KLASIFIKASI VIRUS

Summary

This video provides an in-depth explanation of virus classification. It covers the three basic virus shapes—icosahedral, helical, and complex—and explores their structural characteristics, including the nucleic acid content of DNA and RNA viruses. The video also details the differences between enveloped and non-enveloped viruses, as well as the variations in the number of capsomeres. Additionally, it touches on how viruses affect different hosts, including humans, animals, plants, and bacteria. Examples such as the coronavirus, HIV, and bacteriophages are discussed to highlight these distinctions.

Takeaways

• 😀 Viruses can be classified based on their shape into three categories: icosahedral, helical, and complex-shaped viruses.
• 😀 Icosahedral-shaped viruses have a structure with 20 equal-sided triangles, examples include polio and adenoviruses.
• 😀 Helical-shaped viruses are cylindrical with a protein sheath wrapping around their genetic material, like the tobacco mosaic virus.
• 😀 Complex viruses have structures beyond a nucleocapsid, with additional components like a head, neck, and tail sheath, such as bacteriophages.
• 😀 Viruses are classified based on their nucleic acid into DNA viruses and RNA viruses.
• 😀 DNA viruses use DNA polymerase for replication and are divided into groups 1 and 2 in the Baltimore classification, with examples like marco and adenoviruses.
• 😀 RNA viruses replicate using RNA as genetic material, divided into groups 3, 4, and 5 in the Baltimore classification, with examples like coronavirus and rubella virus.
• 😀 Enveloped viruses have a membrane covering the nucleocapsid, containing phospholipids, proteins, and viral glycoproteins, such as the coronavirus.
• 😀 Non-enveloped viruses lack a membrane and consist only of nucleic acid and nucleocapsid, like the adenovirus.
• 😀 Viruses can be further categorized by the number of capsomeres (protein subunits forming the capsid), with examples ranging from adenoviruses (252 capsomeres) to parvovirus B19 (32 capsomeres).
• 😀 Viruses also vary in their host range, with specific types targeting humans (e.g., HIV), animals (e.g., Newcastle disease virus), plants (e.g., tomato spotted wilt virus), and bacteria (e.g., bacteriophages).

Q & A

What are the basic forms of viruses mentioned in the video?

The basic forms of viruses mentioned are icosahedral-shaped viruses, helical-shaped viruses, and complex-shaped viruses.

What is the structure of icosahedral-shaped viruses?

Icosahedral-shaped viruses have a spatial form consisting of 20 triangles with equal sides. Examples include polio viruses and adenoviruses.

How are helical-shaped viruses structured?

Helical-shaped viruses are cylindrical in shape, with the capsid helix built from a single type of protomer. The genetic material is wrapped inside the structure, producing rod-shaped virions, such as the tobacco mosaic virus.

What distinguishes complex viruses from other virus shapes?

Complex viruses have a structure beyond the nucleocapsid, including a head, neck, and tail sheath. An example of a complex virus is a bacteriophage.

How are viruses classified based on their nucleic acid content?

Viruses are classified into DNA viruses and RNA viruses. DNA viruses use DNA polymerase for replication, while RNA viruses use RNA for their genetic material.

What is the difference between DNA and RNA viruses?

DNA viruses contain deoxyribonucleic acid (DNA) as their genetic material and are categorized into groups 1 or 2 in the Baltimore classification. RNA viruses contain ribonucleic acid (RNA) and are placed in groups 3, 4, or 5 in the Baltimore system.

What are enveloped and non-enveloped viruses?

Enveloped viruses have a membrane surrounding the nucleocapsid, which includes phospholipids and glycoproteins from the host cell. Non-enveloped viruses lack this membrane and consist only of nucleic acid and nucleocapsid.

How do the envelopes of viruses help in their identification?

The glycoproteins on the surface of the viral envelope are crucial for identifying the virus and binding to receptors on host cell membranes. For example, coronavirus is an enveloped virus.

What is the significance of capsomeres in virus structure?

Capsomeres are the protein subunits that make up the capsid of the virus. The number of capsomeres varies among viruses, with examples being adenovirus (252 capsomeres), herpesvirus (162 capsomeres), and picornavirus (60 capsomeres).

How are viruses classified based on their host organisms?

Viruses can be classified based on the organisms they infect, including human viruses (like HIV), animal viruses (like Newcastle virus), plant viruses (like the tomato spotted wilt virus), and bacterial viruses (bacteriophages).