Board exam

Which one of the following processes results in the production of recombinants in future generations ?

1. (i)
   Mutation
2. (ii)
   Independent assortment during meiosis I
3. (iii)
   Independent assortment during meiosis II
4. (iv)
   Crossing over of bivalents

Choose the option that gives the correct number of pollen grains that will be formed after 325 microspore mother cells undergo microsporogenesis.

1. A325
2. B650
3. C1300
4. D975

The organism used in construction of the first artificial recombinant DNA by Cohen and Boyer in 1972 was :

1. AE. coli
2. BSalmonella typhimurium
3. CAgrobacterium tumefaciens
4. DBacillus thuringiensis

Assertion (A) : A patient of ADA deficiency undergoing treatment for gene therapy requires periodic infusion of genetically engineered lymphocytes. Reason (R) : Lymphocytes are immortal.

1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. BBoth Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. CAssertion (A) is true, but Reason (R) is false.
4. DAssertion (A) is false, but Reason (R) is true.

Assertion (A) : A cattle egret and grazing cattle in close association is a classic example of commensalism. Reason (R) : As grazing cattle move through the field, they stir up and flush out insects from the vegetation that otherwise might be difficult for egrets to find and catch.

1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. BBoth Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. CAssertion (A) is true, but Reason (R) is false.
4. DAssertion (A) is false, but Reason (R) is true.

Assertion (A) : Endosperm is completely consumed during the development of embryo in ex-albuminous seeds. Reason (R) : Castor, pea and beans are all examples of ex-albuminous seeds.

1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. BBoth Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. CAssertion (A) is true, but Reason (R) is false.
4. DAssertion (A) is false, but Reason (R) is true.

Assertion (A) : Birds like pigeon have heterogametic females whereas the males are homogametic. Reason (R) : In pigeons, females have Z and W sex chromosomes whereas males have ZZ sex chromosomes.

1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. BBoth Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. CAssertion (A) is true, but Reason (R) is false.
4. DAssertion (A) is false, but Reason (R) is true.

1. aFrom which end of the ovule, and how does the pollen tube gain its entry into the embryo sac of a Hibiscus flower ?
2. bState the fate of the male nuclei present in the pollen tube.