Practice: Heredity & Variations (Basic Genetics)
Knowledge Check
Heredity and Variations
Q1: Heredity mainly explains which of the following observations?
A) Why all individuals of a species are exactly identical
B) Why children resemble their parents in many traits
C) Why environment never affects organisms
D) Why mutations never occur in nature
Q2: The basic unit of heredity which controls a particular trait is called:
A) Chromosome
B) Gene
C) DNA helix
D) Nucleus
Q3: Which statement about variation in a population is correct?
A) Variation never occurs among offspring
B) Variation has no role in evolution
C) Variation helps some individuals survive better in changing environment
D) Variation is always harmful and must be stopped
Q4: Muscular body of a trained athlete is an example of:
A) Inherited variation
B) Acquired variation
C) Chromosomal mutation
D) Dominant trait always from parents
Q5: Which of the following is most clearly a discontinuous variation?
A) Height in a class of students
B) Weight in a class of students
C) Blood group (A, B, AB, O)
D) Colour shade of skin from very fair to dark
Q6: In human body cells, the total number of chromosomes normally present is:
A) 23
B) 44
C) 46
D) 92
Q7: Which combination is correctly matched?
A) DNA – present in cytoplasm only
B) Gene – present on chromosome
C) Chromosome – made only of proteins
D) Trait – never controlled by genes
Q8: Which feature in a child is most strongly influenced by heredity rather than daily habits?
A) Language spoken
B) Blood group
C) School uniform colour
D) Writing style in notebook
Q9: Which statement correctly compares inherited and acquired traits?
A) Both are always passed to next generation
B) Inherited traits are genetic; acquired traits arise from environment and practice
C) Only acquired traits are controlled by genes
D) Neither inherited nor acquired traits are influenced by genes
Q10: Which term refers to the observable appearance of a character such as tall or dwarf?
A) Genotype
B) Phenotype
C) Karyotype
D) Gametotype
Mendel’s Experiments on Inheritance
Q11: Gregor Johann Mendel is known as:
A) Father of Evolution
B) Father of Genetics
C) Father of Physiology
D) Father of Ecology
Q12: Mendel mainly performed his classical experiments on which plant?
A) Wheat
B) Rice
C) Garden pea (Pisum sativum)
D) Cotton plant
Q13: A cross between tall pea plant (TT) and dwarf pea plant (tt) is an example of:
A) Monohybrid cross
B) Dihybrid cross
C) Test cross
D) Back cross with recessive parent only
Q14: In Mendel’s monohybrid cross of pure tall and pure dwarf pea plants, the F₁ generation showed:
A) All dwarf plants
B) All tall plants
C) Half tall and half dwarf plants
D) 3 tall : 1 dwarf plants
Q15: In the same monohybrid cross, the phenotypic ratio in F₂ generation is:
A) 1 tall : 1 dwarf
B) 3 tall : 1 dwarf
C) 1 tall : 3 dwarf
D) 1 TT : 2 Tt : 1 tt only (phenotype)
Q16: When pure tall (TT) pea plant is crossed with pure dwarf (tt), the genotype of all F₁ plants is:
A) TT
B) tt
C) Tt
D) TTTT only in all cells
Q17: Which pair of terms correctly represents alleles?
A) TT and tt
B) T and t
C) Tall plant and dwarf plant
D) Flower and fruit only
Q18: Which statement best describes a recessive trait in Mendel’s experiments?
A) It is always expressed, even in presence of dominant allele
B) It appears in F₁ generation only
C) It is masked in F₁ but reappears in F₂ generation
D) It never appears in F₂ generation at all
Q19: In a monohybrid F₂ generation, which genotype combination gives tall phenotype?
A) TT and Tt
B) Tt and tt
C) TT and tt
D) Only tt always
Q20: Mendel’s conclusion that factors separate during gamete formation corresponds to which modern concept?
A) Mutations in somatic cells
B) Segregation of alleles during meiosis
C) Fusion of gametes during fertilisation
D) Crossing over between chromatids only in all cells
Sex Determination
Q21: In humans, sex of the child is mainly determined by:
A) Mother’s blood group
B) Father’s sperm carrying X or Y chromosome
C) Mother’s food habits during pregnancy
D) Number of autosomes present in egg cell only
Q22: The normal chromosomal constitution of a human male is:
A) 44 + XX
B) 44 + XY
C) 22 + X
D) 22 + Y only in all body cells
Q23: Which combination will result in birth of a female child in humans?
A) X egg + X sperm
B) X egg + Y sperm
C) Y egg + X sperm
D) Y egg + Y sperm
Q24: In human females, the sex chromosomes in all body cells are:
A) XY
B) YY
C) XX
D) XO always in all cells of body
Q25: Which statement about sex determination in humans is scientifically correct?
A) Mother decides the sex of child
B) Father decides the sex of child by contributing X or Y chromosome
C) Sex of child depends on food eaten before conception
D) Sex chromosomes of parents have no role in sex determination
Q26: In humans, a sperm cell differs from an egg cell in that only sperm can have:
A) 23 chromosomes
B) Autosomes
C) Either X or Y sex chromosome
D) Only X sex chromosome always in all sperm cells
Q27: If a couple has two daughters, which statement is correct scientifically?
A) Mother is responsible for daughters
B) Father is responsible for daughters
C) Both parents have consciously selected daughters
D) Sex of children is decided by environment only, not chromosomes at all
Q28: In birds (for basic awareness), sex determination pattern is opposite to humans. Here the female has:
A) XX and male has XY
B) XY and male has XX
C) ZZ and male has ZW
D) ZW and male has ZZ sex chromosomes
Q29: Which of the following genotypes correctly represents a human female and a human male?
A) Female XX, male XY
B) Female XY, male XX
C) Female XO, male YY (normal)
D) Female XX, male YY (normal)
Q30: Which message is most appropriate to teach with topic of sex determination at school level?
A) Gender of child depends on mother’s wishes
B) Only sons are important for family and society
C) Sex of child is a natural chromosomal event and girls and boys deserve equal respect
D) Scientific information is not needed for understanding family decisions at all