Cell transport

Define diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

What's diffusion role in cellular activities?

It's important because diffusion is involved in the transport of substances in and out of the cell. Therefore, it is responsible for the uptake of essential substances the cell needs and the removal of waste products produced by cell.

Define concentration gradient

A difference in solute concentration between across a membrane that drives movement of particles from higher to lower concentration.

Define Active transport

The movement of molecules and ions from an area of low concentration to high concentration, against the concentration gradient. They bind onto protein pumps (changes their shape) and forcefully carries them across the membrane. This requires the expense of energy (ATP)

Define facilitated diffusion

The passive movement of molecules and ions across the plasma membrane through protein channels and etc., going with the concentration gradient; from an area of high concentration to low concentration.

Define osmosis

The passive movement of water molecules across a semi-permeable membrane from a high water potential to a low water potential.

What is the differences and similarities between active transport and facilitated diffusion

Both forms of transports molecules and ions through the help of proteins, but faciliated transport is the passive movement of molecule moving from an area of high to low concentration via protein channels. Active transport requires the expense of energy (ATP) to move molecules against the concentration gradient via protein pumps.

What is Dynamic equilibrium?

When the concentration of molecules/ions from both areas (inside and outside the cell) are equal. There's no longer a concentration gradient that drives the passive movement of molecules/ions, but they still move back and forth randomly across the membrane but in equal amounts. Therefore, the net movement of molecules/ions are equal.

When does Active transport, Facilitated diffusion, and osmosis stop?

Facilitated diffusion and active transport stops when dynamic equilibrium is reached, where there's no longer a concentration gradient that drives passive net movement of molecules/ions. Active transport will endlessly carry on because molecules/ions move against the concentration gradient, until there's no more ATP.