What are the factors affecting the rate of diffusion?

Answer 1

Factors Affecting the Rate of Diffusion

Size

Small molecules can slip by the polar heads of the phospholipids and through the membrane to the other side. Oxygen gas, carbon dioxide and water can move in this manner. Very large molecules like proteins cannot diffuse across the membrane at all.

Shape

Glucose is able to get into cells much faster than other sugars. This is accomplished by facilitated diffusion. A carrier protein specific for glucose (not other sugars) combines with it on the outer surface, closes around it, and then opens to the inside of the cell where the glucose is released. The carrier then returns to its original shape and is ready to transport another glucose molecule. These carriers can move up to 100 glucose molecules per second across the cell membrane.

Concentration

The greater the concentration gradient between the outside and inside of the membrane the greater the rate of diffusion. If the concentration of oxygen outside the cell increases then it will diffuse more quickly into the cell. The opposite is also true. If a muscle cell for example is working hard and using up large quantities of oxygen in cellular respiration producing ATP, then the low levels inside the cell will increase the concentration gradient compared to outside and the rate of diffusion of oxygen into the cell will increase. The same conditions in a muscle cell would create high concentrations of carbon dioxide inside the cell and increase the rate of diffusion from inside to outside.

Charge (+/-)

Ions or molecules with a charge cannot pass through the lipid bilayer by diffusion. Other mechanisms involving protein carriers and ATP energy are required. The sodium/potassium ion pump is an example of this type of transport.

Lipid Solubility

Lipid soluble molecules can move through the lipid bilayer. Generally these molecules are other lipids. Steroid hormones like testosterone and estrogen are examples of such molecules. This easy access to cells explains the powerful and wide ranging effects of such hormones.

Temperature

In general, increases in temperature cause all molecules to move faster. Diffusion is a passive movement of molecules so quicker molecule movement translates into quicker diffusion.

Rate of diffusion increases as: * Diffusion distance decreases * Concentration gradient increases * Surface area increases

Answer 2

Factors affecting the rate of diffusion include concentration gradient (higher gradient leads to faster diffusion), temperature (higher temperature increases the kinetic energy of molecules, speeding up diffusion), molecular size (smaller molecules diffuse faster), and the medium through which diffusion occurs (diffusion is faster in gases compared to liquids).

Answer 3

There several physical factors that affect the rate at which particles diffuse. These include: the size of the particle, the temperature, the concentration difference, the diffusion distance, the surface area, and permeability.

Answer 4

The concentration difference and the temperature !

Answer 5

1. Size of particles

2. Concentration gradient

3. Temperature

4. Surface area

Answer 6

distance and the material through which diffusion is occurring (each material has a diffusion coefficient).

Answer 7

Temperature is one of them. Cold slows it.

Answer 8

gravity, mass, and density

Answer 9

Consintration temperature and pressure

Answer 10

Temperature

Steepness