Virus structure and replication
Start with the big picture
A virion’s genome and capsid form its core structure; some viruses also have an envelope bearing glycoproteins that help mediate attachment and fusion. Capsids can have icosahedral, helical, or complex symmetry. Genome polarity and virus type shape replication: for example, positive-sense RNA can serve as mRNA, while negative-sense RNA viruses carry RNA-dependent RNA polymerase to make mRNA. Replication proceeds through attachment, penetration, uncoating, synthesis, assembly, and release. These stages, along with differences in replication sites and release mechanisms, help explain how viruses interact with host cells. The lesson also introduces genome segmentation and replication errors as sources of viral variation.
What you'll learn
- Describe the components of a virion and distinguish enveloped from non-enveloped viruses.
- Identify major capsid symmetries and explain the role of capsomers.
- Relate genome polarity and virus type to strategies for making viral proteins.
- Outline the stages of the viral replication cycle and their key events.
- Recognize how genome segmentation and replication errors contribute to viral variation.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
