UNIT 1: How Viruses Work

Unit Focus

How viruses infect healthy cells and how soap prevents infection.

Related Wise Bodies Videos

• HIV/AIDS 101

• How is HIV Transmitted?

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Objectives

Learners will differentiate between types of viruses and understand how science can influence public health information.

Key Concepts

• Attachment proteins – Proteins that are involved in binding other proteins to cell structures.

• Viral envelope – The outer coating of a virus, often made of fatty acids, that encases and protects the virus. May be covered in attachment proteins.

• Enveloped virus – A virus (such as HIV) that contains a viral envelope.

Teacher Tip

Use sprinkles that do not dissolve in water, as they will hold up better in the experiment. Ones that have a waxy coating work best. Soak for 2-3 minutes in warm water to test if needed.

Discussion Points

Viruses are non-living microscopic parasites that can infect organisms by attaching themselves to cells in the body and transmitting genetic material, such as RNA and DNA, into the host. This genetic material is encased in a protein shell called a capsid, which stores the RNA or DNA until the virus attaches to a host. As such, most viruses are coated with attachment proteins, also known as spikes, that enable them to hook onto their unfortunate host cells.

Two main kinds of viruses exist: Enveloped viruses, which are coated with lipids (fat), and non-enveloped viruses, which do not have a lipid layer (see image below). Soap is particularly effective at neutralizing enveloped viruses like HIV as it disintegrates the lipid layer, rendering the viruses unable to attach to their hosts and infect them. This is because the attachment proteins are stuck to the lipid bilayer, which is destroyed by soap. For more information check out: cdc.gov/handwashing/faqs.html

• Based on what you know about how HIV is transmitted, like which body fluids carry the virus, how might knowing that it is an enveloped virus help you prevent contracting it or spreading it?

• If you were the leader of a country facing an outbreak of an enveloped virus, what recommendations would you make to your citizens to prevent its spread?

Source: floraldaily.com/article/9225090/viruses-in-irrigation-water/

Assessment

Learners will be assessed on how well their experiments support their findings, even if the results do not go as planned.