structure and functions (movement of substances)

define diffusion + its concentration gradient direction

the net movement of particles from an area of high concentration to low concentration

(down the concentration gradient)

diffusion is a _____ process. no ____ needed

diffusion is a PASSIVE process. no ENERGY needed

what is the end result of diffusion (e.g. left for a long time)

even concentration throughout space

define osmosis, include moves across a ____

the net movement of free water particles from a hypotonic to hypertonic solution, across a partially permeable membrane.

define hypo/hypertonic

hypo - lower solute concentration (than)

hyper - higher solute concentration (than)

draw osmosis diagram

osmosis is also/a type of _______ because water moves ______ concentration gradient

osmosis is also DIFFUSION because water moves DOWN the concentration gradient

why can the results of osmosis be so severe in animals cels

the lack of a cell wall to support the cell means results can be severe

animal cell in concentrated solution:

• cell is hypotonic to concentrated solution

• osmosis: water moves hypo to hyper

• water exits the cell

• cell shrinks/shrivels

  • cell is CRENATED, this is CRENATION

animal cell in dilute solution:

• cell is hypertonic to dilute solution

• osmosis: water moves hypo TO hyper

• water enters cell

• cell swells/bursts

  • cell is LYSED, this is LYSIS

lysis etymology lol

luo in greek! luein to loosen, untie
cell bursts forth

plant cell protected from _______ by ________

plant cell protected from BURTSTING by CELL WALL

plant cell in concentrated solution (6)
- prev time forgot physical(?) state of cell after effect

• plant cell is hypotonic to concentrated solution

• osmosis: water moves from hypo to hyper

• water exits cell vacuole

• cell membrane pulls away from cell wall

• cell retains its shape but isn’t stiff

  • cell is PLASMOLYSED, this is PLASMOLYSIS

etymology of plasmolysis

plasmo - (basically cell membrane, mould)

lysis - loosening, releasing

loosening of the cell membrane

plant cell in dilute solution

-last time forgot what happens after water movement, specifically to do with c__w__ (two stages)

• cell is hypertonic to dilute solution

• osmosis: water moves hypo TO hyper

• water enters cell/vacuole

• vacuole presses against cell wall (TURGOR PRESSURE)

• cell can’t swell anymore

  • becomes TURGID

what is turgor pressure

force within the cell, by vacuole i think, that pushes the cell membrane against the cell wall

write table of concentrated/dilute VS plant/animal

	concentrated	dilute
animal	crenation (shrivels)	lysis (swells/bursts)
plant	plasmolysis (not stiff, cell membrane pulled away)	turgid (swelled, stiff)

define active transport

last time - forgot through where it happens

the movement of particles through a cell membrane from an area of low concentration to high concentration

active transport goes ________ the concentration gradient

active transport goes AGAINST the concentration gradient

active transport needs ______ and involves _____ c______ m________ in the cell membrane

active transport needs ENERGY and involves PROTEIN CARRIER MOLECULES in the cell membrane

4 factors affecting diffusion + explanation

• diffusion distance - shorter distance - faster diffusion

• concentration gradient - greater the difference in concentration - faster diffusion

• surface area - larger SA - more space for diffusion - faster

• temperature → more KE - particles move faster - diffuse faster

explain a Sa:V ratio, e.g. big cube/small cube

a large surface area for a small volume

e.g. big cube has small Sa:V ratio

small cube has large Sa:V ratio

beetroot temperature diffusion experiment CORMMS

think what is necessary to mention in c

C - change temperature of beetroot water environment (20/40/60/80 )

O- same age, health, type of beetroot

R - repeat x3, avgs, anomalies

M - observe colour change of liquid, when whole test tube is purple

M - over 10 mins

S - same volume of water, dimensions of beetroot cube

potato diffusion concentration experiment CORMMS

C - change concentration of solution (sucrose at 0-1mol/dm3)

O - same age, species, health of potato

R - repeat x3, avgs, anomalies

M - measure change in mass of potato cylinders before/after being in the solution

M - for 4 hours

S - same volume of solution, dimensions of potato, dry every potato cylinder before weighing

how to calculate percentage change

final - initial / initial (x100%)

potato in distilled water result

• potato is hypertonic to distilled water, hypo to hyper

• via osmosis water moves into potato cells

• increased mass

• increased tugor pressure - potato is hard

potato in concentrated solution result

• potato is hypotonic to concentrated solution, hypo to hyper

• via osmosis water exits potato cells

• most decreased mass

• potato is floppy

why is the potato floppy in concentrated solution result

little tugor pressure, cells may be plasmolysis

how to tell which concentration the potato is (think ___tonic)

in isotonic solution (equal solution concentrations) - no net movement, no mass change