APH DNA Twist

The APH DNA twist gives students both color and tactile differentiation of the 4 nitrogen bases found in DNA.  The nitrogen bases are the part of the DNA molecule which carries the genetic code.  The model also clearly indicates the shape of DNA (a double helix or twisted ladder).

Strengths: 

The DNA twist offers students a model which can be understood tactually and/or visually.

It is easy to comprehend and clearly shows the base pairing which occurs in DNA.  Adenine pairs with Thymine and cytosine pairs with guanine.

Limitations: 

The color used for each nitrogen base is visible on the sides of the molecule though the nitrogen bases are not located on the backbone of the double helical molecule but in the center.  This portion of the molecule is often described as the rungs of the ladder.  The backbone (sides) of the molecule are composed of phosphate groups and deoxyribose (sugar). 

Students should be told that the phosphate group and sugar that are part of each nucleotide are the same throughout the DNA molecule.

Ordering Info: 

The DNA twist can be purchased from APH.