SB1i - Transporting Substances: diffusion Flashcards
State what diffusion does?
Allows molecules to move in and out of cells.
What is the definition of diffusion?
The spreading of particles resulting in a net (overall) movement from an area of higher concentration to an area of lower concentration
What are three molecules that move in and out of cells by diffusion?
Oxygen, carbon dioxide and urea
Where is the oxygen concentration higher, inside or outside the cell?
Outside the cell
Why is the concentration of oxygen higher outside a cell?
as the molecules move into the cell by diffusion from an area of higher concentration to lower concentration
Why does carbon dioxide move out of the cell?
As there is a lower concentration outside and a higher concentration in
What is urea?
A waste product produced inside cells which diffuses out of them unto the blood plasma
What’s urea excreted by?
The kidneys
What is carbon dioxide in respiration?
The waste product
What’s oxygen used for?
Generate energy in respiration
What are the factors diffusion’s effected by?
The difference in concentration, the temperature and the surface area of the membrane
What is the difference in concentration called?
Concentration gradient
How is diffusion effected by the concentration gradient?
The greater the concentration gradient, the faster diffusion takes place
How does temperature effect the rate of diffusion?
The higher the temperature the greater the rate of diffusion
Why does high temperature cause a quicker diffusion?
The particles have more kinetic energy and move faster
