Viral Envelope and General Virus Structure Quiz

Viral Structure and Function

• The envelope in viruses functions to protect the nucleic acid and aid in host cell entry.

Types of Viruses

• DNA viruses: an example is Human Papillomavirus (HPV).
• RNA viruses: primary nucleic acid is RNA.

Viral Replication

• Some viruses carry the enzyme reverse transcriptase for replication.

Infectious Cycle

• During the eclipse period, no intact virions appear within the infected host cell.

Viral Diseases

• RNA viruses can cause diseases, such as polio.

Viral Characteristics

• Viruses are obligate intracellular parasites due to their inability to reproduce independently.

Viral Structure

• The capsid is responsible for protecting the nucleic acid and aiding in host cell entry.
• Helical capsid: a continuous helix of capsomers forming a cylindrical nucleocapsid.

Enveloped Viruses

• Enveloped viruses acquire their envelopes from the host cell membrane during budding.
• Animal viruses often possess an external lipid envelope.

Viral Spikes

• Spikes on enveloped viruses play a role in host cell recognition and attachment.

Latency and Oncogenesis

• Some viruses, such as herpesviruses, can show latency.
• HPV can cause cervical cancer.
• Oncogenic viruses, such as retroviruses, can enter the host cell and permanently alter its genetic material, resulting in cancer.

Other Infectious Agents

• Viroids are infectious agents that contain no nucleic acid or covering.
• The condition in which host DNA carries phage DNA is called lysogeny.

RNA Viruses

• RNA viruses with naked strands of RNA, such as poliovirus, lack a capsid or covering.