If substance is less concentration outside a cell which direction is likely difuse across the cell membrance?

Question

If substance is less concentration outside a cell than inside the cell which direction is that substance likely difuse across the cell membrance

Answer 1

the substance will move from the area of high concentration to the area of lower concentration until such point that the concentration on both sides of the membrane are equal. in your case it will diffuse out of the cell

Answer 2

if the substance can actually pass through the semipermeable membrane of the cell, it will move from high concentration to low concentration... it will diffuse down the concentration gradient until an equilibrium is reached (the concenration is the same inside and outside the cell).
Diffusion is the general term that this refers to where any substance moves down its concentration gradient until equilibrium is reached...

in the case of water movement it is then termed Osmosis.. this term is ONLY used for water movement!!

Answer 3

Hi Osmosis usually moves from a higher to a lower concentration.

Answer 4

Toward the outside, until equilibrium. Called, " going down the gradient ".

Answer 5

It depends. Cell membrane is a semi permeable membrane that only allows some substances pass throu it.

Passive transport
From Wikipedia, the free encyclopedia:
Passive transport is a means of moving biochemicals, and other atomic or molecular substances, across membranes. Unlike active transport, this process does not involve chemical energy. Passive transport is dependent on the permeability of the cell membrane, which, in turn, is dependent on the organization and characteristics of the membrane lipids and proteins. The four main kinds of passive transport are diffusion, facilitated diffusion, filtration and osmosis.

Diffusion is the net movement of material from an area of high concentration of that material to an area with lower concentration. The difference of concentration between the two areas is often termed as the concentration gradient, and diffusion will continue until this gradient has been eliminated. Since diffusion moves material from area of higher concentration to the lower, it is described as moving solutes "down the concentration gradient" (compared with active transport, which often moves material from area of low concentration to area of higher concentration, and therefore referred to as moving the material "against the concentration gradient").

If and when the concentration gradient has been eliminated, no net exchange of material occurs. Although material may move forth from one area to the other, it will be balanced by movement of the same amount of material to the opposite direction.

Diffusion is biologically important because it enables the abolishment of concentration gradients in the body. For example, metabolic activity will consume oxygen, which will reduce its concentration in the bloodstream; diffusion of oxygen in the alveoli of the lungs allows it to be replenished.

Facilitated diffusion is movement of molecules across the cell membrane via special transport proteins that are embedded within the cellular membrane. Many large molecules, such as glucose, are insoluble in lipids and too large to fit through the membrane pores. Therefore, it will bind with its specific carrier proteins, and the complex will then be bonded to a receptor site and moved through the cellular membrane. Bear in mind, however, that facilitated diffusion is a passive process, and the solutes still move down the concentration gradient. The alveoli are tiny grapelike sacs located at the end of the bronchial tubes. This is where oxygen diffuses into the alveoli and is exchanged for carbon dioxide.

Filtration is movement of water and solute molecules across the cell membrane due to hydrostatic pressure generated by the cardiovascular system. Depending on the size of the membrane pores, only solutes of a certain size may pass through it. For example, the membrane pores of the Bowman's capsule in the kidneys are very small, and only albumin, the smallest of the proteins, have any chance of being filtered through. On the other hand, the membrane pores of liver cells are extremely large, to allow a variety of solutes to pass through and be metabolized.

Osmosis is the diffusion of a solvent across a membrane to a region of higher solute concentration. (In biological processes then, it usually is diffusion of water molecules). Most cell membranes are permeable to water, and since the diffusion of water plays such an important role in the biological functioning of any living being, a special term has been coined for it -- osmosis.

Water molecules "stick" together via weak hydrogen bond.

Active transport
From Wikipedia, the free encyclopedia:
Active transport is the mediated transport of biochemicals, and other atomic/molecular substances, across membranes. Unlike passive transport, this process requires chemical energy in the form of adenosine triphosphate(ATP). In this form of transport, molecules move against either an electrical or concentration gradient (collectively termed an electrochemical gradient). This is achieved by either altering the affinity of the binding site or altering the rate at which the protein changes conformations.
Types

There are two main types: primary and secondary. In primary transport, energy is directly coupled to the movement of a desired substance across a membrane independent of any other species. Secondary transport concerns the diffusion of one species across a membrane to drive the transport of another.

Primary
Primary active transport directly uses energy to transport molecules across a membrane. Most of the enzymes that perform this type of transport are transmembrane ATPases. A primary ATPase universal to all cellular life is the sodium-potassium pump, which helps maintain the cell potential.

Secondary
In secondary active transport, there is however no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of cells is used. The three main forms of this are uniport, counter-transport (antiport) and co-transport (symport).

In counter-transport two species of an ion or other solutes are pumped in opposite directions across a membrane. One of these species is allowed to flow from high to low concentration which yields the entropic energy to drive the transport of the other solute from a low concentration region to a high one. An example is the sodium-calcium exchanger or antiporter, which allows three sodium ions into the cell to transport one calcium out.

Many cells also possess a calcium ATPase, which can operate at lower intracellular concentrations of calcium and sets the normal or resting concentration of this important second messenger. But the ATPase exports calcium ions more slowly: only 30 per second versus 2000 per second by the exchanger. The exchanger comes into service when the calcium concentration rises steeply or "spikes" and enables rapid recovery. This shows that a single type of ion can be transported by several enzymes, which need not be active all the time (constitutively), but may exist to meet specific, intermittent needs.

Co-transport also uses the flow of one solute species from high to low concentration to move another molecule against its preferred direction of flow. An example is the glucose symporter, which co-transports two sodium ions for every molecule of glucose it imports into the cell.