solute potential

Examples of solute potential in the following topics:

• Water and Solute Potential

  • The water potential in plant solutions is influenced by solute concentration, pressure, gravity, and factors called matrix effects.
  • Solute potential (Ψs), also called osmotic potential, is negative in a plant cell and zero in distilled water.
  • Solutes reduce water potential (resulting in a negative Ψw) by consuming some of the potential energy available in the water.
  • In other words, the amount of available potential energy is reduced when solutes are added to an aqueous system.
  • This is why solute potential is sometimes called osmotic potential.

• Pressure, Gravity, and Matric Potential

  • Water potential is affected by factors such as pressure, gravity, and matric potentials.
  • A plant can manipulate Ψp via its ability to manipulate Ψs (solute potential) and by the process of osmosis.
  • If a plant cell increases the cytoplasmic solute concentration:
  • Ψm is similar to solute potential because the hydrogen bonds remove energy from the total system.
  • However, in solute potential, the other components are soluble, hydrophilic solute molecules, whereas in Ψm, the other components are insoluble, hydrophilic molecules of the plant cell wall. m cannot be manipulated by the plant and is typically ignored in well-watered roots, stems, and leaves.

• Introduction to Osmoregulation

  • The solutes in body fluids are mainly mineral salts and sugars.
  • An electrolyte is a solute that dissociates into ions when dissolved in water.
  • Solutions on two sides of a semi-permeable membrane tend to equalize in solute concentration by movement of solutes and/or water across the membrane.
  • When disease or injury damage the mechanisms that regulate osmotic pressure, toxic waste or water may accumulate, with potentially dire consequences.
  • Response of red blood cells in hypertonic, hypotonic, and isotonic solutions

• Tonicity

  • A solution's tonicity often directly correlates with the osmolarity of the solution.
  • Osmolarity describes the total solute concentration of the solution.
  • A solution with low osmolarity has a greater number of water molecules relative to the number of solute particles; a solution with high osmolarity has fewer water molecules with respect to solute particles.
  • Therefore, a solution that is cloudy with cells may have a lower osmolarity than a solution that is clear if the second solution contains more dissolved molecules than there are cells.
  • Cells in an isotonic solution retain their shape.

• Nerve Impulse Transmission within a Neuron: Action Potential

  • The action potential travels down the neuron as Na+ channels open.
  • Action potentials are considered an "all-or nothing" event.
  • Once the threshold potential is reached, the neuron completely depolarizes.
  • The diffusion of K+ out of the cell hyperpolarizes the cell, making the membrane potential more negative than the cell's normal resting potential.
  • At this point, the sodium channels return to their resting state, ready to open again if the membrane potential again exceeds the threshold potential.

• Concept of Osmolality and Milliequivalent

  • The unit for measuring solutes is the mole.
  • One mole is defined as the molecular weight of the solute in grams.
  • A solution's molarity is the number of moles of solute per liter of solution.
  • On the other hand, a solution's molality is the number of moles of solute per kilogram of solvent.
  • Concentration of solutions; part 2; moles, millimoles & milliequivalents by Professor Fink

• Osmosis

  • Osmosis is the movement of water across a membrane from an area of low solute concentration to an area of high solute concentration.
  • The semipermeable membrane limits the diffusion of solutes in the water.
  • If the volume of the solution on both sides of the membrane is the same but the concentrations of solute are different, then there are different amounts of water, the solvent, on either side of the membrane.
  • If there is more solute in one area, then there is less water; if there is less solute in one area, then there must be more water.
  • In this example, the solute cannot diffuse through the membrane, but the water can.

• Transportation of Photosynthates in the Phloem

  • The sucrose is actively transported against its concentration gradient (a process requiring ATP) into the phloem cells using the electrochemical potential of the proton gradient.
  • Phloem sap is an aqueous solution that contains up to 30 percent sugar, minerals, amino acids, and plant growth regulators.
  • The high percentage of sugar decreases Ψs, which decreases the total water potential, causing water to move by osmosis from the adjacent xylem into the phloem tubes.
  • This reduces the water potential, which causes water to enter the phloem from the xylem.

• Types of Energy

  • The various types of energy include kinetic, potential, and chemical energy.
  • Objects transfer their energy between potential and kinetic states.
  • At the same time, the ball loses potential energy as it nears the ground.
  • This type of potential energy is called chemical energy, and like all potential energy, it can be used to do work.
  • Water behind a dam has potential energy.

• Transport of Electrolytes across Cell Membranes

  • Osmotic pressure is influenced by the concentration of solutes in a solution.
  • It is directly proportional to the number of solute atoms or molecules and not dependent on the size of the solute molecules.
  • Because electrolytes dissociate into ions, adding relatively more solute molecules to a solution, they exert a greater osmotic pressure per unit mass than non-electrolytes such as glucose.
  • Facilitated diffusion of solutes occurs through protein-based channels.