Principles

A.     Assertion: Phenylketonuria is a recessive hereditary disease caused by body’s failure to oxidize an amino acid phenylalanine to tyrosine, because of a defective enzyme.

Reason: It results in the presence of phenylalanine acid in urine.

1.      Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

2.      Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

3.      Assertion is true but Reason is false.

4.      Both Assertion and Reason are false.

• 1

• 2

• 3

• 4

2. 9:7 ratio in the F2 generation represents

• incomplete dominance

• co - dominance

• epistasis

• complementary interaction

ABO blood groups in humans is an example of

• pleiotropy

• only multiple allelism

• multiple allelism and co dominance

• only co dpminance

In a certain flowering plant species, flower color shows incomplete dominance. When a plant with red flowers (RR) is crossed with a plant with white flowers (WW), all F₁ offspring have pink flowers (RW). If two F₁ plants are crossed and 100 seeds are planted, which of the following best explains the expected phenotypic outcome, and how many plants will likely exhibit the parental phenotypes?

• All 100 plants will be pink, as pink is the dominant trait.

• Approximately 25 will be red, 50 pink, and 25 white due to Mendelian segregation with incomplete dominance.

• Only 50 plants will show the parental phenotypes because the rest are heterozygous.

• Incomplete dominance prevents parental traits from reappearing in F₂, so none will be red or white.

Why is the HbA HbS genotype considered advantageous in malaria-endemic regions?

• It causes no symptoms and provides full immunity to all diseases

• It leads to severe anemia but protects against malaria

• It offers resistance to malaria without causing full-blown sickle cell disease

• It prevents malaria by destroying red blood cells quickly

  
  

Which of the following genetic conditions is indicated by the karyotype shown above?

• Turner’s Syndrome

• Down’s Syndrome

• Klinefelter’s Syndrome

• Edward’s Syndrome

The pedigree chart given below represents the pattern of inheritance of thalassemia in a family. What could be the genotype of the affected male?

• TT

• Tt

• tt

• tttt

What conclusion can be drawn from the data regarding the inheritance of skin colour?

• Skin colour follows Mendelian monohybrid inheritance

• The most common skin colour among offspring is the darkest one

• The trait shows discontinuous variation

• The trait is polygenic and shows continuous variation with most offspring having intermediate pigmentation

  
  

Shown below is the karyotype of an individual. Observe the image and state which abnormality during cell division causes such disorders

• Crossing over

• Non-disjunction

• Translocation

• Inversion

A genotype of a plant showing dominant phenotype can be determined by

• test cross

• dihybrid cross

• pedigree analysis

• back cross