Diffusion, Osmosis & Imbibition In Nature : Diffusion, Osmosis & Imbibition In Nature Dr. Subroto Biswas
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BIOLOGICAL SIGNIFICANCE OF WATER : BIOLOGICAL SIGNIFICANCE OF WATER Main constituent of protoplasm (90%)
A medium for gases, minerals, organic subtances
Medium for all vital reaction
Maintains turgidity of cells.
Necessary for enzyme activities.
Increases rate of respiration
Acts as solvent and carrier.
Maintains an optimum temp.
And PH for enzyme reactions.
Water constitutes 80-95% of living tissues.
Sap wood has 35-75% of water
Seeds have 5-15% of H20
What are Plasmodesmata ? : What are Plasmodesmata ? The protoplasmic connection (=Cytoplasmic Bridges)
Plant cells exchange water and nutrients across them
Let is see what is DIFFUSION ? : Let is see what is DIFFUSION ? A Process by which molecules intermingle as a result of their random thermal agitation
OR
It is directed movement from a region of a high
concentration to a region of lower concentration
activity (random thermal motion) of individual
But it is accomplished through the kinetic molecules This presentation is brought to you by ….. Bisbio.in
Slide 6 : Movement of particles or molecules from a region of HIGHER CONCENTRATION to a region of LOWER CONCENTRATION The pictures projected on this free session belong to the beholder on the internet. We thank them
Slide 7 : What is diffusing into what? What do you see here?
Is it a case of diffusion or osmosis? : Is it a case of diffusion or osmosis?
Slide 9 : Three major pathways :
APOPLASTIC PATHWAY (Free space) Water moves exclusive
through the cell wall
without crossing any
membranes
TRANSMEMBRANE PATHWAY : TRANSMEMBRANE PATHWAY Water moves across the cell via two membranes of each cell.
SYMPLASTIC PATHWAY : SYMPLASTIC PATHWAY Water enters cell to cell via PLASMODESMATA.
Movement through entire network of cytoplasm
What is IMBIBTION ? : What is IMBIBTION ? (=Hydration)
Uptake or
Absorption of water by the solid substances without forming a solution
The substance absorbing water are called IMBIBANTS the imbibants do not dissolve in water.
What are the Characteristics of imbibition? : What are the Characteristics of imbibition? Liquid absorption
Swelling up (=volume increase)
Heat release (exothermic)
Development of pressure This presentation is brought to you by ….. Bisbio.in
Role of imbibition in plants : Role of imbibition in plants
Dry seed : Dry seed
Slide 16 :
Wood piece Placed in water : Wood piece Placed in water Absorbs it & swells up
Why would a wooden door not close in rainy days ? : Why would a wooden door not close in rainy days ?
Gum piece : Gum piece
What is OSMOSIS ? : What is OSMOSIS ? Movement of a solvent through a SEMI PERMEABLE
membrane
OR
Movement of water molecules through a S.P.M from Higher to lesser water concentration is called osmosis.
Osmosis was first observed by ABBE NOLLET (1748)
OSMOSIS helps in establishment of an EQUILLIBRIUM in concentration on both sides of the membrane .
Slide 21 : Courtesy : http://people.eku.edu/ritchisong/RITCHISO//301notes1.htm
MEMBRANES : MEMBRANES Permeable : Allow diffusion of both solutes And solvents
Eg. Cell wall of young plant cell
Impermeable : Impermeable Do not allow diffusion of solutes And solvents.
Eg. Heavily cutinized cell walls
Semipermeable : Semipermeable Allow diffusion of solvents
But not of solutes
Eg. Parchment paper
Differentially permeable (=Semipermeable) : Differentially permeable (=Semipermeable) Allow one substance to
pass and not to others.
Plasmalemma : Plasmalemma
Slide 27 :
Tonoplast (around vacuole) : Tonoplast (around vacuole)
Membranes of cell organelles : Membranes of cell organelles
Types of solution : Types of solution WHAT IS ISOTONIC SOLUTION ?
Osmotic pressure of a cell equals to Solution
Eg. Plasmodium in RBC
HYPOTONIC SOLUTION : HYPOTONIC SOLUTION O.P of outer solution is less than Cell sap.
Let us put some Raisins in water : Let us put some Raisins in water What do you think would happen?
Would it be a case of imbibition?
Or osmosis
Or Diffusion
Or all
?
Slide 33 :
HYPERTONIC SOLUTION : HYPERTONIC SOLUTION O. P. Of outer solution is more than Cell sap.
Eg. RBC in con. Sugar soln.
: ENDOSMOSIS
Movement of water INTO THE CELL This presentation is brought to you by ….. Bisbio.in
When is a cell flaccid ? : When is a cell flaccid ? - A cell in hypertonic solution undergoes EXOSMOSIS
- It loses water and shrinks (flaccid) This presentation is brought to you by ….. Bisbio.in
Slide 37 : EXOSMOSIS
Movement of water OUT OF THE CELL
Let us make pickles : Let us make pickles
Slide 39 :
Significance of osmosis : Significance of osmosis Water is absorbed by roots by osmosis.
Slide 41 :
Opening and closing of stomata depend on turgor pressure of guard cells : Opening and closing of stomata depend on turgor pressure of guard cells
Slide 43 :
Cell to cell movement of water : Cell to cell movement of water
Slide 45 : Growth and penetration of roots in the soil is due to osmosis
Shape or form of organelles : Shape or form of organelles
Turgidity of cells of young seedlings help them to come out of the seed. : Turgidity of cells of young seedlings help them to come out of the seed.
Plant can resist drought or frost by O.P. of the cells : Plant can resist drought or frost by O.P. of the cells The pictures projected on this free session belong to the beholder on the internet. We thank them
Bursting of fruits : Bursting of fruits
Movement of leaflets and other parts occur due to osmosis : Movement of leaflets and other parts occur due to osmosis “Sensitive plant” or
“Tickle Me plant” or
“Touch me not”
Slide 51 : Touch me not plant
Transpiration…what is it? : Transpiration…what is it?
What would happen if you dip your finger in detergent water for long : What would happen if you dip your finger in detergent water for long
Why does a plant wilt ? : Why does a plant wilt ?
Slide 55 : Significance of T. P.
Is Turgidity is essential for GROWTH ?
Slide 56 : Plant movements such as nutation are brought about by turgidity or lack of it.
Slide 57 : In Many legumes
Lower their leaves in the evening and raise them in the morning
Fruit Growth : Fruit Growth
Seed dispersal in Sage : Seed dispersal in Sage This presentation is brought to you by ….. Bisbio.in
Slide 60 :
Slide 61 : ? This presentation is brought to you by ….. Bisbio.in
What will you say about this? : What will you say about this?
Slide 63 : The End This presentation is brought to you by ….. Bisbio.in The pictures projected here on this free session belong to the beholder on the internet. We thank them Many a thanks to
Dr Aman Biswas
for her unending assistance and help
Hit at … http://bisbio.inorCall 09814016083, 09855516083oremail … bisbioin@gmail.com or amanbiswas60@gmail.com : Hit at … http://bisbio.inorCall 09814016083, 09855516083oremail … bisbioin@gmail.com or amanbiswas60@gmail.com For all your
Biology Problems
UGC/CSIR NET Life Sciences
PMT
SAT
Advance Program
Civil Services
Entrance to Biotechnology and Post graduate Sciences