All Free Biology MCQs with Answers

• A. The Y-chromosome of males has the genes for distinguishing colours
• B. Genes responsible for certain traits, including colour blindness, are located on the X chromosome, which is part of the sex chromosomes
• C. The trait is dominant in males and recessive in females
• D. None of the above

Explanation: Color blindness is caused by a recessive gene located on the X chromosome.

• A. X-chromosome of father
• B. Y-chromosome of father
• C. One X-chromosome of mother
• D. Both X-chromosomes of mother

Explanation: The gene for hemophilia is located on one of the X-chromosomes of the mother, making her a carrier.

• A. The principle of independent assortment is incorrect
• B. Mendel might not have studied all the combinations
• C. It is impossible
• D. Later studies may be incorrect

Explanation: The correct answer is that Mendel might not have studied all the combinations.

• A. IOIO
• B. IBIB
• C. IAIB
• D. IBIO

Explanation: The child has an O-group, indicating a genotype of IOIO, which means both parents must contribute an IO allele.

• A. Her mother and maternal grandfather were colour blind
• B. Her father and maternal grandfather were colour blind
• C. Her mother is colour blind and father has normal vision
• D. Parents have normal vision but grandparents were colour blind

Explanation: The correct option is B: Her father and maternal grandfather were colour blind.

• A. Recessive character carried by Y-chromosome
• B. Dominant character carried by Y-chromosome
• C. Dominant trait carried by X-chromosome
• D. Recessive trait carried by X-chromosome

Explanation: The correct option is d) Recessive trait carried by X-chromosome.Hemophilia is a genetic disorder that affects the blood's ability to clot…

• A. The trait for albinism is dominant
• B. The albinos have a biochemical to destroy plastids derived from the green male
• C. Plastids are inherited from the female parent
• D. Green plastids of the male must have mutated

Explanation: This question is tough and is included in the QBank for the thorough preparation of Students.The correct answer is that plastids are…

• A. 0%
• B. 25%
• C. 50%
• D. 100%

Explanation: In humans, sex determination is governed by the X and Y chromosomes. A female (XX) can only provide an X chromosome, while a male (XY) can…

• A. A pair of genes governing a specific character
• B. Genes governing eye characters
• C. Multiple forms of genes
• D. Genes present on allosomes

Explanation: Multiple alleles .' Alleles are different versions of the same gene found at a particular locus on a chromosome.

• A. Complete dominance and Co-dominance
• B. Incomplete dominance and Co-dominance
• C. Over dominance and Incomplete dominance
• D. Complete dominance only

Explanation: The ABO blood group system is a classic example of both complete dominance and co-dominance.

• A. Sister chromatids of homologous chromosomes
• B. Non-sister chromatids of homologous chromosomes
• C. Non-sister chromatids of non-homologous chromosomes
• D. Sister chromatids of non-homologous chromosomes

Explanation: The correct answer is B. During meiosis, homologous chromosomes undergo a process called synapsis, where they align closely.

• A. Hemophilia
• B. Color blindness
• C. Phenylketonuria (PKU)
• D. Epilepsy

Explanation: Epilepsy is identified as a neurological disorder characterized by recurrent seizures and is not classified solely as a genetic disorder…

• A. Homozygous and tall heighted
• B. Heterozygous and tall heighted
• C. Homozygous and short heighted
• D. Heterozygous and short heighted

Explanation: Mendel's law of segregation states that alleles separate during gamete formation, and each gamete carries only one allele for each trait.

• A. Option A: Both parents have genotype 'AO'
• B. Option B: Both parents have genotype 'BO'
• C. Option C: Both parents have genotype 'AB'
• D. Option D: Both parents have genotype 'OO'

Explanation: Parents with the genotype 'OO' can only have children with blood group O, as the 'O' allele is recessive.

• A. Physical association of genes on a chromosome
• B. Physiological association of genes
• C. Both physical and physiological associations
• D. Neither physical nor physiological associations

Explanation: The correct answer is Option A: Physical association of genes on a chromosome.

• A. Colour blindness
• B. TFM (Testicular Feminization)
• C. Haemophilia
• D. Leukemia

Explanation: The correct option is D) Leukemia. Leukemia is a form of cancer affecting blood and bone marrow, resulting from genetic mutations not…

• A. Mutation
• B. Genetic recombination during gametogenesis
• C. Gene flow
• D. All A, B, C

Explanation: The correct answer is D: All A, B, C. Each of these processes plays a role in genetic variation. Mutation introduces new genetic variants.

• A. A reduction of blood clotting factors
• B. A malfunction of blood clotting factors
• C. A complete absence of blood clotting factors
• D. A reduction in hemopoietic stem cells

Explanation: The correct answer is Option D: A reduction in hemopoietic stem cells. Hemophilia is specifically related to deficiencies or malfunctions…

• A. Protanopia
• B. Tritanopia
• C. Dichromacy

Explanation: The correct answer is Protanopia. This condition is a severe form of red-green color blindness where individuals cannot perceive red light…

• A. Female genitalia
• B. No breast development
• C. Blind vagina
• D. Degenerated testes

Explanation: The correct answer is Option B: No breast development. Individuals with testicular feminization syndrome usually develop breasts due to…