In this article we will discuss about:- 1. Definition of Viruses 2. Size of Viruses 3. Shape 4. Classification 5. Types. Definition of Viruses: Virus (L. poison) is a nucleoprotein entity which is able to utilize the synthetic machinery of a living cell of another organism for its multiplication which does not involve growth and division. Even before its discovery [...]
The following points highlight the four main Components of Viruses. The components are: 1. Nucleoid 2. Capsid 3. Envelope 4. Enzymes. Component # 1. Nucleoid: It represents the viral chromosome. Nucleoid or viral chromosome is made of a single molecule of nucleic acid. It may be linear or circular with various degrees of coiling. Nucleoid is the infective part of [...]
The following points highlight the two main types of reproductive cycle in virus. The types are: 1. Lytic Cycle 2. Lysogenic Cycle. Type # 1. Lytic Cycle (Fig. 2.5): It is the reproductive cycle of virulent phages, e.g., T4 bacteriophage. The phage attaches itself to the host cell (e.g., Escherichia coli) through its tail fibres. The fibres bend and bring [...]