Biology Study Guide
GK for Exams – Human Body, Plants, Environment, Biotechnology
Introduction to Biology
Biology is the science of life — the study of living organisms, their structure, growth, and evolution.
In the Delhi Police exam, Biology questions often test your knowledge of human anatomy, diseases, vaccines, nutrition, environment, and new technologies like biotechnology & genetics.
Human Body & Health
Digestive System
| Organ | Function |
|---|---|
| Mouth | Chewing and mixing with saliva (salivary amylase breaks starch) |
| Stomach | Protein digestion by pepsin; acid secretion (HCl) |
| Small Intestine | Complete digestion and nutrient absorption |
| Large Intestine | Water absorption |
| Liver | Produces bile for fat digestion |
| Pancreas | Secretes insulin and digestive enzymes |
Circulatory System
| Organ | Function |
|---|---|
| Heart | Pumps blood through arteries and veins |
| Blood | Carries oxygen (RBC), fights germs (WBC), and clots (platelets) |
| Blood Vessels | Arteries carry blood away; veins bring it back |
Respiratory System
| Organ | Function |
|---|---|
| Nose | Filters air |
| Trachea | Air passage |
| Lungs | Gas exchange – Oxygen in, Carbon dioxide out |
| Diaphragm | Helps in breathing movement |
Nervous System
| Part | Function |
|---|---|
| Brain | Controls thoughts, actions, and memory |
| Spinal Cord | Transfers signals between brain and body |
| Nerves | Carry impulses |
Diseases & Vaccines
| Disease | Cause / Pathogen | Vaccine / Prevention |
|---|---|---|
| Tuberculosis (TB) | Bacteria | BCG Vaccine |
| Polio | Virus | OPV (Oral Polio Vaccine) |
| COVID-19 | Coronavirus | Covishield / Covaxin |
| Measles | Virus | MMR Vaccine |
| Tetanus | Bacteria | TT Injection |
Nutrition & Deficiency Diseases
| Nutrient | Deficiency Disease |
|---|---|
| Vitamin A | Night blindness |
| Vitamin B1 (Thiamine) | Beri-Beri |
| Vitamin C | Scurvy |
| Vitamin D | Rickets |
| Iron | Anemia |
| Iodine | Goitre |
Plants & Environment
Photosynthesis
Definition: The process by which green plants make food using sunlight, carbon dioxide, and water.
Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (In presence of chlorophyll and sunlight)
Plant Physiology
| Process | Function |
|---|---|
| Transpiration | Water loss through leaves |
| Respiration | Energy release from food |
| Germination | Growth of seed into plant |
| Pollination | Transfer of pollen to stigma |
Ecosystem & Biodiversity
Ecosystem: Interaction between living (biotic) and non-living (abiotic) components.
- Producers: Plants
- Consumers: Animals
- Decomposers: Fungi, bacteria
- Biodiversity Hotspots in India: Western Ghats, Eastern Himalayas
Pollution Control
| Type | Major Cause | Control Method |
|---|---|---|
| Air Pollution | Vehicles, industries | Tree plantation, filters |
| Water Pollution | Sewage, chemicals | Treatment plants |
| Noise Pollution | Traffic, machines | Silent zones |
| Soil Pollution | Pesticides, waste | Organic farming |
Biotechnology & Genetics
Genetic Engineering
Definition: Artificial modification of DNA to improve or create new organisms.
Uses:
- Production of insulin
- Disease-resistant crops
- DNA fingerprinting
CRISPR Technology
| Category | Details |
|---|---|
| Full Form | Clustered Regularly Interspaced Short Palindromic Repeats |
| Purpose | Gene editing (precise DNA modification) |
| Discovery | Jennifer Doudna & Emmanuelle Charpentier (Nobel Prize 2020) |
Stem Cell Research
| Category | Details |
|---|---|
| Definition | Stem cells are undifferentiated cells that can develop into different cell types |
| Uses | Regenerative medicine, organ repair, cancer treatment |
| Sources | Bone marrow, umbilical cord, embryos |
Cloning & GM Crops
| Concept | Example / Fact |
|---|---|
| Cloning | Creating a genetically identical copy. First cloned animal: Dolly the sheep (1996) |
| GM Crops (Genetically Modified) | Modified for higher yield, pest resistance |
| Example | Bt Cotton – resists bollworm |
Practice Questions (Delhi Police, SSC & State Exams)
Which organ secretes bile?
A) Pancreas B) Liver C) Stomach D) Gall Bladder
Category: Human Body
Show Answer
B) Liver
RBCs carry oxygen through —
A) Plasma B) Hemoglobin C) Platelets D) WBCs
Category: Human Body
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B) Hemoglobin
Which vitamin deficiency causes rickets?
A) Vitamin A B) Vitamin B C) Vitamin C D) Vitamin D
Category: Nutrition
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D) Vitamin D
The process by which green plants prepare food is —
A) Respiration B) Photosynthesis C) Germination D) Pollination
Category: Plants
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B) Photosynthesis
The "God Particle" in biotechnology is known as —
A) DNA B) Gene C) Higgs Boson D) CRISPR
Category: Biotechnology
Show Answer
D) CRISPR (Gene Editing System)
Bt Cotton is an example of —
A) Hybrid Crop B) GM Crop C) Organic Crop D) Seasonal Crop
Category: Biotechnology
Show Answer
B) GM Crop
Dolly, the first cloned animal, was —
A) Goat B) Cow C) Sheep D) Rabbit
Category: Biotechnology
Show Answer
C) Sheep
Which organ controls the human nervous system?
A) Heart B) Brain C) Spinal Cord D) Nerves
Category: Human Body
Show Answer
B) Brain
Quick Revision – One Line Memory
| Concept | Key Point |
|---|---|
| Digestive System | Mouth → Stomach → Intestine |
| Circulatory System | Heart pumps, RBC carries O₂ |
| Respiratory System | Gas exchange in lungs |
| Nervous System | Brain controls all organs |
| Photosynthesis | CO₂ + H₂O + Sunlight = Glucose |
| Pollution Control | 3 Rs – Reduce, Reuse, Recycle |
| CRISPR | DNA editing |
| Stem Cells | Regrow damaged tissues |
| Bt Cotton | GM crop, pest resistant |
Final Concept Recap
- Human Body: Systems for digestion, respiration, circulation, and coordination
- Health: Vaccines, nutrition, and immunity
- Plants: Photosynthesis, transpiration, and ecology
- Environment: Pollution control and biodiversity conservation
- Biotech: CRISPR, cloning, GM crops — modern science in action
Master Biology – Understand Life Sciences!
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