2nd PUC Preparatory Marathon | Biology | Most Important Questions & PYQ's🔥🔥

TLDR;

This YouTube video by PW Kannada is a marathon session aimed at helping students prepare for their preparatory and annual exams in Second PUC Biology. The session covers important questions and concepts from both Zoology and Botany, emphasizing key terminology, diagrams, and high-weightage chapters. The speaker also provides tips on how to approach different types of questions, including MCQs, and stresses the importance of following the blueprint while preparing.

Focus on high-weightage chapters for efficient scoring.
Underline key biological terms for better understanding and MCQ preparation.
Follow the blueprint but understand the concepts thoroughly.
Practice diagrams for potential five-mark questions.

Greetings and Session Overview [0:03]

The session begins with greetings and an overview of the topics to be covered, including Zoology and Botany. The speaker mentions that the session will last approximately six hours, covering important two-mark, three-mark, and five-mark questions, as well as some MCQs. The speaker encourages students to follow the session closely to score well in their preparatory and annual examinations.

Importance of Blueprint and High-Weightage Chapters [4:47]

The speaker emphasizes the importance of following the blueprint for the examination, noting that while there might be a 5-10% variation, it is still a crucial guide. Knowing which chapters have high weightage and which chapters produce five-mark questions can significantly aid in preparation. The speaker mentions that focusing on just five to six chapters out of thirteen can help students score around 50 marks.

Zoology Blueprint Discussion [6:08]

The speaker begins discussing the Zoology portion of the blueprint, highlighting high-weightage chapters such as "Sexual Reproduction in Flowering Plants" (11 marks) and "Human Reproduction" (10 marks). For "Human Reproduction," a diagram is compulsory, and the remaining marks are divided into three-mark, two-mark, or multiple-choice questions. The chapters "Principles of Inheritance" and "Molecular Basis of Inheritance" together account for 26 marks, with two five-mark questions expected from each chapter. "Reproductive Health" carries six marks, with questions divided into three-mark and two-mark segments, focusing on topics like contraceptives and assisted reproductive technologies. The "Evolution" chapter accounts for seven marks, with no five-mark questions, focusing instead on topics like the Stanley Miller experiment and homologous/analogous organs. "Human Health and Diseases" carries 11 marks, with one compulsory five-mark question, likely covering innate immunity, cancer diagnosis, or the life cycle of Plasmodium vivax. Biotechnology chapters will only have five-mark questions this year.

General Tips for Exam Preparation [3:31]

The speaker advises students to underline key terminologies while studying two-mark, three-mark, and five-mark questions, as these can be helpful for answering MCQs. The speaker cautions against treating MCQs as separate entities but rather integrating them into the overall study approach.

Question Paper Pattern [11:13]

The speaker outlines the question paper pattern, which includes MCQs and fill-in-the-blanks, two-mark and three-mark questions (with a choice to answer any five out of seven), and five-mark questions. The last main question will be more indirect and require a deeper understanding of the concepts.

Example Questions and Answers: Human Reproduction [14:27]

The speaker provides several example questions and explains how to approach them. These include:

Name the two layers of the blastocyst and write their significance: The two layers are the outer trophoblast and the inner cell mass. The trophoblast is responsible for implantation, while the inner cell mass develops into the embryo. A diagram may also be required.
What is the fetal ejection reflex, and how does it help in parturition?: The fetal ejection reflex is triggered by a fully developed fetus and the placenta, leading to mild uterine contractions. This triggers the maternal pituitary gland to release oxytocin, causing strong uterine contractions and the expulsion of the baby.
What are the phases of the menstrual cycle and the hormones that regulate it?: The phases are the menstrual phase, proliferative phase, ovulatory phase, and luteal phase. The hormones involved are LH, FSH, estrogen, and progesterone.
Describe the hormonal regulation of spermatogenesis: This involves the hypothalamus releasing GnRH, which stimulates the anterior pituitary to produce LH and FSH. LH acts on Leydig cells to produce androgens, while FSH stimulates Sertoli cells for spermatogenesis.
Write a brief note on the hormonal regulation of oogenesis: Oogenesis starts during the embryonic stage and is completed at fertilization. GnRH stimulates the anterior pituitary to release LH and FSH, which help in follicular growth and ovulation.
What is the placenta, and mention its functions?: The placenta is a structural and functional unit between the developing embryo and the maternal body. Its functions include providing nutrients and oxygen, removing carbon dioxide and waste, and acting as an endocrine tissue by producing hormones like hCG and estrogen.
Draw a neat labeled diagram of the human sperm: The diagram should include the head (acrosome and nucleus), neck, middle piece (mitochondria), and tail.
Draw a neat labeled diagram of the sectional view of the female reproductive system: The diagram should include the uterus, fallopian tubes, ovaries, cervix, and vagina.
Schematic representation of spermatogenesis: The process starts at puberty with spermatogonia undergoing mitosis to form primary spermatocytes (diploid). Meiosis I leads to secondary spermatocytes (haploid), and Meiosis II forms spermatids, which differentiate into spermatozoa.
Schematic representation of oogenesis: Oogenesis starts during the embryonic stage. Oogonia undergo mitosis to form primary oocytes, which are arrested in prophase I. After puberty, meiosis I completes, forming a secondary oocyte and a polar body. Meiosis II occurs only if fertilization takes place, resulting in an ovum and another polar body.
What is the menstrual cycle? Describe the various events that occur during the menstrual cycle: The menstrual cycle involves the menstrual phase (shedding of the endometrium), the follicular phase (follicular development), the ovulatory phase (release of the ovum), and the luteal phase (formation of the corpus luteum).

Example Questions and Answers: Reproductive Health [1:26:48]

What is MTP (Medical Termination of Pregnancy)? Mention the safe period for MTP: MTP is the intentional termination of pregnancy before full term. The safest period is during the first trimester (up to 12 weeks).
List any four ideal characteristics of a contraceptive and give an example of a barrier method of contraception: Ideal characteristics include being user-friendly, easily available, effective, reversible, and having minimal side effects. Examples of barrier methods are condoms and diaphragms.
What is amniocentesis? Give one reason for the statutory ban on amniocentesis: Amniocentesis is a fetal sex determination test based on chromosomal patterns in amniotic fluid. It is banned to prevent female feticide.
Name any two reproductive health problems faced in India: These include lack of awareness about personal hygiene, leading to STDs, and early marriage, leading to high maternal and infant mortality rates.
What is infertility? Mention any two techniques implemented in assisted reproductive technology: Infertility is the inability to conceive despite unprotected sexual cohabitation. Techniques include IVF (In Vitro Fertilization) and GIFT (Gamete Intra-Fallopian Transfer).

Example Questions and Answers: Evolution [1:59:46]

Mention any two examples of evolution by anthropogenic action: Examples include industrial melanism and the overuse of pesticides, leading to resistant varieties.
List the period, brain size, skeletal structure, and dietary preference of Homo habilis and Homo erectus: Homo habilis had a brain size of 650-800 cc, while Homo erectus had a brain size of 900 cc. Homo erectus was fully erect and consumed both meat and plants.
Differentiate between divergent and convergent evolution: Divergent evolution involves homologous organs with similar origins but different functions, while convergent evolution involves analogous organs with different origins but similar functions.
What are analogous organs? Give two examples: Analogous organs have different anatomical structures but perform similar functions. Examples include the wings of a butterfly and a bird, and the eyes of an octopus and a mammal.
State Hardy-Weinberg equilibrium or principle and list the factors affecting it: The principle states that allele frequencies in a population are stable and remain constant from generation to generation. Factors affecting it include gene flow, genetic drift, mutation, genetic recombination, and natural selection.
What is adaptive radiation? Give any two examples: Adaptive radiation is the evolutionary process where a single ancestral lineage evolves into a variety of different forms to occupy different ecological niches. Examples include Darwin's finches and the marsupials of Australia.
Give the diagrammatic representation of the Stanley Miller experiment: The diagram should include components like methane, ammonia, hydrogen, water vapor, electrodes, a condenser, and a liquid trap.

Example Questions and Answers: Human Health and Diseases [2:23:39]

Name the causative agents of Ascariasis and Malaria: Ascariasis is caused by Ascaris lumbricoides, and malaria is caused by Plasmodium species.
What is an allergy? Mention their symptoms: An allergy is an exaggerated response of the immune system to certain antigens. Symptoms include sneezing, watery eyes, and difficulty breathing.
Draw a neat labeled diagram of the structure of an antibody molecule: The diagram should include heavy chains, light chains, variable regions, constant regions, and disulfide bonds.
Differentiate between active and passive immunity: Active immunity develops after exposure to an antigen and is long-lasting, while passive immunity involves receiving ready-made antibodies and is short-lived.
What is a placenta? Mention the functions of the placenta: The placenta is a structural and functional unit between the developing embryo and the maternal body. Its functions include providing nutrients and oxygen, removing carbon dioxide and waste, and acting as an endocrine tissue by producing hormones like hCG and estrogen.
What are the different phases of the menstrual cycle and the hormones involved?: The phases are the menstrual phase, proliferative phase, ovulatory phase, and luteal phase. The hormones involved are LH, FSH, estrogen, and progesterone.
What is cancer? Mention the types of tumors: Cancer is uncontrolled cell division leading to tumor formation. The types of tumors are benign and malignant.
List any three characteristic features of cancer cells: These include uncontrolled cell division, loss of contact inhibition, and metastasis.
What are carcinogens? List their types: Carcinogens are agents that cause cancer. Types include chemical, physical, and biological carcinogens.
Name any three drugs and the plants from which they are extracted: Examples include morphine (from Papaver somniferum), cannabinoids (from Cannabis sativa), and cocaine (from Erythroxylum coca).
Explain the events of embryonic development: This includes fertilization, cleavage, morula formation, blastocyst formation, implantation, and the development of various organs during different trimesters.
Draw a neat labeled diagram of the male reproductive system: The diagram should include the testes, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, and penis.
Draw a neat labeled diagram of the female reproductive system: The diagram should include the ovaries, fallopian tubes, uterus, cervix, and vagina.
Draw a neat labeled diagram of the mammary gland: The diagram should include mammary lobes, alveoli, ducts, ampulla, and nipple.

Example Questions and Answers: Biotechnology [20:11]

What are the steps involved in PCR (Polymerase Chain Reaction) technique?: The steps are denaturation, annealing, and extension.
What are the methods to introduce alien DNA into the host cell?: Methods include chemical methods (using divalent cations) and physical methods (microinjection and biolistics).
Classify the restriction enzymes based on their action on DNA: Restriction enzymes are classified into endonucleases (which cut within the DNA) and exonucleases (which remove nucleotides from the ends of the DNA).
List any three tools used for recombinant DNA technology: Tools include restriction enzymes, DNA ligase, and vectors.
Explain the method of naming the restriction enzyme by giving an example: The naming convention includes the genus and species of the bacteria from which the enzyme is isolated, followed by the strain and the order of discovery. For example, EcoRI is from Escherichia coli.
Draw a neat labeled diagram of PBR322: The diagram should include the origin of replication (ori), antibiotic resistance genes (ampR and tetR), and restriction enzyme sites.
Explain the steps involved in the separation and isolation of DNA fragments by gel electrophoresis: The steps include cutting DNA into fragments, loading the fragments into a gel, applying an electric field, staining the gel with ethidium bromide, and visualizing the DNA bands under UV light.
What is a plasmid? A plasmid is an extrachromosomal, self-replicating, circular DNA molecule found in bacteria and some other microorganisms.
What are cloning vectors? List the salient features of a cloning vector: Cloning vectors are DNA molecules used to carry foreign DNA into a host cell. Salient features include an origin of replication, a selectable marker, and cloning sites.
Explain the steps involved in recombinant DNA technology: The steps include isolation of DNA, fragmentation of DNA, separation of DNA fragments, amplification of the gene of interest, ligation of DNA fragments into a vector, insertion of recombinant DNA into the host cell, culturing the host cells, and extraction and purification.
What is biopiracy? With reference to Basmati, explain: Biopiracy is the use of bio-resources by multinational companies without proper authorization from the countries or people concerned. The Basmati rice patent by an American company is an example.
Explain the structure of insulin: Insulin consists of two polypeptide chains (A and B) linked by disulfide bridges.
What are the steps involved in curing ADA deficiency by gene therapy?: The steps include isolating lymphocytes from the patient's blood, introducing a functional ADA gene into these cells using a retroviral vector, and reintroducing the genetically engineered lymphocytes into the patient's body.
Explain how Bt cotton is formed and how it helps in pest control: Bt cotton is formed by introducing Bt toxin genes from Bacillus thuringiensis into cotton plants. The Bt toxin kills specific pests when they ingest the cotton.
List five benefits of transgenic animals: Transgenic animals are used for studying normal physiology and development, studying diseases, producing biological products, testing chemical safety, and vaccine safety.

Example Questions and Answers: Microbes in Human Welfare [5:26:37]

What is BOD (Biochemical Oxygen Demand)? Mention its significance: BOD is the amount of oxygen required by microorganisms to decompose organic matter in a water sample. Its significance lies in indicating water quality and pollution levels.
Name the microbes responsible for the production of Swiss cheese and acetic acid: Swiss cheese is produced by Propionibacterium sharmanii, and acetic acid is produced by Acetobacter aceti.
How is secondary treatment of effluent carried out?: Secondary treatment involves passing the primary effluent into aeration tanks, where aerobic microbes consume organic matter, reducing BOD. The effluent is then transferred to settling tanks, where the flocs settle, and the treated water is released.
Explain the role of microbes as biocontrol agents: Microbes like ladybird beetles (controlling aphids), Bacillus thuringiensis (producing Bt toxin), and viruses (like baculoviruses) are used to control pests and diseases in plants.
What are biofertilizers? Give examples: Biofertilizers are organisms that enrich the nutrient quality of the soil. Examples include Rhizobium (nitrogen fixation in legumes), Azotobacter (free-living nitrogen fixer), and mycorrhiza (enhancing nutrient absorption).
List the different methods of household products: Microbes are used in making curd, cheese, dosa, idli, bread, and alcoholic beverages like toddy.

Botany Section Conclusion [3:54:54]

The speaker concludes the Zoology section and transitions to Botany, encouraging students to stay focused and noting that the Botany section will also cover important questions and diagrams.