molecules of life

evidence for evolution

- this refers to evidence which supports the theory of evolution; the view that all organisms on earth are descended from one or a few common ancestors and that they have changed and diversified over time. - there is a huge variety of different organisms on earth but they all share some biochemistry. they all contain the same groups of carbon-based compounds that interact in similar ways - for example, they share the same nucleic acids as genetic material and the same amino acids to build proteins. - these similarities suggest that animals and plants have a common ancestor, which provides evidence for evolution. 

monomers and polymers

- most carbohydrates, proteins and nucleic acids are polymers; large complex molecules which are formed of long chains of monomers joined together.- monomers are small, basic, molecular units which can form a polymer. examples of monomers include monosaccharides, amino acids and nucleotides. 

making polymers

- most biological polymers are formed from their monomers by condensation reactions. a condensation reaction forms a chemical bond between monomers, releasing a molecule of water. exam tip ; if you're asked to show a condensation reaction, don't forget to put the water molecule in as a product. 

breaking down polymers

- biological polymers can be broken down into monomers by hydrolysis reactions. a hydrolysis reaction breaks the chemical bond between monomers using a water molecule. it's basically the opposite of a condensation reaction. tip ; a condensation reaction removes one molecule of water, but a hydrolysis reaction adds a molecule of water. tip ; it's easy to remember what a hydrolysis reaction does as 'hydro' means water and 'lysis' means breaking down.