Viruses

What are the main chemical components of a virus?

Protein coat

Nucleic acid (DNA or RNA)

Reasons for classifying viruses as living

Possess genetic material

Protein coat

What are the main chemical components of a virus?

Protein coat

Nucleic acid (DNA or RNA)

Reasons for classifying viruses as living

Possess genetic material

Protein coat

Reasons for classifying viruses as non-living

Non-cellular

Only have DNA or RNA (not both)

Viruses shapes

Round

Rod shaped

Complex in shape

What are the benefits of viruses?

Genetic engineering

Control of infections

Manufacturing of vaccines

What is the benefit of genetic engineering?

Transfer genes from one organism to another

What is the benefit of control of infections?

Bacteriophages are viruses that infect bacteria

Disadvantages of viruses

Human diseases

Plants diseases

Animal diseases

What are examples of human diseases?

Common colds, influenza, chicken pox, AIDS

What are examples of plant diseases?

Tobac mosaic disease, potato mosaic disease

What are examples of animal diseases?

Myxomatosis

What is replication?

Viruses need another cell to replicate (obligate parasites)

5 stages in virus replication

Attachment

Entry

Synthesis

Assembly

Release

Describe the attachment stage

Virus attaches itself to the host cell

Describe the entry stage

Nucleic acid is pushed in the host cell

Describe the synthesis stage

Host’s structures are used to produce more viral nucleic acid and proteins

Describe the assembly stage

Virus assembly occurs, resulting in new viruses being made inside the host cell

Describe the release stage

Host cell burst, releasing new viruses

How does the human body control viral infections?

Vaccinations encourage the body to form antibodies

Anti-viral drugs help fight the viral infection

How is HIV transmitted?

HIV enters the body through blood or semen

What are the effects of HIV?

Enters the white blood cell, where it may remain dormant and produce no effects or disable the white blood cells

How do we control & prevent HIV?

Avoid sexual intercourse

One sexual partner

Condoms