Viruses are sub-microscopic infectious agents that can infect all living organisms. A virus consists of genetic material surrounded by a protein coat. The genetic material may be present in the form of DNA or RNA.
Most of the viruses, infecting plants, have single stranded RNA as genetic material. On the other hand, the viruses infecting animals have single or double stranded RNA or double stranded DNA.
Bacteriophages or viruses infecting bacteria mostly have double stranded DNA. Their protein coat called capsid is made up of capsomere subunits. These capsomeres are arranged in helical or polyhedral geometric forms.
A.I.D.S, small pox, mumps, and influenza are some common examples of viral diseases.
LIST I (Microbe) | LIST II (Natural habitat) | ||
A. | Streptomyces | I. | Aquatic habitat |
B. | Influenza virus | II. | Terrestrial Environment |
C. | Spirulina | III. | Sewage treatment |
D. | Giardia | IV. | Airborne pathogen |
List I | List II | ||
A | Clonal propagation | I | Meristem culture |
B | Virus free plant | II | Cell line culture in a bioreactor |
C | Haploid plant production | III | Axillary bud |
D | Secondary metabolite production | IV | Anther culture |
Choose the correct answer from the options given below:
List I Virus | List II Disease | ||
A. | H1N1 Virus | I. | Guillian Barre Syndrome |
B. | Flavi virus | II. | Severe Accute Respiratory Syndrome |
C. | Corona Virus | III. | Yellow Fever |
D. | Zika Virus | IV. | Swine Flu |
Figures 9.20(a) and (b) refer to the steady flow of a (non-viscous) liquid. Which of the two figures is incorrect ? Why ?
The process of grouping living organisms into categories is called biological classification. The most modern 5-kingdom classification was put ahead by an eminent scientist R.H.Whittaker. The five-kingdom classification is based on the criteria like cell structure, mode of nutrition, body form, and reproduction. One of the most important characteristics of this system is that it follows the evolutionary sequence of living organisms. The organisms are classified into distinct taxa or levels like Kingdom, Phylum, Division, Class, Order, Family, Genus, and Species. The 5 kingdoms are as follows: