NEET BIOLOGY Unit 15
TRANSPORT IN PLANTS
Introduction
The study of metabolism and various vital activities of plants is known as plant physiology.
Stephan Hales is known as father of plant physiology.
J.C. Bose is known as father of Indian plant physiology.
Plants grow in soil
It absorb water and minerals, which are available in soil.
Water has great importance for plant. Water forms 80-90% of fresh weight of plant body. The method or technique,
plant cells obtain water, comes under the heading of water relations.
INTRODUCTION (TRANSPORT IN PLANTS)
In flowering plants, substances that would require to be transported are water, organic and mineral nutrients & plant growth harmone / regulators. Transport over longer distances proceeds through the vascular system (xylem and phloem) and i called as Translocation. The small distance transport means transport with in the cell or across the membrane or from cell to cell in a tissue which occurs by diffusion, facilitated diffusion (Passive transport) and by active transport.
In rooted plants, transport in xylem (of water and minerals) is essentially unidirectional, from roots to the stems.organic and mineral nutrients however, undergo multidirectional transport. Transport in phloem, means transport of organic compounds synthesized in the photosynthetic leaves which is bidirectional (from leaves to storage organs and later fromstorage organs to other growing parts).
Means of transport:- Transport in planst is of two typesa.
a. Short distance transport
b. Long distance transport
DIFFUSION
"The movement of molecules or atoms or ions of a materials from an area of higher concentration to an area of their lower concentration is called diffusion."
The diffusion is continue till the dynamic equilibrium is not established. At this stage the net movement of molecules is equal in both direction.
The kinetic energy, which is present in the molecules of material is distributed equally in their available space by their nature.
Diffusion rate ® Gas > Liquid > Solid
Diffusion is a slow process
Diffusion does not depend on living system.
Diffusion rates are affected by gradient of concerntration, the permeability of the membrane temperature and pressure.
Is is very important for plants as it is only means for gaseous movement with in the plant body.
Molecules or ions which are diffused exert a pressure, onthe substance or medium in which diffusion takes place, is known as diffusion pressure.
Over small distances substances move by difusion and cytoplasmic steaming .
Long distance transport is called TRANSLOCATION
Organic substances move - Multidirectional
Inorganic substances & H2O Unidirectional
Diffusion - passive, random slow and not dependent on living system .
Gaseous exchange-is due to diffusion
Diffusion rate depends on concentration gradient, permeability, temperature & pressure.
Facilitated diffusion Carried out for those substances having hydrophilic moiety
Gradient required, carrier mediated, without energy
Water channels made up of aguaporins
Active transport Uphill transport, energy & carrier proteins both required.
Common features to Facilitated and Active transport saturation, selectivity, Inhibition
Hormone regulation Water potential difference of Kinetic energy
Solute potential loss of free energy (Kinetic energy) due to addition of solutes
Pressure potential change in free energy due to external pressure (other than atmospheric pressure)
Tonoplast and plasma membrane are two important determinants of movement of molecules in or out of the cell.
Net direction and rate of osmosis depends on both pressure gradient and concentration gradient. OP= s
During plasmolysis water lost first from cytoplasm and then from vacuole
Imbibition depends on diffusion, water potential gradient & affinity between adsorbant and liquid
Bulk flow - can be acheived either through positive hydrostatic pressure gradient or negative hydrostatic pressure gradient.
Xylem - water, minerals and organic nitrogen, hormones
Pholoem - Organic substances, inorganic nutrients (mobile elements)
Apoplastic path - Cellwall & intercellular space (Non living path)
Symplastic path - Systems of interconnected protoplasts (Living path)
Root-pressure - positive hydrostatic pressure, leads to guttation, mosdest push in overall water tarnsport, greatest contribution - reestablishments of continuity of water column.
Cell wall of guard cells show radial arrangement of microfibrils.
Cohesion, adhesion and surface tension -are three physical properties of water which provide - Tensile strength and capillarity
Evolutions of C4 photosynthetic path is for maximising CO2 utilisation and to minimising water loss.
Plants obtain their most of the carbon & oxygen from CO2
Plants obtain most of their minerals from soil actively because
(1) Minerals present in soil as charged particles
(2) In soil mineral concentration is lower than plant cell.
Active mineral absorption helps in creation of waters potential gradient.
Some ions can move passively by mass flow.
Transport proteins of endodermal cells are control points, where a plant adjust the quantity and types of solutes
that reach to xylem, hence it allow transport of ions in one direction only.
BIOLOGY FOR NEET & AIIMS
Ex.1 Best soil for healthy and vigorous growth of a plant
is
(A) Sandy soi (B) Loam
(C) Clay (D) None of these
Sol. (B) : Loam are sufficiently aerated and have good
water holding capacity. Therefore, they are very
good for water absorption and growth.
Ex.2 Attractive forces of cell walls for water molecules is
termed as
(A) Adhesion (B) Cohesion
(C) Osmosis (D) Plasmolysis
Sol. (A) : Walls of tracheids and vessels of xylem are
made up of lignin and cellulose and have strong
affinity for water (adhesion).
Ex.3 The relationship = nRT is not obeyed by
(A) Concentrated solution
(B) Dilute solution
(C) Extermely dilute solution
(D) All of these
Sol. (C)
Ex.4 Selective permeability identifies the process of
transmission through semipermeable membrane is
called
Or
The movement of water from higher water potential
to lower water potential through a semi-permeable
membrane is called
Or
Living cells placed in isotonic solution (0.9 % saline)
retain their size and shape. This is based on the
concept of
(A) Diffusion (B) Osmosis
(C) Plasmolysis (D) Imbibition
Sol. (B) : Osmosis is a special type of diffusion of a
liquid, when solvent moves through a
semipermeable membrane.
Ex.5 In rainy season, the doors get wet due to
(A) Imbibition (B) Absorption
(C) Diffusion (D) Endosmosis
Sol. (A) : Due to adsorption of water molecules into
wodden furniture it get swelled.
Ex.6 The plant undergoes wilting when
(A) Xylem is blocked
(B) Cambium is blocked
(C) Phloem is blocked
(D) Some roots are reduced in number
Sol. (A) : Xylem is responsible for transport of water. If
xylem is blocked, plant will undergo wilting due to
the lack of proper transport of water.
Ex.7 Root pressure develops due to
(A) Low osmotic potential in soil
(B) Passive absorption
(C) Increase in transpiration
(D) Active absorption
Sol. (D)
Ex.8 In xerophytes, the osmotic concentration of cell sap
is
(A) Less than normal
(B) Normal
(C) More than normal
(D) No osmotic pressure at all
Sol. (C) : Osmotic pressure is dependent upon the
concentration of solutes. It is higher in xerophytes
as compared to mesophytes.
Ex.9 Which one of the following statements is wrong
(A) Water potential is the chemical potential of the
water
(B) Solute potential is always negative
(C) Pressure potential is zero in a flaccid cell
(D) Water potential equals solute potential in a fully
turgid cell
(E) Pressure potential is negative in a plasmolyzed
cell
Sol. (A)
Ex.10 Upwards movement of water in plants is called
(A) Sucking (B) Ascent of sap
(C) Translocation (D) None of these
Sol. (B)
Ex.11 Which of the following would be in insignificant
amount in xylem sap
(A) Sugar (B) Nitrates
(C) Phosphates (D) Water
SOLVED EXAMPLE
TRANSPORT IN PLANTS
1. The physical process involved in the release of
molecular oxygen from leaves is :-
(A) Diffusion (B) Transpiration
(C) Osmosis (D) Capillarity
2. Pieces of beet root do not lose their colour in cold
water, but do so in boiling water because :-
(A) The cell wall is killed in boiling water
(B) Hot water can enter the cells readily
(C) The plasma membrane gets killed in boiling water
and becomes permeable
(D) The pigment is not soluble in cold water
3. What statement can be cited for 10% sodium chloride
solution and 10% sugar solution present ?
(A) Both have equal OP
(B) The concentration of sodium chloride solution
will be less than concentration of sugar solution
(C) The OP of sugar solution will be higher than OP
of sodium chloride solution
(D) DPD of sodium chloride solution will be higher
than DPD of sugar solution
4. If a plant cell is immersed in water, the water continues
to enter the cell until the :-
(A) Concentration of the salts is the same inside the
cell as outside
(B) Cell bursts
(C) Concentratioin of water is the same inside the
cell as out side
(D) Diffusion pressure deficit is the same inside the
cell as out side
5. If a cell is reduced in size (shrinks) of placing in a
solution of sugar, the solution is :-
(A) Hypertonic (B) Hypotonic
(C) Isotonic (D) None of the above
6. The process of osmosis involves :-
(A) Movement of solute through a semipermeable
membrane
(B) Movement of solvent through a semipermeable
membrane
(C)Movement of solution through semipermeable
membrane
(D) None of the above
7. Grapes placed in salt solution shrink due to :-
(A) Imbibition (B) Endosmosis
(C) Exosmosis (D) Osmosis
8. Process of selective transmission of a liquid through
semi permeable membrane is called :-
(A) Diffusion (B) Osmosis
(C) Plasmolysis (D) Transmission
9. When a cell is fully turgid which of the following
will be zero ?
(A) Turgor pressure (B) Wall pressure
(C) Suction pressure (D) Osmotic pressure
10. Water from the soil enters in to the root hairs on
account of :-
(A) Turgor pressure
(B) Suction pressure or DPD
(C) Barometric pressure
(D) Osmotic pressure
11. In a fully turgid cell the values of DPD, OP and TP
should be :-
(A) DPD = 10 atm., OP = 15 atm., TP = 5 atm.
(B) DPD = 5 atm., OP = 12 atm., TP = 7 atm.
(C) DPD = 2 atm., OP = 7 atm., TP = 5 atm.
(D) DPD = 0 atm., OP = 15 atm., TP = 15 atm.
12. When the cell is placed in water, it takes water this is
due to ?
(A) Osmotic pressure
(B) Suction pressure
(C) Diffusion
(D) Water potential and TP
13. What is the direction of the movement of water if
two cells have the same OP but differ in TP ?
(A) No net flow
(B) From lower T.P to higher TP
(C) From higher TP to lower TP
(D) Data insufficient
14. When water enters into a cell what happens to its
OP, TP and DPD ?
(A) OP & TP increase & its DPD increase
(B) OP & DPD increase & TP decrease
(C) TP & DPD decrease & OP increase
(D) OP & DPD decrease & TP increase
SINGLE Exercise # 1 OBJECTIVE NEET LEVEL
BIOLOGY FOR NEET & AIIMS
1. Which helps in maintaining form and structure of
cells & soft parts of plants ?
(A) Osmotic pressure
(B) Turgor pressure
(C) Atmospheric pressure
(D) DPD
2. Which process occurs against a concentration
gradient of solute ?
(A) Diffusion (B) Osmosis
(C) Transpiration (D) Translocation
3. When beet root slices are washed and then placed
in cold water, anthocyanin does not come out,
because plasma membrane is ?
(A) Differentially permeable to anthocyanin
(B) Dead structure
(C) Impermeable to anthocyanin
(D) Permeable to anthocyanin
4. The osmotic pressure of distilled water will be :-
(A) Minimum
(B) Maximum
(C) Higher than any solution
(D) Variable
5. Tonoplast is :-
(A) Permeable membrane
(B) Semi permeable membrane
(C) Impermeable membrane
(D) Selectively permeable membrane
6. If in a cell suction pressure value is 30 atm. while
osmotic pressure 42 atm. then calculate the turgidity
developed in form of TP in the cell :-
(A) 12 atm. (B) 72 atm.
(C) –12 atm. (D) 1.4 atm.
7. Osmosis is the phenomenon expressed by :-
(A) Solutes present in the solution
(B) Solution
(C) Semi-permeable membrane
(D) O2
8. The osmotic pressure of the cell is measured by :-
(A) Plasmolysis method
(B) Osmometer
(C)Molar concentration of the cell sap
(D) Deplasmolysis
9. Maximum osmotic pressure is found in :-
(A) Root hair
(B) Cortex cell of the root
(C) Passage cell of the root
(D) Mesophyll cell
10. The osmotic pressure is due to :-
(A) Solute
(B) Semi permeable membrane
(C) Hypertonic solution
(D) Water
11. When the solute has been added in the solution,
then following observation can be made ?
(A) The DPD of the solution decreases
(B) The w of the solution increases
(C) DPD of the solution decreases while its w
increases
(D) DPD of the solution increases while its w
decreases
12. If the given solution is of 25% concentration; then
what cannot be presented for this :-
(A) OP (B) DPD
(C) Solute potential (D) TP
13. In a flaccid cell which condition does not occur-
(A) TP = 0 (B) SP = 0
(C) WP = 0 (D) SP = OP
14. Osmotic pressure of a cell is zero when :-
(A) T.P. is maximum (B) DPD is maximum
(C) T.P. is zero (D) Not possible
15. In which condition the Turgor pressure of the cell
becomes equal to the osmotic pressure :-
(A) In flaccid cell (B)In plasmolysed cell
(C) In fully turgid cell (D) It never happens
Exercise # 2 SINGLE OBJECTIVE AIIMS LEVEL
1. Match Column - I with Column - II and select the correct option from the codes given below.
Column - I Column - II
A. Hypotonic i. No net flow of water
B. Hypertonic ii. Water moves into the cell
C. Isotonic iii.Water moves out of the cell
(A) A-ii, B-iii, C-i (B) A-iii, B-ii, C-i
(C) A-i, B-ii, C-iii (D) A-ii, B-i, C-iii
2. Match Column - I with Column - II and select the correct option from the codes given below.
Column - I Column - II
A. Vein ending i. Transpiration
B. Necessary evil ii. Osmosis
C. Semipermeable iii. Transpiration pull membrane
D. Cohesion iv. Guttation
E. Stomata closure (v) ABA
(A) A-iv, B-i, C-iii, D-ii, E-(v) (B) A-iv, B-i, C-ii, D-iii, E-(v)
(C) A-iii, B-(v), C-i, D-ii, E-iv (D) A-i, B-ii, C-iii, D-iv, E-(v)
3. Match Column I with Column - II and select the correct option from the codes given below.
Column - I Column - II
A. Dixon and Jolly i. Root pressure
B. Stomata ii. Only water available to plants
C. Manometer iii. Transpiration
D. Capillary water iv. Transpiration pull
E. Potometer (v) Rate of transpiration
(A) A-iv, B-iii, C-(v), D-ii, E-i (B) A-i, B-iii, C-iv, D-ii, E-(v)
(C) A-iv, B-iii, C-i, D-ii, E-(v) (D) A-(v), B-iv, C-iii, D-ii, E-i
4. Match the following and choose the correct option
A. Leaves i. Anti-transpirant
B. Seed ii. Transpiration
C. Roots iii. Negative osmotic potential
D. Aspirin iv. Imbibition
E. Plasmolyzed cell (v) Absorption
Options :
(A) A-ii, B-iv, C-(v), D-i, E-iii
(B) A-iii, B-ii, C-iv, D-i, E-(v)
(C) A-i, B-ii, C-iii, D-iv, E-(v)
(D) A-(v), B-iv, C-iii, D-ii, E-i
Exercise # 3 PART - 1 MATRIX MATCH COLUMN
BIOLOGY FOR NEET & AIIMS
1. When enters a cell due to : [CBSE AIPMT 2001]
(A) O.P. (B) S.P.
(C) T.P. (D) W.P.
2. In which of the following plant sunken stomata are
found : - [CBSE AIPMT 2001]
(A) Nerium (B) Hydrilla
(C) Mango (D) Guava
3. Glycolate induces opening of stomata in : -
[CBSE AIPMT 2001]
(A) Presence of oxygen (B) Low CO2 conc.
(C) High CO2 (D) CO2 absent
4. Opening and closing of stomata is due to the : -
[CBSE AIPMT 2002]
(A) Hormonal change in guard cells
(B) Change in Turgor pressure of guard cells
(C) Gaseous exchange
(D) Respiration
5. Stomata of CAM plants :- [CBSE AIPMT 2003]
(A) Open during the night and close during the day
(B) Never open
(C) Are always open
(D) Open during the day and close at night
6. Stomata of a plant open due to : -
[CBSE AIPMT 2003]
(A) Influx of hydrogen ions
(B) Influx of calcium ions
(C) Influx of potassium ions
(D) Efflux of potassium ions
7. The translocation of organic solutes in sieve tube
members is supported by- [CBSE AIPMT 2006]
(A) P-proteins
(B) Mass flow involving a carrier and ATP
(C) Cytoplasmic streaming
(D) Root pressure and transpiration pull
8. Two cells A and B are contiguous. Cell A has osmotic
pressure 10 atm, turgor pressure - 7atm and
diffusion pressure deficit 3 atm. Cell B has osmotic
pressure 8 atm, turgor pressure 3 atm and diffusion
pressure deficit 5 atm. The result will be:
[CBSE AIPMT 2007]
(A) Movement of water from Cell B - A
(B) No movement of water
(C) Equilibrium between the two
(D) Movement of water of Cell A - B
9. The rupture and fractionation do not usually occur
in the water column in vessel/tracheids during the
ascent of sap because of : [CBSE AIPMT 2008]
(A) lignified thick walls
(B) cohesion and adhesion
(C) weak gravitational pull
(D) transpiration pull
10. Guard cells help in : [CBSE AIPMT 2009]
(A) Protection against grazing
(B) Transpiration
(C) Guttation
(D) Fighting against infection
11. In land plants, the guard cells differ from other epidermal
cells in having : [CBSE AIPMT 2011]
(A) Mitochondria
(B) Endoplasmic reticulum
(C) Chloroplasts
(D) Cytoskeleton
12. Which of the following criteria does not pertain to
facillitated transport ? [NEET 2013]
(A) Requirement of special membrane proteins
(B) High selectivity
(C) Transport saturation
(D)Uphill transport
13. A column of water within xylem vessels of tall trees
does not break under its weight because of :
[CBSE AIPMT 2015]
(A) Dissolved sugars in water
(B) Tensile strength of water
(C) Lignification of xylem vessels
(D) Positive root pressure
Exercise # 4 PART - 1 PREVIOUS YEAR (NEET/AIPMT)
1. When a molecule moves across a membrane independent of other molecules the process is called
(i) uniport (ii) symport (iii) antiport.
(A) (i) only (B) (i) and (ii) only (C) (i) and (iii) only (D) (ii) and (iii) only
(E) (iii) only
2. The cellular transport method which involves use of transmembrane proteins without energy expenditure is called
(A) diffusion (B) facilitated diffusion (C) active transport (D) exocytosis
3. The type of transport taking across the biomembranes without the help of proteins is
(A) facilitated diffusion (B) active transport (C) simple diffusion (D) diffusion via symport
4. Which of these is/are not a property of facilitated transport?
A. Requires special membrane proteins B. Highly selective
C. Uphill transport D. Requires ATP energy
(A) A and B only (B) C and D only (C) A and C only (D) B and C only
(E) B and D only
5. Consider the following statements with reference to facilitated transport.
A. Requires ATP energy B. Transport saturates
C. Highly selective D. Requires special membrane properties
E. Uphill transport
Of the above statements
(A) A, B and C are relevant but D and E are irrelevant
(B) B, C and E are relevant but A and D are irrelevant
(C) C, D and E are relevant but A and B are irrelevant
(D) A, D and E are relevant but B and C are irrelevant
(E) B, C and D are relevant but A and E are irrelevant
6. What do A, B , C and D represent in the following figure?
Membrane
(A) A : carrier protein, B : symport, C : uniport, D : antiport
(B) A : carrier protein, B : uniport, C : antiport, D : symport
(C) A : carrier protein, B : antiport, C : symport, D : uniport
(D) A : carrier protein, B : uniport, C : symport, D : antiport
Readers, Please look further for Update of the Blog for new materials.
You can also visit https://neetscoretamil.blogspot.com
Comments
Post a Comment