Select the wrong statement:
1. | The viroids were discovered by D.J lvanovsky. |
2. | W.M. Stanley showed that viruses could be crystallized. |
3. | The term 'contagium vivum fluidum' was coined by MW Beijerinck. |
4. | Mosaic disease in tobacco and AIDS in human beings are caused by viruses. |
Which of the following shows coiled RNA strand and capsomeres?
1. | Poliovirus | 2. | Tobacco mosaic virus |
3. | Measles virus | 4. | Retrovirus |
Viruses have:
1. DNA enclosed in a protein coat
2. Prokaryotic nucleus
3. Single chromosome
4. Both DNA and RNA
Which statement is wrong for viruses?
1. All are parasites
2. All of them have helical symmetry
3. They have the ability to synthesize nucleic acids and proteins
4. Antibiotics have no effect on them
Virus envelope is known as:
1. capsid
2. virion
3. nucleoprotein
4. core
Infectious proteins are present in:
1. geminiviruses
2. prions
3. viroids
4. satellite viruses
Given below is the diagram of a bacteriophage. In which one of the options, all the four parts A, B, C and D are correct?
A | B | C | D | |
1. | Sheath | Collar | Head | Tail fibres |
2. | Head | Sheath | Collar | Tail fibres |
3. | Collar | Tail fibres | Head | Sheath |
4. | Tail fibres | Head | Sheath | Collar |
T.O. Diener discovered a:
1. free infectious RNA
2. free infectious DNA
3. infectious protein
4. bacteriophage
The causative agent of mad-cow disease is a:
1. bacterium
2. prion
3. worm
4. virus