Diffusion Flashcards

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1
Q

What is diffusion?

A

It is overall the net, or overall, movement of particles from a higher concentration to a lower concentration, the process is passive process, it continues until equilibrium is reached where there is no difference in concentrations.

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2
Q

Why does diffusion happen?

A

The particles in a state (except solids) have kinetic energy, the movement is random and will eventually become an equal distribution, equilibrium doesn’t mean the particles aren’t moving there is no difference in concentrations.

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3
Q

Factors affecting the rate of diffusion

A

Temperature - an increase in temperature increases the kinetic energy of the particles. Concentration difference - the greater the difference in concentration between the two regions the faster the rate of diffusion, as the overall movement of molecules will be larger.

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4
Q

Diffusion across membranes

A

The movement across membranes are involved in the passing of the phospholipid billayer, or if they are permeable to the substance they will not be allowed to enter ( e.g 02) the hydrophobic interior repels charges ions

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5
Q

Facilitated diffusion

A

Diffusion across a membrane through protein channels is called facilitated diffusion, membranes with protein channels are selectively permeable, these protein channels are specific to molecules or ions.

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6
Q

Factors affecting facilitated diffusion

A

The rate is dependent on temperature, concentration gradient, membrane surface area and thickness, the more protein channels leads to a higher rate of diffusion.

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7
Q

A channel protein

A

Its pore can open and close but is specific to a molecule or ion, this type of facilitated diffusion has a high rate of diffusion.

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8
Q

A carrier protein

A

Its pore is open fully across a membrane, the protein changes shape when a specific molecule or ion binds to the protein causing conformational shape allowing the molecule to cross the cell membrane, this protein allows a slower rate of diffusion due to the limited carrier proteins available. The changing of the conformational shape comes from the molecule or ion to the protein, not from ATP.

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