Download Transport in plants

Transport in
plants
Grade 8 biology
Diffusion
A
type of passive transport(not requiring
energy) involving the movement of
particles from an area of higher
concentration to an area of lower
concentration.
 Diffusion is spontaneous and automatic.
Osmosis
 passage
of water from a region of high
water concentration, through a semipermeable membrane, to a region of low
water concentration.
Endosmosis
inward osmosis
 inward passage of liquid through a
membrane of a cell or cavity

Exosmosis
 outward
osmosis
 outward passage of liquid through a
membrane of a cell or cavity
Plasmolysis
Hypertonic hypotonic and
isotonic solutions
 Videos
on
 Elodea in hypertonic solution
 Elodea in hypotonic solution
 Demonstration
Turgor pressure( video)
 also
called turgidity,
 is the main pressure of the cell contents
against the cell wall in plant cells.
 Turgor is a force exerted outward on a
plant cell wall by the water contained in
the cell.
 This force gives the plant rigidity, and may
help to keep it erect.
 Turgor can result in the bursting of a cell.
Exercise
 Write
a letter from the cell membrane to
cell wall of a plant cell, explaining how
their closeness or interactions depend on
the availability of water in their respective
surroundings.
 Make sure you use all the terms you have
learnt till now !!
Wall pressure
It
is the pressure exerted by the
cell wall on the contents of the
cell, including the cell
membrane.
Turgid and flaccid cells




Plant cells need to be turgid (i.e rigid) to
support plant tissues.
Plant cells become turgid when water moves
into the cell by osmosis, and the central
vacuole swells and pushes against the cell
wall.
When plant cells are placed in concentrated
sugar solutions they lose water by osmosis and
they become "flaccid"; this is the exact
opposite of "turgid"
Turgid plant cells contain more water than
flaccid cells and exert a greater osmotic
pressure on its cell walls.