أسئلة ريتين السابعة ميكرو دمياط (قبل التعديل)

A virus is defined as a sub-microscopic, obligate intracellular parasite that is only active inside viable dividing host cells.

Virions are virus particles that do not grow or divide; they form through the assembly of pre-formed viral protein components.

Envelope glycoproteins help viruses attach to target cells, defining the specificity of the interaction with the host's receptors.

<p>Viral penetration can occur via translocation of the entire virion, endocytosis into vacuoles, or fusion of the viral envelope with the cell membrane.</p> Signup and view all the answers

<p>A nucleocapsid is the structure formed by the capsid together with its enclosed nucleic acid.</p> Signup and view all the answers

<p>Viruses with an RNA genome must either make or bring their own polymerases to replicate, as mammalian cells only produce DNA and RNA in the nucleus.</p> Signup and view all the answers

<p>Early proteins are typically DNA or RNA polymerases, while late proteins include structural components like capsid or envelope proteins.</p> Signup and view all the answers

<p>The specificity determines the host species and cell tropism, influencing which cells and tissues the virus can infect.</p> Signup and view all the answers

<p>New mutants with clinical importance.</p> Signup and view all the answers

<p>In the nucleus, cytoplasm, or at the cell surface while budding.</p> Signup and view all the answers

<p>They are accumulations of virions at assembly sites, useful for diagnosing viral infections.</p> Signup and view all the answers

<p>Viral genome detection by PCR, viral antigen detection, and detection of antibodies to the virus.</p> Signup and view all the answers

<p>It allows virus particles enclosed in vesicles to exit by fusing with the cell membrane.</p> Signup and view all the answers

<p>The viral genome remains in the host cell without effect; reactivation occurs due to changes in the host's immune status.</p> Signup and view all the answers

<p>PCR and antigen tests assess acute infection, while antibody tests provide evidence of prior infection.</p> Signup and view all the answers

<p>Immunofluorescence, ELISA, and rapid tests.</p> Signup and view all the answers

<p>Bacteria are single-celled organisms that can reproduce independently, while viruses are much smaller and require a host cell to replicate.</p> Signup and view all the answers

<p>The main types of influenza viruses are A, B, and C, with sources of infection often being respiratory droplets from infected individuals or contaminated surfaces.</p> Signup and view all the answers

<p>Acyclovir treats herpes virus infections, Zidovudine (AZT) is used for HIV, and Tamiflu is used for influenza.</p> Signup and view all the answers

<p>Different vaccines are necessary each year because influenza viruses constantly mutate, leading to new strains that escape the immune response.</p> Signup and view all the answers

<p>Yes, viruses can be cultured and isolated using specific laboratory techniques on appropriate cell cultures.</p> Signup and view all the answers

<p>Public health measures, such as vaccination and hygiene practices, help minimize the spread of viral infections in populations.</p> Signup and view all the answers

<p>Live attenuated vaccines contain weakened forms of the virus, while inactivated vaccines contain killed viruses; the difference affects immune response and safety.</p> Signup and view all the answers

<p>Protease inhibitors block the protease enzyme, which is crucial for viral replication, thereby inhibiting the virus's ability to reproduce.</p> Signup and view all the answers

<p>Seasonal vaccines are important as they prepare the immune system to fight against the most recent circulating strains of the influenza virus.</p> Signup and view all the answers

<p>The specificity of antiviral agents ensures that they target only the intended virus, reducing the risk of harming host cells and other beneficial bacteria.</p> Signup and view all the answers

<p>The specificity of viral infection is defined by the interaction between viral surface proteins and specific receptors on suitable host cells.</p> Signup and view all the answers

<p>Viruses replicating in the cytoplasm must carry their own polymerases since mammalian cells can only produce DNA and RNA in the nuclear compartment.</p> Signup and view all the answers

<p>Capsomers are clusters of structural units that make up the capsid, providing the protective shell for the viral nucleic acid.</p> Signup and view all the answers

<p>Segmented genomes consist of multiple RNA molecules, while non-segmented genomes contain a single RNA molecule.</p> Signup and view all the answers

<p>The viral envelope facilitates the attachment and fusion with the host cell membrane, enabling viral entry through active penetration.</p> Signup and view all the answers

<p>'Early' proteins include enzymes like polymerases essential for replication, whereas 'late' proteins are structural proteins like capsid or envelope components.</p> Signup and view all the answers

<p>Enveloped viruses acquire their outer membrane from the host cell, while non-enveloped viruses do not have a membrane and rely solely on their capsid.</p> Signup and view all the answers

<p>Endocytosis allows the virus to be engulfed in a cellular vacuole, eventually delivering it to the cytoplasm for replication.</p> Signup and view all the answers

<p>Transcriptional errors can lead to new mutations that may have clinical significance.</p> Signup and view all the answers

<p>Some viruses exit by budding through the cell membrane, while others may cause cell lysis.</p> Signup and view all the answers

<p>PCR or antigen detection tests are designed to identify acute viral infections.</p> Signup and view all the answers

<p>Latent viruses can reactivate due to changes in the immune status of the host.</p> Signup and view all the answers

<p>Inclusion bodies can accumulate at sites of viral assembly and are useful for diagnosing viral infections.</p> Signup and view all the answers

<p>Antibody tests provide evidence of prior infections, while PCR or antigen tests assess active infections.</p> Signup and view all the answers

<p>Damaged host cells may release progeny viruses over time without undergoing cell death.</p> Signup and view all the answers

<p>Viral vaccines are essential for establishing immunity and preventing infection before exposure to the virus.</p> Signup and view all the answers

<p>Antiviral drugs specifically target virus replication and have limited spectra of activity, whereas antibiotics target bacterial functions.</p> Signup and view all the answers

<p>Seasonal vaccines are updated annually to match circulating virus strains, ensuring effective immunity.</p> Signup and view all the answers

<p>Molecular biology techniques help identify viral targets and mechanisms, facilitating the design of specific antiviral agents.</p> Signup and view all the answers

<p>Genetically engineered vaccines use modified genetic material to induce immunity, while traditional vaccines often use live attenuated or inactivated pathogens.</p> Signup and view all the answers

<p>Emerging viruses often mutate rapidly, making it difficult to create effective antiviral drugs that remain effective over time.</p> Signup and view all the answers

<p>Public health measures help prevent virus transmission and reduce infection rates, enhancing the overall impact of antiviral treatments.</p> Signup and view all the answers

<p>Side effects may include nausea, diarrhea, and, in some cases, serious allergic reactions.</p> Signup and view all the answers

<p>Protease inhibitors block viral proteolytic enzymes, preventing virus maturation and replication.</p> Signup and view all the answers

<p>The specificity of antiviral drugs minimizes off-target effects, allowing for effective treatment with reduced risk of damaging host cells.</p> Signup and view all the answers

<p>Knowledge of whether a virus has DNA or RNA and its structure can guide the development of drugs that target specific replication processes.</p> Signup and view all the answers