Structure and Function — Plants
Complete Formula Sheet & Shortcut Bible · BITSAT 2026
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Plant Morphology Quick Facts
Floral Formula Symbols
K = Calyx (sepals)
C = Corolla (petals)
P = Perianth (tepals)
A = Androecium (stamens)
G = Gynoecium (carpels)
Br (Bracteate), ⊕ (Actinomorphic), % (Zygomorphic)
C = Corolla (petals)
P = Perianth (tepals)
A = Androecium (stamens)
G = Gynoecium (carpels)
Br (Bracteate), ⊕ (Actinomorphic), % (Zygomorphic)
Placentation Types
Marginal: Pea
Axile: Tomato, Lemon
Parietal: Mustard, Argemone
Free Central: Dianthus, Primrose
Basal: Sunflower, Marigold
Axile: Tomato, Lemon
Parietal: Mustard, Argemone
Free Central: Dianthus, Primrose
Basal: Sunflower, Marigold
Aestivation Types
Valvate: Calotropis
Twisted: China rose, Cotton
Imbricate: Cassia, Gulmohar
Vexillary (Papilionaceous): Pea, Bean
Twisted: China rose, Cotton
Imbricate: Cassia, Gulmohar
Vexillary (Papilionaceous): Pea, Bean
Root Modifications
Storage: Carrot, Turnip (Tap); Sweet Potato (Adventitious)
Support: Prop (Banyan); Stilt (Maize)
Respiration: Pneumatophores (Rhizophora)
Support: Prop (Banyan); Stilt (Maize)
Respiration: Pneumatophores (Rhizophora)
Stem Modifications
Underground: Potato (Tuber), Ginger (Rhizome)
Sub-aerial: Grass (Runner)
Aerial: Cucumber (Tendril), Bougainvillea (Thorn)
Sub-aerial: Grass (Runner)
Aerial: Cucumber (Tendril), Bougainvillea (Thorn)
Plant Anatomy & Tissues
Vascular Bundles: Root vs. Stem
Dicot Root: Radial arrangement, Xylem is Exarch.
Dicot Stem: Conjoint, Collateral, Open. Xylem is Endarch.
Monocot Stem: Conjoint, Collateral, Closed. Scattered bundles.
Dicot Stem: Conjoint, Collateral, Open. Xylem is Endarch.
Monocot Stem: Conjoint, Collateral, Closed. Scattered bundles.
Complex Permanent Tissues
Xylem (Water): Tracheids, Vessels, Xylem Parenchyma, Xylem Fibres.
Phloem (Food): Sieve Tubes, Companion Cells, Phloem Parenchyma, Phloem Fibres.
Phloem (Food): Sieve Tubes, Companion Cells, Phloem Parenchyma, Phloem Fibres.
Meristematic Tissues
Apical: At root & shoot tips (Primary growth - length).
Intercalary: At base of internodes/leaves (Regrowth in grasses).
Lateral: Vascular & Cork cambium (Secondary growth - girth).
Intercalary: At base of internodes/leaves (Regrowth in grasses).
Lateral: Vascular & Cork cambium (Secondary growth - girth).
Key Anatomical Features
Casparian Strips: Suberin deposition in endodermis of roots, blocks apoplast pathway.
Bulliform Cells: Large, empty cells in monocot leaves for rolling/unrolling.
Bulliform Cells: Large, empty cells in monocot leaves for rolling/unrolling.
Transport in Plants
Water Potential (Ψw)
Ψw = Ψs + Ψp
Ψw: Water Potential
Ψs: Solute Potential (always ≤ 0)
Ψp: Pressure Potential (usually > 0)
Ψw: Water Potential
Ψs: Solute Potential (always ≤ 0)
Ψp: Pressure Potential (usually > 0)
Water moves from a region of higher Ψw to lower Ψw. Pure water has Ψw = 0.
Transport Pathways
Apoplast: System of adjacent cell walls. Faster.
Symplast: System of interconnected protoplasts via plasmodesmata. Slower.
Symplast: System of interconnected protoplasts via plasmodesmata. Slower.
Transpiration Pull Theory
Cohesion: Mutual attraction between H₂O molecules.
Adhesion: Attraction of H₂O to tracheary elements.
Surface Tension: H₂O molecules attracted more in liquid phase than gas phase.
Adhesion: Attraction of H₂O to tracheary elements.
Surface Tension: H₂O molecules attracted more in liquid phase than gas phase.
Also known as the Cohesion-Tension-Transpiration Pull Model.
BITSAT Transport Triggers
Adding solutes always makes Ψs and Ψw more negative (decreases them).
Positive pressure (turgor) increases Ψp and thus increases Ψw.
In a flaccid cell, Ψp = 0, so Ψw = Ψs.
Guttation is due to root pressure, not transpiration.
Casparian strips in the endodermis force water from apoplast to symplast.
Mineral Nutrition
Macro vs. Micro Nutrients
Macronutrients (>10 mmole/kg): C, H, O, N, P, K, S, Ca, Mg
Micronutrients (<10 mmole/kg): Fe, Mn, Cu, Mo, Zn, B, Cl, Ni
Micronutrients (<10 mmole/kg): Fe, Mn, Cu, Mo, Zn, B, Cl, Ni
Mobile vs. Immobile Elements
Mobile (N, P, K, Mg): Deficiency appears in older leaves first.
Immobile (Ca, S): Deficiency appears in younger leaves first.
Immobile (Ca, S): Deficiency appears in younger leaves first.
Key Roles in N-Cycle
Nitrification: NH₃ → NO₂⁻ (Nitrosomonas) → NO₃⁻ (Nitrobacter)
N₂ Fixation: N₂ → NH₃ (Rhizobium, Azotobacter)
Denitrification: NO₃⁻ → N₂ (Pseudomonas)
N₂ Fixation: N₂ → NH₃ (Rhizobium, Azotobacter)
Denitrification: NO₃⁻ → N₂ (Pseudomonas)
Photosynthesis Core Concepts
Overall Reaction
6CO₂ + 12H₂O → C₆H₁₂O₆ + 6H₂O + 6O₂
Note: O₂ released comes from the splitting of H₂O, not CO₂.
Note: O₂ released comes from the splitting of H₂O, not CO₂.
Calvin Cycle (C3) Summary
For 1 Glucose:
6 CO₂ + 18 ATP + 12 NADPH are required.
Key Enzyme: RuBisCO
6 CO₂ + 18 ATP + 12 NADPH are required.
Key Enzyme: RuBisCO
C4 Pathway Summary
Primary CO₂ acceptor: PEP (in Mesophyll cells).
Key Enzyme: PEP carboxylase (PEPcase).
No photorespiration due to high CO₂ conc. in bundle sheath cells.
Key Enzyme: PEP carboxylase (PEPcase).
No photorespiration due to high CO₂ conc. in bundle sheath cells.
Cyclic vs. Non-Cyclic Photophosphorylation
Non-Cyclic: PS-II & PS-I involved. Produces ATP, NADPH, O₂.
Cyclic: Only PS-I involved. Produces only ATP. Occurs when NADPH demand is low.
Cyclic: Only PS-I involved. Produces only ATP. Occurs when NADPH demand is low.
Cellular Respiration Numbers
Net Gain per Glucose
Glycolysis (Cytoplasm): 2 ATP + 2 NADH
Link Reaction (Mito. Matrix): 2 NADH
Krebs Cycle (Mito. Matrix): 2 ATP + 6 NADH + 2 FADH₂
Link Reaction (Mito. Matrix): 2 NADH
Krebs Cycle (Mito. Matrix): 2 ATP + 6 NADH + 2 FADH₂
Respiratory Quotient (RQ)
RQ = Volume of CO₂ evolved / Volume of O₂ consumed
Carbohydrates: 1.0
Fats (Tripalmitin): 0.7
Proteins: 0.9
Organic Acids: > 1.0
Carbohydrates: 1.0
Fats (Tripalmitin): 0.7
Proteins: 0.9
Organic Acids: > 1.0
Final ATP Tally
Total ATP from 1 Glucose:
Glycolysis: 2 ATP + 2 NADH (~5 ATP) = 7 ATP
Link Rxn: 2 NADH (~5 ATP) = 5 ATP
Krebs Cycle: 2 ATP + 6 NADH (~15 ATP) + 2 FADH₂ (~3 ATP) = 20 ATP
Total ≈ 32 ATP (via new convention)
Glycolysis: 2 ATP + 2 NADH (~5 ATP) = 7 ATP
Link Rxn: 2 NADH (~5 ATP) = 5 ATP
Krebs Cycle: 2 ATP + 6 NADH (~15 ATP) + 2 FADH₂ (~3 ATP) = 20 ATP
Total ≈ 32 ATP (via new convention)
High-Yield Comparison: C3 vs. C4 Photosynthesis
| Feature | C3 Plants (e.g., Rice, Wheat) | C4 Plants (e.g., Maize, Sugarcane) |
|---|---|---|
Primary CO₂ Acceptor | RuBP (5-Carbon) | PEP (3-Carbon) |
First Stable Product | 3-PGA (3-Carbon) | Oxaloacetic Acid (4-Carbon) |
Kranz Anatomy | Absent | Present (Mesophyll + Bundle Sheath) |
Photorespiration | High rate | Negligible or Absent |
Optimal Temperature | 20-25 °C | 30-45 °C |
CO₂ Compensation Point | High (50-100 ppm) | Low (0-10 ppm) |