BIO - 2d. movement of substances

diffusion + example

The net movement of particles from an area of higher conc. to an area of lower conc., it is a passive process

gas exchange in lungs ( oxygen + carbon dioxide)

osmosis + example

the net movement of water molecules from an area of higher water potential to an area of lower water potential across a partially permeable membrane

PRACTICAL - movement of water into/ out of potatoes depending on sucrose concentration of solution placed in

PRACTICAL - movement of water into/ out of red onion tissue

movement of water into rbc from blood plasma

active transport + example

the movement of substances from an area of lower concentration to an area of higher concentration through a carrier protein in the cell membrane using energy from respiration

absorption of mineral ions in root hair cells

reabsorption of glucose back into the blood in the PCT during selective reabsorption in nephron of kidney

why are cell membranes partially permeable

It means they can allow small substances e.g. carbon dioxide, oxygen and prevent large substances from entering e.g. rbc, wbc

what does a large surface area do to diffusion

increases diffusion rate

net movement

more particles moving in one direction than another, the overall movement

factors that effect diffusion

temperature

concentration gradient

distance

surface area

mass of particles

size of particles

temperature

warmer temp = more KE in particles = increased speed of particles = more collisions = causing particles to spread out

concentration gradient

higher conc. gradient will increase the rate of diffusion, this is because on the side with the higher conc. there are more random collisions causing the particles to spread out faster

distance

shorter diffusion distance = higher rate of diffusion, less distance for particles to travel

surface area: volume

the larger SA:V the faster the rate of diffusion because there is a larger area for particles to enter

mass of particle

the heavier the particle the lower the rate of diffusion since they will be harder to move

size of particle

larger size of particle = slower diffusion rate, to large to fit through cell membrane

what does SLAPUK stand for

scale

line

axes

points

units

key

is the independent variable on the left or right of a table

left

when graphing do you start at 0

no

do you need 0,0 on graphs

yes, leave even gaps between each

what is a hypertonic solution and what happens to animal and plant cells

more concentrated solution

shrivelled

plasmolysed (cell membrane has pulled away from cell wall)

what is a isotonic solution and what happens to animal and plant cells

solution has same conc. as inside cell#

normal

flaccid

what is a hypotonic solution and what happens to animal and plant cells

more dilute solution

lysed (bursting)

turgid

why is a red onion used

pigment makes it easier to see

percentage change equation

final mass - initial mass

——————————-- x 100

initial mass