What are some examples of facilitated diffusion?

Example of Facilitated Diffusion. In the cell, examples of molecules that must use facilitated diffusion to move in and out of the cell membrane are glucose, sodium ions, and potassium ions. They pass using carrier proteins through the cell membrane without energy along the concentration gradient.
A.

What are some substances that move through the membrane by facilitated diffusion?

Certain small nonpolar substances, such as oxygen, can diffuse directly through the membrane in a process called simple diffusion. Large, polar or charged molecules and ions either cannot squeeze through the small membrane spaces or are repelled by the hydrophobic membrane interior.
  • Is facilitated diffusion active or passive?

    This process is called passive transport or facilitated diffusion, and does not require energy. The solute can move "uphill," from regions of lower to higher concentration. This process is called active transport, and requires some form of chemical energy.
  • What are the factors that affect the rate of diffusion?

    The rate of diffusion is increased when: The distance is decreased. The surface area is increased. The concentration difference (concentration gradient) is increased.
  • Why is facilitated diffusion important to cells?

    A concentration gradient exists that would allow ions and polar molecules to diffuse into the cell, but these materials are repelled by the hydrophobic parts of the cell membrane. Facilitated diffusion uses integral membrane proteins to move polar or charged substances across the hydrophobic regions of the membrane.
B.

What is needed for facilitated diffusion?

The solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. This process is called passive transport or facilitated diffusion, and does not require energy.
  • What does the process of facilitated diffusion require?

    The solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. This process is called passive transport or facilitated diffusion, and does not require energy.
  • How are simple diffusion and facilitated diffusion different?

    Simple diffusion does not require energy: facilitated diffusion requires a source of ATP. Simple diffusion can only move material in the direction of a concentration gradient; facilitated diffusion moves materials with and against a concentration gradient.
  • Is diffusion from low to high?

    Diffusion happens when the particles are free to move. This is true in gases and for particles dissolved in solutions. Particles diffuse down a concentration gradient, from an area of high concentration to an area of low concentration.
C.

What are the substances involved in diffusion?

Diffusion
ExampleSubstance(s) involvedMoved from (high concentration region)
Gas exchange in lungsCarbon dioxideBlood circulating through lungs
Gas exchange in a leafCarbon dioxideAir outside the leaf
Exchange in the small intestineDigested food molecules, eg amino acids and glucoseSmall intestine
  • What is an example of facilitated diffusion?

    Example of Facilitated Diffusion. In the cell, examples of molecules that must use facilitated diffusion to move in and out of the cell membrane are glucose, sodium ions, and potassium ions. They pass using carrier proteins through the cell membrane without energy along the concentration gradient.
  • What are some factors that can affect the rate of diffusion?

    List Some Factors That Would Increase the Rate of Diffusion
    • Temperature. As temperature increases the average kinetic energy of particles increases.
    • Density of the Diffusing Substance. Density is defined as the amount of material that exists within a given volume.
    • Medium of Diffusion. Diffusion also depends upon the medium in which it takes place.
    • Concentration Gradient.
  • What substances use active transport?

    Active transport is usually associated with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acids. If the process uses chemical energy, such as from adenosine triphosphate (ATP), it is termed primary active transport.

Updated: 2nd October 2019

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