Transcript Carbohydrates

Based on a small number of
chemical elements – mainly carbon
Are very large
Made up of monomers combined
to produce polymers
Made by the process known as
condensation
Carbohydrates
Compounds of carbon, hydrogen and
oxygen
They have the common formula Cx(H2O)y
where x and y are variable numbers
Three main types Monosaccharides
Disaccharides
Polysaccharides
Monosaccharides
The simple sugars
Have the general formula (CH2O)n – n can be
any number from 3 – 7
Grouped according to value of n
N=3
triose
N=4
tetrose
N=5
pentose
N=6
hexose
N=7
heptose
Glucose
A hexose sugar with formula C6H12O6
Is the main energy source for most
living cells
Exhibits ISOMERISM - when
molecules have the same chemical
formula but a different structural
formula
Two common isomers are a-glucose and
b-glucose
O
H
H
a Glucose
OH down
OH
HO
b Glucose
OH up
H
HO
O
OH
H
Fructose
A hexose sugar with formula C6H12O6
Is the sugar found in most fruits
Disaccharides
Formed when two monosaccharides
join together
This reaction releases water and is
therefore called a CONDENSATION
REACTION.
The link between the 2
monosaccharide molecules is called a
GLYCOSIDIC BOND
O
H
HO
H
O
H
H
OH
OH HO
H2O
H
HO
OH
H
O
O
Glycosidic bond
H
OH
1-4 glycosidic bonds
Disaccharides can be formed by joining
together:
2 similar monosacs eg maltose – 2 glucose
2 different monosacs eg sucrose –glucose+
fructose
Disaccharides can be broken back down
into monosaccharides by the process
known as HYDROLYSIS – adding a
molecule of water