Cell transport Flashcards
What is diffusion?
The net movement of particles from a high to low concentration (down a concentration gradient), across a cell membrane until equilibrium is reached.
What is meant by net?
Overall.
What is meant by equilibrium?
The same on both sides.
Why is diffusion important in the human body?
Diffusion is important in the human body when getting oxygen into the bloodstream from the alveoli. It is also important when removing carbon dioxide and when absorbing nutrients in the intestines.
What is passive transport?
This is a type of membrane transport that does not require energy to move substances across a cell membrane. The two types are simple and facilitated diffusion.
What is simple diffusion?
The passive movement of particles from a high to low concentration through a cell membrane, until equilibrium is reached.
Small non-polar molecules can easily diffuse across a membrane (oxygen and carbon dioxide).
What is facilitated diffusion?
The use of protein channels and carrier proteins to transport ions or molecules from a high to low concentration.
This is the movement of larger or charged ions or molecules (H2O).
What is active transport?
The movement of molecules or ions across a cell membrane against a concentration gradient (low to high).
This requires energy and the concentration shifts further from equilibrium.
What is co-transport?
The movement of molecules or ions coupled to the movement of another. This requires energy and the two forms of this are symport and anti-port.
What is symport?
This is when two molecules or ions pass through a cell membrane in the same direction (together).
What is anti-port?
This is when two molecules or ions pass through a cell membrane in opposite directions.
Give an example of symport?
Glucose and sodium travel together when glucose is moving across a gradient.
