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Genetics and Heredity MCQs 2026

50 questions with detailed answers · 21 from past papers · 5 quiz batches available

📚 Biology Mcqs 📄 21 Past-Paper Qs ✓ Free · No Login Needed
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Read each question, think about the answer, then click Show Answer to reveal the correct option and explanation. Load 10 at a time so it stays manageable — perfect for one-topic study sessions on the bus or during a break.

Page 1 of 1 Questions 1–10 of 50
  1. Q1 Past Paper · PPSC/FPSC/NTS medium

    The dihybrid cross ratio predicted by Mendel's Law of Independent Assortment in the F2 generation is

    1. A 3:1
    2. B 1:2:1
    3. C 9:3:3:1
    4. D 1:1:1:1
    💡 Explanation:

    A dihybrid cross between two double heterozygotes produces a 9:3:3:1 phenotypic ratio in the F2 generation.

  2. Q2 medium

    A cross involving two different traits simultaneously, such as seed shape and color, follows Mendel's Law of

    1. A Segregation
    2. B Independent Assortment
    3. C Dominance
    4. D Linkage
    💡 Explanation:

    The Law of Independent Assortment states that genes for different traits assort independently during gamete formation.

  3. Q3 Past Paper · PPSC/FPSC/NTS easy

    The flow of genetic information described as DNA to RNA to protein is known as the

    1. A Central Dogma of molecular biology
    2. B Law of independent assortment
    3. C Hardy-Weinberg equilibrium
    4. D Lamarckian theory
    💡 Explanation:

    The central dogma, proposed by Francis Crick, describes the unidirectional flow of genetic information.

  4. Q4 Past Paper · PPSC/FPSC/NTS easy

    A visual representation of an individual's complete set of chromosomes, arranged by size and shape, is called a

    1. A Genome map
    2. B Pedigree
    3. C Gene bank
    4. D Karyotype
    💡 Explanation:

    A karyotype displays an organism's chromosomes ordered by size, used to detect numerical or structural abnormalities.

  5. Q5 medium

    Thomas Hunt Morgan's work with fruit flies (Drosophila) provided key evidence for the

    1. A Central Dogma
    2. B Law of Segregation
    3. C Chromosomal theory of inheritance
    4. D Hardy-Weinberg principle
    💡 Explanation:

    Morgan's fruit fly experiments showed genes are located on chromosomes, confirming the chromosomal theory of inheritance.

  6. Q6 Past Paper · PPSC/FPSC/NTS easy

    The father of modern genetics, known for his pea plant experiments, is

    1. A Gregor Mendel
    2. B Charles Darwin
    3. C Thomas Morgan
    4. D James Watson
    💡 Explanation:

    Gregor Mendel's work on pea plants in the 1860s established the fundamental laws of inheritance.

  7. Q7 medium

    In a test cross, an organism showing the dominant phenotype is crossed with an organism that is

    1. A Heterozygous dominant
    2. B Also showing the dominant phenotype
    3. C Sterile
    4. D Homozygous recessive
    💡 Explanation:

    A test cross with a homozygous recessive individual reveals whether the dominant parent is homozygous or heterozygous.

  8. Q8 easy

    An organism with two identical alleles for a given trait is said to be

    1. A Heterozygous
    2. B Homozygous
    3. C Hybrid
    4. D Diploid only
    💡 Explanation:

    Homozygous individuals carry two identical alleles, either both dominant or both recessive, for a trait.

  9. Q9 easy

    The alternative forms of a gene found at the same locus on homologous chromosomes are called

    1. A Genotypes
    2. B Phenotypes
    3. C Alleles
    4. D Loci
    💡 Explanation:

    Alleles are different versions of the same gene occupying the same position on homologous chromosomes.

  10. Q10 Past Paper · PPSC/FPSC/NTS easy

    A cell division process that produces four genetically different haploid daughter cells is called

    1. A Mitosis
    2. B Binary fission
    3. C Cytokinesis
    4. D Meiosis
    💡 Explanation:

    Meiosis involves two successive divisions producing four genetically distinct haploid gametes.

  11. Q11 Past Paper · PPSC/FPSC/NTS easy

    Human gametes (sperm and egg) contain how many chromosomes

    1. A 23
    2. B 46
    3. C 22
    4. D 24
    💡 Explanation:

    Gametes are haploid, carrying only one chromosome from each pair, totaling 23.

  12. Q12 Past Paper · PPSC/FPSC/NTS easy

    The total number of chromosomes found in a normal human somatic cell is

    1. A 23
    2. B 46
    3. C 44
    4. D 48
    💡 Explanation:

    Human somatic cells are diploid, containing 46 chromosomes arranged in 23 homologous pairs.

  13. Q13 Past Paper · PPSC/FPSC/NTS easy

    An organism whose genetic material has been altered using genetic engineering techniques is called a

    1. A Hybrid
    2. B Mutant
    3. C Clone
    4. D Genetically Modified Organism (GMO)
    💡 Explanation:

    A GMO has had its genome deliberately altered through biotechnology to introduce a new trait.

  14. Q14 medium

    A technique used to separate DNA fragments by size using an electric current is called

    1. A PCR
    2. B Karyotyping
    3. C Gel electrophoresis
    4. D Cloning
    💡 Explanation:

    Gel electrophoresis separates charged DNA fragments through a gel matrix based on their size.

  15. Q15 Past Paper · PPSC/FPSC/NTS medium

    The technique used to make millions of copies of a specific DNA segment in the laboratory is called

    1. A Polymerase Chain Reaction (PCR)
    2. B Gel electrophoresis
    3. C DNA fingerprinting
    4. D Southern blotting
    💡 Explanation:

    PCR uses repeated cycles of heating and cooling with DNA polymerase to exponentially amplify a target DNA sequence.

  16. Q16 medium

    The non-coding sequences within a eukaryotic gene that are removed before translation are called

    1. A Exons
    2. B Introns
    3. C Operons
    4. D Promoters
    💡 Explanation:

    Introns are non-coding regions spliced out of pre-mRNA, leaving only exons in the mature mRNA.

  17. Q17 Past Paper · PPSC/FPSC/NTS easy

    A sequence of three nucleotides on mRNA that specifies a particular amino acid is called a

    1. A Gene
    2. B Allele
    3. C Intron
    4. D Codon
    💡 Explanation:

    Each codon, a triplet of mRNA bases, corresponds to a specific amino acid or stop signal during translation.

  18. Q18 Past Paper · PPSC/FPSC/NTS easy

    A segment of DNA that codes for a specific protein or functional RNA is called a

    1. A Gene
    2. B Codon
    3. C Chromatid
    4. D Operon
    💡 Explanation:

    A gene is the basic unit of heredity, a DNA sequence that codes for a protein or RNA product.

  19. Q19 medium

    According to Chargaff's rule, the amount of adenine in DNA is approximately equal to the amount of

    1. A Guanine
    2. B Cytosine
    3. C Thymine
    4. D Uracil
    💡 Explanation:

    Chargaff observed that purine and pyrimidine base pairs occur in equal amounts, with A always pairing with T.

  20. Q20 medium

    X-ray diffraction images crucial to solving DNA's structure were produced by

    1. A Erwin Chargaff
    2. B Rosalind Franklin
    3. C Barbara McClintock
    4. D Thomas Morgan
    💡 Explanation:

    Rosalind Franklin's Photo 51 provided key structural evidence used by Watson and Crick.

  21. Q21 Past Paper · PPSC/FPSC/NTS medium

    The Hershey-Chase experiment using bacteriophages confirmed that the genetic material is

    1. A Protein
    2. B RNA
    3. C Lipid
    4. D DNA
    💡 Explanation:

    Using radioactive labeling of phage protein and DNA, Hershey and Chase showed DNA enters bacteria and carries genetic information.

  22. Q22 medium

    The experiment that first demonstrated bacterial transformation, later linked to DNA as the genetic material, was conducted by

    1. A Frederick Griffith
    2. B Gregor Mendel
    3. C Thomas Morgan
    4. D Rosalind Franklin
    💡 Explanation:

    Griffith's 1928 experiment with pneumococcus bacteria revealed a transforming principle later identified as DNA.

  23. Q23 Past Paper · PPSC/FPSC/NTS easy

    Mendel's experiments were primarily conducted on which plant

    1. A Maize
    2. B Fruit fly
    3. C Garden pea
    4. D Tobacco
    💡 Explanation:

    Mendel used the garden pea (Pisum sativum) because of its clear contrasting traits and easy controlled breeding.

  24. Q24 Past Paper · PPSC/FPSC/NTS easy

    The process by which the genetic code on mRNA is used to synthesize a protein is called

    1. A Replication
    2. B Transcription
    3. C Translocation
    4. D Translation
    💡 Explanation:

    Translation is the process where ribosomes read mRNA codons to assemble a polypeptide chain.

  25. Q25 hard

    The phenomenon in which one gene masks or suppresses the expression of another gene at a different locus is called

    1. A Codominance
    2. B Linkage
    3. C Incomplete dominance
    4. D Epistasis
    💡 Explanation:

    In epistasis, the alleles of one gene interfere with or mask the phenotypic expression of another gene.

  26. Q26 medium

    The exchange of genetic material between homologous chromosomes during meiosis is called

    1. A Crossing over
    2. B Mutation
    3. C Translation
    4. D Duplication
    💡 Explanation:

    Crossing over occurs during prophase I of meiosis and increases genetic variation among offspring.

  27. Q27 medium

    Genes located close together on the same chromosome that tend to be inherited together are said to show

    1. A Independent assortment
    2. B Linkage
    3. C Codominance
    4. D Epistasis
    💡 Explanation:

    Linked genes are physically close on a chromosome and are usually inherited together unless crossing over occurs.

  28. Q28 easy

    A grid used to predict the possible genotypes of offspring from a genetic cross is called a

    1. A Pedigree chart
    2. B Chromosome map
    3. C Punnett square
    4. D Linkage map
    💡 Explanation:

    A Punnett square organizes parental alleles to predict offspring genotype and phenotype ratios.

  29. Q29 easy

    A diagram showing the inherited traits of a family across generations is called a

    1. A Pedigree chart
    2. B Punnett square
    3. C Karyotype
    4. D Gene map
    💡 Explanation:

    A pedigree chart traces the inheritance of a trait through multiple generations of a family.

  30. Q30 easy

    The complete set of genetic instructions of an organism is called its

    1. A Phenotype
    2. B Proteome
    3. C Karyotype
    4. D Genome
    💡 Explanation:

    The genome is the entire hereditary information encoded in an organism's DNA.

  31. Q31 Past Paper · PPSC/FPSC/NTS easy

    The physical, observable characteristics of an organism are collectively called its

    1. A Genotype
    2. B Phenotype
    3. C Karyotype
    4. D Genome
    💡 Explanation:

    Phenotype refers to the observable traits resulting from the interaction of genotype and environment.

  32. Q32 Past Paper · PPSC/FPSC/NTS medium

    Color blindness in humans is most commonly inherited as a

    1. A Autosomal dominant trait
    2. B Autosomal recessive trait
    3. C X-linked recessive trait
    4. D Y-linked trait
    💡 Explanation:

    The gene for red-green color blindness lies on the X chromosome and is recessive, making it more common in males.

  33. Q33 medium

    Cystic fibrosis is inherited in which pattern

    1. A Autosomal recessive
    2. B Autosomal dominant
    3. C X-linked recessive
    4. D Y-linked
    💡 Explanation:

    Cystic fibrosis requires two copies of the mutated CFTR gene, following an autosomal recessive pattern.

  34. Q34 Past Paper · PPSC/FPSC/NTS medium

    Sickle cell anemia is caused by a mutation affecting the

    1. A White blood cells
    2. B Blood plasma proteins
    3. C Platelets
    4. D Beta-globin chain of hemoglobin
    💡 Explanation:

    A single amino acid substitution in the beta-globin gene causes hemoglobin to form rigid, sickle-shaped cells.

  35. Q35 easy

    According to Mendel's Law of Segregation, allele pairs

    1. A separate during gamete formation
    2. B always blend permanently
    3. C remain together in gametes
    4. D combine to form new genes
    💡 Explanation:

    The two alleles for a trait separate during gamete formation, so each gamete carries only one allele.

  36. Q36 Past Paper · PPSC/FPSC/NTS easy

    The molecule that carries hereditary information in most living organisms is

    1. A RNA
    2. B DNA
    3. C ATP
    4. D Protein
    💡 Explanation:

    DNA (deoxyribonucleic acid) stores and transmits genetic information across generations.

  37. Q37 Past Paper · PPSC/FPSC/NTS easy

    In a DNA molecule, adenine always pairs with

    1. A Cytosine
    2. B Guanine
    3. C Uracil
    4. D Thymine
    💡 Explanation:

    Adenine forms a complementary base pair with thymine via two hydrogen bonds, per Chargaff's rule.

  38. Q38 Past Paper · PPSC/FPSC/NTS easy

    The scientists credited with discovering the double helix structure of DNA are

    1. A Mendel and Morgan
    2. B Griffith and Avery
    3. C Watson and Crick
    4. D Hershey and Chase
    💡 Explanation:

    James Watson and Francis Crick proposed the double helix model of DNA in 1953.

  39. Q39 medium

    A cross between two heterozygous individuals for a single trait (Aa x Aa) typically produces offspring in the phenotypic ratio of

    1. A 1:2:1
    2. B 9:3:3:1
    3. C 3:1
    4. D 1:1
    💡 Explanation:

    A monohybrid cross between two heterozygotes yields a 3:1 dominant to recessive phenotypic ratio.

  40. Q40 medium

    When neither allele is dominant and the heterozygote shows a blended phenotype, such as red and white flowers producing pink, this is called

    1. A Incomplete dominance
    2. B Codominance
    3. C Epistasis
    4. D Polygenic inheritance
    💡 Explanation:

    In incomplete dominance, the heterozygous phenotype is an intermediate blend of both parental traits.

  41. Q41 medium

    Human blood type AB is an example of

    1. A Incomplete dominance
    2. B Codominance
    3. C Recessive inheritance
    4. D Sex-linked inheritance
    💡 Explanation:

    In codominance, both alleles (A and B) are fully and simultaneously expressed in the phenotype.

  42. Q42 medium

    A person with genotype XhY, where Xh is the recessive hemophilia allele, will be

    1. A A carrier female
    2. B An unaffected male
    3. C An affected female
    4. D An affected male
    💡 Explanation:

    Males have only one X chromosome, so a single recessive allele on it is always expressed.

  43. Q43 Past Paper · PPSC/FPSC/NTS easy

    Down syndrome in humans is caused by

    1. A An extra copy of chromosome 21
    2. B A missing X chromosome
    3. C A point mutation in a single gene
    4. D An extra Y chromosome
    💡 Explanation:

    Down syndrome results from trisomy of chromosome 21, giving three copies instead of two.

  44. Q44 medium

    Turner syndrome in females results from having

    1. A An extra chromosome 21
    2. B Only one X chromosome (XO)
    3. C An extra X chromosome (XXY)
    4. D An extra chromosome 18
    💡 Explanation:

    Turner syndrome is caused by monosomy of the X chromosome, giving the karyotype 45,XO.

  45. Q45 medium

    Klinefelter syndrome is characterized by the karyotype

    1. A 45,XO
    2. B 47,XX,+21
    3. C 47,XXY
    4. D 46,XY
    💡 Explanation:

    Klinefelter syndrome occurs in males with an extra X chromosome, giving karyotype 47,XXY.

  46. Q46 medium

    Traits controlled by multiple genes, such as human skin color and height, show

    1. A Simple Mendelian inheritance
    2. B Polygenic inheritance
    3. C Codominant inheritance
    4. D Sex-linked inheritance
    💡 Explanation:

    Polygenic traits are influenced by several genes acting together, producing continuous variation.

  47. Q47 easy

    The process of copying a DNA sequence into a complementary mRNA strand is called

    1. A Transcription
    2. B Translation
    3. C Replication
    4. D Reverse transcription
    💡 Explanation:

    Transcription synthesizes mRNA from a DNA template using RNA polymerase.

  48. Q48 easy

    A change in the sequence of nucleotides in DNA is known as a

    1. A Crossing over
    2. B Mutation
    3. C Recombination
    4. D Translocation event
    💡 Explanation:

    A mutation is any permanent alteration in the DNA nucleotide sequence.

  49. Q49 medium

    A mutation that inserts or deletes a number of nucleotides not divisible by three, shifting the reading frame, is called a

    1. A Point mutation
    2. B Frameshift mutation
    3. C Silent mutation
    4. D Missense mutation
    💡 Explanation:

    Frameshift mutations alter the triplet reading frame downstream, usually causing a nonfunctional protein.

  50. Q50 medium

    A mutation that changes a codon but still codes for the same amino acid is called a

    1. A Nonsense mutation
    2. B Frameshift mutation
    3. C Silent mutation
    4. D Missense mutation
    💡 Explanation:

    Due to the redundancy of the genetic code, some base changes do not alter the resulting amino acid.

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