Science (English Medium) Class 12 - CBSE Question Bank Solutions

Name and explain the technique used for separating DNA fragments and making them available for biotechnology experiments.

Answer the following question:
Name the group of bacteria involved in setting milk into curd. Explain the process they carry in doing so. Write another beneficial role of such bacteria.

Answer the following question:
Why does 'Swiss Cheese' develop large holes?

What is the cell that receives a recombinant gene called?

Give a reason why :
Proteases are added during the isolation of DNA for genetic engineering.

Name the microbes that help the production of the following product commercially:
Citric acid

A cross between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of both the parents?

In a dihybrid cross, if you get 9:3:3:1 ratio it denotes that ______.

In a testcross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates ______.

Two linked genes a and b show 20% recombination. The individuals of a dihybrid cross between ++ /++ × ab/ab shall show gametes ______.

A normal green male maize is crossed with albino female. The progeny is albino because ______.

A dihybrid condition is ______.

Mendel’s last law is ______.

The process of mating between closely related individuals is ______.

A fruit fly exhibiting both male and female traits is ______.

In a dihybrid cross AABB x aabb, F2 progeny of AABB, AABb, AaBB and AaBb occurs in the ratio of ______.

In a dihybrid cross, F₂ phenotypic ratio is 13 : 3. It is case of ______.

Mendel’s Law of independent assortment holds good for genes situated on the ______.

Two genes ‘A’ and ‘B’ are linked. In a dihybrid cross involving these two genes, the F₁ heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?

Chargaff’s rules are applicable to ______.