Ch. 19 SA

No they cannot protect you from viruses. This is because viral infections do not have a cure and even a vaccine for that infection may not be 100%.

Can anti-bacterial soaps and wipes really protect you from viruses? Discuss and defend your response.

There are 6 different classes. It depends on the type of genetic material, whether it is single or double stranded, and if the RNA is a template for mRNA or DNA.

Describe how are animal viruses are classified and explain the basis of the classification system.

A typical virus has a core made of DNA or RNA and is surrounded by a protein layer.

Describe the structure of a typical virus.

The two phage reproductive cycles are the lytic cycle and the lysogenic cycle. The lytic cycle is a phage replicative cycle that culminates in the death of the host cell. It breaks open the host cell's wall and releases viruses. The lysogenic cycle replicates the phage genome without destroying the host.

Describe the two phage reproductive cycles.

They can only reproduce within a host cell because the viruses do not have the proteins for DNA synthesis and replication. They also do not use energy, which means they cannot reproduce by standing alone.

Describe why viruses can only reproduce within a host cell.

A pandemic is a global epidemic, where the majority of the population is affected.

Discuss what is meant by a "pandemic".

This is because HIV uses RNA as a template to produce double stranded DNA in a host cell. It also uses reverse transcriptase to copy RNA, which is not the typical way.

Discuss why HIV is called a retrovirus and how these viruses violate the Central Dogma of Biology.

They are so difficult to treat because viruses cannot be treated by antibiotics, and antiviral drugs can be used to help relieve some of the symptoms.

Discuss why viruses are so difficult to treat once the host is infected.

No because once the virus has placed its DNA into the host's DNA, it is permanent.

Explain if a person is "cured" of a virus such as Herpes or cold sores.

A virus is an envelope made of membrane. Its genome is closed within a protective coat, and can only reproduce in the host cell. A viroid is the infectious genetic material. It does not contain a capsid or envelope. A prion is an infectious protein, and it has no genetic material.

Identify the differences between a virus, a viroid and a prion.

This can be dangerous because the new host that the virus just jumped to may not have any immunization towards the virus, so it cannot defend itself.

Viruses can sometimes jump between host species such as with swine flu, SARS, or avian flu. Discuss why this is a serious health concern.