Remark: In polygenic inheritance, the effect of each allele is additive. The underlying mechanism of pleiotropy involves the effect of a gene on metabolic pathways. Polygenic traits are influenced by the environment. A single gene exhibiting multiple phenotypic expressions is called a pleiotropic gene.
Match List-I (Pedigree Symbol Description) with List-II (Figure 4.13 Symbol Meaning):
List-I
List-II
A. Square
I. Male
B. Circle
II. Female
C. Shaded shape
III. Affected individual
D. Line connecting male and female
IV. Mating
Choose the correct answer from the options given below:
Remark: In pedigree analysis, a square denotes a male. A circle denotes a female. A shaded shape denotes an affected individual. A horizontal line connecting a male and female denotes mating.
Match List-I (Mendelian Contrasting Traits) with List-II (Dominant/Recessive Pair):
List-I (Character)
List-II (Traits)
A. Pod colour
I. Green/yellow
B. Flower position
II. Axial/terminal
C. Pod shape
III. Inflated/constricted
D. Seed shape
IV. Round/wrinkled
Choose the correct answer from the options given below:
Remark: These are four of the seven contrasting traits studied by Mendel. Pod colour is Green (dominant)/yellow (recessive). Flower position is Axial (dominant)/terminal (recessive). Pod shape is Inflated (dominant)/constricted (recessive). Seed shape is Round (dominant)/wrinkled (recessive).
Match List-I (Historical Figure) with List-II (Specific Context/Timeline):
List-I
List-II
A. J. D. Watson (PhD)
I. Study of effect of hard X-rays on bacteriophage (1950)
B. F. H. C. Crick (PhD)
II. Thesis entitled “X-ray Diffraction: Polypeptides and Proteins” (1954)
C. Proposal of Double Helix
III. Early in March 1953
D. Mendel’s Hybridisation Experiments
IV. Seven years (1856-1863)
Choose the correct answer from the options given below:
Remark: Watson received his Ph.D. in 1950 studying X-rays on bacteriophage. Crick completed his Ph.D. in 1954 on X-ray Diffraction: Polypeptides and Proteins. The double helix configuration was proposed early in March 1953. Mendel conducted his experiments for seven years (1856-1863).
Match List-I (Pedigree Symbol) with List-II (Meaning):
List-I (Symbol)
List-II (Significance)
A. Square
I. Male
B. Circle
II. Female
C. Shaded Symbol
III. Affected individual
D. Diamond
IV. Sex unspecified
Choose the correct answer from the options given below:
Remark: In pedigree analysis, a square denotes a male. A circle denotes a female. A shaded shape denotes an affected individual. A diamond shape (not explicitly shown in text but implied by Figure 4.13 captions in typical texts) represents sex unspecified.
Match List-I (Chromosomal Disorder) with List-II (Cause/Karyotype):
List-I
List-II
A. Down’s Syndrome
I. Trisomy of chromosome 21
B. Klinefelter’s Syndrome
II. Additional copy of X-chromosome (47, XXY)
C. Turner’s Syndrome
III. Absence of one X chromosome (45, X0)
D. Aneuploidy
IV. Failure of segregation of chromatids during cell division cycle
Choose the correct answer from the options given below:
Remark: Down’s Syndrome is caused by trisomy 21. Klinefelter’s Syndrome is due to 47, XXY. Turner’s Syndrome is caused by 45, X0. Aneuploidy results from the failure of chromatid segregation.
Match List-I (Allele Interaction) with List-II (Genotype and Phenotype):
List-I
List-II
A. Co-dominance
I. $I^A I^B$ genotype results in AB phenotype (resembles both parents)
B. Incomplete Dominance
II. F1 (Rr) is pink (intermediate phenotype)
C. Complete Dominance
III. F1 (Tt) is tall (resembles one parent)
D. Multiple Alleles
IV. Gene I has $I^A, I^B,$ and $i$ alleles
Choose the correct answer from the options given below:
Remark: Co-dominance (AB blood group) results in the F1 resembling both parents. Incomplete dominance (Snapdragon) results in an intermediate phenotype. Complete dominance (Pea height) results in the F1 resembling only one parent. Multiple alleles are present when three or more alleles govern one character, like the I gene.
Match List-I (Sickle-Cell Anaemia Molecular Change) with List-II (Specific Detail):
List-I (Molecular Change)
List-II (Specific Detail)
A. Type of Mutation
I. Point Mutation
B. Codon altered (6th position)
II. GAG changed to GUG
C. Amino acid substituted
III. Glutamic acid by Valine
D. Effect under low oxygen tension
IV. Polymerisation of mutant haemoglobin causing RBC shape change
Choose the correct answer from the options given below:
Remark: Sickle-cell anaemia is caused by a point mutation. The 6th codon changes from GAG to GUG. This results in Glutamic acid being substituted by Valine. The mutant haemoglobin polymerizes under low oxygen tension, changing the RBC shape.
Match List-I (Polygenic/Pleiotropy Concept) with List-II (Mechanism/Example):
List-I
List-II
A. Polygenic trait
I. Controlled by three or more genes
B. Allelic contribution in polygenic trait
II. Additive effect on phenotype
C. Pleiotropic gene underlying mechanism
III. Effect on metabolic pathways
D. Phenylketonuria manifestation
IV. Mental retardation and reduction in hair/skin pigmentation
Choose the correct answer from the options given below:
Remark: Polygenic traits are controlled by three or more genes. The effect of each allele is additive in polygenic traits. Pleiotropy works by affecting metabolic pathways. Phenylketonuria manifests as mental retardation and reduced pigmentation.
Match List-I (Blood Disorder Classification) with List-II (Disease Example/Problem Type):
List-I
List-II
A. Qualitative problem
I. Sickle-cell anaemia (incorrectly functioning globin)
B. Quantitative problem
II. Thalassemia (synthesizing too few globin molecules)
C. Autosome linked recessive trait
III. Sickle-cell anaemia and Thalassemia
D. X-linked recessive trait
IV. Haemophilia and Colour blindness
Choose the correct answer from the options given below:
Remark: Sickle-cell anaemia is a qualitative problem (incorrect globin function). Thalassemia is a quantitative problem (too few globin molecules synthesized). Both Sickle-cell anaemia and Thalassemia are autosomal recessive traits. Haemophilia and Colour blindness are X-linked recessive traits.
