966873
Description
Mind Map by charl.mallon, updated more than 1 year ago
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Created by charl.mallon
over 10 years ago
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BIOLOGY 4.1
- OSMOSIS
- The net movement of water molecules
across a partially permeable membrane from
a region of high concentration of water to a
region of low concentration of water
- High water conc = dilute
- Low water conc = concentrated
- High water conc = dilute
- A partially permeable membrane
is one with very small holes in it
- The water molecules pass both ways
through the membrane during osmosis
- This is because water
molecules move about
randomly all the time
- This is because water
molecules move about
randomly all the time
- Small molcules ie water can pass
through, bigger ones ie sucrose can't
- The water molecules pass both ways
through the membrane during osmosis
- Because there are more water molecules on one
side than on the other, there's a steady net flow of
water into the region with fewer water molecules
- This means the concentrated solution gets more
dilute - the water acts like it's trying to 'even up'
the concentration on either side of the membrane
- This means the concentrated solution gets more
dilute - the water acts like it's trying to 'even up'
the concentration on either side of the membrane
- The net movement of water molecules
across a partially permeable membrane from
a region of high concentration of water to a
region of low concentration of water
- TURGOR PRESSURE
- Turgid = when a plant is well watered, its cells will draw
water in by osmosis and become plump and swollen
- Turgor pressure: when the
contents of the cell push
against the inelastic cell wall
- Flaccid = no water in soil =
cells lose water & turgor
pressure - plant starts to wilt
- Plasmolysed cell: when really short of
water, the cell's cytoplasm starts to shrink &
the membrane pulls away from the cell wall.
- Doesn't totally lose its shape
because of inelastic cell wall
- Doesn't totally lose its shape
because of inelastic cell wall
- Plasmolysed cell: when really short of
water, the cell's cytoplasm starts to shrink &
the membrane pulls away from the cell wall.
- Flaccid = no water in soil =
cells lose water & turgor
pressure - plant starts to wilt
- Turgor pressure: when the
contents of the cell push
against the inelastic cell wall
- Turgid = when a plant is well watered, its cells will draw
water in by osmosis and become plump and swollen
- ANIMAL VS PLANT
- Animal cells don't have a cell wall
- If an animal cell takes in too
much water, it bursts - lysis
- If an animal cell loses too much
water it shrivels up - crenation
- Animal cells don't have a cell wall
- DIFFUSION
- The net movement of particles from
high concentration to low concentration
- Liquids & gases
- CELL MEMBRANES:
hold the cell together but
also let things in and out
- Only very small
molecules can diffuse
through cell membranes
- Rate depends on:
- Surface area: more space for
particles to move across
- Concentration gradient: substances move
more quickly when there is more of a
difference - if there are lots more particles on
one side, there are more there to move across
- Distance: the smaller
the distance, the
quicker the movement
- Surface area: more space for
particles to move across
- The net movement of particles from
high concentration to low concentration
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