Question 1

Which acellular pathogen is responsible for the plant disease shown in the first image, characterized by leaf discoloration and necrosis, and lacks a protein coat?

Accepted Answer

Viroid

Question 2

The scientist credited with the discovery of viruses after isolating the Tobacco Mosaic Virus (TMV) is shown in the second image. What was the key experimental insight that led to this discovery?

Accepted Answer

Filtering out all known bacteria did not prevent plant disease, indicating an agent smaller than bacteria was responsible.

Question 3

The third image shows a viral structure. What is the function of the capsid in this structure?

Accepted Answer

It protects the viral nucleic acid from degradation when outside the host cell.

Question 4

In the fourth image, which viral component is essential for attachment to host cells and is exposed on the surface of the viral envelope?

Accepted Answer

Spike

Question 5

The fifth image depicts a helical virus. Which virus is a classic example of this structure and was pivotal in early virology research?

Accepted Answer

Tobacco Mosaic Virus (TMV)

Question 6

The sixth image shows an icosahedral capsid. What is the geometric property of this structure?

Accepted Answer

It has 20 sides and 12 corners.

Question 7

The seventh image is an electron micrograph of a complex virus. Which virus family is known for lacking a typical capsid and instead being covered by a dense layer of lipoproteins?

Accepted Answer

Poxviruses

Question 8

The eighth image shows a schematic of a complex virus. Which feature distinguishes complex viruses from helical and icosahedral viruses?

Accepted Answer

They have atypical structures that do not fit helical or icosahedral classification.

Question 9

The ninth image shows the structure of a poxvirus. Which of the following statements about poxvirus structure is correct?

Accepted Answer

Poxviruses have a core envelope, palisade layer, and surface tubules, lacking a typical capsid.

Question 10

The tenth image shows a bacteriophage attaching to a bacterial cell. Which step in the lytic cycle does this image represent?

Accepted Answer

Attachment

Question 11

The eleventh image shows a bacteriophage. Which structural feature allows bacteriophages to inject their genome into the host cell?

Accepted Answer

Sheath

Question 12

The twelfth image shows an enveloped virus with a DNA core. Which release mechanism is most likely used by this virus?

Accepted Answer

Budding (exocytosis)

Question 13

The thirteenth image shows a virus with spikes made of glycoproteins. What is the primary function of these spikes?

Accepted Answer

Attachment to specific host cell receptors

Question 14

The fourteenth image shows a retrovirus. Which enzyme is unique to retroviruses and is responsible for converting RNA into DNA?

Accepted Answer

Reverse transcriptase

Question 15

The fifteenth image shows the structure of the influenza virus. Which two glycoprotein spikes are key virulence factors for influenza?

Accepted Answer

Hemagglutinin and Neuraminidase

Question 16

The sixteenth image shows a virus with a segmented genome and multiple spikes. Which process allows for major genetic changes in influenza viruses, potentially leading to pandemics?

Accepted Answer

Antigenic shift

Question 17

The seventeenth image shows a variety of virus structures. Which virus type is most likely to be released by cell lysis?

Accepted Answer

Naked virus

Question 18

The eighteenth image shows a herpesvirus under electron microscopy. Which property of herpesviruses allows them to cause recurrent infections?

Accepted Answer

Latency

Question 19

The nineteenth image shows a cytopathic effect in host cells. Which cytopathic effect is characterized by the fusion of multiple host cells into a single giant cell?

Accepted Answer

Syncytium formation

Acellular Pathogens: Viruses, Viroids, and Prions – Structure, Classification, and Effects (chapter 6)

Guida di studio - Domande di pratica

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