Chapter 11 Transport in plants Class 11 2027 ,Biology Short notes NCERT + PYQ PDF Download

Hello NEET Aspirants! 👋

NEET Dropper here dropping Ch-11: Transport in Plants

Complete Notes + PYQ Tod + No Ratta Only Samajh 🧠

Water Moves = High Ψw to Low Ψw

Xylem = Up Only, Phloem = Up + Down

Transpiration Pull = Dixon Jolly = Tall Trees ka Hero

1-2Q Pakka NEET 2027 me!

### *1. MEANS OF TRANSPORT* `Basic = 1Q`

**Process** **Energy** **Direction** **Example** **NEET Point**

**Diffusion** Passive = No ATP High → Low Conc. Gas Exchange Stomata Slow, Short Distance Only

**Facilitated** Passive = No ATP High → Low Conc. Glucose, Amino Acid via Carrier/Channel Saturable + Specific + Inhibitable

**Active Transport** Active = ATP Use Low → High Conc. Mineral Ions into Root Hair Against Gradient + Pumps

**Bulk Flow** Pressure Driven Mass Movement Xylem + Phloem Long Distance = Litres/hr

*Trick*: *D*iffusion *F*ree, *A*ctive *A*TP = DFAA

*A. Diffusion Factors*

1. Concentration Gradient = More Diff = Faster Rate

2. Membrane Permeability = Lipid Soluble = Faster = Steroids

3. Temperature = Increase Temp = Increase Rate

4. Pressure = Increase Pressure = Increase Rate

*B. Facilitated Diffusion - 2 Types*

1. Channel Proteins = Porins + Aquaporins = Water Channels = Always Open/Gated

2. Carrier Proteins = Bind Solute = Change Shape = Slower than Channels

Properties: Specific + Saturable + Can be Inhibited = Like Enzyme

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### *2. WATER RELATIONS* `Osmosis = 1Q Fix`

*A. Water Potential = Ψw* `NEET Math Wala`

Ψw = Ψs + Ψp

Ψw Pure Water = 0 = Maximum Value = Unit = Bar/MPa

Ψs = Solute Potential = Always Negative = Solute Add = Ψs Decrease

Ψp = Pressure Potential = Positive = Turgor, Negative = Xylem Tension

Cell to Cell Movement = Water Moves High Ψw → Low Ψw

*B. Osmosis Terms*

Hypotonic = External Solution Dilute = Ψw High = Water Enters = Cell Swells = Turgid

Hypertonic = External Solution Conc. = Ψw Low = Water Exits = Cell Shrinks = Plasmolysed

Isotonic = External = Internal Ψw = No Net Movement = Flaccid

Plasmolysis = Reversible = Protoplast Shrinks from Wall = Limiting Plasmolysis = Incipient

*C. Imbibition* `Special Diffusion`

Definition = Adsorption of Water by Solids = Colloids = Swelling

Example: Dry Seeds + Wooden Doors in Rain

Conditions: Water Potential Gradient + Affinity Between Adsorbent + Liquid

Imbibition Pressure = Huge = Seedling Emerges from Soil

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### *3. LONG DISTANCE TRANSPORT* `Xylem + Phloem`

*A. Pathways of Water Movement*

1. Apoplast = Cell Wall + Intercellular Space = Fast = No Membrane = No Casparian Strip

2. Symplast = Cytoplasm + Plasmodesmata = Slow = Regulated = Through Cells

3. Transmembrane = Cell Wall → Membrane → Vacuole → Membrane → Cell Wall

Casparian Strip = Suberin Band = Endodermis = Apoplast Block = Symplast Compulsory

*B. Root Pressure* `Positive Pressure`

Definition = Active Absorption → Ions Pumped into Xylem → Ψw Decrease → Water Enters

Value = 1-2 atm = Low = Can't Lift Water to Tall Trees

Guttation = Water Loss as Liquid = Hydathodes = Root Pressure Proof = Early Morning

Limitations: Absent in Gymnosperms, Not in Tall Trees, Low Magnitude

*C. Transpiration Pull = Cohesion-Tension Theory* `Main Theory = 1Q`

Proposed = Dixon + Jolly 1894 = Most Accepted

Steps:

1. Transpiration = Stomata se Water Loss → Leaf Cells ka Ψw Low

2. Tension = Negative Pressure = -30 Bars Develops in Xylem

3. Cohesion = H-Bond between Water Molecules = Continuous Column

4. Adhesion = Water Sticks to Xylem Wall = Lignin

5. Pull = Tension Transmitted Down = Root to Leaf = 15 m/hr Speed

Strength: Cohesion 350 atm, Adhesion 45-50 atm

NEET Point: Tall Trees me Only Transpiration Pull Works

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### *4. TRANSPIRATION* `Stomata = 1Q`

*A. Types*

Stomatal = 90-95% = Through Stomata = Regulated

Cuticular = 5-10% = Through Cuticle = Unregulated = Xerophytes me Kam

Lenticular = <1% = Through Lenticels = Woody Stem

*B. Stomatal Mechanism* `Guard Cell`

Day: K+ Pump into Guard Cell → Ψs Decrease → Water Enters → Turgid → Stomata Open

Night: K+ Pump Out → Water Exits → Flaccid → Stomata Close

Hormone: ABA = Abscisic Acid = Stress Hormone = Closes Stomata = Anti-transpirant

Factors: Light + High Temp + Low CO2 + Low Humidity = Open

*C. Significance*

Advantage: Cooling Effect + Mineral Absorption + Ascent of Sap

Disadvantage: 99% Water Loss = Wastage = Necessary Evil

Anti-transpirants = ABA, PMA, Silicon Oil, Colourless Plastics

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### *5. PHLOEM TRANSPORT* `Food Translocation`

*A. Munch Pressure Flow Hypothesis* `Most Accepted`

Source = Leaf = Sucrose Loaded → Ψs Decrease → Water Enters → Turgor High

Sink = Root/Fruit = Sucrose Unloaded → Ψs Increase → Water Exits → Turgor Low

Flow = High Turgor Pressure → Low Turgor Pressure = Bulk Flow

Evidence: Aphid Stylet Experiment = Exudate from Phloem

*B. Phloem Loading/Unloading*

Loading = Active = Symport = Sucrose + H+ = Companion Cell Help = ATP Used

Unloading = Active + Passive Both = Sink me

Direction = Bidirectional = Up + Down = Not Unidirectional like Xylem

Girdling Experiment = Bark Remove → Food Accumulates Above = Proves Phloem Function

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### *6. MINERAL ABSORPTION + TRANSPORT*

*A. Absorption*

Passive = Simple Diffusion = Along Conc. Gradient = No Energy

Active = Ion Pumps = Against Gradient = ATP Used = Selective

Nitrogen = Nitrate NO3- + Ammonium NH4+ = Most Imp

*B. Transport*

Xylem = Unidirectional = Root → Shoot = With Transpiration Stream

Phloem = Bidirectional = Source → Sink = Organic Form

Remobilised Elements = N, P, K, S = Deficiency in Old Leaves First

Immobilised Elements = Ca, Fe, B = Deficiency in Young Leaves First

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### *7. LAST 5 YEAR PYQ ONE LINERS* `Ratta Maar Le`  

1. *Casparian Strip* = Endodermis = Suberin = Apoplast Block = NEET 2024  

2. *Guttation* = Root Pressure = Hydathodes = Liquid Water = NEET 2024  

3. *Cohesion-Tension* = Transpiration Pull = Dixon Jolly = NEET 2023  

4. *Phloem Loading* = Active + Symport + Sucrose-H+ = NEET 2023  

5. *Stomata Open* = K+ Entry + Guard Cell Turgid = NEET 2022  

6. *Apoplast* = Cell Wall Route = Faster = NEET 2022  

7. *Imbibition* = Seed Germination = Colloids + Water = NEET 2021  

8. *Munch Hypothesis* = Pressure Flow = Source to Sink = NEET 2021  

9. *ABA* = Stress Hormone = Stomata Close = NEET 2020  

10. *Water Potential* = Pure Water = Zero = Maximum = NEET 2020  

11. *Symplast* = Plasmodesmata = Cytoplasmic Connection = NEET 2019  

12. *Transpiration* = Necessary Evil = Cooling + 99% Loss = NEET 2019  

13. *Root Pressure* = Positive = Max 2 atm = Not in Tall Trees = NEET 2018  

14. *Girdling* = Phloem Remove = Food Stops = NEET 2018  

15. *Aquaporins* = Water Channels = Facilitated Diffusion = NEET 2017  

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### *8. GOOGLE SE HATKE TRICKS* 🔥  

*A. Ψw Formula Yaad*

Ψw = S + P = Solute + Pressure

Pure Water = 0, Solution = Negative, Turgid Cell = 0, Plasmolysed = Negative

Water Moves = High Ψw to Low Ψw = Upar se Neeche

*B. Xylem vs Phloem Table*

Xylem = Water + Minerals + Unidirectional + Upward + Dead = Tracheids + Vessels

Phloem = Food + Bidirectional + Up + Down + Living = Sieve Tube + Companion Cell

Trick: **X**ylem = **X**tra Up, **P**hloem = **P**ar Up-Down

*C. Stomata Open/Close*

Day = Light = Photosynthesis = CO2 Kam = K+ In = Open

Night = Dark = CO2 Zyada = K+ Out = Close

ABA = Anti-transpirant = Close = Stress me

*D. Apoplast vs Symplast*

Apoplast = **A** = **A**waz nahi karta = Fast = Cell Wall

Symplast = **S**low = Cytoplasm se

Endodermis = Apoplast ka Breaker = Casparian Strip

*1-2Q Pakka Distribution*:  

1Q = Water Potential/Osmosis, 1Q = Transpiration Pull/Phloem Transport  

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