Characteristics of viruses

1. CHARACTERISTICS OF
VIRUSES

2. VIRUSFrom the Latin word meaning "poison“
Pathogen: infectious agent causing disease
Ebola Virus

3. VIRUS STRUCTURE
Viruses are tiny!
Virus: 20 - 500 nm
Bacteria: 200 - 2000 nm
Human Cells: 5000 – 100000
nm

4. VIRUS STRUCTURE
Viruses are acellular
 Not a cell as it has no nucleus, cytoplasm
or organelles
Viruses consist of two main parts:
1. Nucleic Acid – DNA or RNA found at the
core of the virus
2. Capsid – Protein coat surrounding the
genetic material
Some viruses have an outer envelope made
of lipids (fats) and proteins covering the
capsid

5. VIRUS SHAPE
Viruses come in a variety of shapes:
Rod Spherical Irregular or Tadpole

6. LIVING CHARACTERISTICS OF
VIRUSES
Contains genetic material
Able to reproduce (within host cell only)
Able to invade host cell and reprogram cellular machinery
Causes an infectious disease
Able to mutate

7. NON-LIVING CHARACTERISTICS OF
VIRUSES
No metabolic needs – Doesn’t eat, breathe, sleep, produce
etc.
Not made of cells
Able to crystalize and remain dormant
Because viruses contain both living and non-living
characteristics they are considered to be transitional
between life and non-life