Chapter 6: Viral Replication

Steps of Replication in a Permissive Host

1. Attachment of the virion

2. Penetration of the virion nucleic acid.

3. Synthesis of virus nucleic acid and protein by host cell.

4. Assembly of capsids and packaging of genome into new virions.

5. Release of virions from host cell.

Difference Between Pro and Eu Viruses

Nucleic acid entry in prokaryotes and virion entry in eukaryotes.

Growth Curve

Eclipse phase

Maturation

Latent Period

Release

Eclipse Phase

Genome replicated and proteins translated.

Maturation

Packaging of nucleic acids in capsids.

Latent Period

Eclipse + maturation.

Release

Cell lysis, budding, or excretion.

Coliphages

Gut bacteriophages that are a part of the community that modulates human digestion, the immune system, and mental health.

Cell-Surface Receptors

Proteins on the host cell surface that are specific to the host and that bind to a specific component of the virus, mediate contact and attachment.

Host Bacteria Resistance

Bacteria can evolve resistance to phage attachment by acquiring mutations in the amino acid sequences of its surface attachment sites.

Complementary Receptors

Include proteins, carbohydrates, glycoproteins, lipids, lipoproteins, or other cell structures.

Ghost

Phage capsid that has delivered their genome into a cell through the cell envelope, remains outside.

Bacteriophage Types of Replication

Lytic cycle and lysogenic cycle