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Virus - Coggle Diagram
Virus
Common Structural Features of Viruses
Small, fixed size.
Genetic material: DNA or RNA.
Capsid: Protein coat.
No cytoplasm.
Few or no enzymes.
Diversity in Virus Structure
Varied shapes & structures.
Genetic material:
DNA or RNA.
Single- or double-stranded.
Some viruses have an envelope (host cell membrane).
Examples:
Bacteriophage lambda.
Coronaviruses.
HIV.
Origins of Viruses
Diversity suggests different evolutionary origins.
Shared genetic code with living organisms.
Convergent evolution: Common features due to obligate parasitism.
Rapid Evolution in Viruses
High mutation rates due to rapid replication.
Genetic recombination (e.g., reassortment in influenza).
Examples:
Influenza virus: Rapid antigenic changes affect immunity & vaccine effectiveness.
HIV: High mutation rate leads to drug resistance.
Consequences:
Challenges in vaccine development.
Difficulties in treatment & disease control.
Reproduction cycles
Lytic Cycle of a Virus
(Bacteriophage Lambda Example)
Virus hijacks host cell to replicate rapidly.
Attachment to host cell.
Entry: Injects DNA/RNA.
Replication: Host cell makes viral components.
Assembly of new viruses.
Lysis: Host cell bursts, releasing viruses.
Lysogenic Cycle of a Virus
(Bacteriophage Lambda Example)
Viral DNA integrates into host genome as a prophage.
Dormant phase: Host cell continues normal function.
Triggers (e.g., stress) cause activation → Lytic cycle begins.
