Understanding Viruses and Bacteriophages

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Questions and Answers

What is the estimated number of T-even bacteriophages present in the World’s water supply?

1 trillion

10 nonillion (correct)

100 billion

1 quintillion

How does the biomass of bacteriophages compare to that of all of Earth's elephants?

It is less by a factor of 100.

It equals the total weight of all elephants.

It is equal to the weight of one elephant.

It exceeds by more than 1,000-fold. (correct)

What particle count is excreted by an infected whale per day?

10^13 (correct)

10 million

1 trillion

1 billion

What type of virus infects whales and can also infect humans?

Calicivirus Signup and view all the answers

How long would a line of T-even bacteriophages stretch if lined up end to end?

200 million light years Signup and view all the answers

How many virus particles are estimated to be found in just one teaspoon of ocean water?

5 million Signup and view all the answers

Which organisms do viruses NOT infect according to the provided information?

Fungi Signup and view all the answers

What is the significance of the discovery of viruses in C.elegans?

It indicates the presence of viruses in most living organisms. Signup and view all the answers

What percentage of human DNA is derived from retroviral sequences?

42% Signup and view all the answers

In what scenario do viruses become a significant health problem for individuals?

When the immune system is compromised Signup and view all the answers

What role do viruses play in the survival of certain species of grass found around hot springs?

They allow the fungus colonizing the grass to survive at high temperatures Signup and view all the answers

What are all viruses characterized by in their structure?

A genome encapsulated in a protective particle Signup and view all the answers

What is the significance of endogenous retroviruses in human genetics?

They are remnants of ancient viral infections integrated into our DNA Signup and view all the answers

Which factor is crucial for a virus to establish itself in host populations?

The ability of the genome to replicate and manage transmission Signup and view all the answers

What happens to plants if a specific virus is removed from their associated fungus?

The plants will not survive at high temperatures Signup and view all the answers

What is a defining trait of viruses compared to other organisms?

They do not have the machinery for independent reproduction Signup and view all the answers

Study Notes

Viruses Are Ubiquitous

Viruses are present in the environment, inhaled with air, consumed with food, and can enter the body through contact with surfaces.
Daily encounters with billions of virus particles are common.

Infection Across Species

Viruses infect all forms of life, including plants, animals, and bacteria.
Each species has its own unique viruses; recent discoveries include viruses that infect the nematode C.elegans.

Bacteriophages in Water

Approximately 10^30 bacteriophages exist in the world’s water supply.
This figure is equivalent to 1 nonillion, showcasing the immense number of viruses.

Weight and Biomass of Phages

A single phage weighs about a femtogram.
The total biomass of 10^30 phages exceeds that of all Earth’s elephants by over 1,000 times.
In ocean water, there are about 5 million virus particles per teaspoon.

Line of Phages

If all bacteriophages were lined up end to end, they would stretch 200 million light years, far exceeding the distance to the nearest spiral galaxy (2.5 million light years).

Viral Infections in Whales

Whales can be infected by the calicivirus, an RNA virus that causes rashes and gastroenteritis.
Each infected whale can excrete around 10^13 viral particles daily.

Viruses and Human Health

Despite the abundance of viruses, most people are healthy due to robust immune systems.
Immunocompromised individuals, such as those with AIDS or undergoing chemotherapy, face a heightened risk of viral infections.

Beneficial Viruses

Some viruses have positive roles; for example, viruses can aid in the survival of certain plants that thrive in extreme temperatures by supporting symbiotic relationships with fungi.

Viral Genomes in Human DNA

Humans carry viral genomes inherited from ancestors, with a significant portion (42%) of human DNA derived from retroviral sequences.
Integrated viral sequences are part of the genetic material passed to future generations.

Structure and Strategy of Viruses

All viruses consist of a genome encased in a protective particle, facilitating transmission from one cell to another.
Viral genomes contain the information necessary for replicating new virus particles and establishing themselves within host populations.

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Description

Explore the fascinating world of viruses and their interactions with various life forms. This quiz covers the prevalence of viruses in the environment, their unique relationships with species, and the staggering numbers of bacteriophages present in water supplies. Test your knowledge on the remarkable biomass and impact of these microscopic entities.