Virus Structure and Classification Quiz

A virus is a tiny infectious agent that can only replicate inside a living cell. It's made up of two main parts: a core of genetic material (DNA or RNA) and a protective protein coat called a capsid.

A virion is a complete virus particle, meaning it has all the parts needed to infect a host cell. This includes the genetic material (DNA or RNA) and its protective protein coat (capsid).

Viruses are divided into families and sometimes subfamilies based on their characteristics, like the type of genetic material they have (DNA or RNA), how they replicate, their shape, and whether they have an outer membrane.

Viruses are much smaller than the cells they infect. They can't be seen with a regular microscope and can even pass through filters designed to trap bacteria.

The presence or absence of an envelope (a lipid bilayer with proteins) is a key difference between virus groups. Some viruses have an envelope, while others don't.

The viral genome is the genetic material (DNA or RNA) that carries the instructions for how to replicate the virus. It's like a blueprint for creating more viruses.

The capsid is the protein coat that surrounds the viral genome, protecting it and helping it attach to host cells. It's like a shield.

Viruses do not have their own machinery for replication. To multiply, they have to invade a host cell and use the host's cellular machinery to make copies of themselves.

The protein shell that encloses the genetic material (genome) of a virus.

A rod-shaped or coiled structure formed by repeating units of a single protein type.

A spherical or symmetrical structure formed by multiple protein sub-units (capsomers).

A virus's genetic material, which can be RNA or DNA.

The genetic material of a virus is either single-stranded (ss) or double-stranded (ds).

A type of RNA genome that can be directly translated into proteins.

A type of RNA genome that is complementary to messenger RNA and cannot be directly translated.

The basic unit of protein that forms part of a helical capsid.

These are naked viruses with two icosahedral capsid coats and 10 segments of double-stranded linear RNA. They were originally found in the respiratory and enteric tracts, but not associated with any human disease. The main human pathogen is rotavirus, which causes diarrhea in infants.

These are enveloped viruses that have a single-stranded, linear, nonsegmented, positive-polarity RNA genome and an icosahedral capsid. They are known for causing diseases like hepatitis C, yellow fever, dengue fever, West Nile virus, and encephalitis.

They are enveloped viruses with an icosahedral capsid and single-stranded, linear, nonsegmented, positive-polarity RNA. They include two main groups, alphaviruses and rubiviruses, responsible for encephalitis and rubella respectively.

These are enveloped viruses with an icosahedral capsid and two identical strands of single-stranded, linear, positive-polarity RNA. They are known for their unique reverse transcription process, where RNA is converted to DNA. They include oncoviruses like the human T-cell leukemia virus (HTLV) and lentiviruses like HIV.

These viruses are enveloped, with a helical nucleocapsid and eight segments of linear, single-stranded, negative-polarity RNA. They have an affinity for mucins and include the influenza virus.

They are enveloped viruses with a helical nucleocapsid and single-stranded, linear, nonsegmented, negative-polarity RNA. These viruses are very different from orthomyxoviruses despite the similarities in their names. They are responsible for diseases like measles and mumps.

These are naked icosahedral viruses with double-stranded linear DNA. They cause various infections like pharyngitis and respiratory tract disease.

These are small RNA viruses with a naked icosahedral capsid and nonsegmented, positive-polarity RNA. They cause infections like polio, coxsackievirus, and hepatitis A.

These are double-shelled viruses with an icosahedral capsid covered by an envelope. Their DNA is a double-stranded circle with unusual characteristics.

These are enveloped viruses with an icosahedral nucleocapsid and double-stranded linear DNA. They are known for causing latent infections.

These are the largest viruses with a brick-like shape, an envelope, and complex capsid symmetry. They cause skin lesions called 'pocks'.

These are naked viruses with an icosahedral capsid. They possess single-stranded, linear, nonsegmented, positive-polarity RNA.

These are enveloped viruses with an icosahedral nucleocapsid and double-stranded linear DNA. The five important human pathogens are Herpes Simplex Virus types 1 and 2, Varicella-zoster Virus, Cytomegalovirus, and Epstein-Barr Virus.

The three naked icosahedral virus families are followed by three enveloped icosahedral viruses. The remaining eight families are enveloped helical viruses with single-stranded linear or circular RNA.

Bullet-shaped enveloped viruses with a helical nucleocapsid and a single-stranded, linear, nonsegmented, negative-polarity RNA. The term "rhabdo" refers to the bullet shape.

Enveloped viruses with a helical nucleocapsid and single-stranded, linear, nonsegmented, negative-polarity RNA. Known for their long filaments that are 80 nm in diameter but can be thousands of nanometers long. The term "filo" means "thread" and refers to these filaments.

Enveloped viruses with a helical nucleocapsid and a single-stranded, linear, nonsegmented, positive-polarity RNA. The term "corona" refers to the halo of spikes protruding from the envelope.

A respiratory illness caused by a virus in the coronavirus family. This virus is called SARS-CoV-2.

A severe respiratory syndrome caused by a specific type of coronavirus. Emerged in 2002 in China and spread rapidly to other countries, affecting hospital personnel.

A serious respiratory illness caused by a specific type of coronavirus, emerged in 2012, and initially affected the Middle East.

Rabies virus is the only human pathogen in this family. Spread through animal bites and can cause fatal encephalitis.

Ebola virus and Marburg virus are both human pathogens in this family. They cause severe hemorrhagic fevers.

Middle East Respiratory Syndrome (MERS) is a severe respiratory illness caused by a coronavirus, MERS-CoV. It was initially detected in Saudi Arabia in 2012 and has since spread to other countries.

MERS-CoV is a coronavirus closely related to a bat coronavirus. It's thought that bats are the natural reservoir for this virus.

Camel contact is the most likely way humans get infected with MERS-CoV. Although person-to-person transmission is possible, it's less common and usually occurs in healthcare settings with weak infection control measures.

The SARS-CoV-2 virus has an incubation period of 1 to 14 days, meaning it takes that long for symptoms to appear after infection. On average, symptoms develop within 6 days.

The most common COVID-19 symptoms are fever, tiredness, and dry cough. Other symptoms might include body aches, nasal congestion, runny nose, sore throat, or diarrhea. However, some people have no symptoms at all.

Around 16% of people with COVID-19 develop serious illness marked by difficulty breathing. Older adults and individuals with underlying medical conditions like high blood pressure, heart problems, or diabetes are at a higher risk for severe complications.

If you experience fever, cough, and difficulty breathing, it's important to seek medical attention. This can help prevent the disease from becoming more severe.