Okay, everyone. Here we have some practice questions about viruses. So viruses have what characteristics? Okay. Now, what do we know about viruses? Well, we know they're technically not alive and we know that they infect us and many other organisms. So let's have a look at our answers. Answer choice a says they contain both protein and nucleic acids. Now, they're very, very small and they're pretty simple, but they do contain protein and nucleic acids. They are going to have a viral genome, whether that's made of DNA or RNA, basically, nucleic acids. And they are going to have a protein coat, which surrounds that viral genome. Now some viruses are more complex than this and have some other components, but viruses are gonna have those 2 general components. So this is a true statement. Let's rule out the other answers. Answer choice b says, viruses infect only Eukaryotic cells. Absolutely not. Viruses are known to infect every type of living organism on the planet, not just Eukaryotic cells. So there are viruses for things like bacteria and archaea prokaryotic cells as well. Answer choice c says they can grow in the absence of living cells. No. They cannot. This is one of the reasons why they're not considered living things. They cannot reproduce and grow on their own. They have to infect a host cell, use that host cell's cellular machinery to grow and build new viruses. They cannot do it on their own. So that is not correct. Answer choice d says they are generally the same size as prokaryotes. Absolutely not. They are much smaller than any single celled organisms. They're very, very small. So that's not true. Answer choice e says they always kill the cells they infect. Now, viruses do commonly kill the cells they infect or kill the organisms in which they infect, but they don't kill them every single time. Because if they did, then they wouldn't have a host cell or a host organism to reproduce inside of. So most viruses won't kill every single cell that they infect because then they won't have what they need to reproduce. So that is not true. So viruses do contain both protein and nucleic acids, but there's a wide variety of virus morphologies that we will learn about. Okay, everyone. Let's move on to our next video.

Table of contents

1. Introduction to Microbiology3h 22m
2. Disproving Spontaneous Generation1h 18m
3. Chemical Principles of Microbiology3h 38m
4. Water1h 28m
5. Molecules of Microbiology2h 23m
6. Cell Membrane & Transport3h 28m
7. Prokaryotic Cell Structures & Functions5h 52m
8. Eukaryotic Cell Structures & Functions2h 18m
9. Microscopes2h 46m
10. Dynamics of Microbial Growth4h 36m
11. Controlling Microbial Growth4h 10m
12. Microbial Metabolism5h 16m
13. Photosynthesis2h 31m
14. DNA Replication2h 25m
15. Central Dogma & Gene Regulation7h 14m
16. Microbial Genetics4h 44m
17. Biotechnology3h 0m
18. Viruses, Viroids, & Prions4h 56m
19. Innate Immunity7h 15m
20. Adaptive Immunity7h 14m
21. Principles of Disease6h 57m

1. Introduction to Microbiology

Acellular Infectious Agents: Viruses, Viroids & Prions

Microbiology

1. Introduction to Microbiology

Acellular Infectious Agents: Viruses, Viroids & Prions

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Multiple Choice

Viruses:

Contain both protein and nucleic acids.

Infect only eukaryotic cells.

Can grow in the absence of living cells.

Are generally the same size as prokaryotes.

Always kill the cells they infect.

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Verified step by step guidance

Understand that viruses are composed of a protein coat called a capsid and nucleic acids, which can be either DNA or RNA. This is a fundamental characteristic of viruses.

Recognize that viruses can infect a wide range of hosts, including eukaryotic cells, prokaryotic cells (bacteria), and even archaea. They are not limited to infecting only eukaryotic cells.

Acknowledge that viruses cannot grow or replicate on their own in the absence of living cells. They require a host cell's machinery to reproduce, as they lack the necessary components for independent metabolism and replication.

Consider the size of viruses compared to prokaryotes. Viruses are generally much smaller than prokaryotic cells, often requiring electron microscopy to be visualized.

Understand that not all viruses kill the cells they infect. Some viruses can integrate into the host genome and remain dormant, while others may cause persistent infections without immediately killing the host cell.