1.2 Viruses
2026-02-08 21:12
Status: #developing
Viruses
Viral Structure
- Contains a protein capsid (a protection layer)
- Contains DNA/RNA
- Does not contain cytoplasm
- Allows viruses to live for long periods without water
Reproduction
- Viruses penetrate the cell wall and add their DNA to the host
- Viruses are not living beings as they require another organism to effectively reproduce
Virus cycle
- There are two cycles in the viral life cycle (Lytic and Lysogenic cycles)
Lytic Cycle (lysis, Greek for to break)*
- Virus infects a cell
- Eg. Phage attaches to receptor on bacteria cell and inserts DNA
- Cell is used to make new capsid proteins and genetic material needed for a virus
- New viruses are assembled
- Cell death to virus (lysis)
- Viruses escape the cell and new phages are released
Lysogenic Cycle (lysis + genic, Greek to break genes)
-
- Virus infects a cell
- Eg. Phage attaches to receptor on bacteria cell and inserts DNA
- Virus infects a cell
- Virus genetic material become part of host’s genetic material
- Viral DNA is replicated within the cell
- Upon binary fission, the DNA is now part of two cells, waiting to start the lytic cycle upon certain environmental factors