Notes on interactives

DNA profiling

This interactive offers two similar activities: one based on a crime scene, the other on a contested will. In both cases, students start by working through a simulated sampling and testing process, taking several DNA samples and subjecting them to electrophoresis. They then compare the results, looking for matching bands to confirm the presence or otherwise of a suspect at the crime scene, or to check possible family relationships.

DNA zoom

This interactive takes students through a sequence of increasingly close-up views of the skin, through the cell and its nucleus, until they are looking at a model of part of a DNA molecule. It provides a particularly useful way of demonstrating the hierarchy, and relationships between, cells and DNA.

Dog cloning

Students choose one of three dogs to clone. They make choices about which dog to use as the egg donor, and which to use as the surrogate mother, to produce a puppy that is a clone of the originally selected dog. Animations show the key stages involved: removal of DNA from the first dog, replacement of the egg's DNA, and insertion of the egg into the surrogate mother.

Gene probe

This interactive guides students through the steps of using a gene probe to find out which chromosome carries a gene with a particular sequence of bases. An animation takes them through the steps: extracting a cell from the selected organism, treating the cell to release the DNA, separating the two DNA strands, designing a probe (10 bases) to match the known base sequence, and adding it to the test sample of DNA. The final step - microscopic examination of the chromosomes - allows the student to see which chromosome the searched-for gene is located on.

Being able to pair the bases (adenine with thymine and cytosine with guanine) is critical to being able to complete this interactive.

There are five variations of the activity, each with a different organism and a different target gene.

Gene splicing

This interactive lets students work through the key steps in gene splicing: selecting a restriction enzyme which will remove a gene from a piece of DNA (the cut piece must have jagged ends and include the whole of the required gene), cutting open a plasmid with matching 'free' ends, and finding the right enzyme to glue the DNA fragment into the plasmid.

Thylacine cloning

This interactive is similar to the Dog cloning interactive, with the difference that the thylacine, not being alive, cannot be used as a source of eggs nor as a mother for the modified egg. Students can also work with are the numbat and the Tasmanian devil.

Transcription, translation and protein synthesis

This interactive examines the process of protein production from DNA. The first interactive begins with the transcription of DNA into messenger RNA. It uses the same process of delving into the cell to help students understand the relationship of DNA to cells, and vice versa. Students must correctly match the bases together, taking into account the pairing of uracil with adenine in place of thymine. The interactive ends with the newly-transcribed mRNA travelling into the cytoplasm, awaiting its translation to protein.

Translation and protein synthesis follow the mRNA strand's encounter with a ribosome, and generation of an amino acid strand. The importance of codons and anticodons is highlighted and students must match several codon sequences with their correct amino acids.

Bird 'flu

This interactive examines the growing importance of emerging infectious diseases, using the avian influenza virus as an example. Students see the basic structure of the 'flu virus and its genome. They also see that animal 'flu viruses are capable of mixing their genes with human flu viruses, causing some of the dangerous pandemic strains of the past. The interactive also highlights that the current avian influenza strain causing human deaths in Asia could reassort in pigs (a normal reservoir for human 'flu) and develop into the next pandemic influenza strain.