what is a nucleotide?
a monomer of DNA and RNA, made up of a phosphate, a pentose sugar and a nitrogenous base
where is a phosphodiester bond found?
between the sugar of one group and phosphate of another
what type of bond is formed between two nucleotides?
phosphodiester
what type of reaction forms a phosphodiester bond?
condensation
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 type of molecules are DNA and RNA?
information carrying
what is the role of a DNA molecule?
store genetic information
what is the role of an RNA molecule?
to transfer information from DNA to ribosomes
how many polynucleotide chains are in DNA?
2
how many polynucleotide chains are in RNA?
one short one
which nitrogenous bases are in DNA?
adenine, guanine, cytosine, thymine
which nitrogenous bases are in RNA?
adenine, guanine, cytosine, uracile
what type of sugar is found in DNA?
deoxyribose
what type of sugar is found in RNA?
ribose
describe the structure of an RNA molecule
a relatively short polynucleotide chain
describe the structure of a DNA molecule
a double helix made up of two polynucleotide chains held together by hydrogen bonds between complementary base pairs
what does ATP stand for?
adenosine triphosphate
what is ATP made up of?
adenine, ribose sugar and three phosphates
what type of sugar is found in ATP?
ribose
what type of reaction makes up ATP?
condensation
equation for ATP synthesis
ADP + Pi → ATP
which enzyme catalyses an ATP synthesis reaction?
ATP synthase
which type of reaction breaks apart an ATP molecule?
hydrolysis
equation for ATP hydrolysis
ATP → ADP + Pi
which enzyme catalyses an ATP hydrolysis reaction?
ATP hydrolase
what can inorganic phosphate be used for?
phosphorylate other compounds to make them more reactive
uses for ATP
active transport, respiration, muscle contraction
why is DNA stable?
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