B2 DNA

• The structure of DNA consists of two strands twisted around each other, forming a double helix.
• DNA is a polymer of nucleotides, each of which is a deoxyribose sugar, a phosphate group and a nitrogenous base
• RNA is a polymer of nucleotides, each of which is a ribose sugar, a phosphate group and a nitrogenous base
• There are four different types of bases found in DNA: adenine, guanine, cytosine and thymine
• There are four different types of bases found in RNA: adenine, guanine, cytosine and uracil
• Guanine always pairs with cytosine
• Adenine always pairs with thymine or uracil
• The base sequence is universal and is the same in all organisms.
• The base sequence is non-overlapping and each base is only read once.
• The base sequence is degenerate, meaning that different base sequences can code for the same amino acids
• One amino acid is coded for by three DNA base(one triplet). This is know as a codon.
• There are 2 stop codons. These do not code for amino acids.
• The two DNA strands are antiparallel, meaning they are in opposite directions.