(d) DIIFFUSION the movement of molecules across membranes

What kind f process is diffusion

Passive

What does it mean once the particles have reached equilibrium

Movement are equal in both directions

Why dos diffusion jincrease as distance increases

More collisions

Why are cells generally microscopic

Need to be small in order for diffusion to happen fast

What are the factors affecting diffusion

Temperature

Concentration gradient (greater difference the faster the rate of diffusion)

What is simple diffusion

Difusuion without a membrane or barrier

What happens during diffusion with a cell membrane

Particlescross a phospholipid layer

What flows freely down the concentration gradient in a membrane and what doesn’t

Non polar molecules flow freely like 0xygen due to hydrophobic interior

but polar molecules moves much slower

Why are membranes partially permeable

Bigger ions move slower than small ions

Non polar ions move more freely than polar

What factors affect the rate at which passs through membrane

Surface area (larger area = higher rate)

Thicknes of the membrane

What is facilitated diffusion

Diffusion across a membrane through protein channels (which is how ins and polar molecules move)

What are membranes with protein channels called?

SELECTIVELTY PERMEABLE

Most protein channels are —— to —— or

Most protein channels are specific to one molecule or ion

What ca facilitated diffusion involve

Channel proteins fo polar molecules

Can also include carrier proteins which change shape when specific molecule binds to them

What are the factors affecting facilitated diffusion

Temp

Concentration gradient

Number of channel protein

Membrane thickness + surface area