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Related Concept Videos

The Colloidal State01:29

The Colloidal State

The formation of a colloidal system is exemplified by an aqueous solution containing Cl− ions is introduced to another containing Ag+ ions, resulting in the precipitation of solid AgCl as extremely tiny crystals. Instead of settling out as a filterable precipitate, these crystals remain suspended in the liquid, showcasing a colloidal system.A colloidal system involves colloidal particles within the approximate range of 1 to 1000 nm in at least one dimension, dispersed in a medium called the...
Colloids03:22

Colloids

Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles that are visible to the naked eye or can be seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. On the other hand, a solution is a homogeneous mixture in which no settling occurs and in which the dissolved...
Colloids and Suspensions01:17

Colloids and Suspensions

Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
Colloidal precipitates01:09

Colloidal precipitates

The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
Protein Diffusion in the Membrane01:24

Protein Diffusion in the Membrane

Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
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Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...

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High-Resolution Neutron Spectroscopy to Study Picosecond-Nanosecond Dynamics of Proteins and Hydration Water
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THE COLLOIDAL BEHAVIOR OF PROTEINS.

J Loeb1

  • 1Laboratories of The Rockefeller Institute for Medical Research.

The Journal of General Physiology
|October 30, 2009
PubMed
Summary
This summary is machine-generated.

Neutral salts reduce osmotic pressure and potential difference (P.D.) in protein-acid salts. The P.D. is quantitatively linked to the hydrogen ion concentration difference across a membrane, explained by the Donnan equilibrium.

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Area of Science:

  • Colloid and Interface Science
  • Physical Chemistry
  • Biophysical Chemistry

Background:

  • Protein-acid salts exhibit properties like osmotic pressure, swelling, and viscosity that are influenced by neutral salts.
  • The potential difference (P.D.) across semipermeable membranes containing protein-acid salts is a key characteristic.
  • Understanding the factors affecting P.D. is crucial for elucidating membrane transport and protein behavior.

Purpose of the Study:

  • To investigate the relationship between neutral salts and the P.D. of gelatin chloride solutions.
  • To determine if the P.D. can be quantitatively predicted based on hydrogen ion concentration differences.
  • To explore the influence of pH on the osmotic pressure and P.D. of gelatin salts.

Main Methods:

  • Measurements of P.D. between gelatin chloride solutions and an external aqueous solution.
  • Determination of hydrogen ion concentration (pH) inside and outside the gelatin solution.
  • Application of the Nernst formula to correlate pH differences with P.D.

Main Results:

  • Neutral salts depress the P.D. of gelatin chloride solutions proportionally to their effect on osmotic pressure.
  • The P.D. can be quantitatively calculated from the difference in pH across the membrane using the Nernst formula.
  • Osmotic pressure and P.D. of gelatin salts vary with pH, showing maxima at specific pH values.
  • Different gelatin salts (sulfate, chloride, phosphate, oxalate) exhibit parallel P.D. and osmotic pressure curves.

Conclusions:

  • The Donnan membrane equilibrium explains the observed pH differences and resulting P.D.
  • The Nernst formula accurately predicts P.D. based on internal and external pH gradients.
  • The concentration of hydrogen ions significantly influences the P.D. of gelatin salts.