lecture 5 Flashcards
carbohydrates
what do carbohydrates contain
carbon, hydrogen and oxygen in the ratio 1:2:1
what is RNA
a nucleic acid that acts as a messenger carrying instructions from DNA
what is the chemical composition of carbohydrates
an organic compound with the empirical formula (CH20)n. an aldehyde or ketone with multiple hydroxyl groups
what is a monosaccharide
a single sugar unite comprising of an aldehyde or ketone that has two or more hydroxyl groups
what is an isomer
same molecular formula but different structures
what is a constitutional isomer
atoms that are bonded in a different order
what is an N-glycosidic bond
when the N-H group of an amine substitutes a hydroxyl group of a sugar and reacts at the anomeric carbon centre
what is phosphorylation
formed through a condensation reaction (release of water) of phosphoric acid with a hydroxyl group on the sugar
what are reducing sugars
sugars that contain aldehydes (glucose, galactose, ribose, glyceraldehyde) and sugars that contain ketones that can rearrange into aldehydes
what is a polysaccharide
long chains of carbohydrate molecules, composed of more than 20 monosaccharides
what are homopolysaccharides
composed of large numbers of one type of sugar
what are heteropolysaccharides
contain more than one type of sugar
what is glycogen
the main storage polysaccharide of animal cells - extensively branched – prevents tight packing – facilitates rapid hydrolysis to provide high levels of glucose more quickly
what are the two forms of starch
storage of glucose in plants - amylose and amylopectin
what is cellulose
a structural component of the primary cell wall - packs together tightly (pulled together by lots of hydrogen bonds and van der Waals forces) therefore tough and strong structure
