OnScreen DNA™

Lite, Standard, Pro—What's the Difference?

OnScreen DNA Lite™ (Now a Free Download)

Think of OnScreen DNA Lite as a DNA model on steroids—an interactive virtual model with 35 base pairs. Use it to teach the basic structure, composition, and chemical bonds of DNA. Numerous aids to learning and understanding, including popup labels, an auxiliary linear representation of the model, the ability to rotate the model in space and to toggle between single and double strand views, all within a tutorial framework, make this software fun to play with, which makes the learning "painless." With the help of the on-screen tutorial guides, a student becomes completely at home with the double helix structure of DNA and learns the names of its component molecules and chemical bonds. Of course the base pairing is made clear, but so are the polarity and right-handedness of the DNA strands and what those terms mean. Simulations of the lab phenomena of denaturation and renaturation are also included.

You can expect to teach the following points with ease using OnScreen DNA Lite:

• the names of DNA's sugar phosphate, nucleotide bases, and the chemical bonds between them
• how the nucleotides are connected to each other both in the same strand and between strands
• which bases pair with one another
• that the DNA strands have opposite polarity (and what polarity means)
• that DNA is right-handed (and what that means)
• how many bases there are per helical turn
• what the major and minor grooves are and what their physical basis is
• how thermal agitation causes the two DNA strands to separate in denaturation
• how complementary DNA strands reconstitute the double helix through base pairing during renaturation

OnScreen DNA™ Standard ($69)

The Standard edition is a major step up from OnScreen DNA Lite, but a natural step that builds on the knowledge of structure learned in the activities it shares with the Lite edition. With it you get to show DNA in action—and in 3D!

We predict it won't take you but a minute or two of playing with the simulations to understand why the American Biology Teacher called it "extremely engaging" and Apple eNews said it was "fascinating and fun." OnScreen DNA's simulations of gene transcription and DNA replication show all the critical steps in these fundamental biological processes in three-dimensional detail without pretending difficulties such as the end problem in replication don't exist.

DNA separation and unwinding and the construction of messenger RNA and DNA daughter strands, one nucleotide at at time, are all seen in three dimensions. As events unfold, the on-screen tutorials explain what is happening and what its significance is. At the same time, the activation and location of the key enzymes involved are shown in the linear sequence view and an enzyme control panel.

To download a free copy of OnScreen DNA Lite click here.
To purchase a full how-DNA-works edition of OnScreen DNA for only $69 click here.

With OnScreen DNA™ expect to teach all of your students

• how the co-ordinated action of enzymes is necessary for basic processes involving DNA
• how portions of the DNA strands separate and unwind to serve as templates for RNA or DNA daughter strand construction
• how RNA and daughter strands are constructed one nucleotide at a time and the direction in which this proceeds
• that either strand may contain genes and which direction genes are read on each strand
• how primer RNA is required during DNA replication
• why Okazaki fragments are required on the lagging strand
• how primer RNA is replaced and Okazaki fragments are joined together
• how the enzyme pyrophosphatase is essential for DNA-based life
• how telomerase solves the end problem of DNA replication

and much more (really).

OnScreen DNA Pro™ ($99)

The Pro edition adds activities in which the user is empowered and challenged to take active control of transcription and replication. The buttons on the enzyme control panels are now "hot" and used to activate the proper enzymes. The user also has to select the correct nucleotide and drag it to the appropriate spot for chain-building.

The ultimate test of understanding a process is whether you can actually carry out the necessary steps yourself. In addition to the simulations in which events proceed automatically, the student is now presented with simulations which require student actions.

Which enzyme needs to act next to keep the process going? What nucleotide needs to be added next to the chain that is being constructed? RNA or DNA? The Pro edition allows the user to make these choices and demonstrate mastery of the DNA processes in a way that can only come with a virtual hands-on simulation. At the same time, every correction of a false move takes the learner closer to full understanding of how a process proceeds.

The Pro version also empowers teachers. You can, for example, challenge your students to use OnScreen DNA Pro to create a strand of messenger RNA that codes for your choice of one of the several amino acid sequences possible to obtain from the 35-base-pair DNA molecule of the OnScreen DNA model. They then must mark the beginning and end points of the gene for that sequence on the proper DNA template strand and then proceed with the transcription step by step.

Depending on your particular situation and needs, the Pro edition might be overkill. The choice is up to you. And should you decide later that you'd like to upgrade, the price you paid for your edition can be applied to the purchase of a higher edition.