Are Viruses Alive?

Summary

In this episode of Virus Watch, Vincent Dragon Yellow explores the complex question of whether viruses are alive. He discusses the criteria for life, such as cell composition, homeostasis, energy production, and reproduction. Viruses, like the poliovirus, lack these traits outside of a host cell, making them 'not alive'. However, once inside a cell, they reprogram it to reproduce, demonstrating a 'living' phase. The video concludes that viruses exist in two phases: the non-living virus particle and the living, infected cell, offering a nuanced perspective on the nature of viruses.

Takeaways

• 🤔 The debate on whether viruses are alive is complex and requires a definition of life.
• 🔬 Life is typically characterized by properties such as cellular composition, homeostasis, energy production, growth, adaptation, response to stimuli, and reproduction.
• 🦠 A virus particle, such as the poliovirus, lacks these properties on its own and is not considered alive outside a host cell.
• 🧬 Viruses are obligate intracellular parasites, needing to enter a cell to replicate and carry out life processes.
• 🔄 Viruses do evolve and replicate, but these processes occur only after the virus has infected a cell.
• 🌐 The virus's genetic information reprograms the host cell to produce new virus particles.
• 🔑 The definition of a virus is proposed as an organism with two phases: the non-living virus particle and the living infected cell.
• 🔮 The virus particle is not alive, but once inside a cell, it can induce the cell to perform life functions, making the infected cell alive.
• 💡 The distinction between a virus particle and an infected cell is crucial to understanding the duality of viruses' existence.
• 🌟 The infected cell, having been taken over by a virus, continues to live and produce new virus particles until it may be killed by the infection.
• 📺 For further discussions on viruses, viewers are directed to 'this week in viral' on microbe TV.

Q & A

What is the main topic of the video report by Vincent Dragon Yellow?

The main topic of the video report is to discuss whether viruses are considered to be alive.

What are the general properties that define something as living according to the script?

The general properties that define something as living include being composed of one or more cells, having homeostasis, the ability to generate energy, to grow, adapt to new environments through evolution, respond to stimuli, and reproduce.

What is the difference between a virus particle and a living cell in terms of life properties?

A virus particle on its own does not meet any of the requirements for being alive; it is not a cell, lacks homeostasis, cannot make energy, adapt, evolve, or reproduce. In contrast, a living cell possesses all these properties.

What is the role of a virus particle in the context of life?

A virus particle is not considered alive on its own but has the potential to be living once it enters and reprograms a host cell, which then produces new virus particles.

What term is used to describe viruses in relation to their interaction with host cells?

Viruses are referred to as 'obligate intracellular parasites' because they require a host cell to replicate and carry out life processes.

How does a virus reprogram a host cell to produce more virus particles?

Once a virus enters a host cell, its genetic information, either RNA or DNA, takes over the cell's processes, redirecting them to produce new virus particles.

What is the definition of a virus provided by Vincent Dragon Yellow in the script?

A virus is defined as an organism with two phases: the virus particle, which is not alive, and the infected cell, which is clearly alive and produces new virus particles.

What is the distinction between a virus particle and a virus-infected cell as per the script?

The virus particle is not alive and cannot reproduce or evolve without a host cell. The virus-infected cell, however, is a living cell that has been reprogrammed by the virus to produce more virus particles.

Why do viruses need to enter a host cell to be considered as having a form of life?

Viruses need to enter a host cell because it is only within a living cell that they can carry out life processes such as replication and evolution, which are essential aspects of being alive.

What is the significance of the poliovirus model mentioned in the script?

The poliovirus model illustrates the structure of a virus particle, which consists of a protein shell protecting its RNA genome, and highlights that on its own, it does not exhibit any life properties.

What additional resources are suggested for more in-depth discussions about viruses?

For more in-depth discussions about viruses, the script suggests checking out the science show 'This Week in Virology' at Microbe TV.

Outlines

00:00

🧬 The Debate on Viruses' Vitality

Vincent Dragon Yellow introduces the weekly video report on the topic of whether viruses are alive. He begins by discussing the difficulty in defining life and lists the properties that living organisms typically possess, such as being composed of cells, having homeostasis, the ability to generate energy, adapt, evolve, respond to stimuli, and reproduce. Vincent then presents a model of the poliovirus to illustrate that a virus particle on its own does not meet these criteria for life. He explains that viruses are considered obligate intracellular parasites because they require a host cell to replicate, evolve, and carry out life processes. The video suggests that while the virus particle is not alive, the infected cell is, and the virus as an organism with two phases—non-living virus particle and living infected cell—has the potential for life once inside a cell.

05:00

📺 Closing Remarks and Further Exploration

In the concluding paragraph, Vincent Dragon Yellow signs off from the video report, inviting viewers to visit Microbe TV for more in-depth discussions about viruses. He provides a URL for further exploration and reiterates his identity, reinforcing the educational nature of the content. The paragraph serves as a call to action for those interested in learning more about the fascinating world of viruses and their complex relationship with life as we define it.

Keywords

💡Virus

A virus is a small infectious agent that can only replicate inside the living cells of an organism. It is a central concept in the video, which discusses whether viruses are considered 'alive'. The script uses the poliovirus as an example to illustrate the structure and behavior of a virus, highlighting its dependency on a host cell for replication.

💡Life

The term 'life' refers to the characteristic that distinguishes living organisms from non-living entities. The video script explores the definition of life to address the question of viral 'aliveness'. It lists properties such as cell composition, homeostasis, energy production, and reproduction as criteria for life, which are then used to evaluate the status of viruses.

💡Homeostasis

Homeostasis is the ability of an organism to maintain a constant internal environment, crucial for its survival. The script mentions it as one of the properties of living organisms, contrasting it with the virus's inability to maintain such a state on its own, emphasizing the virus's non-living state outside a host.

💡Evolution

Evolution is the process by which species of organisms change over time through genetic variation and natural selection. The script notes that while viruses do evolve, they only do so after entering a host cell, which is a key point in the discussion of whether viruses are considered alive.

💡Reproduction

Reproduction is the biological process by which new individual organisms are produced. The script explains that a virus particle cannot reproduce on its own but can do so once inside a host cell, which is a critical aspect of the debate on the 'life' of viruses.

💡Poliovirus

Poliovirus is a specific type of virus that causes poliomyelitis. The script uses the poliovirus as a model to describe the structure of a virus, with a protein shell protecting its RNA genome, and to illustrate the non-living state of a virus particle outside a host.

💡RNA

RNA, or ribonucleic acid, is a molecule that carries genetic information. In the context of the video, the script describes how the RNA genome of a virus, such as poliovirus, is protected within a protein shell and is essential for the virus's ability to reprogram a host cell.

💡Intracellular Parasite

An intracellular parasite is an organism that lives within the cells of another organism. The script refers to viruses as 'obligate intracellular parasites' because they require a host cell to carry out life processes, such as replication and evolution.

💡Organism

An organism is any individual entity that embodies the properties of life. The script discusses the dual nature of viruses, suggesting that while the virus particle itself is not an organism, the infected cell with viral genetic information is, thus contributing to the ongoing debate about viral life.

💡Mimi Viruses

Mimi viruses, also known as mimiviruses, are a type of large virus with complex structures and large genomes. The script mentions them to contrast with simpler viruses, illustrating the diversity within the viral world and the complexity of defining what constitutes life.

💡Pandora Viruses

Pandora viruses are another type of giant virus with large genomes. The script uses them as an example to show that even the most complex viruses require a host cell to perform life functions, reinforcing the argument that the virus particle itself is not alive.

Highlights

Vincent Dragon Yellow introduces the weekly video report on viruses.

The video aims to address the question of whether viruses are alive.

Defining life is a complex task with many disagreements on the exact definition.

A living thing should be composed of one or more cells, have homeostasis, and the ability to generate energy, grow, adapt, evolve, and reproduce.

A model of the poliovirus is presented to illustrate the virus particle structure.

On its own, a virus particle does not meet the criteria for being alive.

Viruses require a host cell to carry out life processes such as replication and evolution.

Viruses are classified as obligate intracellular parasites due to their dependency on host cells.

The virus genetic information reprograms the host cell to produce new virus particles.

A virus is defined with two phases: the non-living virus particle and the living infected cell.

The virus particle is not alive, but the infected cell is clearly alive and capable of producing more virus particles.

The infected cell, taken over by a virus, is very much alive until the host is killed by the infection.

The video concludes that a virus has two phases, one of which is clearly alive when inside a cell.

The video report provides a solution to the debate on whether viruses are alive by distinguishing between the virus particle and the infected cell.

For more in-depth discussions on viruses, viewers are directed to the science show 'This Week in Virology' at Microbe TV.

The video is part of the 'Virus Watch' series, hosted by Vincent Dragon Yellow.

Transcripts

hello everyone I'm Vincent rock and

yellow and this is virus watch the

weekly video report and what's happening

in the amazing world of viruses today

we're going to tackle the thorny

question that always generates a lot of

discussion are viruses alive first we

have to define life it's not very easy

to do and many people disagree on the

exact definition on what is living but

we have to have a definition otherwise

we can't answer the question of whether

viruses are alive or not so here we go

something that's living should have most

of these following properties it should

be composed of one or more cells it

should have homeostasis this is the

ability to regulate important properties

such as pH or temperature it should have

the ability to make or generate energy

to grow and to adapt to new environments

by evolution also to respond to stimuli

like a plant moving towards light and of

course it must be able to make more of

itself to reproduce here's a model of a

simple virus that happens to be

poliovirus the virus particle consists

of a protein shell that you can see is

this plastic shell that protects the RNA

genome that's inside of it on its own

this virus particle doesn't meet any of

the requirements for being alive it's

not a cell it doesn't have homeostasis

it can't make energy can't adapt to new

environments it can't evolve and can't

reproduce this particle here can't do

any of these things

but wait viruses do evolve right and

they do replicate of course so what's

going on the key is that all the things

carried out by viruses happen only after

the virus enters a cell that's why we

call viruses obligate intracellular

parasites in order to make more viruses

they need to physically get inside of a

cell the virus genetic information

whether it's RNA or DNA enters the cell

and it reprograms the cell so all of the

cell processes are now directed to the

making of new viruses that fact lets us

answer the question of whether viruses

are alive but first we have to define

what we mean by virus I define a virus

as an organism with two phases one phase

is the virus particle whether it's a

simple virus like the one I'm holding or

much bigger virus particles with huge

genomes and complicated structures like

the giant Mimi viruses and Pandora

viruses whether it's any of those that

virus particle can't do anything it

can't reproduce it can't evolve without

getting inside of a cell so that's why I

think the virus particle is clearly not

alive however once the virus is inside

of a cell the virus infected cell is

certainly alive it's simply a cell which

we all agree is living that's been taken

over by a virus the living cell has been

reprogrammed to make more virus

particles in many cases the virus infect

itself will eventually be killed by

infection but until that happens it's

very much alive producing new virus

particles a virus then is an organism

with two phases the virus particle which

is not alive and the infected cell which

is clearly alive when most people say

virus they usually mean the vie

particle but there's a difference

between virus particle and virus

infected cell the virus particle isn't

alive but the infected cell is I think

this is a good solution to the problem

that a virus particle can't possibly be

alive but has the potential to be living

once it enters the cell a virus the

organism with two phases is clearly

alive

that's virus watch for June 13 2016 for

more in depth discussions about viruses

check out our science show this week in

viral adji at microbe TV slash twit I'm

Vincent dragon yellow and I'll see you

next week