Diffusion Flashcards

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1
Q

How do molecules diffuse in a net movement

A

Both ways but the net movement will be to the area of lower concentration and this continues till the particles are evenly distributed

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2
Q

What is the concentration gradient and how do particles move

A

The path of of an area of higher concentration to an area of lower concentration
The particles diffuse down the concentration gradient

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3
Q

Is energy required for diffusion

A

Diffusion is a passive process so no energy is required

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4
Q

How can particles diffuse across the cell membrane

A

They have to move freely through the membrane

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5
Q

What is simple diffusion

A

When molecules diffuse directly through the cell membrane

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6
Q

What type of molecules can do simple diffusion and hive two examples

A

Small molecules
Polar molecules
Oxygen and carbon dioxide

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7
Q

Why does it take longer for charged particles to diffuse slowly

A

They’re water soluble and the centre of the bi layer is hydrophobic

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8
Q

What is facilitated diffusion

A

Charged or large particles diffuse through carrier and channel proteins a in the membrane

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9
Q

How does facilitated diffusion move down the concentration gradient

A

From a high to low concentration

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10
Q

What does carrier proteins move

A

Larger molecules

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11
Q

Can one carrier proteins facilitate all different ions or molecules

A

No different carrier proteins facilitate the diffusion of different molecules

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12
Q

How do carrier proteins work

A

First large molecules attach to a carrier protien in the membrane
Then a the protien changes shape
This releases molecules on the opposite side of the membrane

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13
Q

What do channel proteins form

A

Pores in the membrane for the charged particles to diffuse

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14
Q

Can one channel protien facilitate the diffusion of different molecules

A

Different channel proteins facilitate the diffusion of differently charged particles

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15
Q

What moves mostly in channel proteins

A

Aquaporins - water molecules move through
Ions

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16
Q

What does simple diffusion rate of diffusion depend on

A

Concentration gradient - higher it is the faster the rate of diffusion
The thickness of exchange surfaces - the thinner the exchange surface the faster the rate of diffusion
The surface area -the larger the surface area the faster the rate of diffusion

17
Q

How does microvilli increase surface area for faster diffusion

A

Larger surface area means that more particles can be exchanged in the same amount of time

18
Q

What factors does facilitated diffusion depend

A

The concentration gradient - higher the concentration gradient faster the rate of facilitated diffusion
The number of channel or carrier proteins -greater the number of these proteins the faster the rate of diffusion

19
Q

Why does diffusion rate not increase even if the concentration increases

A

Because if all the proteins are in use facilitated diffusion then the rate doesn’t increase

20
Q

What are aquaporins

A

Special channel proteins that allow facilitated diffusion of water through cell membranes

21
Q

What does having more aqauporins do for the kidneys

A

Allow cells to reabsorb a lot of water that would otherwise be excreted by the body

22
Q

What does having more channel proteins do in facilitated diffusion

A

Increases the rate of diffusion