Principles of Inheritance and Variation (Class - XII)
Comprehensive quiz covering Mendelian inheritance, chromosomal variations, sex determination, and genetic disorders for Class XII Biology
Questions
Chiasmata formation in Drosophila
- generally takes place in males and females
- takes place only in males
- never or rarely takes place in males
- never or rarely take place in females
In which of the following crosses will the progenies obtained be fifty percent homozygous recessive and fifty percent heterozygous?
- TT x Tt
- Tt x Tt
- Tt x tt
- TT x tt
‘Gametes are never hybrid’. It is a statement of the law of
- dominance
- segregation
- independent assortment
- random fertilisation
- linkage
A Barr body is present in a male child. The syndrome most likely to occur is
- Klinefelter’s syndrome
- Down’s syndrome
- Turner's syndrome
- Edward’s syndrome
- Trisomy
A cross between yellow round and green wrinkled seed pea plants gave the following four types of progeny in equal proportions: yellow round, yellow wrinkled, green round and green wrinkled. The genotypes of the parents in this case must be
- YYRR X yyrr
- YyRr X yyrr
- YYRR X YYRR
- YyRr X YYRR
- yyrr X yyrr
Sex-influenced genes are coded by
- autosomal genes
- X linked genes
- Y linked genes
- epistatic genes
- none of the above
Phenylketonuria is a genetic disorder of
- trisomic condition
- monosomic dominant gene
- autosomal dominant gene
- autosomal recessive gene
- None of these
When chromosome sets are present in multiples of ‘n’, the condition is called
- polyploidy
- aneuploidy
- euploidy
- diploidy
- monoploidy
Which of the following chromosome numbers is present in a trisomic individual?
- 2n + 1
- 2n - 1
- 2n - 2
- 2n + 2
Loss of one chromosome from one set is called
- tetrasomy
- nullisomy
- monosomy
- trisomy
The addition or deletion of one or more chromosomes in a set is called
- euploidy
- aneuploidy
- polyploidy
- heteroploidy
What would a gene be called if it is inherited by both males and females, but expressed differently in the phenotype of a boy and a girl?
- Unstable
- Sex-controlled
- Recessive
- Structural
- Dominant
Drosophila flies with XXY genotype are females, but human beings with such genotype are abnormal males. It shows that
- Y-chromosome is essential for sex determination in Drosophila
- Y-chromosome is female determinator in Drosophila
- Y-chromosome is male determinator in human beings
- Y-chromosome has no role in sex determination either in Drosophila or in human beings
- None of the above
Assertion (A): In Klinefelter’s syndrome, the chromosomal constitution of man is 22AA + XXY.
Reasoning (R): Few men have XX karyotype and yet are males. This is a rare phenomenon due to translocation of a small segment of Y chromosome attached to an X chromosome and is inherited in concert with X. Choose the correct option for the above statements.
- Both Assertion and Reasoning are true and R is the correct explanation of A.
- Both Assertion and Reasoning are true and R is not the correct explanation of A.
- A is true and R is false.
- Both A and R are false.
- A is false and R is true.
The genotypic ratio in a monohybrid cross is
- 3 : 1
- 9 : 3 : 3 : 1
- 2 : 2 : 1
- 1 : 2 : 1
- 2 : 1 : 3