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Free Biology shorts

जीव विज्ञान · حیاتیات

24 topics, each a handful of cards plus practice questions with explanations. Free to read in full — no sign-up. Counts for TRE-4, STET, BPSC PCS, CTET, RRB NTPC, SSC CGL.

24 shorts · 192 practice questions

• Animal Kingdom: One-Line Identifiers and the 'Not a Fish' Trapsजंतु जगत: एक पंक्ति की पहचान और 'मछली नहीं है' के जालEvery animal-classification question is answered by one identifying feature per group — stinging cells, flame cells, water vascular system, chambers of the heart. Learn nine phyla and five vertebrate classes as one-line tags and the 'jellyfish is not a fish' traps stop working.6 CARDS · 8 QUESTIONS
• Biomolecules: Carbohydrates, Proteins, Lipids, Enzymes and the Food Testsजैव-अणु: कार्बोहाइड्रेट, प्रोटीन, वसा, एंज़ाइम और भोज्य परीक्षणWhich sugar is in milk, which bond joins amino acids, which enzyme works in the stomach and which test turns purple: the biomolecule facts exams love, in one short.6 CARDS · 8 QUESTIONS
• Biotechnology — Tissue Culture, Bt Cotton, Dolly and DNA Fingerprintingजैव प्रौद्योगिकी — ऊतक संवर्धन, बीटी कपास, डॉली और डी.एन.ए. फ़िंगरप्रिंटिंगFour real cases carry this whole topic: banana plants grown from a few cells, cotton given a bacterial gene, a cloned sheep named Dolly, and a test that identifies a person from a drop of blood.6 CARDS · 8 QUESTIONS
• Blood and the Heart — Counts, Chambers, Valves and Blood Groupsरक्त और हृदय — गणना, कक्ष, कपाट और रक्त समूहAlmost every circulation question is a number or a pairing. RBC lives 120 days, WBC about 15; neutrophil is the most common WBC, monocyte the largest; LAB-RAT fixes the valves — Left Atrium Bicuspid, Right Atrium Tricuspid. O is the universal donor, AB the universal recipient. Pulmonary artery is the one artery with impure blood, pulmonary vein the one vein with pure. Numbers, mnemonics and the exact traps SSC CGL/CHSL, Railway NTPC, BPSC TRE-4, CTET and UPSC set on them.6 CARDS · 8 QUESTIONS
• Cell Division: Mitosis vs Meiosis, Chromosome Counts, Phases and the Where-and-Why Tableकोशिका विभाजन: समसूत्री बनाम अर्धसूत्री, गुणसूत्र संख्या, अवस्थाएँ और कहाँ-क्यों की तालिकाMitosis copies a cell (2n to 2n, two cells); meiosis halves it (2n to n, four cells). Learn the phases, the counting formulas and the swap that creates variation.6 CARDS · 8 QUESTIONS
• Classification of Living Organisms — Five Kingdoms, the Taxonomic Ladder and Binomial Nomenclatureजीवों का वर्गीकरण — पाँच जगत, वर्गीकरण की सीढ़ी और द्विनाम पद्धतिWhittaker's five kingdoms are not five lists to memorise — they are four questions asked in order: is the cell prokaryotic, is the body one cell or many, how does it get food, and what is the cell wall made of. Answer those and any organism sorts itself.6 CARDS · 8 QUESTIONS
• Ecosystem and Environment — Food Chains, the 10% Law, the Nutrient Cycles and the Ozone Hole Caseपारितंत्र एवं पर्यावरण — आहार शृंखला, 10% नियम, पोषक चक्र और ओज़ोन छिद्र का प्रकरणEnvironment questions are the cheapest marks in the general science section and students still lose them, because the chapter is taught as vocabulary and tested as relationships. An ecosystem is producers, three ranks of consumers and decomposers, joined by food chains into a web. Only about 10% of energy crosses each trophic level — Lindeman's law — which is why no chain runs beyond four or five links, and why the pyramid of energy is the only pyramid that is always upright. The nitrogen cycle is four named bacterial jobs, not one. Then two documented cases the papers keep returning to: DDT climbing a food chain, and the Antarctic ozone hole that produced the Montreal Protocol of 1987.6 CARDS · 8 QUESTIONS
• Endocrine Glands and Hormones — Which Gland, Which Hormone, Which Diseaseअंतःस्रावी ग्रंथियाँ और हार्मोन — कौन-सी ग्रंथि, कौन-सा हार्मोन, कौन-सा रोगEndocrine glands are ductless and pour hormones straight into the blood; pancreas and gonads do both jobs, so they are mixed glands. Pituitary is the master gland and the smallest; thyroid is the largest. Growth hormone gives dwarfism, gigantism and acromegaly; thyroxine gives goitre, cretinism in children and myxoedema in adults. Parathormone raises blood calcium, calcitonin lowers it. Insulin from beta cells lowers blood sugar, glucagon from alpha cells raises it. Read the second word in 'diabetes' — mellitus is insulin, insipidus is ADH.6 CARDS · 8 QUESTIONS
• Evolution — Lamarck, Darwin, de Vries, and the Five Kinds of Evidenceजैव विकास — लैमार्क, डार्विन, डी व्रीज़, और प्रमाण के पाँच प्रकारThree men proposed three mechanisms and only one survived testing. Learn evolution as theory-plus-test — Lamarck disproved by a rat-tail experiment, Darwin confirmed by fossils and moths — and the name-matching questions answer themselves.6 CARDS · 8 QUESTIONS
• Heredity — Mendel's Pea Experiment, 3:1 vs 1:2:1, and Who Decides a Baby's Sexआनुवंशिकता — मेंडल का मटर प्रयोग, 3:1 बनाम 1:2:1, और शिशु का लिंग कौन तय करता हैOne monk, one garden, seven pairs of pea traits, and eight years of counting produced the whole of classical genetics. Learn why Mendel chose the pea, what 3:1 and 1:2:1 actually count, why the dihybrid gives 9:3:3:1, and why the father — never the mother — determines a child's sex. That set answers nearly every heredity question in SSC, Railway NTPC, BPSC TRE-4, CTET and UPSC prelims.6 CARDS · 8 QUESTIONS
• Human Diseases — Which Pathogen, Which Vector, Which Vaccineमानव रोग — कौन-सा रोगाणु, कौन-सा वाहक, कौन-सा टीकाAlmost every disease question is one of three: what causes it, what carries it, what prevents it. Sort the diseases into bacterial, viral, protozoan and worm columns once, and the whole chapter collapses into a table you can recall in seconds.6 CARDS · 8 QUESTIONS
• Life Processes — Respiration, Transport and Excretion: Which Organ Does Whatजैव प्रक्रम — श्वसन, परिवहन एवं उत्सर्जन: कौन-सा अंग क्या करता हैBreathing is physical, respiration is chemical; aerobic gives about 38 ATP and anaerobic about 2; yeast makes ethanol while human muscle makes lactic acid; the pulmonary artery is the one artery carrying deoxygenated blood; xylem is one-way and passive while phloem is two-way and active; and the kidney's filtering unit is the nephron, not the neuron. Every pair the exam swaps, laid out side by side.6 CARDS · 8 QUESTIONS
• Living Together: Mutualism, Commensalism, Parasitism and Insectivorous Plantsसाथ-साथ जीना: सहोपकारिता, सहभोजिता, परजीविता और कीटभक्षी पौधेWhich partnership helps whom? A plus-minus-zero map of mutualism, commensalism, parasitism, competition and amensalism, with the plant examples exams love.6 CARDS · 8 QUESTIONS
• Microorganisms: Bacteria, Viruses, Fungi, Protozoa and Algae and the Useful Microbes Exams Askसूक्ष्मजीव: जीवाणु, विषाणु, कवक, प्रोटोज़ोआ और शैवाल तथा परीक्षाओं में पूछे जाने वाले उपयोगी सूक्ष्मजीवFive microbe groups, who does what: Lactobacillus makes curd, yeast ferments, Penicillium gave penicillin, Rhizobium fixes nitrogen, Plasmodium causes malaria. Know the traps: viruses are not cells and antibiotics do not touch them.6 CARDS · 8 QUESTIONS
• Nutrition and the Balanced Diet — Calorific Values, BMI and the Deficiency Mapपोषण एवं संतुलित आहार — कैलोरी मान, बी.एम.आई. और कमी से होने वाले रोगों का नक्शाNutrition is half recall and half arithmetic. Three numbers — 4, 4 and 9 kcal per gram — answer every energy question, one formula (weight in kg over height in metres squared) answers every BMI question, and the swelling-versus-wasting test separates kwashiorkor from marasmus in a single word.6 CARDS · 8 QUESTIONS
• Plants — Photosynthesis, Xylem vs Phloem and the Five Hormonesपौधे — प्रकाश संश्लेषण, जाइलम बनाम फ्लोएम और पाँच हार्मोनThe photosynthesis equation and why the oxygen comes from water, the light and dark reactions and where each happens, xylem versus phloem in one table, transpiration pull versus guttation, and the five plant hormones with the job each one does. Written for the general-science sections of BPSC TRE-4, CTET, SSC CGL/CHSL, Railway NTPC and UPSC Prelims.6 CARDS · 8 QUESTIONS
• Reproduction in Plants and Animals — Asexual Modes, Flower Parts, Pollination and Fertilisationपौधों और जंतुओं में जनन — अलैंगिक विधियाँ, पुष्प के भाग, परागण और निषेचनThis chapter is a pairing exercise, not a theory chapter: organism to mode, plant to the part it grows from, pollinator to its flower. Learn the pairs — Amoeba to fission, yeast to budding, potato to stem tuber, Vallisneria to water — and the one-markers stop being guesses.6 CARDS · 8 QUESTIONS
• The Cell — Organelles and Who Discovered Whatकोशिका — कोशिकांग और किसने क्या खोजाMitochondria the powerhouse, ribosome the protein factory, lysosome the suicide bag. Learn the nicknames and the questions answer themselves.6 CARDS · 8 QUESTIONS
• The Human Digestive System — Which Enzyme Acts Whereमानव पाचन तंत्र — कौन-सा एंजाइम कहाँ काम करता हैSalivary amylase, pepsin and rennin, bile without a single enzyme, trypsin activated by enterokinase, and vitamin K made in the large intestine — the enzyme-to-place map that answers almost every digestion question in SSC, Railway, CTET and teacher-recruitment papers.6 CARDS · 8 QUESTIONS
• The Human Eye and Ear — Structure, Function and the Defects Exams Testमानव आँख और कान — संरचना, कार्य और वे दोष जो परीक्षाएँ पूछती हैंThe eye and ear are the two most exam-favourite sense organs, because they combine memorable parts (iris, cochlea, the three smallest bones in the body) with clean numbers (20 Hz–20,000 Hz) and a trap that catches almost everyone: mixing up myopia's concave-lens fix with hypermetropia's convex-lens fix.6 CARDS · 8 QUESTIONS
• The Nervous System — Brain Parts, the Neuron and Why Reflexes Skip the Brainतंत्रिका तंत्र — मस्तिष्क के भाग, न्यूरॉन और प्रतिवर्ती क्रिया मस्तिष्क तक क्यों नहीं जातीCerebrum thinks, cerebellum balances, medulla keeps you breathing, hypothalamus sets your temperature — and the spinal cord alone handles reflexes. Plus the neuron, the synapse, 12 cranial and 31 spinal nerve pairs, and the trap questions built on each.6 CARDS · 8 QUESTIONS
• The Skeletal System — 206 Bones, Every Record-Holder and the Five Jointsकंकाल तंत्र — 206 हड्डियाँ, हर रिकॉर्ड और पाँच प्रकार के जोड़This is a pure recall block, so the marks go to whoever has the numbers ready: 206 bones in an adult against about 300 at birth, 80 axial and 126 appendicular, 22 in the skull, 26 vertebrae, 12 pairs of ribs. Plus every record-holder papers ask for — femur the longest, stapes the smallest, hyoid the one bone attached to no other — and the five movable joints with the exact traps SSC, Railway NTPC, BPSC TRE-4, CTET Paper 2 and UPSC set on them.6 CARDS · 8 QUESTIONS
• Tissues — Plant and Animal: Meristem, Parenchyma, Xylem, Phloem and the Four Animal Tissuesऊतक — पादप एवं जंतु: विभज्योतक, मृदूतक, दारु, पोषवाह तथा चार जंतु ऊतकBlood is a connective tissue, cardiac muscle is striated but involuntary, and phloem is alive except its fibres. Three sentences that decide most tissue questions in SSC, Railway and TET papers.6 CARDS · 8 QUESTIONS
• Vitamins — Chemical Names, Deficiency Diseases and the ADEK Trickविटामिन — रासायनिक नाम, कमी से होने वाले रोग और ADEK की युक्तिOne table decides two to three marks in every general science paper: which vitamin is fat-soluble, what each one is chemically called, and which disease its absence causes — plus the four swaps examiners keep using to make you lose the mark.6 CARDS · 8 QUESTIONS