6.3+Defence+against+infectious+disease

6 Physiology - 6.1 Digestion - 6.2 The transport system - 6.3 Defence against infectious disease - 6.4 Gas exchange - 6.5 Nerves, hormones and homeostasis - 6.6 Reproduction - Physiology Labs

6.3 Defence against infectious disease
A Scishow video on the five deadliest diseases in the world makes for a morbidly fun watch media type="custom" key="24648470"
 * Starter**

In search of a cure for AIDs. What are the ethical considerations of running human trials of retro-viral drugs? media type="custom" key="23831714"


 * Assessment statements** (IBO notes added to some points to clearly indicate what needs to be understood and what does not)


 * 6.3.1 || Define pathogen. ||
 * 6.3.2 || Explain why antibiotics are effective against bacteria but not against viruses. Antibiotics block specific metabolic pathways found in bacteria. Viruses reproduce using the host cell’s metabolic pathways, which are not affected by antibiotics. ||
 * 6.3.3 || Outline the role of skin and mucous membranes in defence against pathogens. A diagram of the skin is not required. ||
 * 6.3.4 || Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissues. Details of the subdivisions and classifications of phagocytes are not required. ||
 * 6.3.5 || Distinguish between antigens and antibodies. ||
 * 6.3.6 || Explain antibody production. Many different types of lymphocyte exist. Each type recognizes one specific antigen and responds by dividing to form a clone. This clone then secretes a specific antibody against the antigen. No other details are required. ||
 * 6.3.7 || Outline the effects of HIV on the immune system. The effects of HIV should be limited to a reduction in the number of active lymphocytes and a loss of the ability to produce antibodies. ||
 * 6.3.8 || Discuss the cause, transmission and social implications of AIDS. ||


 * Definitions**
 * Pathogen: an organism or virus that causes a disease.

Visit the [|DCS bridge]and download the workbook for this topic. Word versions of workbooks available below for those unable to access the DCS Bridge. media type="custom" key="23831708"
 * Workbook and Worksheets**

An alternative set of notes from i-Biology can be found here media type="custom" key="23684580"

The i-Biology presentation is a great starting point media type="custom" key="23831704"
 * Presentations and Tutorials**

The Khan Academy has a series of video tutorials. Of particular use is the 'r ole of phagocytes in innate or nonspecific immunity'. media type="custom" key="23684586" Topics such as [|Lymphocytes b cells] are also covered, but much of this higher level knowledge and beyond. You may find it helpful, but be aware of what is required of you for the course. Refer back to your assessment statements.

[|KScience] illustrates with basic animations how [|lymphocytes] and [|phagocytes] work**.** You need to understand both types of leukocyte in more detail, but this is a good first step.

[|Specific immunity] needs to be understood thoroughly. There's a lot of detail here, you need only to be able to explain the process, if you aren't sure what you need to know read section [|6.3.5 and 6.3.6 from Click4Biology] before viewing the animation.

A narrated tutorial from sunamas inc. explains the idea of [|producing monoclonal antibodies]

[|Here] you can find an animation on clonal selection

[|Click4Biology] summarises the immune system in a very helpful way.


 * Possible activities**

__Class discussion of the the causes, transmission and social implications of AIDS (6.3.8)__

Viewpoints for individual research and representation in the discussion
 * The causes and origins of AIDS //(this point is for information, it forms a basis for the discussion of proceeding points)//
 * The different methods of transmission of HIV each carry their own risk. How can these risks be minimised or eliminated, what are likely costs involved?
 * Discuss the importance of the social implications of AIDS to sufferers and their families
 * Cases of AIDS are not evenly distributed in the world, consider the severe problems in southern Africa. What are the cultural and economic reasons for differences in the prevalence of AIDS?
 * The moral obligation of those with the technology and the wealth to help others.

Outline for the discussion > a. the validity of information presented (how rigorous was the research?) > b. asking for explanation or clarification on a point > c. questions on the stance or importance of a groups point of view
 * 1) Each group is given time to prepare their point of view and resources
 * 2) Presentations should be 1-4 mins long. Presentations should include a point of view as well as delivering information.
 * 3) After presentations other groups will be asked to raise points on
 * 1) After the presentations there will be an open debate
 * 2) The activity concludes by groups identifiying the keys points (on a board or google doc) to create a set of notes to answer the assessment statement

Vaccines - has the needle had it's day? media type="custom" key="24884340"
 * Interesting Extras and TOK**

Here you can find an [|electron micrograph of a lymphocyte] [|Phagocytosis] is shown in more detail, view 'normal phagocytosis' the other simulations show how phagocytosis can be used against our immune system - interesting, but not necessary for IB DP. The Community College of Baltimore County goes into more detail than you need at IB DP, but still gives a good thorough breakdown of the [|different types of leukocytes] Antibiotic resistance is explained by [|this tutorial] The University of Utah covers [|blood types and antigens] If you are not familiar with how plasmodium (the pathogen responsible for Malaria) causes the disease follow [|this link]
 * Useful links**