CARBOHYDRATES CLASSIFICATION, STRUCTURE, PROPERTIES, AND BIOSYNTHESIS

1. CARBOHYDRATES

2. Agenda / Topics
INTRODUCTION
CLASSIFICATION
STRUCTURE
PROPERTIES
BIOLOGIAL SIGNIFICANCE

3. INTRODUCTION
TERMINOLOGY
The term CARBOHYDRATES has many synonyms like sugar , saccharide , ose , glucide,
polyhydroxy compounds with aldehyde and ketone.
GENERAL FORMULA: The formula Cn (H2O)n.
SIMPLE STRCTURE
Formaldehyde (CH2O) to be the simplest carbohydrate.

4. A biomolecules refers to any molecule that is produced by living
organisms. As such, most of them are organic molecules.
The four major groups of biomolecules include :
 amino acids,
proteins,
 carbohydrates (especially, polysaccharides),
lipids, and
nucleic acids.
A carbohydrate refers to any of the group of organic compounds
consisting of
carbon,
hydrogen, and
oxygen
Usually in the ratio of 1:2:1, hence the general formula: Cn (H2O) n.
Carbohydrates are the most abundant among the major classes
of biomolecules.
Carbohydrate Definition

5. CLASSIFIATION

6. MONOSACCHARIDES
MONOSACCHARIDES are simple sugars.
No.of carbon range from 3-7
The hydroxyl group of one monosaccharide combines with the hydrogen of another monosaccharide,
releasing a molecule of water and forming a covalent bond.
The METABOLISM of any monosaccharide (simple sugar) can produce energy for the cell to use.

7. MONOSACCHARIDE CLASSIFICATON

8. CONTINUATION OF MONOSACCHARIDES
(GLUCOSE)
Glucose is the main type of sugar in the blood
and is the major source of energy for the body's
cells.
Glucose is carried to the cells through the
bloodstream.
Several hormones, including insulin,
control glucose levels in the blood.
GULCOSE:
 The molecular formula C6H12O6
Glucose also called dextrose.

9. CONTINUATION OF MONOSACCHARIDE
(FRUCTOSE)
Fructose, or fruit sugar, is a simple ketonic
simple sugar found in many plants, where it is
often bonded to glucose to form the
disaccharide sucrose.
It is one of the three dietary
monosaccharides, along with glucose and
galactose, that are absorbed directly into blood
during digestion.
Fructose:
The molecular fromula C6H12O6

10. CONTINUATION OF MONSACCHARIDE
(GALACTOSE)
Galactose is a monosaccharide and has the same
chemical formula as glucose, i.e., C6H12O6. It is similar to
glucose in its structure, differing only in the position of
one hydroxyl group.
The major dietary source of galactose is lactose, a
disaccharide formed from one molecule of glucose plus
one of galactose.
The molecular formula C6H12O6
Galactose

11. PROPERTIES OF MONOSACCHARIDES
Colour and shape Monosaccharides are colourless and crystalline
compounds.
Solubility soluble in water.
 Taste sweet taste.
Stereo isomerism D-glucose and L-glucose are mirror images of
each other.

12. DISACCHARIDES
A disaccharide is the sugar formed when two monosaccharides are
joined by glycosidic linkage.
Like monosaccharides, disaccharides are simple sugars soluble in
water.
DISACCHARIDES 12 carbon atoms
A disaccharide is a double sugar formed when two monosaccharides are
joined via dehydration synthesis. In this type of synthesis reaction, one
water molecule is lost as the bond is made. The formula of dehydration
synthesis is as follows:

13. DISACCHARIDES CLASSIFICATION

14. COTINUATION OF DISACCHARIDE
(Sucrose)
Sucrose is common sugar.
It is a disaccharide, a molecule composed of two monosaccharides:
glucose and
fructose
Sucrose is produced naturally in plants, from which table sugar is
refined.
Sucrose is composed of a molecule of glucose joined to a molecule
of fructose by an α-1,β-2-glycosidic linkage.
 It has the molecular formula
Sucrose
C12H22O11

15. COTINUATION OF DISACCHARIDE
(LACTOSE)
Lactose is composed of a molecule of galactose joined to a
molecule of glucose by a β-1,4-glycosidic linkage.
It is a reducing sugar that is found in milk.
LACTOSE
Molecular Formula: C12H22O11

16. COTINUATION OF DISACCHARIDE
(MALTOSE)
Maltose is composed of two units of D- glucose linked
together through alpha 1,4 glycosidic bond.
MALTOSE
Chemical Formula: C12H22O11

17. PROPERTIES OF DISACCHARIDES
The glycosidic bond can be formed between any hydroxy group on
the component monosaccharide.
Depending on the monosaccharide constituents, disaccharides are
sometimes crystalline, sometimes water-soluble, and sometimes
sweet-tasting and sticky-feeling.
Disaccharides can serve as functional groups by forming glycosidic
bonds with other organic compounds, forming biosides.

18. OLIGOSACCHARIDES
An oligosaccharide is
a saccharide polymer containing a small
number of monosaccharides (simple sugars).
Oligosaccharides can have many functions
including cell recognition and cell binding.
For example, glycolipids have an important
role in the immune response.
They are normally present as glycans:
oligosaccharide chains linked to lipids or
to compatible amino acid side chains
in proteins, by N- or O-glycosidic bonds
N-Linked oligosaccharides O-Linked oligosaccharides

19. OLIGOSACCHARIDES CLASSIFICATION

20. CONTINUATION OF OLIGOSACCHARIDE
(RAFFINOSE)
RAFFINOSE
Raffinose is a trisaccharide composed of
galactose, glucose, and fructose.
It can be found in beans, cabbage, brussels
sprouts, broccoli, asparagus, other vegetables, and
whole grains.
Formula: C18H32O16

21. CONTINUATION OF OLIGOSACCHARIDES
(STACHYOSE)
STACHYOSE
Stachyose is a tetrasaccharide consisting of two α-
D-galactose units, one α-D-glucose unit, and one β-D-
fructose unit sequentially linked as
gal(α1→6)gal(α1→6)glc(α1↔2β)fru.
Together with related oligosaccharides such
as raffinose, stachyose occurs naturally in
numerous vegetables (e.g. green beans, soybeans and
other beans) and other plants
Molecular Formula: C24H42O21

22. PROPERTIES OF OLIGOSACCHARIDES
Physicochemical properties of oligosaccharides
The oligosaccharides are about 0.3–0.6 times as sweet as sucrose, this low
sweetness attribute is exploited in food formulations as a replacement of sucrose.
Further, the low caloric densities make the oligosaccharides useful as bulking
agents in food formulations.
They are used as humectants because of their high moisture-retaining capacity
without increasing water activity.
Based on their physiological properties, these carbohydrates are grouped
as digestible or non-digestible.
Low pH and high temperature tend to impair the physicochemical properties
and reduce nutritional value of oligosaccharides.

23. POLYSACCHARIDES
Polysaccharides are long chains of monosaccharides linked by glycosidic bonds.
Three important polysaccharides, starch, glycogen, and cellulose, are
composed of glucose.
Starch and glycogen serve as short-term energy stores in plants and animals,
respectively.
The glucose monomers are linked by α glycosidic bonds
Functions of a Polysaccharide
Depending on their structure, polysaccharides can have a wide variety of
functions in nature.
Some polysaccharides are used for storing energy, some for sending cellular
messages, and others for providing support to cells and tissues.

24. POLYSACCHARIDE CLASSIFICATION

25. CONTINUATION OF POLYSACCHARIDES
(CELLULOSE)
oCellulose is the most abundant biopolymer available in
nature, since it is one of the major components of the
cell walls of most of the plants.
oIt is a homopolymer of anhydroglucose, with the
glucose residues linked in a ß-1,4 fashion.
oCell walls of plant cells attribute their mechanical
strength to cellulose.
oCellulose owes its structural properties to the fact that
it can retain a semi-crystalline state of aggregation even
in an aqueous environment, which is unusual for a
polysaccharide.
CELLULOSE
oChemical formula: (C6H10O5)n

26. CONTINUATION OF POLYSACCHARIDES
(STARCH)
STARCH
•Starch is composed of two types of polymer chains known as
amylose and amylopectin.
•Amylose possesses a linear structure with α1–4 glycosidic
linkage while amylopectin possesses a branched structure with
α1–4 as well as α1–6 glycosidic linkages
Chemical formula: (C6H10O5)n +(H2O)
•Starch or amylum is a polymeric carbohydrate consisting of
numerous glucose units joined by glycosidic bonds.
•This polysaccharide is produced by most green plants for energy
storage.
•It is the most common carbohydrate in human diets and is contained
in large amounts in staple foods like potatoes , maize (corn), rice,
wheat.

27. CONTINUATION POLYSACCHARIDE
(GLYCOGEN)
Glycogen is a glucose polysaccharide occurring in most
mammalian and nonmammalian cells, in microorganisms,
and even in some plants.
It is an important and quickly mobilized source of
stored glucose.
In vertebrates it is stored mainly in the liver as a
reserve of glucose for other tissues.
Formula : (C6H10O5)n
GLYCOGEN

28. PROPERTIES OF POLYSACCHARIDES
Polysaccharides are characterized by the following chemical properties:
(1) not sweet in taste,
(2) many of which are insoluble in water,
(3) do not form crystals when desiccated,
(4) compact and not osmotically active inside the cells,
(5) can be extracted to form white powder, and
(6) general chemical formula of Cx(H2O)y

29. BIOLOGICAL SIGNIFICANCE
1. Storage role: Carbohydrates serve as the storage of metabolic fuel for a living
organism. For example, starch and glycogen are present as the storage form in plants
and animals respectively. The storage form is broken down into glucose units which serve
to provide energy.
2. Structural role: Carbohydrates like cellulose, hemicellulose, and lignin provide a
mechanical and protective function to the cell wall of plants. It also provide a definite
shape to the plant cell. Chitin forms the part of the exoskeleton in insects and
crustaceans.
3. Communication role: Carbohydrates are covalently bound to either protein or lipid
to form glycoproteins or glycolipids. Glycoproteins act as a harmones
Glycolipid acts as an enzyme, immunoglobins