2. Name : SOURABH TARAKESHWAR CHAUHAN
Class : S.Y.B Pharm
Roll No : 03
Division : D.S.Y
Subject : Physical Pharmaceutics โ โ
College : Shree D.D. Vispute College Of Pharmacy And Research Center, Gate No-04,
Vichumbe, New Panvel.
3. DiffusionPrinciplesinBiologicalSystems
The process by which molecules move from an area of high
concentration to an area of low concentration.
Importance of diffusion in biological systems
โข Facilitates the movement of various substances across cell membranes
โข enabling essential processes such as nutrient uptake and waste removal.
4. Factors influencing diffusion:
โข Concentration gradient: The difference in solute concentration between two regions
affects the rate of diffusion.
โข Temperature: Higher temperatures increase the kinetic energy of molecules,
accelerating diffusion.
โข Molecular size and charge: Smaller, uncharged molecules diffuse more rapidly than
larger or charged molecules.
5. Examples of diffusion in biological systems:
โข Gas exchange in the lungs: Oxygen diffuses from alveoli into the bloodstream,
while carbon dioxide moves from the bloodstream to the alveoli for exhalation.
โข Nutrient absorption in the intestines: Nutrients from digested food diffuse
across the intestinal lining into the bloodstream for distribution.
6. Importance of diffusion in cell signaling:
โข Signaling molecules, such as hormones or neurotransmitters, diffuse across
extracellular fluid to reach target cells, initiating specific cellular responses.
โข Diffusion gradients play a role in establishing concentration gradients
necessary for cell signaling.
7. SolubilityofGasinLiquids
Definition: The ability of a gas to dissolve in a liquid.
Factors affecting gas solubility:
โข Pressure: Higher pressure increases gas solubility, while lower pressure decreases it.
โข Temperature: Generally, gas solubility decreases as temperature rises.
8. Solubility of Gas in Liquids
โข Henry's Law: At a constant temperature, the concentration of a dissolved gas is
directly proportional to its partial pressure.
โข Equation: C = k * P, where C is the concentration, k is Henry's Law constant, and
P is the partial pressure.
9. Examples:
โข Carbonation in beverages: Carbon dioxide dissolves in liquids under pressure,
creating carbonated drinks.
โข Oxygen in aquatic environments: Oxygen dissolves in water, supporting aquatic
life.
10. Gas solubility and gas exchange in the body:
โข Oxygen dissolved in the bloodstream is crucial for cellular
respiration.
โข Carbon dioxide dissolved in the blood is transported to the lungs
for exhalation.
11. SolubilityofLiquidinLiquids
Definition : The ability of one liquid to dissolve in another liquid.
Miscibility : Liquids that mix in all proportions are miscible, forming
homogeneous solution.
12. Factors affecting liquid solubility:
โข Nature of liquids: Liquids with similar polarities and intermolecular forces are
more likely to be miscible.
โข Molecular structure: Liquids with similar molecular structures, such as
functional groups or chain lengths, are more likely to be miscible.
โข Temperature: In some cases, temperature can affect liquid solubility
โข Pressure: Unlike gas solubility, pressure has minimal impact on the solubility of
liquids in liquids.
13. Examples of liquid solubility:
โข Ethanol and water: Ethanol and water are miscible liquids due to their similar
polarities, allowing them to mix in any proportion.
โข Oil and water: Oil and water are immiscible liquids due to their different
polarities, resulting in the formation of distinct layers.
14. Applications:
โข Pharmaceutical industry: Solubility of active ingredients in liquid solvents is
crucial for drug formulations.
โข Extraction processes: Liquid-liquid extraction utilizes the solubility differences
of compounds in different solvents for separation and purification.
15. Summary
โข Diffusion is a fundamental process in biological systems, facilitating the
movement of substances across cell membranes and enabling cell signaling.
โข Gas solubility in liquids is influenced by pressure, temperature, and the nature
of the gas and liquid.
โข Liquid solubility is affected by the nature of the liquids, including their polarity
and intermolecular forces.
