What is biotechnology?

Using biotechnology to make yoghurt

Making yoghurt is one of the earliest forms of traditional biotechnology. Specific forms of bacteria, most commonly Streptococcus and Lactobacillus, are used to turn milk into yoghurt. This activity shows how this can be done in the classroom or at home.

This activity includes a control (i.e. a jar with no starter culture added). It is important that both jars are sterilised (either in boiling water or in an autoclave if you have one).

The breakdown of lactose (the sugar in milk) by the bacteria is shown by the equation: Lactose + water = lactic acid.

The lactic acid causes the casein molecules in milk to coagulate in acidic conditions (pH 4.6-4.7). The production of lactic acid is the reason that people who are lactose-intolerant can eat yoghurt, but not drink milk. The acidic pH causes yoghurt to taste slightly sour.

You may wish to investigate further the effects of:

• different amounts of starter culture on the taste and texture of the yoghurt (keeping all other conditions the same)
• using different types of milk (skim, full cream, homogenised)
• additions before and after the bacteria have had a chance to grow (different amounts of sugar, pieces of raw or cooked fruit, honey or jam)

How gene technology is carried out

Using internet-based resources, students find out about Australian research on genetic modification of an organism that interests them. They work in pairs to choose an organism from a list of CSIRO research projects, find out about the genetic modification technique being used and develop a flow chart to describe it.

You may wish to broaden the discussion of why modify organisms in the first place. The section Why do we do biotechnology? gives a short overview of some examples of current uses of biotechnology.

Relevant sections in Biotechnology Online include:

• How do you do biotechnology?
• Gene splicing interactive

Extracting DNA in your kitchen

This experiment, reproduced from the CSIRO's The Helix magazine, uses readily available materials to extract DNA from an onion. DNA extraction and manipulation are a fundamental part of gene technology. Encouraging students to see DNA for themselves can be very powerful.

Quantities and the sizes of some of the pieces of equipment are described broadly. It might be wise to try the experiment for yourself to be sure exactly what will be suitable before setting it for the class. Different organisms will yield different amounts of DNA.

This can extend into discussions of what scientists do with the DNA they extract.

DNA line dancing

Each student takes on the role of one of the four bases in the DNA chain, and the class as a whole models the 'unzipping' of a DNA double helix molecule and the growth of two identical new molecules by means of base pairing.

Another useful way to begin discussion of DNA replication is by watching the scientifically accurate animated depiction of replication from DNA Interactive (go to www.dnai.org/a/index.html and then Code, Copying the Code, Putting it together, Replication).

When a gene code is altered

Students use library or internet resources to research a disease where an altered form of a gene is known to be involved, and then prepare a presentation for other students. Several diseases are suggested, but students are given the option of finding a different one for themselves.

Some guidance might be needed on the type and complexity of the presentation to be developed.

External websites suggested in the worksheet as a starting points are:

• The Centre for Genetics Education (Sydney) and
• The Dolan DNA Learning Centre (USA)

Both sites have a wide range of information about a number of genetic diseases - not just what causes them, but also how they are inherited and what it means to live with the condition. Further discussion could range into genetic testing of these sorts of diseases and the implications for individuals and their families, no matter what the results show.

Ask the experts

This worksheet guides students through the process of inviting, hosting and thanking a guest speaker who has expertise on a topic of interest. There are no specific suggested topics, as the availability of experts will depend on where you live and what kinds of research are going on in your area. It will also vary with what your class finds interesting and what is in the news. It is also important to note that experts need not necessarily be scientists.

Broad topic areas to consider are medical research, plant research and environmental biotechnology.

This worksheet is designed to encourage students to think from one point of view and to consider why people have differing opinions on biotechnology applications. You can also explore the ability of speakers to influence their audiences, at what point differing points of view become confusing to the audience, and whether people tend to listen out for views that affirm their own.

DNA sequencing

This pen and paper activity introduces students to the process of identifying DNA sequences. Students practice pairing bases to interpret the results of two DNA sequencing tests.

DNA sequencing was the cornerstone technique of the Human Genome Project and is a common feature of research institutes across the world (a profile of Ilya Henner, the DNA sequencing facility manager at the Westmead Millennium Institute, can be found in the Careers section).

The worksheets need to be in colour. As suggested on the sheet, the students could colour their sheets from an on-screen example before they start. Other ways of providing the colours could be using a whiteboard, or a written list of the order in which the colours occur in the four relevant sections of the worksheet.

A useful way to illustrate the process of DNA sequencing is by watching the scientifically accurate animated depiction from DNA Interactive (go www.dnai.org/b/index.html, go to Techniques, then Sorting and sequencing, Cycle sequencing).

Branching discussion into the Human Genome Project is a good way to look at the broader application and importance of the technique. Information about the sequencing of the human genome can be found at: www.genome.gov/Pages/EducationKit/online.htm

Plant tissue culture in the classroom

This experiment allows students to produce clones of a plant (cauliflower, rose, African violet or carnation). It is presented in six stages, which include preparation and sterilisation of all the equipment and materials required. Some of this preparation could be done in advance to save class time, provided that students understand what has been done and the importance of the sterilisation process.

The work sheet includes a recipe for the growing medium as well as contact details for a supplier.

Cloning is most often associated with animals, and especially Dolly the sheep. But scientists use this term in broader senses than this. The cloning sections in What is biotechnology? highlight these differences. Cloning plants is a common procedure in horticulture and is sometimes known as striking.