This document summarizes key facts about polysaccharides and carbohydrates: - Polysaccharides are long chains of sugars, with cellulose consisting only of glucose molecules. Starch and glycogen store energy in plant and animal tissues, while inulin is a polymer of fructose. - Polysaccharides have reducing and non-reducing ends. Starch forms helical structures that can bind iodine, while cellulose cannot. Plant cell walls and paper are made of cellulose. - Carbohydrates are polyhydroxy aldehydes or ketones or compounds that produce them. Monosaccharides are single sugar units like glucose or fructose. Oligosaccharides are short chains of monos

1. NCERT----
 Polysaccharides are long chains of sugars
 cellulose is a polymeric polysaccharide consisting of only one type of
monosaccharide i.e., glucose
 Cellulose isa homo-polymer
 Starch is a polysaccharidesact as a store house of energyin plant tissues.
 Animals have glycogenas a stored product
 Inulinis a polymer offructose.
 In a polysaccharide chain (say glycogen),the right end is calledthe reducing endand the
leftendis calledthe non-reducingend
 Starch forms helical secondary structures.In fact, starch can hold I2 moleculesinthe
helical portion.The starch-I2 is blue incolour.
 Cellulose doesnotcontain complexhelicesandhence cannot holdI2 .
 Plant cell walls are made of cellulose.
 Paper made from plant pulpand cotton fibre is cellulosic.
 amino-sugarsand chemicallymodifiedsugars(e.g.,glucosamine,N-acetyl galactosamine,
etc.).Exoskeletonsofarthropods, for example,have a complexpolysaccharide called
chitin.These complexpolysaccharidesare mostlyhomopolymers.
Carbohydrates may be definedaspolyhydroxyaldehydesorketonesor compounds which
produce themon hydrolysis
Many, but notall,carbohydrateshave the empirical formula(CH2O)n;
Monosaccharidesor simple sugars,consistof a single polyhydroxyaldehydeorketone unit.
E.g- D-glucose,
Oligosaccharidesconsistof short chainsof monosaccharide units,orresidues,joinedby
characteristiclinkagescalledglycosidicbonds.E.g-sucrose (cane sugar),whichconsistsof the
six-carbonsugarsD-glucose andD-fructose.
The polysaccharides are sugarpolymerscontainingmore than20 or so monosaccharide
units;some have hundredsorthousandsof units.Some polysaccharides, suchascellulose,
are linearchains;others,suchas glycogen,are branched.
The Two FamiliesofMonosaccharides Are
Aldosesand KetosesMonosaccharidesare colorless,crystalline solidsthat are freely
soluble inwater but insoluble innonpolarsolvents.Most have a sweettaste
monosaccharides
Aldose ketose

2. If the carbonyl groupisat an endof the carbonchain (thatis,in an aldehyde group) the
monosaccharide isanaldose;
if the carbonyl group isat any otherposition(inaketone group) the monosaccharide isa
ketose
Basedon the number of carbon atoms, the monosaccharides are
regardedas trioses (3C), tetroses (4C), pentoses (5C), hexoses (6C) and
heptoses (7C)