Human Disease
These resources introduce students to the range of microbes that can cause disease. This helps them to get away from thinking just of 'germs' and allows them to distinguish between bacteria, viruses, protozoa and fungi.
How pathogens are passed from one person to the next are investigated through a series of simple practical activities.
Students consider the immune system before looking at how antibiotics are used to treat bacterial infections and seeing how resistant strains can develop.
The final resource is useful for stimulating debate and thought about how we measure health and fitness in the wider sense.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Infectious Diseases - Pathogens
Internet research can often result in students wasting time and finding untrustworthy sources of information. This web site can either be viewed on-line, or downloaded and quickly installed onto stand-alone computers. It has been written specifically for key stage 4 students and includes information on disease-causing bacteria, viruses, fungi and protozoa. There is also a section on the body’s barriers to infection.
It is possible to download the web site and install it onto stand-alone computers. This means there is no need to access the internet.
You could divide the class into groups that to look at each section separately. These are:
• Bacteria
• Fungi
• Viruses
• Protozoa
• Parasites
• How pathogens are spread
• How pathogens cause disease and the body’s defence mechanisms
• Growth of pathogen populations
Depending on your specifications, it is useful to provide a framework to guide research in each topic. For example, to define the structure of the microbe being researched. Each group then becomes class ‘experts’. There are several options for disseminating information to the whole group. This could include:
• Produce a poster presentation on their particular topic.
• Produce an A5 leaflet to be copied and shared with the class.
• Present information via a multimedia presentation to be made available on the school network.
• Each group sends representatives to the other groups to talk about and explain their topic.
• Produce a set of questions and a ‘mark scheme’ that is then used as the basis of a homework followed by peer-marking.
In taking such an approach, students are encouraged to become responsible for their own learning and develop information-handling skills.
Contamination Detectives
This activity, along with Sneeze Zone and Handshake Hazards look at how disease-causing pathogens can be spread. All three together will fill a lesson.
A good start is to ask students to suggest different routes by which infections can be spread. They are going to play the part of contamination detectives to investigate how pathogens can be spread by droplets in the air or direct contact.
Students could then undertake the investigation in Contamination Detectives. A gel that glows in ultraviolet light is used to model a bacterial contamination. Working in groups, students investigate different surfaces in the classroom to find sites of contamination.
Discus how this could model the spread of a pathogen from a person with contaminated hands.
Further reinforcement can be achieved with the idea of spread from contaminated surfaces. This can be looked into using the Handshake Hazard activity. Hand washing can be used to reduce the spread and students should consider a way of testing how effective their hand washing technique is.
Finally, the Sneeze Zone activity looks at how droplets in air can spread pathogens.
A plenary could include asking students to produce a public information leaflet to advise people on how to reduce the spread of pathogens. This can also include independent research into other routes such as via contaminated drinking water or sexual contact.
Cholera: Death by Diarrhoea *suitable for home teaching*
This resource addresses the spread of pathogens in contaminated drinking water. It follows on from the spread of pathogens through direct contact that was investigated in the previous resources.
The booklet is quite detailed and 12 pages in length, so it is advisable to select extracts appropriate for students’ abilities.
One approach is to first describe to students the work of Jon Snow and Robert Koch (see pages 2, 3 an 11 of the materials). Cholera is caused by a bacteria transmitted in faeces-contaminated water. Severe diarrhoea causes dehydration and, if untreated, can lead to death.
Students could first read pages 6 and 7 of the publication. They can be asked to find the symptoms and modes of transmission. Then, in small groups, students can be asked to decide on a set of five rules that should be followed to try and prevent transmission of the disease. Groups can share their ideas with the class and then, as a whole group, compare their suggestions with those made on page 7.
The session can be concluded by looking at the work of a charity such as Water Aid. Short video clips and personal stories can be found at:
http://www.wateraid.org/uk/what-we-do/our-impact
Secondary: Immune Defences *suitable for home teaching*
This resource contains a detailed presentation that describes passive and active immunity. The resource considers:
• Skin, mucus and tears as a barrier to infection.
• Non-specific immunity as white blood cells phagocytosis pathogens.
• Production of antibodies in specific immunity.
The presentation can be used to introduce the topic before students then go on to make notes on the process or answer questions to assess their understanding.
The presentation contains certain animated features. Check that these run on your version of PowerPoint before running.
The animations are a little slow but can be used to get students to produce flow-diagrams showing the series of events in both phagocytosis and antibody production.
Secondary: Antibiotics and Medicines
This activity is a bit of a ‘cheat’ but it is a good model for a standard procedure.
Different antibiotics are represented by acid of different strengths. A bacterial culture is represented by an agar plate containing phenol red indicator. When ‘antibiotics’ are added to wells in the agar, the ‘zones of inhibition’ can quickly be measured.
An alternative can be to cut small paper disks to soak up the antibiotic. These are then placed onto the agar surface.
The accompanying video clip need not be shown. If it is used, students are seen to have the agar plate open to the atmosphere and in front of them. Remind students that to prevent contamination and the escape of potentially harmful microbes, the lids should be kept on the petri dishes. Likewise, when adding the antibiotics, open the lid (angled away from them) by the minimum required and quickly add the antibiotics to the wells.
Antibiotics and their use can be introduced with the Antibiotic Resistance presentation. Images of results need not be used but are useful for reference.
The student stimulus materials contain a good set of instructions and a range of questions. Do not feel that they must complete all of them. The main point of the practical is to interpret the results and choose the appropriate antibiotic to treat the different patients.
Infectious Diseases - Medicines
This web-based resource can be downloaded and used on stand-alone computers. This helps to keep students on-task as they are not on the internet doing less focussed research.
The web site contains a lot of good information but a focus of this task is to be found on page 3 of the resource. It looks at the development of antibiotic resistance in bacteria; so-called ‘superbugs.’
Students can look at the page and then produce their own description of how strains of antibiotic resistant bacteria can develop. This could be in the form of an extended piece of writing or more visually as a flow-diagram. Include precautions that can be taken to help reduce the development of resistant strains.
The task can be completed by having students discuss in groups what would happen if antibiotics were no longer effective against bacterial infections. Allow plenty of time for this discussion. There are many wide-ranging implications. Not only for human health but also in the areas of food production. Pull ideas together in a plenary.
Fighting Fit *suitable for home teaching*
Are the fittest people necessarily the healthiest? This Catalyst article looks at how exercise affects our immunity and susceptibility to infection.
Research suggests that physical activity can affect the immune system’s efficiency. Low levels of exercise result in poor immunity. Moderate levels of exercise improve immunity but prolonged intense activity can actually reduce immunity.
The article can be used as a homework exercise. Set it up by discussing with the class their images of a fit and healthy person. What are their thoughts about sports people who train intensively for prolonged periods of time? How can ‘healthiness’ be measured? How does the research in the article address this? Is it a valid measurement? What factors may influence healthiness? This article looks at exercise alone.
Allow plenty of time for students to consider their answers, as these are questions that need to be thought about.
You may wish to give students the article to read for homework and then revisit the discussion at the beginning of the next lesson.
This activity is good as it challenges a view that more exercise is necessarily better (see the shape of the graph in the article). They can be asked to recall other times in biology when optimum conditions are encountered.
