Biology Basics Questions for RRB NTPC

The Cell — Basic Unit of Life

Every living thing is made of cells. Robert Hooke first observed cells in 1665 using a cork slice. Cells have two main types: Prokaryotic (no nucleus — bacteria, blue-green algae) and Eukaryotic (has nucleus — plants, animals, fungi). The cell membrane controls what enters and exits. The nucleus holds DNA and controls all cell activities. Mitochondria produce energy (ATP) and are called the powerhouse of the cell.

• Prokaryotic cells: no membrane-bound nucleus. Example: Bacteria.
• Eukaryotic cells: have a true nucleus. Example: Human cells.
• Mitochondria = Powerhouse of the cell (energy/ATP production).
• Chloroplasts = found only in plant cells, site of photosynthesis.
• Ribosome = site of protein synthesis — present in ALL cells.
• Cell wall is present in plant cells, bacteria, and fungi — NOT in animal cells.

Human Body Systems — Quick Overview

The human body has several organ systems working together. RRB NTPC frequently asks about the digestive system, circulatory system, respiratory system, and nervous system. Remember which organ does what job — that is the typical question format.

• Digestive system: Digestion starts in the mouth (salivary amylase breaks starch). Stomach secretes HCl and pepsin. Small intestine does maximum absorption of nutrients.
• Circulatory system: Heart has 4 chambers. RBC carries oxygen via haemoglobin. WBC fights infection. Platelets help in clotting.
• Respiratory system: Oxygen enters lungs, CO2 exits. Exchange happens in alveoli.
• Nervous system: Brain, spinal cord, nerves. Neuron is the basic unit. Synapse is the gap between two neurons.
• Excretory system: Kidneys filter blood and produce urine. Basic unit of kidney is nephron.
• Endocrine system: Glands release hormones. Insulin (pancreas) controls blood sugar. Thyroid controls metabolism.

Nutrition — Vitamins and Deficiency Diseases

Vitamins are organic compounds needed in small amounts. They are divided into fat-soluble (A, D, E, K) and water-soluble (B complex, C). Deficiency of each vitamin causes a specific disease — this is a very high-frequency pattern in RRB NTPC. Minerals like iron, calcium, and iodine are also tested.

• Vitamin A: Night blindness. Source: Carrots, liver.
• Vitamin B1 (Thiamine): Beriberi.
• Vitamin B12: Pernicious anaemia.
• Vitamin C: Scurvy (bleeding gums). Source: Citrus fruits.
• Vitamin D: Rickets in children, Osteomalacia in adults. Made by skin in sunlight.
• Vitamin K: Required for blood clotting.
• Iron deficiency: Anaemia. Iodine deficiency: Goitre.

Diseases — Causes and Types

RRB NTPC frequently asks which microorganism causes which disease — bacterial, viral, fungal, or protozoan. Knowing the carrier (vector) for diseases like malaria is also important. Remember: viruses are NOT cells and cannot reproduce on their own.

• Bacterial diseases: Tuberculosis (TB), Cholera, Typhoid, Plague.
• Viral diseases: Common cold, Influenza, Dengue, Rabies, Polio, HIV/AIDS.
• Protozoan diseases: Malaria (Plasmodium, carried by female Anopheles mosquito), Amoebic dysentery.
• Fungal diseases: Ringworm, Athlete's foot.
• Dengue and Chikungunya are spread by Aedes mosquito.
• Antibiotics kill bacteria — they do NOT work on viruses.

Photosynthesis and Plant Biology

Plants make their own food using sunlight, CO2, and water. This process is called photosynthesis and occurs in the chloroplast. The green pigment chlorophyll absorbs sunlight. Transpiration is the loss of water vapour from leaves through tiny pores called stomata.

• Photosynthesis equation: 6CO2 + 6H2O + sunlight = C6H12O6 (glucose) + 6O2.
• Chlorophyll is the green pigment that captures sunlight.
• Stomata are pores on leaves — control gas exchange and water loss.
• Xylem carries water and minerals upward from roots.
• Phloem carries food (glucose) from leaves to other parts.
• Respiration in plants happens 24 hours; photosynthesis only in light.

Genetics and Heredity — Quick Facts

Genetics is the study of how traits are passed from parents to offspring through genes. DNA carries genetic information in a double helix structure, discovered by Watson and Crick in 1953. Chromosomes carry genes. Humans have 46 chromosomes (23 pairs). Sex is determined by sex chromosomes: XX = female, XY = male.

• DNA double helix model: Watson and Crick (1953).
• Humans: 46 chromosomes = 23 pairs.
• Sex chromosomes: XX = female, XY = male. Father determines sex of child.
• Father of Genetics: Gregor Mendel (worked with pea plants).
• Gene is a segment of DNA that codes for a specific protein or trait.
• Mutation is a change in the DNA sequence — can cause diseases.

• Confusing the vector for Malaria (female Anopheles mosquito) with Dengue (Aedes mosquito). Both are mosquito-borne but different species and different diseases.
• Mixing up Vitamin D deficiency diseases: Rickets is in children, Osteomalacia is in adults — both from same deficiency.
• Thinking antibiotics work on viral infections. Antibiotics only kill bacteria. This is a classic trap question.
• Confusing Xylem and Phloem: remember X for eXit of water upward (Xylem), Ph for Food transport (Phloem).
• Assuming cell wall is only in plant cells — Bacteria and Fungi also have cell walls. Animal cells do NOT have cell walls.

• FAT soluble vitamins: A, D, E, K — remember the word ADEK or think Fat DEKA (deka means ten in Greek — these 4 vitamins need fat).
• Powerhouse story: Mito the power plant (Mitochondria = Powerhouse of cell). Chloro the chef (Chloroplast = food making in plants).
• Disease vector trick: MAlaria = MAlE (actually female Anopheles — so the trick is MAle is wrong, FEmale Anopheles is correct). Dengue = AEDES = A for Aedes, A for Afternoon biting mosquito.
• Xylem vs Phloem: X goes up like an X-ray beam shooting upward (Xylem carries water up). Phloem = Food flows (carries food made in leaves to rest of plant).

• RRB NTPC typically asks 3 to 5 direct factual questions from Biology. Most are single-line recall types — who discovered what, which vitamin causes which disease, which organ does what.
• Vitamin deficiency diseases are almost guaranteed in every RRB NTPC paper. Memorise the table: vitamin, deficiency disease, and one food source — that covers most combinations asked.
• Cell biology questions focus on organelles and their functions. Most common: mitochondria, ribosome, chloroplast, nucleus. The question format is usually which organelle is responsible for this function.
• Disease and microorganism questions often come with a twist — they name a disease and ask if it is bacterial, viral, fungal, or protozoan. TB, cholera = bacterial; dengue, polio = viral; malaria = protozoan.
• Human body system questions focus on digestive and circulatory systems most often. Questions like which enzyme acts on starch, where absorption occurs, how many chambers the heart has — these are repeated patterns in PYQs.