Step-by-step ICSE solutions and marking scheme for Cell Division, Genetics & Chromosomes from Selina Concise Biology (Class 10) - H.S. Vishnoi and 5 generated practice problem sets.

Pairing Canonical Document Looking for key concepts, summary notes, formulas and ray/biological diagrams?

📘 Open Chapter Notes (class10_biology_cell_division_genetics_and_chromosomes.html) →

Biology Chapter 1 1 Textbook + 5 Generated Exercises 12 - 14 Marks in ICSE Board Exam

Cell Division, Genetics & Chromosomes — Solved Textbook & 5 Practice Sets

Prescribed Reference Textbook: Selina Concise Biology (Class 10) - H.S. Vishnoi

Canonical Link: https://icse.smartindia.pro/class10_biology_solved_exercise_cell_division_genetics_and_chromosomes.html

Prerendered HTML Page: class10_biology_solved_exercise_cell_division_genetics_and_chromosomes.html

📘 Prescribed Textbook Solved Exercise (Selina Concise Biology (Class 10))

Primary Curriculum Benchmark

Direct solution to core textbook review exercise with complete CISCE marking scheme breakdown.

Selina Chapter 2 - Exercise B, Question 4 Selina Concise Biology Class 10

3 Marks Allotted

Differentiate between Karyokinesis and Cytokinesis on the basis of: (i) Definition, (ii) Occurrence, (iii) Method in plant cells.

Step-by-Step ICSE Evaluator Marking Key

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 Verified Answer: Karyokinesis is nuclear division; Cytokinesis is cytoplasmic division occurring via cell plate in plants. (Key Units: Biological terms)

💡 Examiner Directive: Present differences strictly in a clean tabular form with heading criteria.

🎯 5 Generated Practice Exercises with Step-Marking

CISCE Syllabus Graded Set

Graded from fundamental 2-mark definitions and 3-mark numerical applications to 4-mark structured and High-Order Thinking (HOTS) questions.

Generated Practice Set 1 - Core Concept (2 Marks) Difficulty: Easy

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 Directive: Avoid colloquial explanations. Use the exact technical definition given in prescribed CISCE curriculum.

Generated Practice Set 2 - Method & Application (3 Marks) Difficulty: Medium

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 Directive: In derivation and numerical questions, every intermediate mathematical step carries fractional credit.

Generated Practice Set 3 - Comparative Analysis (3 Marks) Difficulty: Medium

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 Directive: Always construct a comparative answer in a two-column table with an explicit "Point of Difference" header column.

Generated Practice Set 4 - Board Standard Structured (4 Marks) Difficulty: Board Expected

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 Directive: Notice the mark distribution in multi-part questions; allocate your answering time and detail strictly in proportion to allotted marks.

Generated Practice Set 5 - Higher Order Thinking (HOTS) (4 Marks) Difficulty: Hard

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 Directive: HOTS questions in ICSE evaluate depth of conceptual understanding. Avoid superficial guessing; reason backward from core laws.

🔑 Mandatory ICSE Examiner Technical Keywords Required in Solutions

Required for Step-Marking Credit

CISCE evaluators check for the explicit usage of mandatory technical terminology when scoring reasoning questions and step derivations. The table below outlines each key term, its technical description, the examiner marking directive, and the exact model answer phrasing expected in ICSE board examination solutions.

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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"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 Examiner Directive & Marking Rubric:

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 Solutions):

"The physiological role of Mendel’s Laws of Inheritance is characterized by "Alleles separate in gametogenesis", ensuring proper structural and functional regulation."

⚖️ CISCE Evaluation Directives for Biology

Step-Mark Allocation: Every sub-step, formula statement, and intermediate substitution carries independent marks. Writing final answers without formula yields zero in Section B numericals.

Mandatory SI Units: In ICSE Science and Mathematics, omitting SI units or writing incorrect unit exponents causes automatic 1/2 mark deduction per problem.

Examiner Technical Vocabulary: CISCE evaluators look for exact prescribed terms in definitions and reasoning questions. General paraphrasing often loses full credit.

📚 Other Class 10 Biology Solved Exercises

Solve Exercises Interactively in the App

Bookmark questions, get real-time AI Mentor hints for tough steps, and test your exam readiness with live timed quizzes.

⚡ Practice in Interactive ICSE Hub