Biology
Chapter 1
Board Weightage: 12 - 14 Marks in ICSE Board Exam
Cell Division, Genetics & Chromosomes
Prescribed Textbook: Selina Concise Biology (Class 10) - H.S. Vishnoi
Canonical Link:
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🔑 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: Stages of Mitosis (PMAT)
1 Mark (Structural Location / Physiological Function)
"Equatorial plate"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Equatorial plate" 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: "Equatorial plate".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Stages of Mitosis (PMAT) is characterized by "Equatorial plate", ensuring proper structural and functional regulation."
Mandatory Keyword #2
Core Definition
Chapter Concept: Stages of Mitosis (PMAT)
1 Mark (Structural Location / Physiological Function)
"Sister chromatids"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Sister chromatids" 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: "Sister chromatids".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Stages of Mitosis (PMAT) is characterized by "Sister chromatids", ensuring proper structural and functional regulation."
Mandatory Keyword #3
Core Definition
Chapter Concept: Stages of Mitosis (PMAT)
1 Mark (Structural Location / Physiological Function)
"Centromere split"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Centromere split" 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: "Centromere split".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Stages of Mitosis (PMAT) is characterized by "Centromere split", ensuring proper structural and functional regulation."
Mandatory Keyword #4
Core Definition
Chapter Concept: Stages of Mitosis (PMAT)
1 Mark (Structural Location / Physiological Function)
"Opposite poles"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Opposite poles" 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: "Opposite poles".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Stages of Mitosis (PMAT) is characterized by "Opposite poles", ensuring proper structural and functional regulation."
Mandatory Keyword #5
Core Definition
Chapter Concept: Stages of Mitosis (PMAT)
1 Mark (Structural Location / Physiological Function)
"Diploid 2n"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Diploid 2n" 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: "Diploid 2n".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Stages of Mitosis (PMAT) is characterized by "Diploid 2n", ensuring proper structural and functional regulation."
Mandatory Keyword #6
Scientific Law
Chapter Concept: Mendel’s Laws of Inheritance
1 Mark (Structural Location / Physiological Function)
"Law of Segregation"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Law of Segregation" 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: "Law of Segregation".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Mendel’s Laws of Inheritance is characterized by "Law of Segregation", ensuring proper structural and functional regulation."
Mandatory Keyword #7
Experimental Precaution
Chapter Concept: Mendel’s Laws of Inheritance
1 Mark (Structural Location / Physiological Function)
"Monohybrid phenotypic ratio 3:1"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Monohybrid phenotypic ratio 3:1" 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: "Monohybrid phenotypic ratio 3:1".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Mendel’s Laws of Inheritance is characterized by "Monohybrid phenotypic ratio 3:1", ensuring proper structural and functional regulation."
Mandatory Keyword #8
Experimental Precaution
Chapter Concept: Mendel’s Laws of Inheritance
1 Mark (Structural Location / Physiological Function)
"Genotypic ratio 1:2:1"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Genotypic ratio 1:2:1" 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: "Genotypic ratio 1:2:1".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Mendel’s Laws of Inheritance is characterized by "Genotypic ratio 1:2:1", ensuring proper structural and functional regulation."
Mandatory Keyword #9
Core Definition
Chapter Concept: Mendel’s Laws of Inheritance
1 Mark (Structural Location / Physiological Function)
"Alleles separate in gametogenesis"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Biology (Cell Division, Genetics & Chromosomes), "Alleles separate in gametogenesis" 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: "Alleles separate in gametogenesis".
📝 Model Answer Application (Exact Phrasing for Board Exam):
"The physiological role of Mendel’s Laws of Inheritance is characterized by "Alleles separate in gametogenesis", 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: Selina Chapter 2 - Exercise B, Question 4
Selina Concise Biology Class 10
3 Marks Total
Differentiate between Karyokinesis and Cytokinesis on the basis of: (i) Definition, (ii) Occurrence, (iii) Method in plant cells.
Step-by-Step Marking Breakdown
Step 1: Compare Definitions: Karyokinesis is the division of the cell nucleus. Cytokinesis is the division of the cytoplasm.
1 Mark
Step 2: Compare Occurrence: Karyokinesis precedes cytokinesis during the M-phase.
1 Mark
Step 3: Compare Method in Plant Cells: In plant cells, cytokinesis occurs by the formation of a cell plate proceeding from the centre towards the periphery (centrifugal). Karyokinesis occurs without asters.
1 Mark
Final Answer: Karyokinesis is nuclear division; Cytokinesis is cytoplasmic division occurring via cell plate in plants.
(Units: Biological terms)
💡 Examiner Tip: Present differences strictly in a clean tabular form with heading criteria.
🎯 Generated Set: Generated Practice Set 1 - Core Concept (2 Marks)
ICSE Class 10 Exam Blueprint - Chapter 1
2 Marks Total
Define "Stages of Mitosis (PMAT)" 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: 1. Prophase: Chromatin condenses into chromosomes, nuclear membrane disappears. 2. Metaphase: Chromosomes align along equatorial plate. 3. Anaphase: Centromere splits, sister chrom...
1 Mark
Step 2: Mandatory Technical Criteria: Ensure the definition contains mandatory keywords: Equatorial plate, Sister chromatids, Centromere split.
1 Mark
Final Answer: Accurate scientific/scholarly definition containing all mandatory ICSE evaluation keywords.
(Units: N/A)
💡 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
A system governed by "Mendelian Cross Ratios" has standard parameters. Using the relation Monohybrid: 3:1 (Phenotype) | 1:2:1 (Genotype) || Dihybrid: 9:3:3:1, calculate the required variable when other quantities are doubled. State the formula and show step-by-step substitution.
Step-by-Step Marking Breakdown
Step 1: State the Formula / Conceptual Principle: Write the primary governing equation: Monohybrid: 3:1 (Phenotype) | 1:2:1 (Genotype) || Dihybrid: 9:3:3:1. Define each symbol clearly.
Formula: Monohybrid: 3:1 (Phenotype) | 1:2:1 (Genotype) || Dihybrid: 9:3:3:1
1 Mark
Step 2: Mathematical / Procedural Deduction: Substitute the modified parameters: Let initial state be S₁ and new state be S₂. Set up the ratio S₂ / S₁ and simplify algebraically.
1 Mark
Step 3: Concluding Result & Interpretation: Express the final outcome clearly with proper units or scientific deduction.
1 Mark
Final Answer: Result derived directly from Monohybrid: 3:1 (Phenotype) | 1:2:1 (Genotype) || Dihybrid: 9:3:3:1
(Units: N/A)
💡 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 "Stages of Mitosis (PMAT)" and "Mendel’s Laws of Inheritance" 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: Stages of Mitosis (PMAT) focuses on Equatorial plate, whereas Mendel’s Laws of Inheritance emphasizes Law of Segregation.
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 "Cell Division, Genetics & Chromosomes":
(i) State the fundamental law or rule governing "Stages of Mitosis (PMAT)". [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 Equatorial plate with related quantities. The correct understanding requires strict application of Mendel’s Laws of Inheritance.
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 "Cell Division, Genetics & Chromosomes": An experiment is performed under non-ideal conditions involving "Stages of Mitosis (PMAT)" and "Mendel’s Laws of Inheritance".
(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: Equatorial plate, Sister chromatids, Centromere split, Opposite poles.
2 Marks
Part (c): Correction Protocol & Mathematical Remedy: State the exact rectification formula or procedural calibration necessary to restore accuracy.
Formula: Monohybrid: 3:1 (Phenotype) | 1:2:1 (Genotype) || Dihybrid: 9:3:3:1
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.