilic nature of whatever molecule it is found on.
  • Other functional groups, such as the carbonyl group, have a partially negatively charged oxygen atom that may form hydrogen bonds with water molecules, again making the molecule more hydrophilic.

• Phospholipids

  • A phospholipid is an amphipathic molecule which means it has both a hydrophobic and a hydrophilic component.
  • A single phospholipid molecule has a phosphate group on one end, called the "head," and two side-by-side chains of fatty acids that make up the lipid "tails. " The phosphate group is negatively charged, making the head polar and hydrophilic, or "water loving."
  • As the phosphate groups are polar and hydrophilic, they are attracted to water in the intracellular fluid.
  • If a drop of phospholipids are placed in water, the phospholipids spontaneously forms a structure known as a micelle, with their hydrophilic heads oriented toward the water.
  • The formation of a micelle is a response to the amphipathic nature of fatty acids, meaning that they contain both hydrophilic and hydrophobic regions.

• Selective Permeability

  • The hydrophobic and hydrophilic regions of plasma membranes aid the diffusion of some molecules and hinder the diffusion of others.
  • Recall that plasma membranes are amphiphilic; that is, they have hydrophilic and hydrophobic regions.

• Bile

  • The bile salts are ionically charged, with a hydrophobic end and a hydrophillic end.
  • When exposed to water mixed with fat, like in the small intestine, the bile salts congregate around a fat droplet, with their hydrophobic side pointing towards the fat and their hydrophillic side pointing towards the water .

• Water’s Solvent Properties

  • Sugar, sodium chloride, and hydrophilic proteins are all substances that dissolve in water.
  • Since many biomolecules are either polar or charged, water readily dissolves these hydrophilic compounds.

• ABC Transporters

  • The substrates that can be transported include ions, amino acids, peptides, sugars, and other molecules that are mostly hydrophilic.
  • The membrane-spanning region of the ABC transporter protects hydrophilic substrates from the lipids of the membrane bilayer thus providing a pathway across the cell membrane .

• Antimicrobial Peptides

  • These evolutionarily conserved peptides are usually positively charged and have both a hydrophobic and hydrophilic side that enables the molecule to be soluble in aqueous environments yet also enter lipid-rich membranes.