Biology
Chapter 5
Board Weightage: 6 - 8 Marks in ICSE Board Exam
Chemical Coordination in Plants: Plant Hormones
Prescribed Textbook: Selina Concise Biology (Class 10) - Chapter 7
Canonical Link:
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📖 Syllabus Scope & Overview
Plant growth regulators (phytohormones): Auxins (apical dominance, cell elongation, phototropism, rooting), Gibberellins (internode elongation, breaking seed dormancy), Cytokinins (cell division, delay of senescence), Abscisic Acid (ABA - stress hormone, stomatal closure, abscission), Ethylene (gaseous hormone, fruit ripening); Tropic movements (phototropism, geotropism, hydrotropism, thigmotropism) vs Nastic movements (thigmonasty in Mimosa pudica).
🔑 Mandatory ICSE Examiner Technical Keywords with Detailed Description
Official CISCE Evaluation Benchmark
According to CISCE board marking schemes, evaluators allocate marks based on the explicit presence of mandatory technical keywords. General or colloquial explanations fail to secure full marks. The table below details every required technical term, its scientific/academic description, the evaluator directive, and its exact model answer usage.
Mandatory Keyword #1
Core Definition
Chapter Concept: Auxin Action & Tropic Movements
1 Mark (Structural Location / Physiological Function)
"Auxin causes cell elongation and apical dominance"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Chemical Coordination in Plants: Plant Hormones), "Auxin causes cell elongation and apical dominance" is an indispensable physiological term, anatomical structure, or biological process defined in the prescribed ICSE syllabus.
CISCE biology evaluators deduct marks for incorrect phonetic spelling or vague layperson descriptions. Candidates must use exact biological terminology: "Auxin causes cell elongation and apical dominance".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Auxin Action & Tropic Movements is characterized by "Auxin causes cell elongation and apical dominance", ensuring proper structural and functional regulation."
Mandatory Keyword #2
Core Definition
Chapter Concept: Auxin Action & Tropic Movements
1 Mark (Structural Location / Physiological Function)
"Auxin accumulates on shaded side"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Chemical Coordination in Plants: Plant Hormones), "Auxin accumulates on shaded side" is an indispensable physiological term, anatomical structure, or biological process defined in the prescribed ICSE syllabus.
CISCE biology evaluators deduct marks for incorrect phonetic spelling or vague layperson descriptions. Candidates must use exact biological terminology: "Auxin accumulates on shaded side".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Auxin Action & Tropic Movements is characterized by "Auxin accumulates on shaded side", ensuring proper structural and functional regulation."
Mandatory Keyword #3
Core Definition
Chapter Concept: Auxin Action & Tropic Movements
1 Mark (Structural Location / Physiological Function)
"ABA is stress hormone inducing stomatal closure"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Chemical Coordination in Plants: Plant Hormones), "ABA is stress hormone inducing stomatal closure" is an indispensable physiological term, anatomical structure, or biological process defined in the prescribed ICSE syllabus.
CISCE biology evaluators deduct marks for incorrect phonetic spelling or vague layperson descriptions. Candidates must use exact biological terminology: "ABA is stress hormone inducing stomatal closure".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Auxin Action & Tropic Movements is characterized by "ABA is stress hormone inducing stomatal closure", ensuring proper structural and functional regulation."
Mandatory Keyword #4
Core Definition
Chapter Concept: Auxin Action & Tropic Movements
1 Mark (Structural Location / Physiological Function)
"Ethylene is gaseous hormone promoting fruit ripening"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Chemical Coordination in Plants: Plant Hormones), "Ethylene is gaseous hormone promoting fruit ripening" is an indispensable physiological term, anatomical structure, or biological process defined in the prescribed ICSE syllabus.
CISCE biology evaluators deduct marks for incorrect phonetic spelling or vague layperson descriptions. Candidates must use exact biological terminology: "Ethylene is gaseous hormone promoting fruit ripening".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Auxin Action & Tropic Movements is characterized by "Ethylene is gaseous hormone promoting fruit ripening", ensuring proper structural and functional regulation."
Mandatory Keyword #5
Core Definition
Chapter Concept: Auxin Action & Tropic Movements
1 Mark (Structural Location / Physiological Function)
"Thigmonasty in Mimosa pudica (sleeping movement)"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Chemical Coordination in Plants: Plant Hormones), "Thigmonasty in Mimosa pudica (sleeping movement)" is an indispensable physiological term, anatomical structure, or biological process defined in the prescribed ICSE syllabus.
CISCE biology evaluators deduct marks for incorrect phonetic spelling or vague layperson descriptions. Candidates must use exact biological terminology: "Thigmonasty in Mimosa pudica (sleeping movement)".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Auxin Action & Tropic Movements is characterized by "Thigmonasty in Mimosa pudica (sleeping movement)", ensuring proper structural and functional regulation."
Complete step-by-step evaluator solutions for textbook problems and 5 generated practice sets adhering to CISCE marking schemes.
📘 Textbook Problem: Textbook Exercise 5 - Review Questions Q.5
Selina Concise Biology (Class 10) - Chapter 7 - End-of-Chapter Review
3 Marks Total
With reference to Chemical Coordination in Plants: Plant Hormones: (i) Define the biological process of Auxin Action & Tropic Movements. (ii) State its exact location and physiological significance in the living organism.
Step-by-Step Marking Breakdown
Step 1: Scientific Definition with Technical Keywords: Define Auxin Action & Tropic Movements incorporating mandatory ICSE terminology: Auxin causes cell elongation and apical dominance, Auxin accumulates on shaded side, ABA is stress hormone inducing stomatal closure.
1 Mark
Step 2: Anatomical / Cellular Location: State the precise anatomical site or organelle where this biological process occurs.
1 Mark
Step 3: Biological Significance / Function: Explain the physiological necessity of this process for organismal survival, homeostasis, or reproduction.
1 Mark
Final Answer: Precise scientific definition, exact organ/organelle location, and physiological function
(Units: Biological Nomenclature)
💡 Examiner Tip: Underline key technical terms in biological definitions. CISCE examiners specifically look for mandatory keywords.
🎯 Generated Set: Generated Practice Set 1 - Core Concept (2 Marks)
ICSE Class 10 Exam Blueprint - Chapter 5
2 Marks Total
Define "Auxin Action & Tropic Movements" in the context of ICSE Class 10 Biology. State its primary characteristic or SI unit/standard symbol.
Step-by-Step Marking Breakdown
Step 1: Precise Technical Definition: Auxins promote cell elongation. In phototropism, auxins migrate towards the shaded side of shoot tip, causing shaded cells to grow faster and bending shoot towards light. In root, ...
1 Mark
Step 2: Mandatory Technical Criteria: Ensure the definition contains mandatory keywords: Auxin causes cell elongation and apical dominance, Auxin accumulates on shaded side, ABA is stress hormone inducing stomatal closure.
1 Mark
Final Answer: Accurate scientific/scholarly definition containing all mandatory ICSE evaluation keywords.
(Units: Theoretical definition)
💡 Examiner Tip: Avoid colloquial explanations. Use the exact technical definition given in prescribed CISCE curriculum.
🎯 Generated Set: Generated Practice Set 2 - Method & Application (3 Marks)
ICSE Question Bank & Specimen Framework - Biology
3 Marks Total
Explain the procedural method or practical demonstration used to verify "Auxin Action & Tropic Movements". State the working apparatus/setup and key precautions.
Step-by-Step Marking Breakdown
Step 1: State the Formula / Conceptual Principle: State the fundamental principle governing Auxin Action & Tropic Movements.
1 Mark
Step 2: Mathematical / Procedural Deduction: Describe the experimental procedure with step-by-step observational recording.
1 Mark
Step 3: Concluding Result & Interpretation: Express the final outcome clearly with proper units or scientific deduction.
1 Mark
Final Answer: Verified procedural conclusion for Auxin Action & Tropic Movements
(Units: Procedural steps)
💡 Examiner Tip: In derivation and numerical questions, every intermediate mathematical step carries fractional credit.
🎯 Generated Set: Generated Practice Set 3 - Comparative Analysis (3 Marks)
ICSE Exemplar Practice Paper - Biology
3 Marks Total
Differentiate between "Auxin Action & Tropic Movements" and "Auxin Action & Tropic Movements" on the basis of: (i) Fundamental definition/mechanism, (ii) Key working condition or formula, (iii) Real-world practical example or application.
Step-by-Step Marking Breakdown
Point 1: Conceptual Difference: Contrast the primary mechanisms: Auxin Action & Tropic Movements focuses on Auxin causes cell elongation and apical dominance, whereas Auxin Action & Tropic Movements emphasizes Auxin causes cell elongation and apical dominance.
1 Mark
Point 2: Quantitative / Operational Difference: Highlight differences in formulas, governing laws, operating environments, or physical behavior.
1 Mark
Point 3: Exemplary Differentiation: Provide one clear, unambiguous textbook example illustrating each concept under everyday conditions.
1 Mark
Final Answer: Three-point structured comparative table with clear opposing criteria.
(Units: Tabular points)
💡 Examiner Tip: Always construct a comparative answer in a two-column table with an explicit "Point of Difference" header column.
🎯 Generated Set: Generated Practice Set 4 - Board Standard Structured (4 Marks)
ICSE Board Marking Blueprint - Class 10
4 Marks Total
A comprehensive ICSE examination question based on "Chemical Coordination in Plants: Plant Hormones":
(i) State the fundamental law or rule governing "Auxin Action & Tropic Movements". [1 Mark]
(ii) How does this concept change with temperature / pressure / time / scale? [1 Mark]
(iii) State one common mistake students make in this chapter and provide the correct scientific reasoning. [2 Marks]
Step-by-Step Marking Breakdown
Part (i): Statement of the Law: State the formal principle verbatim as recognized by CISCE syllabus committees.
1 Mark
Part (ii): Dependency Analysis: Explain the direct or inverse variation of the target variable with respect to environmental or operational factors.
1 Mark
Part (iii): Error Analysis & Correct Resolution: Identify the frequent pitfall: Students often confuse Auxin causes cell elongation and apical dominance with related quantities. The correct understanding requires strict application of Auxin Action & Tropic Movements.
2 Marks
Final Answer: Structured 4-mark solution completely addressing parts (i), (ii), and (iii).
(Units: Multi-part breakdown)
💡 Examiner Tip: Notice the mark distribution in multi-part questions; allocate your answering time and detail strictly in proportion to allotted marks.
🎯 Generated Set: Generated Practice Set 5 - Higher Order Thinking (HOTS) (4 Marks)
ICSE High-Achiever Challenge Series - Class 10
4 Marks Total
A critical scenario-based problem in "Chemical Coordination in Plants: Plant Hormones": An experiment is performed under non-ideal conditions involving "Auxin Action & Tropic Movements" and "Auxin Action & Tropic Movements".
(a) Predict what happens to the expected outcome if the boundary condition fails.
(b) Give complete scientific justification.
(c) State the critical safeguard or correction formula to rectify the error.
Step-by-Step Marking Breakdown
Part (a): Prediction of Anomalous Outcome: Accurately predict the deviation from theoretical expectations when standard assumptions are violated.
1 Mark
Part (b): Scientific Justification: Provide a rigorous scientific explanation using first principles and mandatory keywords: Auxin causes cell elongation and apical dominance, Auxin accumulates on shaded side, ABA is stress hormone inducing stomatal closure, Ethylene is gaseous hormone promoting fruit ripening.
2 Marks
Part (c): Correction Protocol & Mathematical Remedy: State the exact rectification formula or procedural calibration necessary to restore accuracy.
1 Mark
Final Answer: Full scenario analysis with anomaly prediction, first-principles justification, and correction method.
(Units: HOTS Analytical Reasoning)
💡 Examiner Tip: HOTS questions in ICSE evaluate depth of conceptual understanding. Avoid superficial guessing; reason backward from core laws.