DNA Model

• Product type: three-dimensional demonstration model of the DNA molecule
• Height: 900 mm
• Material: plastic, durable and safe
• Structures reproduced: double helix, sugar-phosphate backbone, complementary pairs of nitrogenous bases
• Colouring: colour-coded, with each type of element in its own colour, so that the elements are told apart from any side without extra labelling
• Mounting: on a stable base, for permanent display in the classroom
• Recommended age: 10 years and older (grade 5 and above), under teacher supervision

Product passport: ULABS-B030 (PDF)

Safety

• Use the model only for the purpose described in its documentation; protect it from impacts, falls and excessive mechanical load.
• Carry the model holding the base with one hand and supporting the helix closer to its middle with the other — the model is tall and works loose at the connections if carried by the upper part alone.
• Set the model up where it will not be knocked in passing: against a wall or well inside the demonstration table, not at its edge.
• Do not stretch the helix along its axis and do not untwist the chains by hand — the connections between the backbone elements and the base pairs are designed to carry only the weight of the model.
• Do not keep the model near heating appliances or in direct sunlight — the plastic warps and the colouring fades, and the colour coding of the nucleotides loses its meaning.
• Do not use the model as a pointer and do not lean on it. Students work with the model under the supervision of a teacher.

Setting Up

• Free the model from its packaging, removing it from the top downward, and set it on its base in the position in which the helix stands vertically. Check that the lower end of the helix is fixed firmly in the base: the model must not tilt or turn under its own weight.
• Inspect the helix over its full height. All base pairs should be in place and connected to both backbones, the elements free of cracks and chips, and the colouring even and identical for elements of the same type. If an element has come away, put it back before the demonstration: with an incomplete helix the principle of complementarity cannot be shown.
• Choose a place where the model stands on a level horizontal surface and is visible from the audience over its full height, with nothing shading it. A plain light background behind it makes the coloured elements easiest to read.

Demonstration

• Start with the overall view: show that the molecule consists of two chains wound into a helix around a common axis, and that the helix repeats — identical sections alternate over the full height of the model.
• Move on to the backbone: trace one chain from the bottom upward with a finger or a pointer, showing the alternation of sugar and phosphate units. Then do the same for the second chain and show that the chains run in opposite directions.
• Show the cross-connections: each step of the helix is a pair of nitrogenous bases joined to each other. The colours of the elements show that a base of one type always stands opposite a base of one particular type — this is complementarity. Go along several pairs in a row so that the rule is seen in the repetition rather than in a single example.
• To show the model from another side, turn it together with its base while supporting the helix; do not rotate the helix relative to the base.
• After the demonstration, return the model to its permanent place. If it is left on view in the classroom, place it where it cannot be reached by accident and cover it against dust.

Maintenance

• Remove dust from the model with a soft dry brush or a stream of air, working from the top downward. Wipe the freely accessible elements with a soft cloth lightly moistened with water and dry them immediately. Do not use solvents, alcohol or abrasives — they wash off the colouring by which the types of elements are told apart.
• Periodically check the connections: the fixing of the helix in the base, the junctions of the backbone units and the base pairs. Restore any loose connection at once, before the element is lost.

Operating Conditions and Storage

• Air temperature: +5 °C to +40 °C
• Relative humidity: 40% to 60%
• Atmospheric pressure: 84 to 107 kPa
• Store the model upright on its base in a dry heated room, covered with a case or a cloth against dust. It should not be laid flat for long periods — the helix gradually loses its shape.

Warranty and Compliance

• Defect repair and replacement of defective parts or equipment covered by the warranty for three years; spare parts and consumables available for five years.
• The product meets the general product safety requirements of European Union legislation. It is not electrical or electronic equipment, so the WEEE marking does not apply to it.