Botany-Principles of Inheritance and Variation - Online Test

Q1. The pairs of chromosomes present in human beings somatic cells are
Answer : Option C
Explaination / Solution:

In human beings 23 pairs of chromosomes are present out of which 22 pairs are called autosomes and 1 pair is called sex chromosome.

Q2. Genes are
Answer : Option A
Explaination / Solution:

Genes are segment of DNA present on chromosome. Large numbers of genes are located on single chromosome. A gene or genes determines the traits of the individual.

Q3. A somatic cell in human male contains
Answer : Option B
Explaination / Solution:

Somatic cells in human male contain 22 pairs of autosomes and 1 pair (XY) of sex chromosome. Y chromosome is smaller in size and do not have allelomorphic pair of X chromosome. So, only one sex-linked gene is available for each character.

Q4. The stage for counting of chromosome is
Answer : Option D
Explaination / Solution:

During cell division, chromosomes get condensed in shape. In metaphase stage of mitosis, the chromosomes are located at center of cell in linear fashion. It can be easily studied at this stage.

Q5. When chromosome sets are present in multiple of ‘n’ the condition is called
Answer : Option B
Explaination / Solution:

Most of the organisms are diploid, contain two set of chromosome (2n) but a number of organisms contains multiple of chromosome set like 3n,4n, 6n etc. This condition of having multiple sets chromosome is called Euploidy.

Q6. Whose karyotype is represented below?

Answer : Option B
Explaination / Solution:

Karyotype is the representation of chromosome in order of shape and size. Male Drosophila fly have 3 pairs of autosomes and 1 pair (XY) sex chromosome.

Q7. The phenomenon of exchange of segments of chromosome between paternal and maternal chromosome is called
Answer : Option C
Explaination / Solution:

The exchange of segments of chromosome between homologous chromosomes during reduction division is called crossing over. It creates variation in the individuals of same parents.

Q8. In somatic cells of human beings chromosomes exists as
Answer : Option A
Explaination / Solution:

Somatic cells of human beings contain 23 pairs of chromosomes, 23 each from male and female gametes. These chromosomes always occurs as homologous chromosome as contain same kinds of trait.

Q9. Haploid chromosome number is 12. What is the number in monosomic?
Answer : Option D
Explaination / Solution:

Monosomic is an aneuploidy in which a chromosome is deficient of its homologous causing genetic imbalance resulting in weaker than normal form. In normal form(2n) 24 chromosome should be present but 1 homologous pair is absent so, only 23 chromosome will be present in monosomic individual.

Q10. In human males, some recessive genes express their effect because
Answer : Option D
Explaination / Solution:

Recessive genes are expressed only in case of homozygous condition but sex chromosomes of males do not have opposite alleles on Y-chromosome. So, the recessive gene located on X-chromosome get expressed in males.