Structure of DNA and RNA

• Cells have 46 chromosomes
• Histones is a type of protein contained in chromosomes
• Nucleotides are the monomers of DNA and RNA
• Double helix is a ladder-like structure made from two polynucleotide molecules wound around each other
• Molecules of DNA are made from a phosphate group, deoxyribose sugar and a nitrogenous base
• Nucleotides are joined together by condensation reactions
• 4 bases = adenine, cytosine, guanine, thymine
• 4 bases of RNA = adenine, cytosine, guanine, uracil
• RNA is made from a ribose sugar
• DNA + histones = chromatin
• Phosphodiester bonds are formed between nucleotides
• Hydrogen bonds are formed between complementary base pairs
• Phosphate from one nucleotide forms a phosphodiester bond with the deoxyribose sugar of another nucleotide forming the backbone of the DNA molecule
• There are 2 hydrogen bonds between AT and 3 between CG
• DNA is an antiparallel molecule = polynucleotide strands arranged in different directions
• DNA is very stable which allows it to be passed down from generation to generation
• Polynucleotide strands are only linked by hydrogen bonds = strands can easily separate during DNA replication
• DNA is a huge molecule so can store vast amounts of information
• DNA is coiled into a double helix = information is protected within the coils
• Base pairing leads to DNA being able to replicated and transfer information as RNA