Question

Antigenic _________ is the result of reassortment of genes responsible for the production of influenza virus spike proteins between different virus particles while in the same host, whereas antigenic ________ is the result of point mutations in the spike proteins.

Short answer

Antigenic shift, antigenic drift.

Step-by-step solution

Identify Key Terms

First, identify the key terms in the problem to understand what is being asked. The terms are 'antigenic _________', 'reassortment of genes', 'influenza virus spike proteins', 'antigenic ________', and 'point mutations in the spike proteins'.

Recall Definitions

Recall the definitions of antigenic drift and antigenic shift. Antigenic shift is the reassortment of genes between different virus particles, leading to new combinations of spike proteins. Antigenic drift refers to small point mutations in the spike proteins of the influenza virus.

Match Definitions to Blanks

Match the definitions to the appropriate blanks in the sentence: Antigenic shift is the result of reassortment of genes responsible for the production of influenza virus spike proteins between different virus particles while in the same host. Antigenic drift is the result of point mutations in the spike proteins.

Fill in the Blanks

Fill in the blanks with the correct terms: Antigenic shift is the result of reassortment of genes responsible for the production of influenza virus spike proteins between different virus particles while in the same host, whereas antigenic drift is the result of point mutations in the spike proteins.

Key concepts

Viral Reassortment

Viral reassortment is a process where different strains of viruses exchange genetic material when they infect the same host cell. This often occurs in influenza viruses because they have segmented genomes.
Each segment can come from different strains, leading to a new combination of genes.

• Produces significant genetic changes
• Can create new virus subtypes
• Often responsible for pandemics

Reassortment allows viruses to acquire new properties rapidly like different spike proteins, which can help them evade the host's immune system.

Influenza Virus

The influenza virus is notorious for causing seasonal flu outbreaks. It's an RNA virus with a segmented genome, meaning its genetic material is divided into separate pieces known as segments.
This segment system makes the virus prone to reassortment.

• Has types like Influenza A, B, and C
• Type A is most prone to causing pandemics
• Seasonal flu is usually caused by Type A and B

The virus has proteins on its surface known as spike proteins that allow it to enter host cells.

Point Mutations

Point mutations happen when there is a small change, or mutation, in the virus’ genetic material. In the context of influenza, point mutations often occur in the genes coding for spike proteins.
These minor changes can have significant effects.

• Cause slight alterations in spike proteins
• Lead to antigenic drift
• Can make it harder for the immune system to recognize the virus

Though these mutations are small, over time they accumulate and can affect the virus' behavior and how well our immune system can fight it.

Spike Proteins

Spike proteins are the components on the surface of viruses, including influenza, that allow the virus to bind and enter host cells. These proteins are crucial for the virus’ ability to infect.
There are two main types: Hemagglutinin (HA) and Neuraminidase (NA).

• HA helps the virus bind to host cells
• NA helps the virus exit the infected cell
• Essential targets for the immune response

Changes in these proteins due to mutations or reassortment can help the virus evade the immune system.

Genetic Variation in Viruses

Genetic variation in viruses occurs through mechanisms like point mutations and reassortment. This genetic diversity is crucial for the virus’s survival and evolution.
It allows the virus to adapt to varying environments and immune responses.

• Enables rapid adaptation
• Increases the chances of evading vaccines
• Leads to new strains or subtypes

This genetic variability is why flu vaccines need to be updated regularly to keep up with the evolving influenza virus.