Biology
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Quick Revision
Study MaterialBiology – Quick Revision
Biology is a crucial section in General Science for almost all competitive examinations including SSC, Banking, Railway, UPSC, Defence, Insurance, CAT, State PSC, and other government exams.
This quick revision guide covers important facts about Cell Biology, Genetics, Human Body Systems, Diseases, Nutrition, Plant Biology, and Ecology. It is designed for last-minute revision and quick recall of biology facts.
About This Quick Revision
Complete guide to Biology for competitive exams:
Cell Biology
- Cell Structure & Organelles
- Prokaryotic vs Eukaryotic
- Cell Division
- Mitosis & Meiosis
Genetics
- DNA & RNA Structure
- Genes & Chromosomes
- Mendel's Laws
- Mutation & Evolution
Human Body Systems
- Digestive, Respiratory
- Circulatory, Nervous
- Excretory, Endocrine
- Reproductive, Skeletal
Diseases
- Bacterial & Viral
- Fungal & Parasitic
- Deficiency Diseases
- Lifestyle Diseases
Nutrition
- Carbohydrates, Proteins
- Fats, Vitamins
- Minerals & Balanced Diet
- Calories & Nutrition
Plant Biology
- Photosynthesis
- Respiration
- Plant Hormones
- Reproduction
Ecology
- Ecosystem & Food Chain
- Biogeochemical Cycles
- Biodiversity
- Conservation
Important Scientists
- Darwin, Mendel
- Watson & Crick
- Louis Pasteur
- Alexander Fleming
Key Topics Covered
This quick revision guide covers important Biology topics for competitive exams:
| Category | Topic | Key Facts |
|---|---|---|
| Cell Biology | Cell Structure, Prokaryotic vs Eukaryotic, Cell Division | Cell = basic unit of life; Mitosis (somatic), Meiosis (gametes) |
| Genetics | DNA, RNA, Genes, Chromosomes, Mendel's Laws | DNA double helix (Watson & Crick); 23 pairs of chromosomes |
| Human Body Systems | Digestive, Respiratory, Circulatory, Nervous, Excretory, Endocrine | Heart pumps blood; Lungs for respiration; Brain controls body |
| Diseases | Bacterial, Viral, Fungal, Parasitic, Deficiency, Lifestyle | Malaria (Parasitic), TB (Bacterial), COVID-19 (Viral), Scurvy (Deficiency) |
| Nutrition | Carbohydrates, Proteins, Fats, Vitamins, Minerals | Balanced diet includes all nutrients; Vitamins A, B, C, D, E, K |
| Plant Biology | Photosynthesis, Respiration, Reproduction, Plant Hormones | Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ |
| Ecology | Ecosystem, Food Chain, Biogeochemical Cycles, Biodiversity | Food chain: Producer → Primary Consumer → Secondary Consumer |
| Scientists | Darwin, Mendel, Watson & Crick, Pasteur, Fleming | Darwin (Evolution), Mendel (Genetics), Pasteur (Germ Theory) |
Biology at a Glance
🧬 Cell Facts
Cell = Basic unit of life | Prokaryotic: No nucleus (Bacteria) | Eukaryotic: Nucleus present (Plants, Animals) | Mitochondria = Powerhouse
🧪 Important Vitamins
A (Night Blindness) | B1 (Beriberi) | B12 (Pernicious Anaemia) | C (Scurvy) | D (Rickets) | K (Bleeding disorder)
🧠 Human Body
Heart: 4 chambers | Lungs: 2 | Kidneys: 2 | Brain: 4 lobes | Blood: 7-8% of body weight | 206 bones in adult
🌿 Plant Facts
Photosynthesis: CO₂ + H₂O → Glucose + O₂ | Chlorophyll = green pigment | Plant hormones: Auxin, Gibberellin, Cytokinin
Quick Comparison: Human Body Systems
Quick Comparison: Vitamins & Deficiency Diseases
Why This Quick Revision is Important
Complete Biology Coverage
Covers Cell Biology, Genetics, Human Body Systems, Diseases, Nutrition, and Ecology.
Quick Reference Tables
Important vitamins, diseases, hormones, and body systems in easy-to-remember formats.
Exam-Oriented Facts
Focus on key definitions, functions, and diseases frequently asked in competitive exams.
High Exam Weightage
Biology questions appear frequently in all competitive examinations.
Competitive Exams Covered
- SSC CGL
- SSC CHSL
- SSC MTS
- Bank PO & Clerk
- IBPS Exams
- Railway Recruitment Exams
- UPSC CSAT
- Defence Exams
- Insurance Exams
- CAT
- State Government Exams
Quick Revision Examples
Question 1:
What is the basic unit of life and who discovered it?
Answer: Cell; Robert Hooke discovered it in 1665
Key Fact: The cell is the structural and functional unit of life. Robert Hooke first observed cells in a cork slice under a microscope in 1665.
Question 2:
What does DNA stand for and who discovered its structure?
Answer: Deoxyribonucleic Acid; Watson and Crick (1953)
Key Fact: DNA is the molecule that carries genetic information. James Watson and Francis Crick proposed the double helix structure of DNA in 1953.
Question 3:
What is the largest organ in the human body?
Answer: Skin
Key Fact: The skin is the largest organ of the human body, covering about 1.5-2 square meters. It protects the body from external factors, regulates temperature, and provides sensation.
Question 4:
What is the deficiency disease of Vitamin C and what are its sources?
Answer: Scurvy; Sources: Citrus fruits, Tomatoes, Green vegetables
Key Fact: Vitamin C is also called ascorbic acid. Its deficiency leads to scurvy, which causes bleeding gums, weakness, and joint pain.
Question 5:
How many blood groups are there and which is the universal donor and recipient?
Answer: 4 blood groups: A, B, AB, O; Universal Donor: O; Universal Recipient: AB
Key Fact: The ABO blood group system has four types. O negative is the universal donor, and AB positive is the universal recipient.
Question 6:
What is the equation for photosynthesis?
Answer: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂
Key Fact: Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight. Chlorophyll is the green pigment that captures sunlight.
Question 7:
How many chambers does the human heart have and what are they?
Answer: 4 chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle
Key Fact: The human heart has four chambers. The right side pumps deoxygenated blood to the lungs, and the left side pumps oxygenated blood to the body. The heart beats about 72 times per minute.
Question 8:
What causes malaria and how is it transmitted?
Answer: Caused by Plasmodium parasite; Transmitted by female Anopheles mosquito
Key Fact: Malaria is a parasitic disease caused by Plasmodium (P. vivax, P. falciparum, etc.). It is transmitted through the bite of infected female Anopheles mosquitoes.
Question 9:
What is the difference between DNA and RNA?
Answer: DNA is double-stranded with deoxyribose sugar; RNA is single-stranded with ribose sugar. DNA has thymine, RNA has uracil.
Key Fact: DNA stores genetic information, while RNA helps in protein synthesis. The sugar in DNA is deoxyribose; in RNA, it is ribose.
Question 10:
What is the function of the pancreas and which hormone does it secrete?
Answer: Pancreas secretes insulin and glucagon; regulates blood sugar levels
Key Fact: The pancreas is both an exocrine and endocrine gland. It secretes insulin (lowers blood sugar) and glucagon (raises blood sugar). Insulin deficiency causes diabetes.
Question 11:
Who proposed the Theory of Evolution by Natural Selection?
Answer: Charles Darwin
Key Fact: Charles Darwin proposed the Theory of Evolution by Natural Selection in his book "On the Origin of Species" (1859). He argued that species evolve through natural selection, where organisms with favorable traits survive and reproduce.
Final Takeaway
Biology is a vital section in all competitive exams. Regular revision of key facts about Cell Biology, Genetics, Human Body Systems, Diseases, Nutrition, and Ecology can significantly improve your score.
This quick revision guide serves as a comprehensive resource for last-minute preparation. Focus on remembering important vitamins, diseases, body systems, and biological processes presented in tables and cards for quick recall during exams.
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