40 Questions
What is the result of the lytic cycle in a host cell?
The host cell's membrane breaks open releasing new phages
What is the function of bacterial restriction enzymes?
To recognize and cut up certain phage DNA
What is the term for the viral DNA molecule integrated into the host cell's chromosome?
Prophage
What triggers the switch from the lysogenic cycle to the lytic cycle?
Environmental signal
What is the term for phages that reproduce only by the lytic cycle?
Virulent phages
What is the result of the lysogenic cycle in a host cell?
The phage genome replicates without destroying the host
What is the term for phages that replicate by both the lytic and lysogenic cycles?
Temperate phages
What is the role of the protease enzyme in the HIV reproductive cycle?
To cut the viral polypeptide produced by translation
What is the primary route of transmission for Hepatitis B virus?
Blood and other biological fluids
What is the characteristic symptom of acute hepatitis?
Jaundice
Which virus attaches to the CD4 receptor on the surface of Th-cells?
Human Immunodeficiency Virus
What is the interval between HIV infection and the onset of AIDS?
10-15 years
What is the current status of Hepatitis C virus vaccine development?
Vaccine has not been developed yet
What is the number of people infected with HIV since the beginning of the pandemic?
85 million
What is the target of anti-retroviral therapy in HIV treatment?
HIV replication cycle
What is the definition of AIDS onset in terms of Th (CD4+) lymphocytes?
< 200 Th cells/mm3 of blood
What is the result of the inhibition of host cell gene expression by the virus?
The host cell's enzymes are used to replicate the virus
What is the function of the viral enzyme Reverse Transcriptase in retroviruses?
To convert the viral RNA into DNA
What is the outcome of the attachment and entry of a retrovirus into a host cell?
The viral RNA is converted into DNA
What is the role of the host's RNA polymerase in the replicative cycle of a retrovirus?
To transcribe the proviral DNA into RNA molecules
What is the difference between the release of non-enveloped viruses and enveloped viruses from the host cell?
Non-enveloped viruses are released by lysis, while enveloped viruses are released by budding
What is the result of the integration of the retroviral genome into the host genome?
The retrovirus becomes a provirus
What is the function of the viral glycoprotein in the replicative cycle of a retrovirus?
To bind to the host cell receptor
What is the central dogma of transfer of genetic information that retroviruses are an exception to?
DNA → RNA → protein
What is the human disease caused by consuming contaminated beef infected with prions?
Creutzfeldt-Jacob disease (CJD)
What is the characteristic of prions that allows them to cause fatal CNS infections?
Their ability to aggregate and form infectious particles
What is the term for viral diseases that affect plants?
Viral diseases in plants
What is the genome of most plant viruses composed of?
Single-stranded RNA
Which of the following viruses is responsible for causing oral herpes?
Herpes simplex virus-1 (HSV-1)
What is the term for the human disease caused by the Varicella Zoster Virus?
Chickenpox
Which of the following viruses is responsible for causing Infectious mononucleosis?
Epstein-Barr Virus (EBV)
What is the name of the coronavirus disease that was first identified in 2019?
COVID-19
What is the name of the malignant tumor of the endothelial cells of the blood vessels?
Κaposi sarcoma
How can HIV be transmitted from mother to child?
During pregnancy, birth or breast feeding
What is the purpose of the window period in HIV diagnosis?
To indicate the time during which the virus cannot be detected but can still be transmitted
What is the main reason why there is no vaccine available for HIV?
Due to the high mutation rate of the virus
What is the purpose of Highly Active Anti-Retroviral Therapy (HAART)?
To treat HIV infection with a combination of antiretroviral drugs
What is the mechanism of action of nucleotide analogues in antiretroviral therapy?
Inhibit the viral RNA replication by being incorporated into the growing cDNA chain
What is a common problem of antiretroviral therapy?
Toxicity and resistance
How many weeks after infection can HIV be detected in the blood using RT-PCR?
3 weeks
Explore the different stages of a virus's life cycle, from assembly to release, and learn how they interact with host cells. Understand the mechanisms of non-enveloped and enveloped viruses. Test your knowledge of virology!
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