Name:______________________
Introducing…Viruses
Blk:____ Date:_______________
The word virus comes from the Latin word for poison.
Viruses exhibit some of the characteristics of living organisms but not all:
√ They can replicate (*reproduce), but only in living cells.
√ They can mutate (adapt to their environment)
√ They are complex. Virus structure is organized and they are made of smaller subunits
or building blocks.
X Viruses cannot grow or move independently.
X Viruses do not maintain homeostasis.
*Viruses are called pathogens because
they may cause disease in their host.
X Viruses are not cellular.
The shapes and sizes of viruses
Viruses come in many different sizes, ranging from tiny (10 nanometers) to large (750
nanometers). They can be spherical, string-like, or even be shaped the first lunar lander!
Viruses that infect bacteria are called bacteriophages.
Protein coat
The head
Nucleic acid core
The tail
Tail fibres