Subject
Science
Class
Year 11
Unit
Micro-organisms
Topic
Viruses (Lessons 1,2 & 3)
Achievement Objective(s) X Living World Planet Earth and Beyond Physical World Material World
Life processes: Identify the key structural features and functions involved in the life processes of plants and animals. Describe the organization of life at the cellular level.
Learning Outcome(s)/ Learning Intention(s)
Describe what a virus is and why it is important to study them.
Explain how viruses cause illness in living organisms
Describe how a virus replicates using the nuclear material from a host cell
Describe the structure of viruses and how the structure relates to function.
Give examples of how viruses can be of use to people (Biotechnological applications)
Key Competency Focus
Thinking
Nature of Science Focus
Understanding about science
Time Student
Activities
5min
Learning Teacher Activities (including focus questions)
Introduction to viruses
Refer to Powerpoint slides – Tell students that all the slides will be placed on Moodle as a PDF and a summary handout of the 6 most important slides will be handed out during the next lesson.
Describe that the focus of the next three lessons will be:
1. What is a virus and why do we need to know about them?
2. How viruses replicate and are structured
- why structure is important to their reproduction
- build a model of a virus (practical exercise) and case study
3. Applications of viruses - Introduction to the use of viruses in biotechnology
Explain that during the lesson I will write a list of important words they need to know on the side of the whiteboard.
These will need be added to their glossary of important terms.
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5min
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Students to offer answers - what they know/believe about viruses.
Students start working on the worksheet as I go through the Powerpoint slides.
Students name some viral diseases
Students say how viruses are transmitted
Students explain pictures
Students say what each letter of MRS GREN stands
Hand out the worksheet and explain that during the lesson they need to fill in the answers. All the answers will be in the slides.
Focus questions:
What is a virus and why do we need to know about them?
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Viruses consist of a nucleic acid (either DNA or RNA) associated with proteins encoded by that nucleic acid.
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In other words, they are a piece of genetic material (DNA or RNA) packaged in a protein shell.
IMPORTANT POINT - Their shape and the symmetric interaction of proteins and nucleic acids.
Why study viruses? What is virology ?
(the study of viruses: the branch of science and medicine that deals with the study of viruses and the diseases caused by them)
Why do we need to know about viruses?
They cause diseases (are pathogens ) and kill lots of people.
Learning about the biology and structure of viruses can help us better understand the diseases that they cause, their prevention and treatment.
Viruses can cause a variety of diseases from common cold and the flu to serious illnesses such as AIDS, dengue fever, measles, small pox and avian (bird) flu.
A pathogen is: An agent of disease. A disease producer. The term pathogen most commonly is used to refer to infectious organisms. These include bacteria (such as staph ), viruses (such as HIV ), and fungi (such as yeast ). The term pathogen was devised about 1880 and was compounded from patho meaning disease + -gen indicating a producer. Hence, a disease producer.
What diseases do viruses cause? – Ask class for answers. Write on the board
How are viruses transmitted? – Ask class for answers. Write on board
Very small so can spread in all sorts of ways: airborne, contaminated food or water, vectors (mosquitoes) or infected animal bite, sexual contact, contaminated blood products.
How do we defend ourselves against viruses? (ask them to explain each picture)
Take precautions not to catch the virus, drugs, vaccination, healthy immune system.
Viruses cannot be destroyed with antibiotics. The best protection from viruses (after basic hygiene) is immunisation.
Why does immunisation work for some viruses but not all?
Immunisation – some viruses change their genetic code slightly. This means that the outside protein cost is not recognised by our immune system.
Comparison between the polio vaccine and common cold.
Are viruses living or dead?
Go through MRS GREN – ask students to say what each letter represents.
This depends on the definition of life. To avoid arguments, we often refer to whether they have or have lost some aspect of their
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Students draw a cell and replication cycle in their notes.
Students start Dengue virus modeling activity biological activities rather than referring to living or dead viruses. Hence we talk about number of infectious particles , or number of plaque forming particles rather than number of living particles .
MRS C GREN - Movement; Respiration; Sensitivity; Growth; Reproduction; Excretion; Nutrition (seven characteristics of life)
How do viruses replicate? – Draw on the whiteboard
Describe the stages of replication. Emphasise replication NOT reproduction.
Replication of Viruses
Viruses need a host cell to replicate.
The virus attaches to the host cell.
Viral genes are inserted into the host cell.
The host cell replicates the genetic material of the virus and produces copies of the protein coat.
The new viruses are released from the cell, often by the cell bursting.
How are viruses different from other microorganisms (like bacteria)?
END OF LESSON 1
START OF LESSON 2
Go through worksheet answers as a way of recapping previous lesson.
Tell them that this lesson we’ll be looking at the structure of viruses and how the structure is important for function.
We’re going to make a model of a virus and we’ll use Dengue Virus as an example.
What do viruses look like? (Start with Slide 20)
Viruses are commonly either icosahedral or helical. Some viruses are enveloped with a membrane. Tailed phages have a complex structure with a phage head, where the genetic material is packaged, a helical tube and tail fibers to attach to the host cell surface.
Some viruses are enveloped with a membrane.
Tailed phages have a complex structure with a phage head, where the genetic material is packaged, a helical tube and tail fibers to attach to the host cell surface.
Take home message: The shape and structure of viral proteins are specific for their function.
How is the structure of viruses important for their function?
Use the Analogy ( a comparison made to show such a similarity) of a kitset house
What is an icosohedron? 20 sided geometric figure
Hand out sheets of card with Dengue virus templates printed onto it.
Also hand out scissors, tape, glue and thread.
Point out that we’re going to look at some slides of the Dengue virus and watch a short film about it.
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Students look at slides of
Dengue virus and watch short film.
Students do Mind map of influenza words then
Influenza pandemic planning exercise or poster
Students read essay aloud.
Watch Quicktime movie
Discuss questions – first between themselves then report back to class.
Students do dice activity – come up with own questions
Students do test http://www.teachersdomain.org/resource/den08.sci.life.stru.dengue/
Since viruses can only be seen by powerful microscopes, this scientific visualization modelling experiment is to acquaint students in recognizing the various shapes and life cycles of viruses through the process of making both a simple physical model.
Lesson 3 Impact of and Applications of viruses
Impact of Influenza virus
Students to do a mind map activity using images and words associated with Influenza pandemic to come up with a summary of how pandemics can be prevented and limited. Influenza pandemic planning exercise
Show students the Ministry of Health Flu poster from the hallway. Ask if they have read it
Hand out Mind map words and images and newsprint
Viruses and Biotechnology –
Recap of virus structure, multitude of diseases and replication strategies.
Genetically Engineering the Avian Flu
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Read background essay
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Watch video avian flu movie
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Discuss the questions
Rabbit calicivirus – Biocontrol
Give overview of what goes on in the University of Otago Microbiology Dept
My MSc on Baculoviruses – techniques used such as culturing cells, culturing viruses in cells, extract and purify viruses, extract the DNA, analyse the DNA and characterise some genes involved in pathogensis.
Richard Webby gone to work at a prestigious influenza lab
Who/what/why dice exercise (if time) – Give students ideas for questions to ask themselves for dice activity
Test at end of lesson 3
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Student
Activities
Learning Teacher Activities (including focus questions)
Equipment
Resources Powerpoint presentation, sheets of coloured card with bacteriophage model template pre-printed onto it, test, who what where dice,
Assessment Formative Summative
Teacher Evaluation
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