Bacteria reproduce sexually by

Find out the correct combination based on the methods of genetic material exchange which occur in bacteria.

Plasmids have the following characters.

i) They contain fewer genes than the bacterial chromosome.

ii) They have single stranded DNA

iii) They can be used as vectors

iv) They contain linear form of DNA

v) Plasmids confer protection to drugs

The correct combination is

A student grew virus in three different media containing ${\mathrm{P}}^{32}, {\mathrm{S}}^{35}$ and DNAase separately and allow this virus to attack to E. coli. The series of observation made by the students are as follows:

a) ${\mathrm{P}}^{32}$ labelled phage particles were produced in E. coli.
b) ${\mathrm{S}}^{35}$ containing phage particles were produced E. coli.
c) Phage particles were observed in E. coli.

d) ${\mathrm{P}}^{32}$ was not observed in phage particles produced by E. coli.
e) ${\mathrm{S}}^{35}$ was not observed in phage particles produced by E. coli.

The correct observations are

Statement $\left(\mathrm{S}\right):$ In ciliates, conjugation restores the vigour and vitality which are lost due to chromosomal imbalance in the macronuclei due to repeated amitotic divisions.

Reason $\left(\mathrm{R}\right):$ Conjugation is temporary union of senile ciliates belonging to same mating types. It often prevents exchange of nuclear material.

A bacterial strain $\mathrm{S}$ was heat killed. Another strain $\mathrm{R}$ (living) was taken and mixed with this S strain. This mixture of $\mathrm{S}+\mathrm{R}$ strains were injected into mice. Which of the following are observed by Griffith?

I. The cells of $\mathrm{S}$ strain were dead in dead mice.

II. The bacterial cells without polysaccharide coat are transformed into virulent strain in the injected mice.

II. Griffith could not find living $\mathrm{S}$ strain in the body of dead mice.

IV. Griffith could find living $\mathrm{S}$ strain in the body of dead mice.

The correct combination is: