What Is a Virus?
A virus is considered nonliving because it:
A. Is made of proteins only
B. Cannot maintain homeostasis
C. Cannot reproduce without a host cell
D. Lacks genetic material
C. Cannot reproduce without a host cell
The protein coat that surrounds a virus is called the:
A. Envelope
B. Capsid
C. Cell wall
D. Membrane
B. Capsid
Viruses can contain which type(s) of genetic material?
A. DNA only
B. RNA only
C. Both DNA and RNA
D. DNA or RNA
D. DNA or RNA
The first step of viral infection is:
A. Replication
B. Assembly
C. Attachment
D. Release
C. Attachment
Which cycle results in immediate destruction of the host cell?
A. Lysogenic
B. Chronic
C. Lytic
D. Latent
C. Lytic
Which best describes a virus?
A. A single-celled organism
B. A prokaryotic pathogen
C. Genetic material enclosed in a protein coat
D. A type of bacteria
C. Genetic material enclosed in a protein coat
What is the function of the capsid?
A. Replication
B. Protection of genetic material
C. Energy production
D. Protein synthesis
B. Protection of genetic material
Why do viruses contain either DNA or RNA, but not both?
A. To avoid mutation
B. To simplify replication
C. To resist antibiotics
D. To infect more hosts
B. To simplify replication
What occurs during viral uncoating?
A. Virus binds host receptor
B. Viral genome is released
C. New viruses exit cell
D. Capsid forms
B. Viral genome is released
During the lysogenic cycle, viral DNA:
A. Immediately kills the host
B. Integrates into host genome
C. Is destroyed
D. Leaves the cell
B. Integrates into host genome
Why must viruses infect a host cell to reproduce?
A. They lack ribosomes
B. They lack a nucleus
C. They lack enzymes
D. They lack cytoplasm
A. They lack ribosomes
Enveloped viruses differ from non-enveloped viruses because they:
A. Have DNA only
B. Are always pathogenic
C. Have a lipid membrane
D. Lack a capsid
C. Have a lipid membrane
RNA viruses often evolve faster than DNA viruses because they:
A. Are larger
B. Use host enzymes
C. Have higher mutation rates
D. Have envelopes
C. Have higher mutation rates
Why is attachment highly specific?
A. Viruses bind any cell
B. Host receptors must match viral proteins
C. Capsids determine host range
D. Viruses target organelles
B. Host receptors must match viral proteins
Why can the lysogenic cycle be dangerous long-term?
A. It prevents immunity
B. It mutates host DNA
C. It blocks replication
D. It prevents viral spread
B. It mutates host DNA
Which statement correctly compares viruses to cells?
A. Viruses perform metabolism like cells
B. Viruses are smaller and simpler than cells
C. Viruses contain organelles
D. Viruses divide by mitosis
B. Viruses are smaller and simpler than cells
Which virus component helps attach to host cells?
A. RNA
B. Ribosome
C. Surface proteins
D. Cytoplasm
C. Surface proteins
Which viral genome requires reverse transcription?
A. dsDNA
B. ssDNA
C. ssRNA (−)
D. Retrovirus RNA
D. Retrovirus RNA
Which step involves making viral proteins and genomes?
A. Entry
B. Assembly
C. Replication
D. Release
C. Replication
A bacteriophage undergoing lysogeny forms a:
A. Capsid
B. Provirus
C. Prophage
D. Envelope
C. Prophage
Which feature is NOT found in viruses?
A. Capsid
B. DNA or RNA
C. Ribosomes
D. Surface proteins
C. Ribosomes
Which virus type is generally more sensitive to disinfectants?
A. Non-enveloped viruses
B. Enveloped viruses
C. Bacteriophages
D. Prions
B. Enveloped viruses
Which statement is TRUE about viral genomes?
A. All viruses use the same replication strategy
B. Viral genomes can be double or single stranded
C. Viral genomes contain introns
D. Viral genomes replicate independently
B. Viral genomes can be double or single stranded
Which sequence correctly orders the lytic cycle?
A. Attachment → Entry → Replication → Assembly → Release
B. Entry → Attachment → Assembly → Release → Replication
C. Attachment → Replication → Entry → Release → Assembly
D. Replication → Entry → Attachment → Assembly → Release
A. Attachment → Entry → Replication → Assembly → Release
What triggers a switch from lysogenic to lytic cycle?
A. Antibiotics
B. Host stress
C. Vaccination
D. Cell division
B. Host stress