A Review Quiz On Microbiology! Trivia

Viruses are unable to multiply outside of a host cell because they lack the necessary cellular machinery to carry out essential life processes independently. They rely on the host cell's machinery to replicate and produce more virus particles. Without a host cell, viruses cannot carry out their reproductive cycle and therefore cannot multiply. This is why they are considered obligate intracellular parasites.

The core of every virus particle can contain either DNA or RNA. Viruses are classified based on the type of genetic material they possess. Some viruses have DNA as their genetic material, while others have RNA. This genetic material carries the instructions for the virus to replicate and infect host cells. Therefore, the core of a virus particle can contain either DNA or RNA, depending on the type of virus.

Bacteriophages are viruses that specifically infect bacteria. They attach to the surface of bacterial cells and inject their genetic material into the host cell, taking over the cell's machinery to produce more phages. This eventually leads to the lysis or destruction of the bacterial cell, releasing new phages to infect other bacteria. Unlike viroids and prions, which are infectious agents that do not have a viral structure, bacteriophages are true viruses that have a protein coat and genetic material. Therefore, the correct answer is bacteriophages.

Virus capsids are the protein shells that enclose the genetic material of a virus. These capsids are composed of repeating subunits called capsomeres. Each capsomere is made up of multiple protein molecules that come together to form the structure of the capsid. Therefore, capsomeres are the correct answer as they are the building blocks of virus capsids.

Chronic latent viruses are persistent viruses that can reactivate periodically. These viruses remain in a dormant state within the host's cells, allowing them to evade the immune system and establish a long-term infection. Periodically, these viruses can reactivate and cause recurrent infections or symptoms. Examples of chronic latent viruses include herpesviruses, such as herpes simplex virus and varicella-zoster virus, which can cause recurrent cold sores and shingles respectively.

Most DNA viruses multiply in the host cell's nucleus because they require access to the host cell's DNA replication machinery in order to replicate their own DNA. On the other hand, most RNA viruses multiply in the host cell's cytoplasm because they carry their own RNA polymerase enzyme, which allows them to replicate their RNA genome in the cytoplasm without the need for access to the host cell's nucleus.

Viroids are infectious naked strands of RNA that affect plants. They are smaller than viruses and do not have a protein coat like viruses do. Viroids can cause diseases in plants by interfering with the normal functioning of plant cells. They replicate within the host plant cells and can spread to other plants through mechanical contact, contaminated tools, or insect vectors. Viroids are unique in that they do not code for any proteins, unlike viruses. Their ability to cause diseases in plants makes them a significant concern in agriculture and plant health.

The correct sequence of events in viral multiplication starts with adsorption, where the virus attaches to the host cell. Then, penetration occurs, where the virus enters the host cell. After penetration, uncoating takes place, where the viral genetic material is released from the protein coat. Next, synthesis occurs, where the viral genetic material is replicated and viral proteins are produced. Assembly follows, where new viral particles are assembled using the replicated genetic material and proteins. Finally, release happens, where the newly formed viral particles are released from the host cell to infect other cells.

Viruses do not have metabolism. Unlike living organisms, viruses cannot carry out metabolic processes such as respiration, growth, or reproduction on their own. They are considered to be non-living entities that rely on host cells to replicate and carry out their life cycle. While viruses do contain genetic material (genes) and have the ability to infect host cells, they lack the ability to independently perform metabolic activities.

Prions are infectious protein particles that can cause diseases in animals and humans. Unlike viruses, bacteria, or fungi, prions do not contain genetic material such as DNA or RNA. They are composed of a misfolded form of a normal cellular protein, which can convert other normal proteins into the misfolded form. This misfolding process leads to the accumulation of abnormal proteins in the brain, causing neurodegenerative disorders such as Creutzfeldt-Jakob disease and mad cow disease. Therefore, prions are the correct answer for the given question.

Oncoviruses are mammalian viruses that have the ability to initiate tumor formation. These viruses can integrate their genetic material into the host's DNA, leading to uncontrolled cell growth and the development of tumors. Unlike other options listed, such as chronic latent viruses, syncytia, inclusion bodies, or cytopathic, oncoviruses specifically have a direct association with tumor formation.

Herpesviridae represents a virus family name. It is a taxonomic family of viruses that includes the herpes simplex virus, as well as other viruses such as varicella-zoster virus and Epstein-Barr virus. The suffix "-viridae" is used to denote a family of viruses, making Herpesviridae the correct option. The other options mentioned are either specific virus species or genera, not family names.

Prions are infectious proteins that lack genetic material and can cause diseases in animals and humans. Viroids, on the other hand, are infectious RNA strands that can cause diseases in plants. Therefore, the correct answer is "Prions, viroids."

Viruses cannot be seen in a light microscope because they are much smaller than the resolution limit of the light microscope. Viruses are submicroscopic particles that can only be visualized using electron microscopes, which have much higher resolution capabilities. Therefore, the statement that viruses cannot be seen in a light microscope is accurate.

Lysogeny refers to the process in which a viral genome inserts itself into the chromosome of a bacterial host. This integration allows the viral genetic material to be replicated along with the host's DNA during cell division, leading to the stable inheritance of the viral genome in subsequent generations of bacteria. Lysogeny is a form of viral latency, where the viral genes are not actively transcribed and the virus remains dormant within the host cell until it is triggered to enter the lytic cycle, resulting in the production of new viral particles.

The host range of a virus refers to the range of host species that the virus can infect. The type of host cell receptors on the cell membrane plays a crucial role in determining the host range. Viruses can only enter host cells that have specific receptors on their cell membranes, which the virus can recognize and bind to. If the host cell does not have the required receptors, the virus cannot enter and infect the cell. Therefore, the type of host cell receptors on the cell membrane is a determining factor in limiting the host range of a virus.

Creutzfeld-Jacob disease is a spongiform encephalopathy of humans. This means that it is a neurological disorder characterized by the degeneration of brain tissue, leading to the formation of small holes or vacuoles, giving the brain a spongy appearance. The disease is not caused by a chronic latent virus, an oncogenic virus, or a viroid. It is also distinct from "mad cow disease," although both are classified as spongiform encephalopathies.

In order to cultivate viruses in the lab, in vitro systems called cell cultures are commonly used. Cell cultures involve growing cells in a controlled environment outside of their natural setting. This allows scientists to study the behavior and replication of viruses in a controlled and easily accessible manner. Embryos, plaques, bacteriophages, and eggs are not typically used as in vitro systems for cultivating viruses in the lab.

The viral spikes are responsible for binding the viral capsid and envelope together. This allows for the structural integrity of the virus and helps in the process of infecting host cells. The spikes are typically derived from host proteins and are always present on enveloped viruses. They play a crucial role in the virus's ability to evade host defenses and establish infection. Therefore, all of the choices provided in the question are correct.