What are viruses | Cells | Biology | FuseSchool

Summary

This video delves into the world of viruses, the most abundant biological entities on Earth, which are microscopic parasites infecting all forms of life. It explains their simple structure, composed of a protein coat and genetic material, and their unique method of reproduction by hijacking host cells. The video highlights common viruses like influenza and HIV, discusses the human immune system's response, and touches on the effectiveness of vaccines and antiviral drugs, while clarifying the ineffectiveness of antibiotics against viral infections.

Takeaways

• 🌐 Viruses are the most common biological unit on Earth, outnumbering all other types combined.
• 🔍 Viruses are microscopic organisms too small to be seen by the naked eye, much smaller than bacteria and human cells.
• 🧬 They consist of a protein coat surrounding genetic material, which can be either DNA or RNA.
• 🤝 Some viruses have an envelope that they 'steal' from the host cell's membrane to evade detection.
• 🚫 Viruses are not made up of cells and are considered to be between living organisms and chemicals.
• 🧬 There are different types of viruses, not species, with common examples being influenza and HIV/AIDS.
• 🐛 Viruses are parasites that can only reproduce within other living cells, hijacking the host's genetic machinery.
• 🤒 They cause illness by infecting and eventually killing host cells, leading to the release of more viral particles.
• 💉 The human immune system can often combat viral infections, sometimes preventing entry or destroying the virus after infection.
• 🏥 Some viruses have vaccines, like smallpox, which has been eradicated, while others like HIV are more challenging to vaccinate against.
• 💊 Antibiotics are ineffective against viruses and are only for bacterial infections; antiviral drugs exist for some viruses, like HIV.

Q & A

What are viruses and how are they different from other microorganisms?

Viruses are a type of microorganism that are much smaller than bacteria and about 100 times smaller than human cells. Unlike other organisms, they are not made up of cells and are considered to be halfway between a living organism and a chemical.

What shapes do viruses come in and where can they be found?

Viruses come in many different shapes and are present wherever there are cells to infect. They are the most common biological unit on earth, outnumbering all other types combined.

Which types of organisms can viruses infect?

Viruses can infect a wide range of organisms including humans, animals, plants, and even bacteria.

What are the basic components of a virus?

A virus is made up of a protein coat that surrounds a strand of genetic material, which can be either DNA or RNA. Sometimes, a membrane called an envelope surrounds a virus particle, which is actually stolen from the host cell's membrane.

Why are viruses considered to be non-living?

Viruses are considered non-living because they cannot reproduce on their own and require a host cell to do so. They lack the cellular structure and metabolic processes that characterize living organisms.

How do viruses cause illness in their hosts?

Viruses cause illness by being parasites that can only reproduce in other living cells. They anti-host cell, hijack the host's genetic machinery, and produce more virus particles, leading to the death of the host cell and the release of new viral particles to infect more cells.

What are some common types of viruses mentioned in the script?

Some common types of viruses mentioned in the script include influenza, HIV or AIDS.

How does the human immune system combat viral infections?

The human immune system can recognize viruses as intruders and destroy them before they gain entry into a cell. Even after infection, the immune system can destroy the virus, leading to recovery.

What are some examples of diseases caused by viruses?

Examples of diseases caused by viruses include the common cold, influenza, rabies, yellow fever, HIV/AIDS, pneumonia, bird flu, Zika, Ebola, and cancer caused by HPV.

Why are vaccinations important in controlling viral diseases?

Vaccinations are important as they help in building immunity against viruses, leading to the eradication of some viruses like smallpox. They prevent the spread of viral diseases and protect the population from serious illnesses.

Why are antibiotics ineffective against viruses?

Antibiotics are ineffective against viruses because they target bacterial infections. Viruses require different treatment approaches, such as antiviral drugs, which can be specifically designed to combat viral infections.