What is a concentration gradient?

Question

This is in relation to Human Biology - The Cell and its structures; tissues and organs.

Answer 1

A concentration gradient is basically in your case the difference in concentration between the cell and the surrounding solution.
In diffusion and osmosis cases molecules such as oxygen usually move from a high to a low concentration (down a concentration gradient). ie. from a high conc in the alveolar air space (air sacs) to the cappillaries surrounding the alveoli.

The exception is in active transport where molecules move against or up a concentration gradient (from low to high conc) using energy. This happens in order to bring ions such as sodium or potassium into the cell where they are required in a higher conc than the surrounding medium.

Answer 2

The posters above have a general idea which is generally correct but are all not directly related to THE most important aspect of the concentratioing gradient.

THE MOST important concentration gradient takes place inside the cell, in fact, within the innermembrane space of the mitochondria. The mitochondria has two membrane - the inner and outer ones and between them is a very high concentration of protons. Protons have to flow from high concentration to low concentration (because protons repel each other's same charges) and when they flow from the mitochondrial innermembrane space into the matrix, this results in the formation of ATP via ATP Synthase.

Another very important aspect of concentration gradient uses calcium ions. Inside the cell, there's not a lot of calcium but outside of the cell, calcium is usually many folds higher. Cells use the influx of calcium to induce cellular activity and neuronal signal transduction.

-Kevin

Answer 3

Concentration gradient = increase or decrease (in concentration) over distance
Though it is related to diffusion (random molecular movement in all directions) but is also guided by probability - a molecule has a higher probability of moving from a high concentration to a low concentration than vice versa. Thus there is a net spontaneous but directional movement of molecules and refers to overall movement away from the center of concentration,
In the absence of other forces or constraints (e.g., pressure) a substance will diffuse from where it is more concentrated to where it is less concentrated.
--A substance diffuses down its own concentration gradient.
--It is not affected by the gradients of other substances in the same place.
--This occurs spontaneously with rate dependent on rates of diffusion. The probability that it occurs is dependent upon the degree to which the low concentration and high concentration environments differ in terms of solute concentration.

Answer 4

Another phraqse for it is diffusion:
The diffusion process is the net force of matter (particles or molecules), heat, momentum, or light moving from an area of high concentration to an area of low concentration of that matter. Diffusion is one type of transport phenomenon. Diffusion is also a type of Passive Transport, or a transport that dosen't requires enery because the molecules are moving from high concentration to low concentration. Diffusion is the movement of particles from one place to another. (chemical potential can in most cases of diffusion be represented by a change in concentration). It is readily observed, for example, when dried food like spaghetti is cooked; water molecules diffuse into the spaghetti strings, making them thicker and more flexible. It is a physical process rather than a chemical reaction, which requires no net energy expenditure. In cell biology, diffusion is often described as a form of passive transport, by which substances cross membranes.
There is loads more to learn about it on wikipedea.... check it out....

Answer 5

The graduated difference in concentration of a solute per unit distance through a solution.