T. H. Morgan worked on the fruit fly, Drosophila melanogaster . Which of the following is not an advantage of this fly?
1. They could be grown on simple synthetic medium in the laboratory.
2. They complete their life cycle in about two years, and a single mating could produce a large number of progeny flies.
3. There was a clear differentiation of the sexes – the male and female flies are easily distinguishable.
4. It has many types of hereditary variations that can be seen with low power microscopes.
When the two genes in a dihybrid cross are situated on the same chromosome:
1. The proportion of parental gene combinations was much higher than the non-parental type.
2. The proportion of parental gene combinations was much lesser than the non-parental type.
3. The proportion of parental gene combinations was equal to the non-parental type.
4. Only recombinants are formed.
During his observation of spermatogenesis in few insects, Henking found that a nuclear structure was received by 50 % of the sperms. He called this structure as:
1. X – body
2. Y – body
3. X – chromosome
4. Y – chromosome
In birds, the mechanism of sex determination is:
1. XX – XY; male heterogamety
2. XX – XY; female heterogamety
3. XX – XO; male heterogamety
4. ZZ – ZW; male heterogamety
It is unfortunate that in our society women are blamed for producing female children and have been ostracised and ill-treated because:
1. | The sex is determined by the type of sperm fertilizing the egg |
2. | The sex is determined by the type of egg fertilizing the sperm |
3. | The sex is determined by the hormones produced by the fetus |
4. | The sex is determined by the God’s will |
The family pedigree of Queen Victoria shows a number of haemophilic descendants as she was:
1. Affected by the disease
2. Carrier for the disease
3. Did not carry the allele for hemopihilia
4. Was not a queen
Which of the following amino acid substitution in the beta chain of the haemoglobin molecule leads to the development of sickle cell anaemia?
1. Arginine by tyrosine 2. Tyrosine by phenylalanine
3. Valine by Glutamic acid 4. Glutamic acid by Valine
An individual affected with Turner’s Syndrome:
I. Is a female
II. Has 45 chromosomes
III. Has rudimentary ovaries
Of the above statements, the correct statements are:
1. Only I and II 2. Only I and III
3. Only II and III 4. I, II and III
An organism with two different alleles is:
1. Homozygous for that trait
2. Homologous for the allele
3. Heterozygous for the trait
4. Heterologous for the allele
Which one of the following trait is only expressed in the presence of identical allele?
1. Yellow seed
2. Inflated pod
3. Green pod
4. Green seed