DNA

what is a nucleotide?

a monomer of DNA made up of phosphate, deoxyribose and a nitrogenous base

where is a phosphodiester bond found?

between the sugar of one nucleotide and phosphate of another

what type of bond is formed between two nucleotides?

phosphodiester

describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule [2]

a condensation reaction between phosphate and deoxyribose, catalysed by DNA polymerase

what type of bond joins nitrogenous bases?

hydrogen

how many hydrogen bonds between A and T?

2

how many hydrogen bonds between C and G?

3

which molecules form the backbone of DNA?

sugar, phosphate

what is the role of a DNA molecule?

store genetic information

nitrogenous bases in DNA

adenine, guanine, cytosine, thymine

describe the structure of a DNA molecule [5]

a polymer of nucleotides joined by phosphodiester bonds between nucleotides. two strands are in a double helix, held together by hydrogen bonds between adenine and thymine, cytosine and guanine

why is DNA a stable structure?

the phosphodiester backbone protects the more reactive bases inside the helix, strong hydrogen bonds exist between base pairs

how is the structure of DNA adapted for its function?

stable structure which makes mutations rare

very large to carry lots of genetic information

base pairs are protected by the backbone,

the strands are joined with hydrogen bonds so can separate easily during replication and protein synthesis

which scientists proposed the model of DNA structure and replication?

watson and crick