Diffusion

Question 1

what is the definition of diffusion?

Answer 1

the net movement of particles from a region of high concentration to a region of low concentration, due to the random movement of particles

Question 2

when will diffusion stop?

Answer 2

when the equilibrium is reached

Question 3

can solids diffuse by simple diffusion?

Answer 3

no only liquids and gases

Question 4

why can liquids and gases diffuse through simple diffusion?

Answer 4

because their molecules possess kinetic energy and move randomly

Question 5

are water molecules polar or non-polar?

Answer 5

polar

Question 6

are water molecules lipid soluble or insoluble?

Answer 6

insoluble

Question 7

why would you think that water cannot diffuse through the lipid bilayer?

Answer 7

because it polar and lipid insoluble

Question 8

when can water sometimes directly diffuse?

Answer 8

if there is high levels of water molecules

Question 9

how can water molecules diffuse?

Answer 9

some membranes use aquaporin channels to allow water to move across the membrane

Question 10

what are aquaporin?

Answer 10

special water channel proteins that allow water to move across the membrane

Question 11

where are the 2 places facilitated diffusion takes place?

Answer 11

through channel proteins and through carrier proteins

Question 12

what size molecules go through channel proteins?

Answer 12

small

Question 13

what size molecules go through carrier proteins?

Answer 13

large

Question 14

what molecules go through channel proteins and why?

Answer 14

small molecules that have polarity cannot pass through because of the hydrophobic tails

Question 15

how do molecules go through channel proteins?

Answer 15

they pass through water-filled protein channels down a concentration gradient and do not require energy

Question 16

way to remember channel proteins

Answer 16

eurotunnel

Question 17

what molecules go through carrier proteins and why?

Answer 17

larger molecules that are too big to pass through channel proteins and tf require a carrier protein

Question 18

how do molecules diffuse through using carrier proteins?

Answer 18

carrier proteins bind with specific molecules, which opens the protein to allow the molecules to cross the membrane

Question 19

what is special about carrier proteins?

Answer 19

they have a specific shape, normally carrying only one specific shaped molecule

Question 20

what are 5 factors that affect diffusion?

Answer 20

-temperature
-diffusion distance
-surface area
-size and type of diffusing molecule
-concentration gradient

Question 21

summary of diffusion

Answer 21

simple diffusion:
-small molecules
-gases and liquids
-lipid soluble molecules
facilitated diffusion:
-channel proteins
smaller
-carrier proteins
bigger

Question 22

way to remember carrier protein

Answer 22

carry, heavy bigger things

Question 23

explain how temperature affects the rate of diffusion

Answer 23

-as temperature increases, molecules will have more kinetic energy and move faster tf rate of diffusion will increase
-as they lose heat energy, this will slow down the rate of diffusion

Question 24

explain how diffusion distance affects the rate of diffusion

Answer 24

the thinner the membrane, the shorter the diffusion distance tf the rate of diffusion is increased

Question 25

explain how surface area affects the rate of diffusion

Answer 25

-the larger the surface area, the more space there is for diffusion tf the rate of diffusion is increased
-folds and extensions can also increase the rate of diffusion (as they increase SA)

Question 26

explain how the size and type of molecules affects the rate of diffusion

Answer 26

-the smaller the ion/molecule, the faster the rate of diffusion
-lipid soluble molecules cross the membrane faster than water soluble molecules

Question 27

explain how the concentration gradient affects the rate of diffusion

Answer 27

the steeper the gradient, the faster the rate of diffusion