Mendelian disorders are mainly determined by:
1. | Alteration or mutation in a single gene. |
2. | Chromosomal gross structural changes. |
3. | Recombination between linked genes. |
4. | Jumping genes |
In 1900, Mendel’s work was rediscovered by:
1. | Khorana, Nirenberg and Mathei |
2. | de Vries, Correns and von Tschermak |
3. | Avery, McCleod and McCarty |
4. | Watson, Crick and Wilkins |
What can be the blood groups of progeny whose father and mother are of AB and O blood groups, respectively?
1. | A and B only | 2. | AB only |
3. | All except O | 4. | A, B, AB, and O |
In the case of starch synthesis in pea seeds [controlled by the B gene], BB homozygotes produce large and round starch grains; bb homozygotes produce smaller and wrinkled starch grains and heterozygotes produce round seeds of intermediate size. What can be inferred from this observation?
1. | The gene B mutates at a faster rate |
2. | The gene B is easily influenced by the environment |
3. | Dominance is not an autonomous feature of a gene or the product that it has information for. |
4. | Some genes do not follow the law of segregation. |
In birds, the mechanism of sex determination is:
1. | XX – XY; male heterogamety |
2. | ZZ – ZW; female heterogamety |
3. | XX – XO; male heterogamety |
4. | ZZ – ZW; male heterogamety |
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. |
What is the ratio of a typical monohybrid test cross?
1. | 2 : 1 | 2. | 3 : 1 |
3. | 1: 2 : 1 | 4. | 1 : 1 |
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
In Phenylketonuria,
I. | Phenylpyruvic acid and other derivatives are accumulated in the brain resulting in mental retardation. |
II. | These are also excreted through urine because of their poor absorption by the kidney. |
1. | Only I is correct | 2. | Only II is correct |
3. | Both are correct | 4. | Both are incorrect |
The F1 progeny in monohybrid crosses by Mendel resembled:
1. | The parent exhibiting the dominant trait completely |
2. | The parent exhibiting recessive trait comp |
3. | The parent exhibiting the dominant trait partly |
4. | The parent exhibiting recessive traits partly |