Chapter-wise Important and Expected Questions for 2025 HSC Boards

Chapter Priority list:

  1. Control and Coordination
  2. Respiration and Circulation
  3. Reproduction in lower and higher animals
  4. Reproduction in lower and higher plants
  5. Biotechnology
  6. Plant water relationship
  7. Plant growth and Mineral Nutrition
  8. Molecular Basis of inheritance
  9. Inheritance and Variation
  10. Origin and Evolution of life
  11. Enhancement in food production
  12. Human Health and disease
  13. Organism and Population
  14. Ecosystem and Energy flow
  15. Biodiversity, Conservation and Environmental issue

Chapter 1: Reproduction in Lower and Higher Plants

1. Male Gametophyte and Microsporogenesis  

  • Structure of Male Gametophyte: Sketch and label the germinating pollen grain or mature male gametophyte. 
  • Explain the process of pollen development (microsporogenesis).
  • Anther Structure**: Draw a labeled T.S. of an angiospermic anther.

2. Pollination Mechanisms and Adaptations

  • Types of Pollination: Differentiate between geitonogamy, xenogamy, self-pollination, and cross-pollination. Discuss advantages of each.
  • Floral Adaptations: Explain adaptations for anemophily, entomophily, chiropterophily, and hydrophily with examples.
  • Outbreeding Devices: Describe dichogamy, protandry, and other mechanisms to prevent self-pollination.

3. Double Fertilization and Embryo Sac Development

  • Double Fertilization: Explain the process with a diagram and its significance.
  • Female Gametophyte: Sketch the development of the embryo sac from a functional megaspore (monosporic development). Label the parts of an anatropous ovule.

4. Seed and Fruit Development

  • Parthenocarpy and Polyembryony: Define and state types.
  • Seed Structure: Match ovule parts to seed components (e.g., integuments → seed coat).

5. Vegetative Reproduction

  • Artificial Methods: Describe cutting, budding, and grafting. Define "stock" and "scion."

6. Diagrams to Practice

  • V.S. of Anatropous Ovule
  • Germinating Pollen Grain
  • T.S. of Anther
  • Embryo Sac

7. Short Answers (1-2 marks

  • Define: Microsporogenesis, Triple Fusion, Parthenocarpy, Siphonogamy
  • Floral compatibility, Types of endosperms.  

8. Recent Trends (2022–2023)

  • Pollination Adaptations: Focus on anemophily (wind) and hydrophily (water).
  • Double Fertilization: Entry types of pollen tube (porogamy vs. chalazogamy).
Chapter 2: Reproduction in Lower and Higher Animals

1. Human Male and Female Reproductive Systems:

  • Human male reproductive system: Drawing and explaining the structure and function.
  • T.S. of human testis and sperm: Diagrams and explanations of sperm production (spermatogenesis).
  • Human female reproductive system: Diagrams and explanations about the menstrual cycle and hormonal changes.
  • T.S. of ovary: Drawing and explaining the structure of the ovary and menstrual cycle.

2. Gamete Formation and Fertilization:

  • Oogenesis and spermatogenesis: Phases of gamete formation, drawing and labeling diagrams.
  • Fertilization process: Diagrammatically explaining the process of fertilization and early embryonic development.
  • Fate of mesoderm and other germ layers: Explaining the organs developed from the different germ layers.

3. Contraception and Assisted Reproductive Techniques:

  • Contraceptive methods: Mechanisms of contraceptives such as Copper-T, and mechanical methods of birth control.
  • Assisted reproductive techniques: IVF, ICSI, and other techniques for overcoming infertility, sometimes with diagrams.

4. Pregnancy and Development:

  • Stages of pregnancy and parturition: Understanding the process of pregnancy, hormonal changes, and the stages of labor.
  • Pregnancy and lactation: The hormonal regulation of pregnancy and the process of lactation after birth.

5. Reproductive Processes in Lower Animals:

  • Budding in Hydra: Explanation of asexual reproduction in hydra and its process.

6. Other Key Concepts:

  • Hormonal control in the menstrual cycle: Understanding the role of hormones such as estrogen, progesterone, LH, and FSH during the menstrual cycle.
  • Scrotal sac and thermoregulation: Why the scrotal sac serves as a thermoregulator for sperm production.

7. Diagrams: Be prepared to draw and label:

  • Human male and female reproductive systems
  • Spermatogenesis and oogenesis
  • T.S. of testis and ovary
  • Fertilization and early development
Chapter 3: Inheritance and Variation

1. Mendelian Laws and Genetic Crosses:

  • Law of Independent Assortment: Explain with a suitable example (e.g., dihybrid cross) and its significance.
  • Law of Dominance: Definition and explanation, with comparison to incomplete dominance and co-dominance.
  • Test Cross and Back Cross: Definitions, differences, and significance of both crosses.
  • Phenotypic and Genotypic Ratios: Calculation of ratios in crosses involving pea plants (e.g., crossing a homozygous tall with a recessive dwarf).
  • Punnett Square and Checkerboard Method: Use for calculating ratios in genetic crosses (e.g., F1 generation of pea plants).

2. Sex-Linked Inheritance and Disorders:

  • Sex Linkage: Explanation and inheritance of sex-linked traits such as color blindness and hemophilia.
  • Sex Determination: Mechanism of sex determination in humans, honeybees, and birds.
  • X and Y Chromosomes: Structural and functional differences between X and Y chromosomes, their role in inheritance.
  • Sex-linked Diseases: Explanation of diseases like color blindness and hemophilia, and how they are inherited, often with charts.

3. Chromosomal Abnormalities and Syndromes:

  • Chromosomal Disorders: Explanation and identification of disorders such as Down syndrome, Turner syndrome, and Klinefelter syndrome. Mention symptoms and genetic basis.
  • Chromosomal Aberrations: Types of aberrations such as deletions, duplications, inversions, and translocations, with examples.

4. Co-dominance, Incomplete Dominance, and Pleiotropy:

  • Co-dominance and Incomplete Dominance: Comparison between these phenomena, with examples and their impact on phenotypic expression.
  • Pleiotropy: Explanation of pleiotropy and why it leads to ratios like 2:1 (e.g., sickle cell anemia in humans).

5. Genetic Terminology and Concepts:

  • Recessive and Dominant Traits: Explanation and examples of how recessive traits are inherited and expressed.
  • Incomplete Dominance: Define and explain with examples such as the red and white flowered Mirabilis jalapa.

6. Genetic Inheritance in Different Organisms:

  • Inheritance in Pea Plants: Understanding the traits Mendel worked with, such as seed color and plant height, and their inheritance patterns.
  • Haploid and Diploid Chromosome Numbers: Explanation of the haploid number in drones of honeybees, and how it affects inheritance.

7. Genotypic and Phenotypic Ratios in Specific Crosses:

  • Pea Plant Crosses: For example, homozygous yellow, round-seeded plant crossed with its recessive parent; calculation of genotypic and phenotypic ratios.
  • Crosses Involving Multiple Traits: Examples where you calculate ratios from crosses involving seed shape and color or plant height and seed shape.
Chapter 4: Molecular of Basis of Inheritance

1. Genetics and Biotechnology

  • Describe the characteristics of the genetic code.
  • Expected again due to its fundamental importance in understanding gene expression and protein synthesis.
  • Define the terms codon and anticodon.
  • Key for understanding translation in protein synthesis.
  • Explain the experiment of Hershey and Chase to prove that DNA is the genetic material.
  • A classic experiment that is frequently asked to test understanding of DNA's role as the genetic material.
  • Give the names and functions of enzymes involved in lactose metabolism in E. coli.
  • Important for molecular genetics and gene regulation concepts.
  • What is the goal of the Human Genome Project (HGP)?
  • Frequently asked to test awareness of modern genomics applications.

2. DNA Structure and Replication

  • Sketch and label hair-pin model of t-RNA.
  • Commonly asked to test understanding of molecular biology structures.
  • Explain semi-conservative replication of eukaryotic DNA.
  • A key topic in molecular biology, often asked to explain how DNA replication occurs.
  • Sketch and label diagrammatic semi-conservative replication of DNA.
  • Drawings of DNA replication are frequently tested with labels.
  • Draw and label a suitable diagram for transcription and processing of the hnRNA to mRNA in eukaryotes.
  • Important for understanding RNA transcription and processing events.

3. Protein Synthesis

  • Give the central dogma of protein synthesis. Explain the process of translation. 
  • The central dogma is a fundamental concept in biology; translation process explanation is highly likely.
  • Sketch and label clover-leaf model of t-RNA.
  • A different structural representation of t-RNA, which is commonly asked for in exams.

4. Molecular Biology Applications

  • Name the radioactive probe used in India for DNA fingerprinting.
  • An application of biotechnology that might be tested again to check knowledge on forensic genetics.
  • What material is used for isolation of DNA in fingerprint technique?
  • A simple but important concept in biotechnology and forensics.

5. Genomic Concepts

  • Define genomics. Give any two applications of it.
  • Genomics is an emerging field, and understanding its applications is crucial.
  • Write down the full form of RFLP.
  • A small but important question on molecular techniques used in genetics.

6. Miscellaneous

  • What is Anticodon?
  • Frequently asked to test knowledge of codon-anticodon interaction in translation.
  • Distinguish between DNA and RNA.
  • Expected as a simple comparison question, emphasizing basic differences in structure and function.
  • Distinguish between heterochromatin and euchromatin with reference to staining properties.
  • Key for testing knowledge of chromatin structure and gene regulation mechanisms.
  • Write the firms of Human Genome Project.
Chapter 5: Evolution and Origin of life

1. Evolutionary Concepts

  • What is organic evolution?
  • Explain the concept 'survival of the fittest'.
  • Explain the concept of 'struggle for existence'.
  • Explain natural selection with example of industrial melanism.
  • What is gene flow?

2. Darwin’s Theory and Principles

  • Define 'evolution'. Principles of Darwin's theory of natural selection. Mention one objection.
  • What is gene pool?

3. Fossils and Evidence of Evolution

  • Give the importance of fossils in support of organic evolution.
  • Enlist any four sequential evolutionary names of human ancestors.
  • State the major changes in the evolution of man.

4. Human Evolution

  • Enlist the characteristics of Neanderthal Man.
  • Example of connecting link between reptiles and birds.
  • Fossil animal considered connecting link between reptiles and birds.

5. Genetic Variation and Mechanisms

  • Give two factors responsible for genetic variation.
  • Define reproductive isolation and explain two types.

6. Evolutionary Mechanisms

  • What is adaptive radiation?
  • What is protobiogenesis?

7. Miscellaneous Concepts

  • Define 'connecting link'.
  • Country where industrial melanism was observed in moths.
Chapter 6: Plant Water Relationship

1. Water Types in Soil

  • Write a note on hygroscopic water and combined water.
  • Define gravitational water, hygroscopic water, combined water, and capillary water.

2. Root Hair Structure

  • Describe the structure of root hair (diagram not expected).
  • With the help of a neat, labeled diagram, describe the structure of root hair.

3. Importance of Water

  • What is called "elixir of life"? What makes it so important?

4. Forms of Water in Soil

  • Name the different forms of water in the soil.
  • Which form of water is absorbed by the plants?
  • Name the region in the soil from where roots absorb water.

5. Properties of Water

  • Give different properties of water.
  • Water acts as a thermal buffer. Justify the statement.

6. Plant Cells

  • Give the other name for epidermal cells in roots of plants.
  • Give an example of a plant having both kidney and dumbbell-shaped guard cells in stomata.

7. Imbibition

  • Define imbibition.
  • Explain how imbibition helps root hairs in the absorption of water.

8. Thermal Buffer

  • Water acts as a thermal buffer. Justify the statement.
  • Water’s thermal buffering properties.
Chapter 7: Plant Growth and Mineral Nutrition

1. Deficiency Symptoms

  • Give the name of deficiency symptoms caused due to sulfur in stem and root tips.

2. Hormonal Effects

  • Give all four physiological effects and applications of ethylene.
  • Describe the physiological effect and applications of gaseous hormones in plants.
  • Name the stress hormone in plants. Describe its physiological effects.
  • Name the hormone used for early rooting in propagation by cutting.
  • Name the hormone responsible for apical dominance.
  • Explain the role of chlorophyllase enzyme in banana.

3. Hormone Functions Chart

  • Complete a chart with hormones and their functions (e.g., IAA for cell elongation, Zeatin for cell division, etc.).

4. Auxin and IAA

  • Which is the primary precursor of IAA in plants?
  • Explain the application of auxin in flowering in pineapple.

5. Abscisic Acid (ABA)

  • Abscisic acid is the common name for two identical substances isolated separately. Name them and give the chemical features of ABA.
  • Give reasons why ABA is also known as antitranspirant.

6. Mineral Deficiency

  • Complete the box with reference to symptoms of mineral deficiency (e.g., abscission, premature fall of flowers, fruits, and leaves).

7. Apical Dominance

  • Name and describe the plant hormone that will reverse apical dominance.

8. Weed Management

  • A farmer wants to remove broad-leaved weeds from a jawar plantation. Suggest a plant hormone to remove such weeds.

9. Cytokinin Applications

  • Mention two applications of cytokinin.
Chapter 8: Respiration and Circulation

1. Hypertension & Angina Pectoris

  • Describe hypertension. Add a note on angina pectoris.

2. Human Heart Structure

  • With the help of a neat labelled diagram, describe the internal structure of the human heart.
  • Draw a neat and labelled diagram of the ventral view of the heart.
  • Sketch and label the conducting system of the human heart.
  • Describe the conducting system of the human heart with the help of a suitable diagram.

3. Heart Valves

  • Mention the location of the following valves within the human heart:
  • Eustachian valve
  • Thebesian valve
  • Bicuspid valve
  • Tricuspid valve

4. ECG

  • In the electrocardiogram shown, which wave represents ventricular diastole? 
  • In electrocardiogram, QRS complex stands for what?
  • Identify and explain the T-wave in the electrocardiogram.

5. Arteries and Veins

  • Sketch and label the T.S. of an artery.
  • Sketch and label the T.S. of a vein.
  • With the help of neat and labelled diagrams, distinguish between artery and vein.
  • Draw a neat labelled diagram of a blood vessel (e.g., artery) from a cut surface.

6. Blood Cells

  • Describe five types of leucocytes, with the help of diagrams, and their functions.
  • Write a note on erythrocytes.
  • Describe agranulocytes with the help of diagrams.

7. Blood Pressure and Disorders

  • Dilip's B.P. is 120/80 mmHg, and Mohsin's is 160/100 mmHg. Who is suffering from hypertension, and what are the causes?
  • Blood pressure of Vinit was recorded as 180/120 mmHg. State the condition and symptoms.
  • Describe the condition of hypertension and its symptoms.

8. Blood Circulation

  • Complete the following flow diagram of double circulation.
  • What is blood pressure, and how is it measured?
  • Differentiate between an artery and a vein with respect to lumen and wall thickness.

9. Blood Composition and Plasma

  • Classify the composition of blood plasma (serum albumin, bicarbonate, urea, etc.).
  • Write a note on the transport of carbon dioxide by bicarbonate ions at the tissue level.

10. Lymphatic System

  • In the human pharynx, there is a set of lymphoid organs called what?

11. Blood Clotting and Blood Vessel Injury

  • A person met with an accident and bleeds but quickly stops bleeding. Explain the physiological process responsible for this.

12. Breathing Process

  • Describe the steps in the process of breathing.
Chapter 9: Control and Co-ordination

1. Structure and Function of the Brain

  • Sketch and label the lateral view of the human brain (Frequently asked, e.g., July 2018, March 2017).
  • Describe the functional areas of the cerebrum with the help of a labelled diagram (July 2019).
  • Differentiate between the cerebrum and cerebellum (e.g., Oct. 2021).
  • With the help of a neat and labelled diagram, describe the reflex arc (March 2017, July 2020).

2. Endocrine Glands and Hormones

  • Enlist human endocrine glands and describe the structure of the thyroid gland, and add a note on deficiency of thyroxine (March 2017).
  • Name the hormones and glands secreting them (e.g., Growth of thyroid gland, Control of tubular absorption of water in kidneys, Glycogenesis, etc.) (March 2022).
  • Distinguish between hyperthyroidism and hypothyroidism (March 2022).
  • Explain the properties of nerve fibers (March 2022).
  • Describe the mechanism of hormone action through membrane receptors (July 2022).

3. Reflex Action and Nervous System

  • Explain the mechanism of reflex action with a diagram (March 2019).
  • State the names of the cranial nerves (e.g., the 6th and 8th cranial nerves) (July 2018).
  • Differentiate between sympathetic and parasympathetic nervous systems (March 2023).

4. Eye and Vision Mechanism

  • Sketch and label the anatomical structure of the human eye (Oct. 2013). 
  • Explain the mechanism of vision with the help of a labelled diagram (March 2018).
  • Describe the structure of the human eye and explain the mechanism of vision (March 2018).

5. Diseases and Disorders

  • A person is showing symptoms like increased BMR, heart rate, blood pressure, and deposition of fats in eye sockets. Name the disease he is suffering from. (March 2019).
  • A child has low BMR, delayed puberty, and mental retardation. Identify the disease. (March 2023).

6. Miscellaneous Important Questions

  • Give reasons (e.g., why oxytocin is known as the 'birth hormone', or why people in hilly regions are advised to use iodized salt) (July 2019).
  • Describe the structure of the cerebrum with its functions (March 2016).
  • Name the receptors and their location (e.g., mechanoreceptors, statoacoustic receptors, baroreceptors) (March 2020).
  • Complete the diagram for the formation of spinal nerve (Oct. 2021).
Chapter 10: Human Health and Disease

1. HIV and Immunity

  • Name the term for the transmission of HIV from pregnant mother to fetus (March 2013).
  • Write a note on HIV (Oct. 2014).
  • Sketch and label the structure of HIV (March 2017).
  • Explain the mechanism of antibody-antigen complex formation with a labelled diagram (July 2018).
  • Write a note on 'artificial acquired active immunity' (March 2016).

2. Blood Groups and Blood Transfusion

  • Explain the ABO blood group system in humans with a suitable chart (March 2017).
  • With the help of a chart, explain the compatibility of human blood groups (March 2015).
  • Complete the following chart and rewrite (Blood groups, Genotype, Antigens, and Antibodies) (July 2022, Oct. 2021).

3. Diseases and Their Causative Agents 

  • Give the causative agent, mode of transmission, and symptoms of typhoid (March 2022).
  • Name the causative organism of malaria. State any two symptoms and preventive measures (March 2020).
  • Name the disease caused by HPV (March 2023).

4. Cancer and Tumors

  • Enlist the various types of cancer (March 2015).
  • Name the process in which a tumor successfully spreads to other parts of the body, grows, and destroys healthy tissue (July 2019).

5. Vaccination and Immunization

  • Mention the first vaccine developed against any human disease (July 2017).
  • How are 'melt-in-mouth' vaccines administered? Mention two benefits (July 2022).

6. Drugs and Their Effects on Health

  • Give the adverse effects of opioids, cannabinoids, and morphines on human health (March 2013).

7. Miscellaneous

  • Give any two unique features of acquired immunity (July 2016).
  • Sketch a labelled diagram of the causative organism of typhoid (July 2017).
  • Give the symptoms of typhoid fever (July 2017).
Chapter 11: Enhancement in food production

1. Biotechnology Applications and Techniques

  • Give applications of mutation breeding (March 2013).
  • Describe any two applications of tissue culture technique (March 2014).
  • Give the importance of heterocyst in cyanobacteria (March 2014).
  • What is biofortification? (Oct. 2015, March 2019).
  • What is tissue culture? Describe the methodology of tissue culture (March 2015).
  • Give an account of various steps involved in tissue culture (July 2019).
  • What is the composition of bio-gas? Mention any four benefits of bio-gas (March 2023).

2. Microbial Biotechnology

  • What is biopatent? Give examples (March 2014).
  • What is Mycoherbicide? (March 2016).
  • What is biopatent? Explain it with a suitable example (March 2017).
  • What is fermentation? Write the names of substrates for alcoholic and lactic acid fermentation (July 2019).
  • What are the advantages of single-cell protein (SCP)? (Oct. 2013).
  • What is the microbial source of Vitamin B12? (March 2018).
  • What are the requirements for dairy management? Give one example of each Indian and exotic breed of cow (March 2020).

3. Biocontrol and Biofertilizers

  • What are biocontrol agents? Mention any two groups of biocontrol agents and their hosts (March 2013).
  • Give two types of fungal biofertilizers (March 2019).
  • What is VAM? (July 2016).
  • Explain the role of VAM related to soil fertility (Oct. 2015).
  • Name the aquatic fern commonly used in paddy fields as a biofertilizer (July 2017).

4. Sewage Treatment and Microbial Pesticides

  • Explain the role of microbes in sewage treatment (Oct. 2015).
  • Give two examples of microbial pesticides with their hosts (March 2018).

5. Gibberellins, Heterocyst, and Methanogenesis

  • What are gibberellins? Give their applications (Oct. 2014).
  • What is heterocyst? (July 2017).
  • Explain the biogas production process with a labelled figure (July 2018).
  • Explain the stages of biogas production (Methanogenesis) (Oct. 2021).

6. Miscellaneous

  • Name the strain of yeast used in industrial production of wine (July 2018).
  • What is primary treatment of sewage? (March 2018).
  • Give the names of 'two' insect-resistant crop varieties (July 2017).
  • What is the role of microbes in sewage treatment? (Oct. 2015).

7. Match the Following

  • Match the following (e.g., Invertase, Lipase, Cellulase, Pectinase) (July 2019).
  • Match the following microbial sources of products like Vitamin B2, Fumaric acid, Lipase, etc. (March 2022).

Chapter 12: Biotechnology

1. DNA Profiling, PCR, and Genetic Techniques

  • Enlist the steps involved in solving disputed parentage by DNA Profiling (March 2013).
  • What is palindrome in DNA? (March 2013).
  • Draw a neat labelled diagram showing steps of PCR (March 2013).
  • Describe the steps of PCR technique (Oct. 2015, March 2018).
  • Give the applications of PCR technique (Oct. 2014).
  • Enlist the basic steps involved in recombinant DNA technology (March 2018).
  • With the help of a suitable example, illustrate Palindrome (July 2018).

2. Genetic Engineering Applications

  • What is Vaccine? (Oct. 2013, 2014).
  • Give applications of a vaccine (March 2014).
  • What is the use of tissue plasminogen activator? (March 2014).
  • What is the goal of Human Genome Project (HGP)? (Oct. 2014).
  • Give the significance of transgenic animals (Oct. 2015).
  • Describe the steps in recombinant DNA technology (March 2015).
  • Give any two examples of therapeutic products produced by r-DNA technology (March 2016).
  • Give the importance of transgenic animals (March 2016).
  • Write benefits of transgenic animals (March 2018).
  • Give the types of blood proteins and human hormones produced by recombinant DNA-technique (March 2019).
  • Name the first transgenic plant (March 2023).

3. Gene Therapy, Transgenic Organisms, and Biotechnology

  • Enlist the genes used in gene therapy (Oct. 2013).
  • Illustrate any 'three' genes used in gene therapy (March 2016).
  • What are transgenic plants? Explain with any two examples (July 2016).
  • What are plasmids? (July 2017).
  • What are transgenic animals? Explain with examples (March 2019).
  • Explain the benefits of transgenic animals for the betterment of life (July 2016).

4. Biosafety and Biotechnological Issues

  • Explain different biosafety issues that may arise due to genetically modified (GM) organisms (Oct. 2014).
  • Explain any three examples of biopiracy (March 2022).

5. Therapeutic Applications and Bioproducts

  • Name the enzyme responsible for delay in the ripening of tomato fruit (March 2015).
  • Name one therapeutic product of blood proteins made by using r-DNA technology (July 2018).
  • Classify the given proteins produced by rDNA technology to treat various diseases in humans (July 2022).

6. Human Health and Biotechnology

  • What are the effects of biotechnology in relation to human health? (March 2022).
  • What is polymerease chain reaction (PCR)? Describe the three steps involved in the mechanism of PCR (March 2023).

7. Miscellaneous Biotechnology Concepts

  • What is restriction digestion? (March 2014).
  • What does the abbreviation HGP stand for? (March 2015).
  • What is Bacteriophage? (July 2016).
  • Describe the lytic cycle with a labelled diagram (July 2017).
  • What is the meaning of Nif gene? (July 2017).

8. Vaccine Production

  • Write in brief about the production of vaccines (March 2022).
Chapter 13: Organism and Population

1. Population Ecology & Natality

  • Define the term 'natality'. How is natality calculated? (March 2013).
  • Define the term natality. (July 2016).
  • State the formula to calculate natality. (July 2018).
  • Distinguish between Natality and Mortality (March 2015).
  • Describe steady population with the help of a pyramid. (March 2022).
  • With the help of a pyramid, describe the growing population. (July 2016).
  • Identify 'A' in the given graph of population growth (Lag Phase) (March 2023).

2. Interactions Among Species

  • Define commensalism. (March 2013).
  • What is 'Commensalism'? (March 2017).
  • Give any two examples of commensalism. (July 2016).
  • With the help of a suitable example, explain the concept of commensalism. (July 2017).
  • Name the interaction in:
  • Lichen (July 2019)
  • Sucker fish and shark (July 2019)
  • A protozoan living in the digestive tract of a flea living on a dog (July 2019).
  • What type of interaction does the given diagram indicate? Write a note on the same. (July 2022).

3. Adaptations

  • Write a note on desert adaptations. (March 2014).
  • Give the adaptations shown by desert animals. (March 2022).

4. Population Pyramid & Age Structure

  • Describe steady population with the help of a pyramid. (March 2022).
  • Describe diagrammatic representation of age structure showing declining population. (March 2017).
  • With the help of suitable diagrams, explain how age structures determine the trend of population. (July 2017).
  • Draw a diagram showing the growing population. (July 2016).

5. Types of Interactions: Parasitism & Others

  • Define parasitism and give any 'two' types with suitable examples of each. (March 2018).

6. Abiotic Factors & Population Growth

  • Which are the major abiotic factors that influence habitat? (July 2022).

7. Population Growth Phases

  • Identify 'A' in the given graph of population growth - Lag Phase (March 2023).
Chapter 14: Ecosystem and Energy flow

1. Biogeochemical Cycles

  • Define the term 'leaching'. (March 2013, 2018).
  • Give schematic representation of the carbon cycle. (March 2013, 2017).
  • Explain 'Carbon cycle'. (March 2016).

2. Ecosystem Productivity

  • Explain the concept of primary productivity. (Oct. 2013).
  • Define the terms:
  • Gross primary productivity (March 2023).
  • Net primary productivity (March 2023).

3. Ecological Services

  • Mention any two ecological services for the benefit of mankind. (March 2015).

4. Ecological Structure

  • Give diagrammatic representation of the pyramid of numbers. (Oct. 2015).
  • Explain energy pyramid. (March 2018).
  • Give scientific reasons:
  • The pyramid of energy is always upright. (March 2019).
  • In an ecosystem, the energy flow is always unidirectional. (March 2019).

5. Decomposers & Hazardous Effects

  • What is the role of decomposers in an ecosystem? (July 2016).
  • Give the hazardous effects of agrochemicals. (July 2016).

6. Ecological Succession

  • What is ecological succession? (Oct. 2015, March 2016, July 2016).
  • What is meant by ecological succession? (March 2017).
  • Name various seral stages from pioneer species to climax community with a suitable example in hydrarch succession. (March 2022).
  • Write down various sequential stages of hydrarch succession in plants after the phytoplankton stage. (July 2022).
  • What do you mean by Pioneer species? (March 2022).

7. Humification

  • What is Humification? (March 2016).

8. Lichen and Weathering

  • Name the type of Lichen responsible for weathering of rocks and soil formation. (Oct. 2021).

9. Energy Flow and Trophic Levels

  • Complete the following chart regarding energy flow in an ecosystem and rewrite. (March 2022).
Chapter 15: Biodiversity, Conservation and Environmental issue

1. Ecology and Environment

  • Define 'natality' and how it is calculated.
  • What is biomagnification?
  • Define 'greenhouse effect.'
  • Global warming and the greenhouse effect.
  • What is bioaccumulation?
  • Greenhouse gas responsible for global warming.
  • Effects of agrochemicals.
  • How does depletion of ozone affect living organisms?
  • "Ozone in stratosphere is good ozone" - scientific reason.

2. Pollution and Health

  • Effects of water pollution on human health.
  • Effects of air pollutants on human health.
  • Pollution definition – industries pouring poison in water.

3. Conservation and Biodiversity

  • What is 'deforestation' and its effects?
  • Suggest measures to conserve forests.
  • Biodiversity hotspots – number worldwide.

4. In-situ and Ex-situ conservation.

  • What is ex-situ conservation? Name two places.
  • Human Impact on Environment

5. Bioaccumulation effects.

  • Types of air pollutants (Fine vs Coarse).
  • Forest reserves and tiger conservation.

All the Best

Chapter wise notes:

 Biology Notes: