Questions: Select all that apply Identify the three major modes of action of antiviral drugs. Blocking incorporation of virus DNA into host genome Preventing virus maturation Blocking virus transcription and translation Blocking virus binding to host cell receptors Barring virus penetration into host cell

The three major modes of action of antiviral drugs are:

1. Blocking incorporation of virus DNA into host genome
2. Preventing virus maturation
3. Blocking virus transcription and translation

Explanation for each option:

• Blocking incorporation of virus DNA into host genome: This is a major mode of action for antiviral drugs, particularly for retroviruses like HIV. Drugs such as integrase inhibitors prevent the viral DNA from integrating into the host's genome, thereby halting the replication process.

• Preventing virus maturation: This is another key mode of action. Protease inhibitors, for example, prevent the maturation of viral particles by inhibiting the protease enzyme, which is essential for the virus to become fully infectious.

• Blocking virus transcription and translation: This mode of action involves inhibiting the processes by which viral RNA is transcribed into viral proteins. Drugs that inhibit viral polymerases or other enzymes involved in transcription and translation fall into this category.

• Blocking virus binding to host cell receptors: While this is a valid antiviral strategy, it is not one of the three major modes of action. Drugs that block viral entry by preventing the virus from binding to host cell receptors are important but are less commonly used compared to the other mechanisms listed.

• Barring virus penetration into host cell: Similar to blocking virus binding, this is also a valid antiviral strategy but not one of the three major modes of action. Fusion inhibitors, for example, prevent the virus from entering the host cell.

In summary, the three major modes of action of antiviral drugs are blocking incorporation of virus DNA into the host genome, preventing virus maturation, and blocking virus transcription and translation.