HAPPY WEDNESDAY What you need: Writing Utensil, Journal. Have Notecards out ready to be checked Bellwork Today: Copy the following passage and fill in the blanks with the proper vocabulary. Viruses are a type of _________ that can cause diseases. They have a structure that is different from cells. They contain a core of _________ that is surrounded by a protein _________. Some viruses contain an additional layer called an _________ that is made of lipids. The virus will use it’s spikes or ___________ to attach to the surface of the cell it infects. Viruses are considered to be non- ______ because they do not grow, respond to environment and must rely on a _____ cell’s machinery to reproduce. pathogen DNA/RNA capsid envelope glycoproteins living host

BIO.4C The student will: compare the structures of viruses to cells, describe viral reproduction describe the role of viruses in causing diseases such as human immunodeficiency virus (HIV) and influenza.

Notes Continued from Yesterday Notecards due Today Word, Definition, Picture w/color (Pre-AP) Project sketch/outline/rough draft due Tomorrow Last day to make up “Most-Missed Quiz” grade is Friday Virus extension assignment is due Monday Test is Tuesday

Quick Recap… When a virus invades…

There are two ways a virus can accomplish this…. Viruses cannot reproduce on their own! The virus must “use the host cells’ machinery” to make more viruses There are two ways a virus can accomplish this….

1. Lysogenic Cycle

1. Lysogenic Cycle Viruses “hide” for a while inside host cells before becoming active Example = HIV, Herpes, HPV Steps to the Lysogenic Cycle: Virus attaches to cell Virus injects DNA/RNA Virus DNA/RNA Integrates and Waits (months or years) in cell DNA Virus DNA removes/detaches from cell DNA Becomes active (starts lytic cycle) Cell undergoes “lysis” (bursts)

Lysogenic Cycle - Viruses

Ways to remember… Lysogenic is a Looooooong word LYS-ogenic---> sounds like “lies” around or “lays low”

AIDS Caused by the HIV virus HIV is a retrovirus (RNA to DNA) HIV is lysogenic virus AZT = medicine used to treat HIV/AIDS Blocks “reverse trascriptase”

Lytic Cycle

Lytic Cycle Lysis- to cut or to burst Active viruses enter cells and immediately begin to multiply, leading to the quick death of the invaded cells. Steps to the lytic cycle: Attach to cell Inject DNA/RNA Produce (replicate) virus parts Assemble new virons Cell undergoes “Lysis”- viruses are released to infect other cells

Lytic Cycle - Viruses

Ways to remember Lytic = the shorter word, therefore shorter cycle Lytic = Bang Bang (kill you dead) Lytic  sounds like you got “lit up”

Lytic Example: Influenza Enveloped virus with a segmented RNA Symptoms appear within days/weeks Infects a wide range of animals other than humans Undergoes extensive mutations Causes the flu Influenza A virus is the second acute infection to be discussed. Myxovirus Enveloped virus with a segmented RNA genome Infects a wide range of animals other than humans Undergoes extensive antigenic variation Major cause of respiratory infections

Spread of influenza virus Respiratory aerosoles can be generated from the respiratory tract by various means – from speaking to sneezing. During a sneeze, millions of tiny droplets of water and mucus are expelled at about 200 miles per hour (100 metres per second). The droplets initially are about 10-100 micrometres diameter, but they dry rapidly to droplet nuclei of 1-4 micrometres, containing virus particles or bacteria. This is a major means of transmission of several diseases of humans.

Time frame from infection to symptoms… Lytic = days to weeks Lysogenic = months to years

How can viruses cause cancer How can viruses cause cancer? Some virus infections can cause cancer, though the disease often appears several decades afterwards. For example, cancer of the cervix is linked to infection with the human papilloma virus (HPV) that causes genital warts. In this case, the DNA in the virus mixes with the cell's DNA, triggering changes that make the cell grow and multiply out of control. From 2009, girls in the UK have had access to a vaccine that prevents infection with HPV and thus protect them from developing cervial cancer as a result.

Today’s Activity: Sage and Scribe

Sage and Scribe worksheet Partner A will say the answer the question Partner B will record exactly what partner A says the answer is on the paper provided. Partner B will check over the answer and describe any changes they think should be made. Partner A and B will agree on a final answer and make any changes if necessary. For the next problem, repeat steps 1-4 with Partner B starting.

For the rest of class…. Partner activity

Vocab Practice…