Virus
2 Minutes
Viruses for kids: learn what viruses are, how they reproduce inside hosts, their structure, and different shapes. An English science lesson.
- Why viruses are non-living outside but activate inside a host
- Virus structure including genetic material, capsid, and spikes
- Common virus shapes like spherical influenza and helical TMV
What this lesson teaches
A virus is the tiniest microorganism, measuring only 20 to 300 nanometers, and its name comes from the Latin word for poison. It exists as an inactive, non-living particle outside a host, but comes to life and reproduces once it enters a living organism.
How viruses become active
When viruses are outside in the open air or resting on surfaces like a table, they are non-living and completely inactive. A virus only becomes active and comes to life when it manages to enter a living organism, such as the human body. Once inside, it responds to the living host's temperature, radiation, and internal chemicals, and it begins reproducing to create many new viruses.
Parts of a virus
- Genetic material: Strands of DNA or RNA that look like noodles, which store the virus's genetic memory and allow it to reproduce.
- Capsid: A protective outer protein coat that wraps around the genetic material, acting like an eggshell.
- Envelope: An extra protective outer cover found around some viruses, composed of proteins, lipids, and carbohydrates.
- Spikes: Small glycoprotein projections located on the envelope that link and attach the virus firmly to a host cell.
Shapes of viruses
Viruses generally appear in three main shapes, which include spherical, spiral, and helical structures. The influenza virus is spherical in shape and looks like a round ball. The TMV virus has a helical shape that resembles a banana leaf stem. Other viruses, such as the bacteriophage, have unusual shapes that look very different from these simple forms.
Why viruses are dangerous
Viruses are the smallest of all microorganisms, but they are also considered the most dangerous. Even though they are tiny, they frequently cause illnesses such as fevers in humans. Once a virus enters a living body, it immediately multiplies into many new viruses, making it a powerful and harmful microorganism.