A polynucleotide - made up of many nucleotides bonded together in a long chain
DNA molecules
Made up of two polynucleotide strands lying side by side, running in opposite directions (antiparallel)
Structure of DNA polynucleotide strand
1. Alternating deoxyribose sugars and phosphate groups bonded together to form the sugar-phosphate backbone
2. Phosphodiester bonds link the 5-carbon of one deoxyribose sugar to the phosphate group, which is linked to the 3-carbon of the next deoxyribose sugar
3' end and 5' end
Numbers relating to which carbon on the pentose sugar could be bonded with another nucleotide
DNA strands
One is 5' to 3' strand, the other is 3' to 5' strand (they run in opposite directions, are antiparallel)
Nitrogenous bases
Project out from the backbone towards the interior of the double-stranded DNA molecule
Hydrogen bonding
The two antiparallel DNA polynucleotide strands are held together by hydrogen bonds between the nitrogenous bases
Complementary base pairing
Adenine (A) always pairs with thymine (T) (2 hydrogen bonds)
Guanine (G) always pairs with cytosine (C) (3 hydrogen bonds)
DNA is described as a double helix (three-dimensional shape formed by the twisting of the DNA molecule)
