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. |
In a test cross, the plant expressing the dominant phenotype is crossed with the plant:
1. | Which is heterozygous dominant |
2. | Which is heterozygous recessive |
3. | Which is homozygous recessive |
4. | Which is homozygous dominant |
Identify the incorrect statement:
1. | In addition to recombination, the mutation is another phenomenon that leads to variation in DNA. |
2. | Chromosomal aberrations are commonly observed in cancer cells. |
3. | A classical example of a point mutation is sickle cell anemia. |
4. | Non-ionising radiations cannot be mutagens. |
What is incorrect for Hemophilia?
1. | In this disease, a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected. |
2. | In an affected individual, a simple cut will result in non-stop bleeding. |
3. | The heterozygous female (carrier) for haemophilia may transmit the disease to her sons. |
4. | The possibility of a female becoming haemophilic is extremely rare because the mother of such a female has to be hemophilic and the father should be a carrier. |
Mendel’s work remained unrecognised till 1900. Which of the following was not a reason for this?
1. | His work was widely publicised and it brought a bad name to Mendel. |
2. | His concept of factors as stable and discrete units that did not ‘blend’ was not accepted. |
3. | His approach of using mathematics to explain biological phenomena was unacceptable. |
4. | He could not provide any physical proof for the existence of factors or say what they were made of. |
Sickle cell anaemia results from:
1. A chromosomal aberration
2. Non-disjunction of autosome
3. A point mutation
4. Blood transfusion reaction
What is the ratio of a typical monohybrid test cross?
1. | 2 : 1 | 2. | 3 : 1 |
3. | 1: 2 : 1 | 4. | 1 : 1 |
In complete dominance, the recessive allele with respect to the dominant allele:
1. Produces no product
2. Produces a different product
3. Produces half the product
4. Produces no product or a non-functional product
Genes tightly linked on the same chromosome show:
1. | Very high recombination | 2. | Independent assortment |
3. | Very low recombination | 4. | 50 % recombination |