diffusion Flashcards
definition of diffusion
the net movement of particles from a region of higher concentration to a region of lower concentration as a result of their random movement
where does energy for diffusion come from?
the kinetic energy of random of molecules
(Molecules have kinetic energy which means that they’ll constantly be moving)
The cell membrane is a partially/semi permeable membrane what does this mean?
The cell membrane is a partially permeable membrane - this means
* it allows some molecules to cross easily, but others with difficulty or not at all
importance of diffusion of gases and solutes in living organisms
Diffusion helps living organisms to:
-get rid of many of their waste products (Oxygen, which is a waste product of photosynthesis)
-carry out gas exchange for respiration (Cell membranes are freely permeable to oxygen and carbon dioxide, so these gases easily diffuse into and out of cells)
Without diffusion cell would die
GAS-glucose and oxygen for respiration, would not be able to reach the required places.
Solutes-
* Water is needed as a solvent.
* food molecules diffuse across the intestine wall and into the bloodstream
Factors that influence diffusion:
Factors that influence diffusion:
—Concentration gradient
—Temperature
—Surface area
—Distance
surface area
As the surface area increases, the rate of diffusion increases. This is because there is more space available for the substances to diffuse through
Distance
The smaller the distance molecules have to travel the faster transport will occur
This is why blood capillaries and alveoli have walls which are only one cell thick, ensure the rate of diffusion across them is as fast as possible
Temperature
As temperature increases, the rate of diffusion increases. This is because the molecules gain kinetic energy and thus move faster.
Concentration Gradient
The greater the difference in concentration, the faster movement across it will occur
