GUJCET 2026 Biology Question Paper with Solution PDF : Available Here

Step 1: Understand Barrier Methods

Barrier methods are contraceptive techniques that physically prevent sperm from reaching the ovum. These include condoms (male) and diaphragms/cervical caps (female). Hence, barrier methods are applicable to both males and females.

Step 2: Understand Sterilisation

Sterilisation is a permanent method of contraception. In males, it is called vasectomy, and in females, it is called tubectomy. Since both genders have their respective procedures, sterilisation is applicable to both.

Step 3: Evaluate Other Options

Implants and IUDs are used only in females and cannot be used by males.

Final Answer: (A) Quick Tip: Barrier and sterilisation methods are the only contraceptive methods applicable to both males and females.

Step 1: Define Linkage

Linkage refers to the phenomenon where two or more genes are located close to each other on the same chromosome and tend to be inherited together during meiosis.

Step 2: Understand Why It Happens

Since linked genes are physically close, the chances of crossing over between them are low, so they are transmitted together to the next generation.

Step 3: Eliminate Other Options

Gene flow refers to movement of genes between populations. Pleiotropy means one gene affects multiple traits. Recombination involves exchange of genetic material.

Final Answer: (C) Quick Tip: Linkage = genes close together on the same chromosome inherited together.

Step 1: Definition of UTR

UTR stands for Untranslated Regions. These are sections of mRNA that are transcribed from DNA but are not translated into proteins.

Step 2: Types of UTR

There are two types: 5' UTR and 3' UTR. These regions play important roles in regulation of translation, mRNA stability, and localization.

Step 3: Importance

Although they do not code for proteins, UTRs are essential for controlling gene expression and ensuring proper protein synthesis.

Final Answer: (C) Quick Tip: UTR = Untranslated but functionally important regions of mRNA.

Step 1: Identify Key Events

65 million years ago marks the extinction of dinosaurs.

350 million years ago corresponds to evolution of jawless fishes.

500 million years ago marks the rise of early invertebrates.

320 million years ago corresponds to the existence of sea weeds.

Step 2: Match Correctly

(i) \(\rightarrow\) (s), (ii) \(\rightarrow\) (r), (iii) \(\rightarrow\) (q), (iv) \(\rightarrow\) (p)

Step 3: Choose Option

This matching corresponds to option (A).

Final Answer: (A) Quick Tip: Memorize evolutionary timeline: Invertebrates \(\rightarrow\) Fish \(\rightarrow\) Plants \(\rightarrow\) Dinosaurs extinction.

Step 1: Understand Anabolic Steroids

Anabolic steroids are synthetic derivatives of testosterone, the male sex hormone. These substances promote muscle growth and development of male secondary sexual characteristics.

Step 2: Effect on Females

When females use anabolic steroids, they may develop masculine traits such as deepening of voice, increased body hair, and enlargement of the clitoris (clitoromegaly).

Step 3: Eliminate Other Options

Diuretics regulate fluid balance, peptide hormones regulate body functions, and narcotic analgesics relieve pain. None of these cause such masculinizing effects.

Final Answer: (B) Quick Tip: Anabolic steroids mimic testosterone → cause masculinization effects in females.

Step 1: Identify Free-Living Bacteria

Free-living bacteria are those that do not require a host organism and can survive independently in soil.

Step 2: Analyze Options

Trichoderma is a fungus, not a bacterium. Oscillatoria is a cyanobacterium but not primarily known as a nitrogen-fixing soil bacterium. Rhizobium is symbiotic and lives in root nodules of legumes.

Step 3: Correct Choice

Azospirillum is a free-living nitrogen-fixing bacterium found in soil and is associated with plant roots but does not form true symbiotic nodules.

Final Answer: (D) Quick Tip: Azospirillum = free-living nitrogen fixer; Rhizobium = symbiotic.

Step 1: Understand Gel Electrophoresis

In gel electrophoresis, DNA fragments are separated based on size by moving through an agarose gel under an electric field.

Step 2: Extraction Process

After separation, the desired DNA band is cut from the gel and purified. This process of recovering DNA from the gel is called elution.

Step 3: Eliminate Other Options

Micro-injection and biolistics are methods of gene transfer, while extension refers to DNA synthesis during PCR.

Final Answer: (A) Quick Tip: Elution = extraction of DNA from gel after electrophoresis.

Step 1: Understand Recombinant Therapeutics

Recombinant therapeutics are medicines produced using recombinant DNA technology, such as insulin, growth hormone, and vaccines.

Step 2: NCERT Reference

According to standard biology references (NCERT), approximately 30 recombinant therapeutics have been approved for human use globally.

Step 3: Importance

These therapeutics have revolutionized treatment for diseases like diabetes, cancer, and hormonal disorders.

Final Answer: (C) Quick Tip: Remember: NCERT fact → Around 30 recombinant therapeutics approved.

Step 1: Formula for Intrinsic Rate of Increase

The intrinsic rate of increase (r) is calculated as: \[ r = \frac{Births - Deaths}{Initial Population} \]

Step 2: Substitute Values

Births = 30, Deaths = 10, Initial population = 100 \[ r = \frac{30 - 10}{100} = \frac{20}{100} = 0.2 \]

Step 3: Interpretation

This indicates a positive growth rate under favorable environmental conditions.

Final Answer: (C) Quick Tip: Intrinsic rate (r) = (B − D)/N → quick formula for population growth.

Step 1: Analyze Each Statement

(1) Moist conditions enhance microbial activity → True.

(2) Low temperature and lack of oxygen slow decomposition → True.

(3) Nitrogen-rich detritus decomposes faster, not slower → False.

(4) Chitin is resistant to decomposition → slows process → False.

(5) Warm conditions favour microbial growth → True.

Step 2: Select Correct Combination

Correct statements are (1), (2), and (5).

Final Answer: (B) Quick Tip: Decomposition is fastest in warm, moist, oxygen-rich conditions.

Step 1: Identify Species Origins

Dodo was native to Mauritius.

Quagga was found in Africa.

Thylacine (Tasmanian tiger) lived in Australia.

Steller’s sea cow was found near Russia (Bering Sea region).

Step 2: Match Correctly

(i) \(\rightarrow\) (q), (ii) \(\rightarrow\) (p), (iii) \(\rightarrow\) (s), (iv) \(\rightarrow\) (r)

Step 3: Choose Option

This corresponds to option (D).

Final Answer: (D) Quick Tip: Extinct species locations are commonly asked → memorize dodo (Mauritius), thylacine (Australia).

Step 1: Understand Endosperm

Endosperm in angiosperms is triploid (3n), formed by fusion of one male gamete (n) with two polar nuclei (n + n).

Step 2: Calculate Haploid Number

Given: Endosperm = 24 chromosomes (3n) \[ 3n = 24 \Rightarrow n = 8 \]

Step 3: Determine MMC Chromosomes

Megaspore Mother Cell (MMC) is diploid (2n): \[ 2n = 2 \times 8 = 16 \]

Final Answer: (B) Quick Tip: Endosperm = 3n → find n → MMC = 2n.

Step 1: Placental Hormones

The placenta produces several hormones such as human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogen, and relaxin.

Step 2: Analyze Option A

The term "gonadotropin" is a general term referring to hormones like FSH and LH, which are secreted by the pituitary gland, not the placenta.

Step 3: Clarification

Although hCG is a gonadotropin, the option given is generic "gonadotropin", which typically refers to pituitary hormones, hence considered incorrect here.

Final Answer: (A) Quick Tip: Placenta secretes hCG, hPL, estrogen, relaxin — but not FSH/LH.

Step 1: Understand GIFT

GIFT (Gamete Intra-Fallopian Transfer) involves transfer of gametes (sperm and ovum) into the fallopian tube, where fertilisation occurs naturally inside the body.

Step 2: Compare Other Techniques

ZIFT involves transfer of zygote (fertilisation already done in vitro).

IUT involves embryo transfer into uterus.

ICSI involves injection of sperm into ovum in laboratory.

Step 3: Key Concept

Only GIFT allows fertilisation to occur inside the female body (in vivo).

Final Answer: (A) Quick Tip: GIFT = fertilisation inside body; IVF methods = fertilisation outside body.

Step 1: Understand Mutation

Mutation refers to sudden heritable changes in the DNA sequence.

Step 2: De Vries Theory

Hugo de Vries proposed that mutations are large, sudden, and discontinuous changes that lead to evolution.

Step 3: Identify Incorrect Statement

Option (C) states mutation is small and directional, which contradicts De Vries’ theory.

Step 4: Verify Other Options

All other options correctly describe mutation.

Final Answer: (C) Quick Tip: De Vries → mutations are large, sudden, and random (not small/directional).

Step 1: Experiment Overview

Meselson and Stahl demonstrated semi-conservative replication of DNA using isotopes of nitrogen (\(^{15}\)N and \(^{14}\)N).

Step 2: Role of CsCl

They used Cesium chloride (CsCl) density gradient centrifugation to separate DNA based on density differences.

Step 3: Principle

Heavy DNA (with \(^{15}\)N) forms a band at a different position than light DNA (\(^{14}\)N), allowing clear distinction.

Final Answer: (B) Quick Tip: Meselson–Stahl experiment → CsCl density gradient centrifugation.

Step 1: Understand Gnetales

Gnetales are a group of gymnosperms that show some advanced features similar to angiosperms.

Step 2: Geological Timeline

According to evolutionary records, Gnetales appeared during the Cretaceous period.

Step 3: Eliminate Other Options

Permian, Triassic, and Jurassic periods correspond to earlier evolutionary stages.

Final Answer: (D) Quick Tip: Gnetales → advanced gymnosperms → Cretaceous period.

Step 1: Identify the Compound

The given structure corresponds to cannabinoids, which are chemical compounds found in cannabis.

Step 2: Source Plant

Cannabinoids are naturally obtained from Cannabis sativa.

Step 3: Eliminate Other Options

Papaver somniferum produces opium.

Erythroxylum coca produces cocaine.

Atropa belladonna produces atropine.

Final Answer: (B) Quick Tip: Cannabis → cannabinoids; Poppy → morphine; Coca → cocaine.

Step 1: Understand Morphine Derivatives

Morphine undergoes acetylation to form diacetylmorphine.

Step 2: Common Name

Diacetylmorphine is commonly known as heroin or smack.

Step 3: Eliminate Other Options

Charas and hashish are cannabis products, while coke refers to cocaine.

Final Answer: (B) Quick Tip: Morphine + acetylation → heroin (smack).

Step 1: Verify Each Pair

(A) Correct → Citric acid by Aspergillus niger.

(B) Correct → Streptokinase used as clot buster.

(D) Correct → Yeast produces ethanol.

Step 2: Identify Error

Cyclosporin-A is actually produced by Trichoderma polysporum, not Monascus purpureus.

Final Answer: (C) Quick Tip: Monascus → statins; Trichoderma → cyclosporin-A.

Step 1: PCR Steps

PCR involves denaturation, annealing, and extension.

Step 2: Role of Taq Polymerase

Taq polymerase is a heat-stable enzyme that synthesizes DNA during the extension phase.

Step 3: Other Options

Restriction enzymes cut DNA, helicase unwinds DNA, ligase joins fragments.

Final Answer: (A) Quick Tip: PCR extension step → Taq polymerase.

Step 1: Define RNA Interference

RNA interference (RNAi) is a biological process where gene expression is silenced.

Step 2: Mechanism

Double-stranded RNA (dsRNA) binds to complementary mRNA and leads to its degradation, preventing protein synthesis.

Final Answer: (C) Quick Tip: RNAi → dsRNA binds mRNA → gene silencing.

Step 1: Study Description

Connell conducted experiments on barnacles in intertidal zones.

Step 2: Observation

He observed that larger barnacles outcompete and exclude smaller ones from their habitat.

Step 3: Concept

This demonstrates competitive exclusion principle in natural ecosystems.

Final Answer: (A) Quick Tip: Connell → barnacle experiment → competitive exclusion.

Step 1: Apply 10% Law of Energy Transfer

According to Lindeman’s 10% law, only 10% of energy is transferred from one trophic level to the next.

Step 2: Calculate Energy Flow

Producer = 1000 J

Primary consumer = 10% of 1000 = 100 J

Secondary consumer = 10% of 100 = 10 J

Step 3: Interpretation

Energy decreases significantly at each trophic level due to heat loss and metabolic activities.

Final Answer: (D) Quick Tip: 10% law → multiply by 0.1 at each trophic level.

Step 1: Identify Key Scientist

Edward O. Wilson is known for promoting the concept of biodiversity.

Step 2: Contribution

He emphasized conservation of species diversity and ecosystem importance globally.

Final Answer: (B) Quick Tip: Edward Wilson = Father of Biodiversity.

Step 1: Monoecious Plants

Monoecious plants have both male and female flowers on the same plant → prevents autogamy but allows geitonogamy.

Step 2: Dioecious Plants

Dioecious plants have separate male and female plants → prevents both autogamy and geitonogamy.

Step 3: Examples

Caster and maize are monoecious plants.

Final Answer: (D) Quick Tip: Monoecious → same plant; Dioecious → separate plants.

Step 1: Outer Layer

Corona radiata surrounds the ovum externally.

Step 2: Middle Layer

Zona pellucida is a thick glycoprotein layer around the oocyte.

Step 3: Inner Space

Perivitelline space lies between zona pellucida and plasma membrane.

Final Answer: (A) Quick Tip: Order: Corona radiata → Zona pellucida → Perivitelline space.

Step 1: Concept of Polyspermy

Polyspermy refers to entry of more than one sperm into the ovum, which must be prevented for normal development.

Step 2: Role of Zona Pellucida

After one sperm enters, zona pellucida undergoes structural changes (zona reaction) that prevent entry of additional sperms.

Step 3: Eliminate Other Options

Corona radiata helps sperm entry, not blocking. Perivitelline space is just a gap. Theca layer is part of follicle.

Final Answer: (A) Quick Tip: Zona pellucida → blocks polyspermy (very important concept).

Step 1: Curable vs Non-curable

Bacterial infections like gonorrhoea and chlamydia are curable with antibiotics.

Step 2: Viral STIs

Viral infections such as HIV, Hepatitis-B, and Genital herpes are not completely curable.

Step 3: Select Option

Option (C) contains only non-curable diseases.

Final Answer: (C) Quick Tip: Viral STIs → not curable; Bacterial STIs → curable.

Step 1: Understand Inheritance

Colour blindness is an X-linked recessive trait.

Step 2: Parental Genotype

Male (colour blind) = X\(^c\)Y

Female (normal homozygous) = X\(^C\)X\(^C\)

Step 3: Male Children

Male child receives Y from father and X from mother → X\(^C\)Y (normal).

Final Answer: (D) Quick Tip: Sons get X from mother → check mother’s genotype only.

Step 1: Genome Sequencing

Human genome project involved sequencing DNA and identifying genes.

Step 2: Annotation

Assigning functions to identified sequences is called sequence annotation.

Final Answer: (B) Quick Tip: Sequencing = reading DNA; Annotation = assigning function.

Step 1: Types of Natural Selection

Stabilising → favors average traits.

Disruptive → favors extremes.

Directional → shifts population toward one extreme.

Step 2: Interpretation

When individuals move away from mean toward one side → directional selection.

Final Answer: (D) Quick Tip: Directional selection → shift of mean toward one extreme.

Step 1: Understand Passive Immunity

Passive immunity involves transfer of ready-made antibodies into the body.

Step 2: Snake Venom Case

Antivenom contains pre-formed antibodies produced in another organism and injected into patient.

Step 3: Conclusion

Since antibodies are directly provided → passive immunity.

Final Answer: (C) Quick Tip: Passive immunity = ready-made antibodies (instant protection).

Step 1: Define Biocontrol Agents

Biocontrol agents are organisms used to control pests and diseases biologically.

Step 2: Identify Correct Group

Trichoderma → fungal biocontrol agent.

Baculovirus → controls insect pests.

Bacillus thuringiensis (Bt) → insecticidal bacteria.

Final Answer: (C) Quick Tip: Bt, Baculovirus, Trichoderma = key biocontrol agents.

Step 1: Naming Rule

Restriction enzymes are named from organism:

First letter (genus) + next two letters (species) + strain.

Step 2: Apply Rule

Bacillus amyloliquefaciens → Bam

Strain H → H

Roman numeral I → first enzyme

Final Answer: (A) Quick Tip: Naming = Genus + species + strain + number → BamHI.

Step 1: Define Interactions

Competition → both harmed.

Commensalism → one benefits, other unaffected.

Parasitism → one benefits, other harmed.

Amensalism → one harmed, other unaffected.

Step 2: Match Condition

Given condition matches amensalism.

Final Answer: (B) Quick Tip: Amensalism = (-, 0) interaction.

Step 1: Define Somatic Hybridisation

It involves fusion of somatic cells from different plants.

Step 2: Role of Protoplast

Protoplasts are cells without cell wall and can fuse easily.

Step 3: Conclusion

Fusion of protoplasts forms hybrid cells.

Final Answer: (C) Quick Tip: Somatic hybridisation = fusion of protoplasts.

Step 1: When Sparrow Eats Seeds

Seeds are producers → sparrow acts as primary consumer.

Step 2: When Sparrow Eats Insects

Insects are primary consumers → sparrow becomes secondary consumer.

Final Answer: (A) Quick Tip: Plant eater → primary; animal eater → secondary.

Step 1: Broadly Utilitarian Values

These include ecosystem services like oxygen production, pollination, climate regulation.

Step 2: Oxygen Role

Oxygen is essential for life and provided by plants → ecosystem service.

Final Answer: (C) Quick Tip: Ecosystem services → broadly utilitarian values.

Step 1: Analyze Assertion

Geitonogamy involves transfer of pollen between different flowers of same plant → genetically similar to autogamy.

Step 2: Analyze Reason

Pollen comes from same plant → no genetic variation.

Step 3: Relation

Reason correctly explains why it is genetically similar.

Final Answer: (A) Quick Tip: Same plant → no variation → like self-pollination.

Step 1: Outer Layer

Seed coat protects the seed.

Step 2: Endosperm

Large food storage tissue in monocots.

Step 3: Cotyledon

Small structure (scutellum) absorbs nutrients.

Final Answer: (B) Quick Tip: Monocot seed → Endosperm large, cotyledon small.

Step 1: Grass Seed Structure

In monocots, cotyledon is modified into scutellum.

Final Answer: (B) Quick Tip: Monocot cotyledon = Scutellum.

Step 1: Pathway

Seminiferous tubules → rete testis → vasa efferentia → epididymis.

Step 2: Match

They open into vasa efferentia through rete testis.

Final Answer: (D) Quick Tip: Flow: Seminiferous → rete testis → vasa efferentia.