Midterm Exam 2025: Important Questions for Second PUC Biology
- To score 50-60 marks, or potentially 70/70, students should thoroughly study the important questions and topics discussed.
- The video covers important questions from seven chapters, including HOTS questions, diagrams, and questions for one, two, three, and five marks.
Chapter 1: Sexual Reproduction in Flowering Plants
- This chapter is expected to have HOTS (Higher-Order Thinking Skills) questions, typically for five marks.
- HOTS questions are often twisted, requiring a deep understanding of concepts rather than direct recall.
Key Topics for HOTS and Five-Mark Questions
- Artificial Hybridization
- Double Fertilization
- Pollen Pistil Interaction
- Outbreeding Devices
- Development of Embryo Sac: Including how an 8-celled, 7-nucleated embryo sac forms.
- Pollination and its Types: Autogamy, Geitonogamy, and Xenogamy.
- Adaptations of Insect-Pollinated Flowers and Wind-Pollinated Flowers.
One-Mark Questions
- Functions of: Tapetum, Nucellus, Filiform Apparatus, and Endosperm.
- Ploidy of Cells After Fertilization:
- The central cell becomes triploid () due to fusion with a male gamete.
- The egg cell becomes diploid ().
- Definitions with Examples:
- Perisperm and Pericarp.
- False Fruits (e.g., Apple, Strawberry), noting the part from which they develop (e.g., Apple from Thalamus).
- Apomixis (meaning, examples, significance).
- Polyembryony (meaning, example).
- Parthenocarpy (meaning, example).
Two and Three-Mark Questions
- Four Wall Layers of Microsporangium.
- Advantages of Seeds to Angiosperms.
- Water Pollination in Vallisneria.
- Stages of Embryo Development: Such as globular and heart-shaped stages.
- Difference between Autogamy, Geitonogamy, and Xenogamy:
- Xenogamy shows genetic variation as pollination occurs between different plants.
- Autogamy (pollination within the same flower) and Geitonogamy (pollination between different flowers on the same plant) do not show genetic variation.
- Difference between Albuminous and Non-Albuminous Seeds with examples.
- Viability and Use of Pollen Grains.
- Microsporogenesis and Megasporogenesis: Including the number of pollen grains from a microspore or female gametophytes from a megaspore.
Very Important Diagrams
- Microsporangium
- Megasporangium
- Mature Embryo Sac (can be for three marks)
- Stages of Development of Embryo Sac
- Dicot Embryo and Monocot Embryo
- Pollen Grain (can be for two or three marks)
Chapter 2: Human Reproduction
- This chapter does not typically feature HOTS questions.
Key Diagrams (Five-Mark Questions)
- Male Reproductive System
- Female Reproductive System
- Mammary Gland (frequently asked)
- Human Sperm (can be for three marks), including functions of parts like Acrosome and Mitochondria.
- Seminiferous Tubule (can be for three marks).
Five-Mark Questions
- Phases of Menstrual Cycle with Hormones: Explain changes and hormones released in each phase.
One to Three-Mark Questions
- Hormones of Ovulation, Pregnancy, and Parturition.
- Definitions of Spermiogenesis and Spermiation (differentiate between them).
- Definition of Implantation.
- Blastocyst (number of cells) and Trophoblast (definition).
- Colostrum (definition and importance for two marks).
- Accessory Ducts of Male Reproductive System.
- Accessory Glands and their functions.
- Reason for Testes Location Outside the Abdomen.
- Schematic Representation of Spermatogenesis and Oogenesis (very important for three marks).
- Difference between Spermatogenesis and Oogenesis (can be a five-mark question).
- Functions of Placenta and Hormones Released by Placenta (for three marks).
- Hormonal Regulation of Spermatogenesis (two or three marks, rarely asked).
- Foetal Ejection Reflex: Mechanism, signal origin, and associated hormones (can be asked in MCQs).
Chapter 3: Reproductive Health
- This is a simple and scoring chapter, focusing on one, two, and three-mark questions, with no five-mark questions.
Key Topics
- Natural Birth Control Methods: Meaning of Periodic Abstinence, Coitus Interruptus, and Lactational Amenorrhea (can be asked in MCQs).
- Intrauterine Devices (IUDs): Definition, types (Copper-releasing, Non-medicated, Hormonal) and their working mechanisms (e.g., how Copper-releasing IUDs function).
- Barrier Methods: Examples for males and females.
- Surgical Methods: Vasectomy (males) and Tubectomy (females).
- Difference between Tubectomy and Vasectomy.
- Features of an Ideal Contraceptive.
- Reasons for Population Explosion.
- Natality and Mortality (definitions).
- Medical Termination of Pregnancy (MTP): Definition, conditions, and when it was legalized (can be asked in MCQs).
- Sexually Transmitted Diseases (STDs): Examples, prevention methods, and especially non-curable STDs (very important for MCQs).
- Assisted Reproductive Technologies (ARTs): Understanding the meaning of all sub-topics (important for MCQs and potentially a five-mark question in midterms).
Chapter 4: Principles of Inheritance and Variation
- This is a very important chapter, with two five-mark questions expected, one of which will be a HOTS question.
Key Topics for HOTS and Five-Mark Questions
- Dihybrid Cross (more common for HOTS).
- Incomplete Dominance (questions are often twisted).
- Blood Grouping Questions.
- Sickle Cell Anemia: Questions regarding the globin chain, amino acid change, codon change, and affected individuals.
- Mendelian Disorders: Hemophilia, Thalassemia, Color Blindness, PKU (causes, symptoms; can be three marks).
- Sex Determination in Man and Honeybee.
- Morgan's Experiment on Linkage and Recombination and its results.
One to Three-Mark Questions
- Chromosomal Disorders: Karyotype (very important for MCQs) and symptoms of Down's, Klinefelter's, and Turner's Syndromes.
- Definitions with Examples (possible MCQs):
- Pleiotropy, Polygenic Inheritance, Codominance, Multiple Alleles.
- Male Heterogamety, Female Heterogamety.
- Male Heterogamety, Female Heterogamety.
- Pedigree Symbols: Especially for consanguineous mating (marriage between relatives).
- Three Laws of Mendel: Law of Dominance, Law of Segregation, and Law of Independent Assortment.
- Linkage and Recombination (definitions).
- Reasons for Morgan's Selection of Drosophila.
- Difference between Homozygous and Heterozygous Conditions.
- Test Cross: Definition, importance, and why it is performed.
Chapter 5: Molecular Basis of Inheritance
- This is a very important chapter, with two five-mark questions expected, one of which will be a HOTS question.
Key Topics for HOTS and Five-Mark Questions
- Transcription Unit: Components and diagram (previously three marks, now HOTS five marks).
- Packaging of DNA: Nucleosome model (previously three marks, now HOTS five marks).
- Lac Operon (was a five-mark question, can now be HOTS).
- Salient Features of DNA (five features).
- Features of Genetic Code (five features).
- Salient Features of Human Genome Project (HGP).
- Steps of DNA Fingerprinting.
Two and Three-Mark Questions
- Criteria for Genetic Material and why DNA is a better genetic material than RNA.
- Post-Transcriptional Modifications: Splicing, Capping, and Tailing (can be asked in MCQs).
- RNA Polymerase Division of Labor: How RNA Polymerase I, II, and III transcribe different RNAs.
- Dual Function of AUG Codon: It acts as a start codon and codes for the amino acid Methionine.
- Nucleosome Diagram (two or three marks).
- Difference between Euchromatin and Heterochromatin.
- Chargaff's Rule: Definition and problems (e.g., calculating percentage of Guanine/Cytosine if Adenine is given in MCQs).
- Goals of HGP (rarely asked).
Experiments (Often Asked in MCQs)
- Griffith's Experiment
- Hershey-Chase Experiment
- Meselson-Stahl Experiment
- Oswald Avery's Experiment
- Questions may focus on the organisms used, scientists involved, results, and conclusions.
Chapter 6: Evolution
- A five-mark question can be expected in the midterm exam, but not usually in the main exam.
Key Topics for Five-Mark Questions
- Miller's Experiment (diagram, can also be three marks).
- Difference between Homologous and Analogous Organs (specific plant or animal examples may be requested).
- Convergent Evolution and Divergent Evolution with examples.
- Adaptive Radiation (definition and example).
Two and Three-Mark Questions
- Hardy-Weinberg Principle: Definition and equation.
- Factors Affecting Hardy-Weinberg Equilibrium (most frequently asked two-mark question).
- Industrial Melanism in England: Explanation of dark and white-winged moths.
One to Three-Mark Questions (Potential MCQs)
- Evolution of Man: Stages in chronological order (Dryopithecus, Ramapithecus, Australopithecus to Homo sapiens).
- Brain Capacity and specific features of human ancestors (can be asked in MCQs).
- Evidences for Evolution: Paleontological and Embryological Evidences.
- Lamarck's Theory (Theory of Acquired Inheritance).
- Darwin's Natural Selection Theory.
Chapter 7: Human Health and Diseases
- This chapter is very important if included in the midterm syllabus, with HOTS questions expected.
Key Topics for HOTS and Five-Mark Questions
- Diseases: Symptoms, causative organisms, and modes of infection for all diseases.
- Drugs: Source (scientific and common names) and their effects.
- Prevention Methods.
- Replication of HIV Retro Virus (diagram).
- Plasmodium Life Cycle (diagram, rarely asked but review).
One to Three-Mark Questions
- Antibody Diagram (two marks).
- Types of Innate Immunity Barriers.
- Difference between Active and Passive Immunity.
- Malignant vs. Benign Tumor (identify which is more fatal).
- Allergy: Antibody produced and chemical secreted during an allergic reaction.
- Cancer: Detection methods and treatment methods.
- Carcinogens: Definition and types.
- AIDS Prevention Methods.
- Infective Stage of Plasmodium.
- Chemical Secreted by Plasmodium upon RBC Rupture.
- Tests for Detection: AIDS (ELISA Test) and Typhoid (Widal Test) (can be asked in MCQs).
- Primary Lymphoid Organs (name them).
- Secondary Lymphoid Organs (name them).
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