Match List-I (Sex Chromosome Complement) with List-II (Organism/Sex):
List-I
List-II
A. Autosomes + XX
I. Human/Drosophila female
B. Autosomes + XY
II. Human/Drosophila male
C. Autosomes + ZW
III. Female bird
D. Autosomes + ZZ
IV. Male bird
Choose the correct answer from the options given below:
Human/Drosophila females have XX. Human/Drosophila males have XY. Female birds exhibit ZW chromosomes (female heterogamety). Male birds exhibit ZZ chromosomes.
Question 312 of 519
📘 CLASS XII
Match List-I (Mendelian Trait Pair) with List-II (Dominant/Recessive):
List-I
List-II
A. Seed colour
I. Yellow (Dominant) / Green (Recessive)
B. Seed shape
II. Round (Dominant) / Wrinkled (Recessive)
C. Pod shape
III. Inflated (Dominant) / Constricted (Recessive)
D. Flower position
IV. Axial (Dominant) / Terminal (Recessive)
Choose the correct answer from the options given below:
Seed colour contrast is Yellow/Green. Seed shape contrast is Round/Wrinkled. Pod shape contrast is Inflated/Constricted. Flower position contrast is Axial/Terminal. Yellow, Round, Inflated, and Axial are the dominant traits, respectively.
Question 313 of 519
📘 CLASS XII
Match List-I (Honey Bee Sex Determination) with List-II (Chromosome Status/Mechanism):
List-I
List-II
A. Female (Queen/Worker)
I. Diploid (32 chromosomes)
B. Male (Drone)
II. Haploid (16 chromosomes)
C. Development of Male
III. Parthenogenesis (unfertilised egg)
D. Sperm production in males
IV. Mitosis
Choose the correct answer from the options given below:
Females are diploid (32 chromosomes). Males are haploid (16 chromosomes). Males develop from unfertilised eggs via parthenogenesis. Males produce sperm by mitosis.
Question 314 of 519
📘 CLASS XII
Match List-I (Mechanism of Change in Chromosome Number) with List-II (Description/Cause):
List-I
List-II
A. Aneuploidy
I. Failure of chromatid segregation during cell division cycle
B. Trisomy
II. Presence of an additional copy of a chromosome
C. Monosomy
III. Lack of one of any one pair of chromosomes
D. Polyploidy
IV. Failure of cytokinesis after telophase stage of cell division
Choose the correct answer from the options given below:
Aneuploidy results from failure of chromatid segregation. Trisomy means an additional copy of a chromosome. Monosomy means lacking one chromosome of a pair. Polyploidy results from the failure of cytokinesis after telophase, increasing the whole set of chromosomes.
Question 315 of 519
📘 CLASS XII
Match List-I (Genetic Disorder Type) with List-II (Example/Defining Cause):
List-I
List-II
A. Mendelian Disorder
I. Determined by alteration or mutation in a single gene
B. Chromosomal Disorder
II. Caused due to absence or excess of one or more chromosomes
C. Thalassemia
III. Quantitative problem of synthesizing too few globin molecules
D. Sickle-cell anaemia
IV. Qualitative problem of synthesizing an incorrectly functioning globin
Choose the correct answer from the options given below:
Mendelian disorders are caused by single gene mutations. Chromosomal disorders are caused by abnormal chromosome arrangements or numbers. Thalassemia is a quantitative problem (too few globin molecules). Sickle-cell anaemia is a qualitative problem (incorrectly functioning globin).
Question 316 of 519
📘 CLASS XII
Match List-I (Genetics Pioneer) with List-II (Key Area of Work):
List-I
List-II
A. Gregor Mendel
I. Used statistical analysis and mathematical logic in biology
B. T.H. Morgan
II. Coined the terms linkage and recombination
C. Watson and Crick
III. Proposed the complementary double-helical configuration of DNA
D. W. Sutton
IV. United chromosomal segregation with Mendelian principles
Choose the correct answer from the options given below:
Mendel was the first to use statistical analysis in biology. Morgan coined the terms linkage and recombination. Watson and Crick proposed the DNA double-helical configuration. Sutton united chromosomal segregation with Mendelian principles.
Question 317 of 519
📘 CLASS XII
Match List-I (Mendelian Observation) with List-II (Resulting Concept/Law):
List-I
List-II
A. F1 always resembled one parent
I. Dominance
B. Recovery of both traits in F2 (3:1)
II. Segregation
C. Dihybrid F2 ratio (9:3:3:1)
III. Independent Assortment
D. Crossing F2 tall plant with dwarf plant
IV. Test Cross
Choose the correct answer from the options given below:
F1 resembling one parent supports the Law of Dominance. Recovery of both traits in F2 supports the Law of Segregation. The 9:3:3:1 ratio in dihybrid crosses supports the Law of Independent Assortment. Crossing an F2 dominant phenotype with the recessive parent is a Test Cross.
Question 318 of 519
📘 CLASS XII
Match List-I (Human Disorder Symptom) with List-II (Condition):
List-I
List-II
A. Broad flat face, furrowed tongue, mental retardation
I. Down’s Syndrome
B. Gynaecomastia, overall masculine development, sterility
II. Klinefelter’s Syndrome
C. Rudimentary ovaries, lack of secondary sexual characters, sterility
III. Turner’s Syndrome
D. Accumulation of phenylpyruvic acid in brain
IV. Phenylketonuria
Choose the correct answer from the options given below:
Down’s Syndrome symptoms include short stature, small round head, furrowed tongue, and mental retardation. Klinefelter’s Syndrome symptoms include masculine development and gynaecomastia (development of breast). Turner’s Syndrome symptoms include rudimentary ovaries and sterility in females. Phenylketonuria is characterized by the accumulation of phenylalanine derivatives in the brain, leading to mental retardation.
Question 319 of 519
📘 CLASS XII
Match List-I (Concept/Term) with List-II (Mendel’s Idea):
List-I
List-II
A. Units of inheritance
I. Factors
B. Opposing traits
II. Manifested as contrasting pairs (e.g., Tall/Dwarf)
C. True-breeding line
III. Stable trait inheritance over several generations through self-pollination
D. Basis of heredity
IV. Inheritance
Choose the correct answer from the options given below:
Mendel called units of inheritance 'factors'. He investigated characters manifested as two opposing traits. A true-breeding line shows stable trait inheritance after continuous self-pollination. Inheritance is the basis of heredity.
Question 320 of 519
📘 CLASS XII
Match List-I (Mendelian Trait) with List-II (Allelic Pair in True Breeding Variety):
List-I
List-II
A. Tall plant
I. TT
B. Dwarf plant
II. tt
C. Homozygous dominant
III. Capital letters (e.g., RR)
D. Heterozygous
IV. Dissimilar alleles (e.g., Tt)
Choose the correct answer from the options given below:
True breeding tall plant is homozygous TT. True breeding dwarf plant is homozygous tt. Homozygous dominant uses capital letters. Heterozygous means dissimilar alleles.
