carbohydrates Flashcards
how bonds between monomers are formed?
a α /β-1, 4 glycosidic bond forms between the -OH group of carbon 1 of one glucose monomer and the -OH group of carbon 4 of another α/β-glucose monomer
condensation reaction which involves the removal of one water molecule
require energy and is catalysed by enzymes
structure of cellulose
consists of a long chain of β-glucose residues linked by β-1. 4 glycosidic bonds which makes the cellulose chain straight
successive β-glucose residues are rotated 180° with respect to adjacent residue which results in the OH groups projecting outwards from each chain in all directions.
structure of amylose
an unbranched chain structure that consists of many α-glucose residues linked by α-1, 4 glycosidic bonds
The angle of these bonds causes the chain to coil helically into a more compact
shape, allowing the packing of many glucose molecules per unit volume ;
function of amylose
large number of glucose molecules present serves as a good energy source in plants, as glucose is oxidised during respiration to produce ATP
nature of amylose
most of the -OH groups are projected into the interior of the amylose helix, there are no free -OH groups to form hydrogen bonds with water, insoluble molecule
structure of amylopectin
has a backbone of α-glucose residues held together by α-1, 4 glycosidic bonds. highly branched with side chains formed by α-1, 6 glycosidic bonds
function of amylopectin
many branched ends allow many hydrolytic enzymes to act on branched ends at any one time
can be easily broken down into its glucose monomers to be used as respiratory substrates. serves as an accessible source of glucose
cellulose high tensile strength, stability, support
hydrogen bonds formed between -OH groups of neighbouring cellulose chains lying in parallel
cross-linking between adjacent cellulose chains binds the chains rigidly together form bundles called microfibrils
