About Tac Light. Tac Light is a small-but-powerful flashlight by Bell & Howell that has been advertised on television in 2016. The official product website is trytaclight.com, which was registered in April 2016. The screenshot below was taken of the official website in May 2016. 22 times brighter than regular flashlights (600 lumens)
However, only four bases: A (adenine), C (cytosine), G (guanine), and T (thymine) constitute the backbone of the molecule. The DNA molecule is made up of two polynucleotide strands intertwined together to form a long helical structure, the DNA double helix.
The DNA molecule is a double helix: that is, two long, thin strands twisted around each other like a spiral staircase. The DNA double helix showing base pairs. The sides are sugar and phosphate molecules. The rungs are pairs of chemicals called 'nitrogenous bases', or 'bases' for short.