Class 12/Question Bank
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Questions on Principle of Inheritance
Who is known as the "Father of Genetics"? a) Charles Darwin b) Gregor Johann Mendel c) Thomas Hunt Morgan d) Walter Sutton
Mendel conducted his experiments on which plant? a) Pisum sativum b) Mirabilis jalapa c) Antirrhinum majus d) Drosophila melanogaster
The Law of Dominance states that: a) All traits are equally expressed b) Only one allele expresses itself in heterozygous individuals c) Both alleles express themselves d) Traits blend together
A cross between F1 hybrid and its recessive parent is called: a) Back cross b) Test cross c) Monohybrid cross d) Dihybrid cross
The graphical representation to calculate probability of offspring genotypes is: a) Pedigree chart b) Karyotype c) Punnett square d) Genetic map
Alternative forms of a gene are called: a) Genotypes b) Phenotypes c) Alleles d) Chromosomes
An individual with TT genotype is: a) Heterozygous b) Homozygous dominant c) Homozygous recessive d) Codominant
In incomplete dominance, the F2 phenotypic ratio is: a) 3:1 b) 9:3:3:1 c) 1:2:1 d) 1:1
The ABO blood group system is an example of: a) Incomplete dominance b) Codominance c) Multiple alleles d) Both b and c
Which blood group genotype shows codominance? a) IAIA b) IBIB c) IAIB d) ii
Traits controlled by multiple genes are called: a) Polygenic b) Pleiotropic c) Codominant d) Recessive
When one gene affects multiple traits, it is called: a) Polygenic inheritance b) Pleiotropy c) Codominance d) Incomplete dominance
The study of inheritance patterns through family history is: a) Karyotype analysis b) Pedigree analysis c) Genetic mapping d) Mutation analysis
The Chromosomal Theory of Inheritance was proposed by: a) Mendel and Morgan b) Sutton and Boveri c) Watson and Crick d) Darwin and Wallace
In humans, sex determination follows: a) XY type b) ZW type c) XO type d) Haplodiploidy
In birds, which sex is heterogametic? a) Males b) Females c) Both d) Neither
Honeybee males are: a) Diploid b) Haploid c) Triploid d) Tetraploid
Linkage was discovered by: a) Mendel b) Morgan c) Sutton d) Boveri
Crossing over occurs during: a) Prophase I of meiosis b) Metaphase I of meiosis c) Prophase II of meiosis d) Mitosis
The frequency of crossing over is proportional to: a) Gene size b) Chromosome size c) Distance between genes d) Number of alleles
A sudden heritable change in DNA is called: a) Variation b) Mutation c) Recombination d) Segregation
Replacement of A by G is an example of: a) Transition b) Transversion c) Frameshift d) Deletion
Haemophilia is a: a) Autosomal dominant disorder b) Autosomal recessive disorder c) X-linked dominant disorder d) X-linked recessive disorder
Colour blindness is more common in: a) Males b) Females c) Both equally d) Neither
Thalassemia is an: a) X-linked disorder b) Y-linked disorder c) Autosomal recessive disorder d) Autosomal dominant disorder
Sickle-cell anaemia is caused by: a) Chromosome deletion b) Point mutation c) Frameshift mutation d) Chromosome duplication
PKU is caused by deficiency of: a) Insulin b) Hemoglobin c) Phenylalanine hydroxylase d) Clotting factor
Down's syndrome is also called: a) Trisomy 18 b) Trisomy 21 c) Monosomy X d) XXY syndrome
Turner's syndrome has karyotype: a) 47, XXY b) 47, XYY c) 45, XO d) 46, XX
Klinefelter's syndrome affects: a) Females only b) Males only c) Both sexes d) Neither sex
The Law of Segregation is also known as: a) Law of Dominance b) Law of Independent Assortment c) Law of Purity of Gametes d) Law of Linkage
Mendel conducted experiments for how many years? a) 5 years b) 7 years c) 10 years d) 12 years
The period of Mendel's experiments was: a) 1856-1863 b) 1850-1857 c) 1860-1867 d) 1855-1862
A dihybrid cross involves: a) One pair of contrasting characters b) Two pairs of contrasting characters c) Three pairs of contrasting characters d) Multiple pairs of characters
The F2 ratio in a dihybrid cross is: a) 3:1 b) 1:2:1 c) 9:3:3:1 d) 1:1:1:1
Test cross is used to determine: a) Phenotype b) Genotype c) Linkage d) Mutation
Red flower (RR) × White flower (rr) gives pink flowers (Rr). This is: a) Complete dominance b) Incomplete dominance c) Codominance d) Multiple alleles
How many alleles control ABO blood group? a) 2 b) 3 c) 4 d) 5
Human skin color is an example of: a) Simple dominance b) Codominance c) Polygenic inheritance d) Sex-linked inheritance
Phenylketonuria affects: a) Only males b) Only females c) Both sexes equally d) More females than males
Starch synthesis in pea seeds is an example of: a) Polygenic inheritance b) Pleiotropy c) Codominance d) Incomplete dominance
Standardized symbols in pedigree analysis represent: a) Only sex b) Only affected status c) Sex, affected status, and relationships d) Only relationships
Chromosomes occur in pairs, similar to: a) Genes b) Alleles c) Phenotypes d) Mutations
Homologous chromosomes separate during: a) Mitosis b) Meiosis c) Both mitosis and meiosis d) Neither
In XY type sex determination, males are: a) Homogametic b) Heterogametic c) Hemizygous d) Homozygous
In ZW type sex determination, the heterogametic sex is: a) Male b) Female c) Both d) Neither
Grasshopper follows which type of sex determination? a) XY type b) ZW type c) XO type d) Haplodiploidy
Linked genes are located: a) On different chromosomes b) On the same chromosome c) On sex chromosomes only d) On autosomes only
Genes that do not assort independently are: a) Linked genes b) Allelic genes c) Polygenes d) Pleiotropic genes
Recombination is caused by: a) Mutation b) Crossing over c) Segregation d) Dominance
Spontaneous mutations occur due to: a) Mutagens b) Radiation c) Errors in DNA replication d) Chemicals
Induced mutations are caused by: a) Natural processes b) Mutagens c) Inheritance d) Dominance
Point mutations affect: a) Entire chromosome b) Multiple genes c) Single base pair d) Chromosome structure
Frameshift mutations are caused by: a) Base substitution b) Insertion or deletion c) Chromosome rearrangement d) Crossing over
Morgan studied sex-linked inheritance in: a) Pea plants b) Mice c) Drosophila d) Humans
Eye color in Drosophila is: a) Autosomal b) Sex-linked c) Polygenic d) Pleiotropic
Haemophilia is also known as: a) Sickle-cell disease b) Bleeder's disease c) Color blindness d) Thalassemia
The most common type of color blindness affects: a) Blue and yellow b) Red and green c) Black and white d) All colors
Mendelian disorders are caused by: a) Chromosome abnormalities b) Environmental factors c) Single gene mutations d) Multiple gene interactions
Thalassemia affects: a) Globin chain synthesis b) Insulin production c) Enzyme activity d) Chromosome structure
In sickle-cell anaemia, glutamic acid is replaced by: a) Alanine b) Valine c) Glycine d) Phenylalanine
Sickle-shaped red blood cells occur under: a) High oxygen tension b) Low oxygen tension c) Normal oxygen tension d) All conditions
PKU leads to accumulation of: a) Glucose b) Phenylalanine c) Hemoglobin d) Insulin
Mental retardation in PKU is caused by: a) Chromosome abnormality b) Enzyme deficiency c) Hormone imbalance d) Vitamin deficiency
Chromosomal disorders are caused by: a) Single gene mutations b) Environmental factors c) Chromosome abnormalities d) Dominant alleles
Down's syndrome is caused by: a) Missing chromosome b) Extra chromosome c) Chromosome rearrangement d) Point mutation
The karyotype of Down's syndrome is: a) 45, XO b) 47, XXY c) 47, XX or XY, +21 d) 46, XY
Turner's syndrome affects: a) Males only b) Females only c) Both sexes d) Neither sex
Sterile females with rudimentary ovaries indicate: a) Down's syndrome b) Turner's syndrome c) Klinefelter's syndrome d) Sickle-cell anaemia
Klinefelter's syndrome shows: a) 45, XO b) 47, XXY c) 47, XYY d) 46, XX
Gynecomastia is a symptom of: a) Turner's syndrome b) Down's syndrome c) Klinefelter's syndrome d) Hemophilia
Mendel's laws apply to genes located on: a) Same chromosome only b) Different chromosomes only c) Sex chromosomes only d) Different chromosomes or far apart on same chromosome
The unit of inheritance according to Mendel is: a) Chromosome b) Gene c) Allele d) Factor
Discrete units controlling characters are called: a) Genes b) Factors c) Alleles d) Both a and b
Gametes receive how many alleles for each gene? a) One b) Two c) Three d) Four
The Law of Independent Assortment applies to: a) Linked genes b) Unlinked genes c) Sex-linked genes d) Lethal genes
Back cross involves: a) F1 × F1 b) F1 × Parent c) F1 × Recessive parent d) Parent × Parent
The purpose of test cross is to determine: a) Dominance b) Recessiveness c) Genotype of dominant phenotype d) Phenotype ratio
Punnett square was developed by: a) Mendel b) Morgan c) Reginald C. Punnett d) Sutton
Probability calculations in genetics use: a) Pedigree charts b) Karyotypes c) Punnett squares d) Genetic maps
Observable characteristics are called: a) Genotype b) Phenotype c) Alleles d) Genes
Genetic constitution is called: a) Phenotype b) Genotype c) Karyotype d) Ideotype
TT genotype shows: a) Heterozygous dominant b) Homozygous dominant c) Heterozygous recessive d) Homozygous recessive
Environment affects: a) Genotype only b) Phenotype only c) Both genotype and phenotype d) Neither
Blended phenotype in heterozygote indicates: a) Complete dominance b) Incomplete dominance c) Codominance d) Multiple alleles
Snapdragon flower color shows: a) Complete dominance b) Incomplete dominance c) Codominance d) Sex-linkage
Four O'clock plant is: a) Pisum sativum b) Antirrhinum majus c) Mirabilis jalapa d) Drosophila melanogaster
Both alleles fully express in: a) Incomplete dominance b) Codominance c) Complete dominance d) Recessiveness
Blood group AB shows: a) Dominance of A b) Dominance of B c) Codominance of A and B d) Recessiveness of both
More than two alleles for a gene in population indicates: a) Polygenic inheritance b) Multiple alleles c) Pleiotropy d) Linkage
Human height is controlled by: a) Single gene b) Two genes c) Multiple genes d) Sex-linked genes
Additive effect of multiple genes results in: a) Qualitative traits b) Quantitative traits c) Sex-linked traits d) Lethal traits
Single gene affecting multiple traits is: a) Polygenic b) Pleiotropic c) Codominant d) Recessive
PKU affects: a) Only intelligence b) Only skin color c) Multiple traits d) Only hair color
Family history study is called: a) Karyotype analysis b) Pedigree analysis c) Linkage analysis d) Mutation analysis
Pedigree analysis helps determine: a) Genotype only b) Phenotype only c) Mode of inheritance d) Mutation rate
Autosomal dominant inheritance shows: a) Horizontal pattern b) Vertical pattern c) Random pattern d) Circular pattern
X-linked recessive traits are more common in: a) Females b) Males c) Both equally d) Neither
Genetic mapping uses: a) Pedigree analysis b) Crossing over frequency c) Mutation rate d) Dominance pattern
The basic unit of genetic mapping is: a) Gene b) Chromosome c) Map unit d) Allele
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