71st BPSC Prelims 2025
General Science Previous Year Questions (PYQs)
Explore 29 solved 71st BPSC Prelims 2025 General Science questions with detailed step-by-step bilingual solutions, option analysis, and answer keys.
In the following question, out of four words given below, three are alike in some manner and fourth word is different. Find the different one.
Detailed Explanation:
Telescope, Microscope, and Periscope are optical instruments that use lenses and mirrors to view objects (distant, tiny, or around obstacles).
Stethoscope is an acoustic medical device used to listen to internal body sounds (heartbeat, lung sounds), not for viewing.
In mycorrhizal association, the advantage of plant is :
Detailed Explanation:
Mycorrhizal association is a symbiotic relationship between fungi and plant roots where the fungal hyphae increase root surface area for enhanced mineral absorption (especially phosphorus) and form a protective barrier against soil-borne pathogens.
✅ Option 4 – Correct: Increased mineral absorption and disease protection are the two primary advantages the plant receives from mycorrhizal fungi.
❌ Option 1 – Incomplete: Protection is only one of the benefits.
❌ Option 2 – Incorrect: The plant provides food (carbohydrates) to the fungus, not vice versa.
❌ Option 3 – Incorrect: Combines an incomplete and an incorrect option.
The part which we eat in Mango is :
Detailed Explanation:
Mango is a drupe fruit with three layers in its fruit wall (pericarp).
The epicarp is the outer skin, the mesocarp is the thick, fleshy, edible middle layer, and the endocarp is the hard stone surrounding the seed.
We eat the mesocarp – the juicy, sweet flesh of the mango.
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Who was first to use the characteristics of vascular tissues in the classification of plants?
Detailed Explanation:
Augustin Pyramus de Candolle was the first botanist to use vascular tissue characteristics (xylem and phloem) for plant classification, dividing plants into vascular (tracheophytes) and non-vascular (bryophytes) groups.
Engler and Prantl developed a phylogenetic system later, while Bentham and Hooker used morphological traits in their natural system, neither being first to use vascular tissues.
Xylem in plants is responsible for following function:
Detailed Explanation:
Xylem is a vascular tissue that transports water and dissolved minerals upward from roots to stems and leaves.
Phloem transports organic nutrients (food and amino acids), while gases diffuse through stomata and intercellular spaces, not through xylem.
Which of the following is a non-sense codon?
Detailed Explanation:
Nonsense codons (also called stop codons) signal the termination of protein synthesis and do not code for any amino acid. The three stop codons are UAA, UAG, and UGA.
AUG is the start codon coding for methionine; UUU codes for phenylalanine; UGC codes for cysteine. Only UAA is a nonsense codon among the given options.
The biological membranes are composed of:
Detailed Explanation:
Biological membranes consist of a phospholipid bilayer with embedded proteins in varying proportions.
The exact ratio of lipids and proteins is specific to each species, cell type, and organelle – e.g., mitochondrial membranes have different composition than plasma membranes.
Which class of immunoglobulin is the first to be produced in response to an infection?
Detailed Explanation:
IgM (Immunoglobulin M) is the first antibody produced during the primary immune response to a new infection.
IgM has a pentamer structure that enables rapid agglutination and complement activation, providing immediate defense before IgG levels rise in secondary responses.
Which one of the following terms characterizes the interaction between the herpes simplex virus and a human?
Detailed Explanation:
Parasitism is a biological interaction where the parasite benefits while the host is harmed.
The herpes simplex virus infects human cells, uses the host's cellular machinery to replicate, damages cells, and causes diseases like cold sores or genital herpes, clearly harming the host while benefiting itself — a classic example of parasitism.
Hormones are secreted by:
Detailed Explanation:
Endocrine glands (such as pituitary, thyroid, adrenal glands) secrete hormones directly into the bloodstream to regulate body functions.
Exocrine glands (like sebaceous and sweat glands) release substances through ducts, not into the blood, so they do not secrete hormones.
Full form of PHBV biodegradable polymer.
Detailed Explanation:
PHBV stands for Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), a biodegradable copolymer produced by bacterial fermentation.
The prefix "co" indicates it is a copolymer formed from two monomer units: 3-hydroxybutyrate and 3-hydroxyvalerate, making it an eco-friendly alternative to conventional plastics.
Which compound is used for increase of octane rating?
Detailed Explanation:
Tetraethyllead (TEL) was historically the most widely used anti-knock agent added to gasoline to increase octane rating and prevent engine knocking.
Though highly effective, TEL is toxic and has been phased out globally; modern fuels use unleaded alternatives like ethanol and aromatic hydrocarbons.
Why oil is not stored in galvanized iron pot?
Detailed Explanation:
Galvanized iron is coated with zinc, which reacts with oil components to form toxic zinc compounds that make the oil unsafe for consumption.
The chemical reaction also causes rancidity, degrading the oil's taste, smell, and nutritional quality.
Moisture and acidic impurities in oil corrode the zinc coating, exposing the underlying iron to rust formation.
Since all three effects—toxicity, quality degradation, and corrosion—occur simultaneously, the correct answer is All of above.
Which compound is used in contraceptive pills?
Detailed Explanation:
Levonorgestrel is a synthetic progestin hormone widely used in oral contraceptive pills and emergency contraception; it prevents pregnancy by inhibiting ovulation, thickening cervical mucus, and altering the uterine lining.
Cholecalciferol is Vitamin D3, Venlafaxine is an antidepressant, and Cetirizine is an antihistamine for allergies—none have contraceptive properties.
Which metal compound is used for treatment of carcinoma?
Detailed Explanation:
Platinum compounds, particularly Cisplatin, are used as chemotherapeutic agents for treating carcinoma by binding to DNA in cancer cells and causing cell death.
Cisplatin is effective against testicular, ovarian, lung, and bladder cancers. Other metals like Chromium (toxic), Iron (nutrient), and Chlorine (disinfectant) are not used for cancer treatment.
Which Material is used for smart film?
Detailed Explanation:
Smart films switch transparency when voltage is applied, requiring a material that is both electrically conductive and optically transparent.
Indium tin oxide (ITO) is a transparent conducting oxide used in smart films, touchscreens, and LCDs. Calcium carbonate is a non-conductive filler in plastics. Zinc chloride is used in batteries, not films. Silica is an insulator used in glass.
Which Compound is known as night glowing pigment from below?
Detailed Explanation:
Europium-doped strontium aluminate (SrAl₂O₄:Eu²⁺,Dy³⁺) is the most efficient modern phosphorescent material used in night glowing pigments.
It absorbs light energy and slowly releases it in darkness, providing a bright afterglow lasting up to 12 hours. Other compounds listed (copper sulphide-doped zinc oxide, barium sulphate-doped copper carbonate, boron oxide-doped copper sulphate) do not exhibit significant or efficient phosphorescence for glow-in-the-dark applications.
pH value of 0.1N HCl solution is approximately:
Detailed Explanation:
HCl is a strong acid that dissociates completely: HCl → H⁺ + Cl⁻. For a monoprotic acid, 0.1N = 0.1M, so [H⁺] = 0.1 M.
pH = -log[H⁺] = -log(0.1) = -(-1) = 1.0. Options with pH 10 or 11 indicate basic solutions, not acids. pH 2.0 would require [H⁺] = 0.01 M, which is ten times more dilute.
What is the device to protect equipments from the electric shock?
Detailed Explanation:
Fuse is a safety device containing a thin wire with low melting point that melts and breaks the circuit when excess current flows, protecting equipment from electric shock, overload, and short circuits.
Generator produces electricity, Motor converts electrical to mechanical energy, and Current controller regulates current but does not automatically disconnect during faults—only the fuse provides automatic protection.
In short circuit, the value of electric current in a time circuit:
Detailed Explanation:
Short circuit occurs when a path of nearly zero resistance forms in a circuit, bypassing the normal load.
According to Ohm's Law (I = V/R), when resistance R approaches zero, the current I increases dramatically to very high values, limited only by the internal resistance of the source.
This surge can cause overheating, fires, and equipment damage, which is why fuses and circuit breakers are used for protection.
Showing 1 to 20 of 29 questions
71st BPSC Prelims 2025 - General Science Chapter-wise Distribution
Physics
11 Qs (37.9%)Biology
10 Qs (34.5%)Chemistry
4 Qs (13.8%)Environmental Science
1 Qs (3.4%)Science and Technology Developments
1 Qs (3.4%)Biotechnology
1 Qs (3.4%)Human Health and Diseases
1 Qs (3.4%)71st BPSC Prelims 2025 - General Science Questions FAQs
Q1 How many General Science questions were asked in 71st BPSC Prelims 2025?
Q2 What is the chapter-wise question distribution for General Science in 71st BPSC Prelims 2025?
- Physics: 11 questions (37.9%)
- Biology: 10 questions (34.5%)
- Chemistry: 4 questions (13.8%)
- Environmental Science: 1 questions (3.4%)
- Science and Technology Developments: 1 questions (3.4%)
- Biotechnology: 1 questions (3.4%)
- Human Health and Diseases: 1 questions (3.4%)