Class 12th Biology – 5 Heredity and Variation MCQs
Haemophilia is more common in males because it is a
Haemophilia is a sex linked recessive trait carried by X chromosome (also known as bleeder's disease).
Which pair is chromosomal aberration?
Duplication & Translocation is chromosomal abberrations. Duplication & translocation both are mutation.
Mendel proposed which of following term for hereditary units?
Mendel factor now known as gene (Johannsen, 1905) is a unit of inheritance.
Mutation caused by a mutagen is
Mutation induced by a mutagen are called as induced mutation.
Mendel’s factors are now known as ____.
Mendel’s factors are now known as genes.
In pea plants, size of starch grains and seed shape is controlled by ____.
In pea plants, size of starch grains and seed shape is controlled by the same gene with two alleles.
A gene is said to be dominant if
A dominant gene would lead to the expression of its phenotype irrespective of the fact whether its allelic gene is dominant or recessive.
Experimental proof for the chromosome theory of inheritance was provided by ____.
Experimental proof for the chromosome theory of inheritance was provided by Morgan.
In co-dominance, F1 hybrids show ____.
In co dominance, F1 hybrids show both dominant and recessive characters side by side.
In man, which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes
An addition or loss of chromosomes is more or less than an entire set of chromosomes, is known as aneploidy.
Frameshift mutations are caused by ____.
Frameshift mutations are caused by deletion or insertion of a nucleotide. As a result of deletion or insertion of nucleotides the entire sequence of triplet codons involved in protein synthesis changes.
Linkage map construction is based on ____.
Linkage map construction is based on crossing over frequency.
Haemophilia is
Haemophilia is a X-linked disease. It is also known as Royal's disease. Haemophilia is due to mutation in factor VIII of blood clotting Anti -Haemophilic Globin factor(AHG) which is also known as AHF (Anti Haemophilic Factor).
Which one of the following traits of garden pea studied by Mendel was a recessive feature?
Yellow seed colour is dominant over green seed colour.
45+X embryos are born with ____.
45 +X, embryos are born with Turner’s syndrome. It affects development in females due to missing X chromosome.
The branch of botany dealing with heredity and variation is called
Genetics is the study of principles and mechanism of heredity and variations.
ZW method of sex determination is seen in ____.
ZW method of sex determination is seen in birds.
Haemophilia is an example of ____ disease.
Haemophilia is an example of a sex-linked recessive disease. It is associated with the X chromosome.
Identify the wrong statement
In domesticated fowls the sex is determined by the ovum.
What type of gametes will form by genotype RrYy?
RrYy is a dihybrid, so four type of gametes are formed as RY, Ry, rY, ry.
Alleles are form of
Allele is an alternative form of a gene for example, T and t alleles represent tall and short stem height of pea plant.
A dihybrid condition is
Dihybrid condition involves simultaneous inheritance of two pairs of mendelian factors or genes.
On inbreeding, the homozygous parents plants will produce ____.
On inbreeding, the homozygous parent plants will produce all similar offspring. Homozygous plants have both the alleles of the same type and hence the offspring produced will of the same type.
Down’s syndrome is a genetic disorder characterized by ____.
Down’s syndrome is a genetic disorder characterized by all body cells having an extra chromosome.
Genes located on Y-chromosome are
Holandric genes are present on the differential region of the Y-chromosome. The differential regions carry completely sex linked genes and they do not undergo crossing over.
An organism with two identical alleles is
Homozygous individuals have identical mendelian factors or genes for a character (TT or tt). They are always pure for a particular trait (character).
The number of autosomes in human female ovum is
In human female ovum, number of autosome are 22 pairs.
The resemblance of individuals to their progenitors is called
Heredity is the transmission of genetic characters from parents to the offspring.
Mutation is
Mutation is generally recessive. Mutation is a process which produces a heritable alteration in the genotype. Mutations are classified into two main types: (a) Chromosomal mutation; (b) Point mutation.
One of the contrasting forms of character is said to be a/an ____.
One of the contrasting forms of character is said to be an allele.
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