Question

why are viruses hard to treat?

why are viruses not alive?

what happens when a virus particle attacks a cell?

what happens to the host cell when a virus replicates inside it?

what 2 components do all viruses contain?

what are the steps in the virus life cycle?

what happens during the lysogenic phase?

what happens in the lytic phase?

what are some diseases caused by a virus?

why are most viruses known?

write down the 6 steps in a lytic infection?

explain the difference between injection and endocytosis?

what is lysogeny?

write the 4 steps in a lysogenic infection?

how is lysogeny different from lytic cycle?

Answer 1

1. Viruses are hard to treat because they have the external envelope which is same as cell membrane and hard to differentiate and destroy

2. Viruses are not live because they cannot reproduce, all they can do is injecting their DNA or RNA into a host cell. Virus has either DNA or RNA, they do not encode genes for the their own ribosomes, genes for sysnthesizing amino acids and proteins for metabolism.

3. attachement occurs when a virus particle attacks a cell, binds to specific receptor sites on the host cell membranes. Attachement to the receptor subsequently induce the viral envelope protein to undergo changes which result in the fusion of viral and cellularmembranes.

4. Depends on the lysogenic or lytic cycles, in the lytic cycle host cells are destroyed by the continues viral replication

5. All viruses contain nucleic acid (DNA or RNA) and Protein capsid

6. Steps in the virus life cycle are i) Attachement ii) Penetration iii) Uncoating iv) Transcription v) Translation vi) Replication vii) Assembly viii) Release

7. Lysogenic phase - Virus DNA replicates along with host cell DNA. In this phase DNA is only replicated but not translated into proteins

In lysogenic phase host cell is not lysed

8. Lytic phase - Virus DNA exists as a separate molecule and replicates separately from the host genome

In the lytic phase, host cell is destroyed

9. Viral diseases are common cold, Measels, Influenza, Hepatitis, HIV, Chickenpox, Ebola etc

10. 6 steps in a lytic infection are i) Attachement ii) Penetration iii)Uncoating iv) Synthesis v) Assembly vi) Release

11. Endocytosis is the process by which a cell takes in a substance that is too big to travel through the semi-permeable membrane. The substance will come into contact with the cell membrane and will cave in a portion of the cell membrane, forming a vesicle around it

12. Lysogeny is one of the two reproductive cycles, which is characteised by the integration of the viral nucleic acid into the host genome

13. Steps in lysogenic infection are i) Viral genome enters cell ii) Integration of viral genome into Host cell genome iii) Hst cell DNA polymerase makes copies of viral chromosome iv) Cell division and virus chromosomes are transmitted into daughter cells

14. key difference is that: In the lytic cycle constant virus replication results in the eventual lysis, or death, of the host cell to release the new viruses.

while in the lysogenic cycle the virus replicates only with the regular cellar mechanism for reproduction and is only released through some seperate event.