Transcript Group A_carbohydrates

LECTURE 3 –STRUCTURE AND
PROPERTIES OF
CARBOHYDRATES
• Structure, properties and function of
carbohydrates and their derivatives
• Classification of carbohydrates
Course outcome:
• Ability to differentiate basic structure,
properties, functions and classification
of important biomolecules.
LECTURE 3 -CARBOHYDRATES
Section
Section
Section
Section
TOPICS:
1. Role & Significance of
Carbohydrates
2. Monosaccharide
3. Oligosaccharides
4. Polysaccharides
Sect.1. ROLE OF CARBOHYDRATES
As a major energy source for living
organisms
As a means of transporting energy
(glucose is a principal energy source in animal and plants)
( exp:
sucrose in plant tissues)
As a structural material
.
As a precursor for other biomolecules
( cellulose in plants, chitin in insects,
building blocks of nucleotides)
(purine, pyrimide)
Sect 1. SIGNIFICANCE OF CARBOHYDRATES
Carbohydrates are the most abundant
biomolecules in nature, having a direct link
between solar energy and the chemical bond
energy in living organisms.
Source of rapid energy production
Structural building blocks of cells
Components of several metabolic pathways
Recognition of cellular phenomena, such as cell
recognition and binding (e.g., by other cells,
hormones, and viruses)
CARBOHYDRATES
Carbohydrate : compounds contains H, C & O with the
comp : (CH2O)n (Hydrate of carbon)
Carbohydrates : Consist of sugar (saccharum)
Sugars : compound that contains alcohol & carbonyl
functional group
Carbonyl func.group : >C=o
Adehyde  aldose
Ketone  ketose
Examples:
Classification
Carbohydrate
Mono
saccharide
Glucose, fructose
Ribose (aldopentose)
Deoxy ribose
Oligo
saccharide
disaccharides
Glycoproteins
(bacterial cell
walls
Poly
saccharide
cellulose, chitin,
starch, glycogen,
glucoaminoglycans
Glyconoconjugates
glycoproteins
and
proteoglycans
Sect2.
MONOSACHARIDES
Sect. 2. Monosacharides
Sub sections :
2.1 Properties & classification
2.2 Stereoisomers
2.3 Cyclic structure
2.4 Important Reactions
2.5 Important monosach
2.6 glycoproteins and proteoglycans
2.7 Monosaccharide derivatives
2.1 Monosach Properties& classification
Colorless, crystalline solids
Soluble in water but insoluble in nonpolar
solvents
One of the carbon atoms is double-bonded to an
oxygen atom to form a carbonyl group; each of
the other carbon atoms has a hydroxyl group.
– Carbohydrates with an aldehyde (-CHO) functional
group are called aldoses e.g. glyceraldehyde (CH OH-CHOH-CHO)
Those with a keto group (-C=O) are ketoses
2
e.g.dihydroxyacetone (CH2OH-C=O-CH2OH)
– Classified according to the number of carbon atoms
they contain
Monosacharides : Exp. aldoses & ketoses
Aldotriose
Ketotriose
Aldotetrose
Ketotetrose
Aldopentoses
Ketopentose
Aldohexose
Ketohexose
2.2. MONOSACCHARIDES
STEREOISOMERS
Isomers: same chemical formulas, different structures
Total no of possible isomers can be determined by Van Hoff’s rule:
compound with n chiral C atoms has a max of 2n possible
stereoisomers.
Chiral: asymmetric carbons, i.e carbon atom with four different
substituents
Eg: n = 4, there are 16 stereoisomers (8-L stereoisomers, 8-D
stereoisomers).
In optical isomers- the ref C is the asymmetric C that is most remote
from the C=O carbon.
In D-aldose family sugars, the OH group is to the right on the chiral
C atom farthest from the most oxidized C (aldehyde group) in the
molecule.
D- and L- enantiomers
Stereoisomers that are not enantiomers
(mirror-image) are called
diastereoisomers.
Eg: aldopentoses, D-ribose and L-ribose
are enantiomers.
The D-ribose and D-arabinose are
diastereomers because they are isomers
but not mirror image.
Diastereomers that differ in the
configuration at a single asymmetric C
atom are called epimers.
Eg: D-glucose and D-galactose are
epimers because they differ only in the
configuration of the OH group at C-4.
D-mannose and D-galactose are not
epimers- differ more than 1 C.
2.2. MONOSACCHARIDES STEREOISOMERS
The simplest aldose, glyceraldehyde, contains one chiral center (the
middle carbon atom) and has two different optical isomers, or
enantiomers
the projection in which the carbohydrate backbone is
drawn vertically with the carbonyl shown on the top.
2.3 Cyclic structure of monosacharides
• in aqueous solution, monosaccharides with five or more carbon atoms in the
backbone occur predominantly as cyclic (ring) structures in which the carbonyl group
has formed a covalent bond with the oxygen of a hydroxyl group along the chain.
• Sir Norman Haworth showed that the linear form of glucose (and other aldohexose)
could undergo intramolecular reaction to form a cyclic hemiacetal.
• the analogous intramolecular reaction of ketose sugar yields a cyclic hemiketal.
The new chiral center in cyclic (c1) is called anomeric carbon
In aldose sugars, the OH group of the
newly formed hemiacetal occurs on C-1
(the anomeric carbon).
The OH group may occur either below the
ring (down position)- α-anomeric form.
Or above the ring (up position)-β anomeric form.
In Fischer projections, the α–anomeric OH
occurs on the right and β–anomeric OH
occurs on the left.
Pyranoses& Furanoses
Pyranoses: six-membered ring compounds ( resemble pyran )
Furanoses : fivemembered rings, (resemble furan)
The structure systematic names glucose & fructose become
HAWORTH STRUCTURES
An English chemist W.N.
Haworth gave a more accurate
picture of carbohydrate
structure.
Haworth Structures
To convert from traditional Fischer formula of a Dpentose or D-hexose to a Haworth formula, the following
steps should be followed:
Draw a 5 or 6-membered ring with the O placed as
shown below:
Starting with anomeric carbon to the right of the ring O,
place OH group either above or below the plane of the
ring. Group that pointing to the left in Fischer projection
should go above (β-) the plane of the ring, and those
pointing right should go below the ring (α-)
In D-sugars, the last C position (eg: C-6 glucose) is
always up
FISHER AND HAWORTH FORMS OF SUGAR
SUMMARY OF SUGAR STRUCTURES
ISOMERS- compounds that have the same chemical formula e.g.
fructose, glucose, mannose, and galactose are isomers of each
other having formula C6H12O6.
EPIMERS- refer to sugars whose configuration differ around one
specific carbon atom e.g. glucose and galactose are C-4 epimers
and glucose and mannose are C-2 epimers.
ENANTIOMERS- a special type of isomerism found in pairs of
structures that are mirror images of each other. The mirror images
are termed as enantiomers and the two members are designated as
D- and L- sugar. The vast majority of sugars in humans are Dsugars.
CYCLIZATION OF SUGARS- most monosaccharides with 5 or more
carbon atoms are predominately found in a ring form, where the
aldehyde or ketone group has reacted with an alcoholic group on the
same sugar group to form a hemiacetal or hemiketal ring.
Pyranose ring- if the ring has 5 carbons and 1 oxygen.
Furanose ring- if the ring is 5-membered (4 carbons and 1 oxygen
2.4.IMPORTANT REACTIONS IN MONOSACCHARIDES
Monosaccharides undergo the following reactions :
1.
2.
3.
4.
5.
6.
Mutarotation
Oxidation
Reduction
Isomerization
Esterification
Glycoside formation
IMPORTANT REACTIONS IN MONOSACCHARIDES
Details
1. Mutarotation –
alfa and beta forms of sugars are readily interconverted when
dissolved in water. Mutarotation produces an equilibrium mixture of
α and β- forms in both furanose and pyranose ring structures.
2
Oxidation and reduction
in presence of oxidising agents, metal ions (Cu2+) and enzymes,
monosacchs undergo several oxidation reactions e.g. Oxidation of
aldehyde group (R-CHO) yields aldonic acid; of terminal CH2OH
(alcohol) yields uronic acid; and of both the aldehyde and CH2OH
gives aldaric acid. The carbonyl groups in both aldonic and uronic
can react with an OH group in the same molecule to form a cyclic
ester known as a lactone.
sugars that can be oxidized by weak oxidizing agent ie. Benedict’s
reagent, called reducing sugars. Because the reaction occurs only
with sugars that can revert to open chain form, all
monosaccharides are reducing sugars.
3. REDUCTION
reduction of the aldehyde and ketone
groups of monosacchs yield sugar
alcohols (alditols) Sugar alcohols
e.g.sorbitol, are used commercially in
processing foods and pharmaceuticals.
sorbitol- improves the shelf-life of candyit helps prevent moisture loss.
IMPORTANT REACTIONS (Cont)
4.
ISOMERIZATION
Monosaccharides undergo several types of isomerization e.g. D-glucose in
alkaline solution for several hours contain D-mannose and D-fructose. Both
isomerization involves an intramolecular shift of a H atom and a relocation
of double bond. The conversion of glucose to mannose is termed s
epimerization.
5
ESTERIFICATION
Free OH groups of carbohydrates react with acids to form esters. This
reaction an change the physical and chemical propteries of sugar.
6.
GLYCOSIDE FORMATIONHemiacetals and hemiketals reaction with alcohols to form the
corressponding aceta or ketal. On the contrary when a cyclic hemiacetal or
hemiketal form of monosaccharide reacts with alcohol, the new linkage is
called glycosidic linkage and the compound glycoside.
Alfa & beta GLYCOSIDIC BOND
REDUCING SUGARS
All monosacchs are reducing sugars.
They can be oxidised by weak oxidising
agent such as Benedict’s reagent
Benedict's reagent is a solution of copper
sulfate, sodium hydroxide, and tartaric
acid.
Aqueous glucose is mixed with Benedict's reagent and heated.
The reaction reduces the blue copper (II) ion to form a brick red
precipitate of copper (I) oxide. Because of this, glucose is
classified as a reducing sugar.
2.5 IMPORTANT MONOSACCHARIDES
GLUCOSE
FRUCTOSE
GALACTOSE
D-Glucose:
D-glucose (dextrose) is the primary fuel in living cells
especially in brain cells that have few or no mitochondria.
Cells such as eyeballs have limited oxygen supply and use
large amount of glucose to generate energy
Dietary sources include plant starch, and the disaccharides
lactose, maltose, and sucrose
Important monosaccharides. Cont
FRUCTOSE
– D-fructose (levulose) is often referred as fruit sugar
and is found in some vegetables and honey
– This molecule is an important member of ketose
member of sugars
– It is twice as sweet as sucrose (per gram basis) and is
used as sweeting agent in processed food products
– It is present in large amounts in male reproductive
tract and is synthesised in the seminal vesicles.
Important monosaccharides. Cont....
GALACTOSE
– is necessary to synthesize a variety of biomolecules
(lactose-in mammalary glands, glycolipids, certain
phospholipids, proteoglycans, and glycoproteins)
– Galactose and glucose are epimers at carbon 4 and
interconversion is catalysed by enzyme epimerase.
– Medical problems – galactosemia (genetic disorder)
where enzyme to metabolize galactose is missing;
accumulation of galactose in the body can cause liver
damage, cataracts, and severe mental retardation
2.7.MONOSACCHARIDE DERVATIVES
URONIC ACIDS – formed when terminal
CH2OH group of a mono sugar is oxidised
– Important acids in animals – D-glucuronic acid
and its epimer L-iduronic acid
– In liver cells glucuronic acid combines with
steroids, certain drugs, and bilirubin to
improve water solubility therby helping the
removal of waste products from the body
– These acids are abundant in the connective
tissue carbohydrate components.
Mono sugar derivatives
AMINO SUGARS –
– Sugars in which a hydroxyl group (common
on carbon 2) is replaced by an amino group
e.g. D-glucosamine and D-galactosamine
– common constituents of complex
carbohydrate molecule found attached to
cellular proteins and lipids
– Amino acids are often acetylated e.g. Nacetyl-glucosamine.
Mono sugar derivatives
DEOXYSUGARS
– monosaccharides in which an - H has replaced an –
OH group
– Important sugars: L-fucose (formed from D-mannose
by reduction reactions) and 2-deoxy-D-ribose
– L-fucose – found among carbohydrate components of
glycoproteins, such as those of the ABO blood group
determinates on the surface of red blood cells
– 2-deoxyribose is the pentose sugar component of
DNA.
GLYCOSIDIC BONDS
• Monosaccharides can be linked by glycosidic bonds
(joining of 2 hydroxyl groups of sugars by splitting out
water molecule) to create larger structures.
• Disaccharides contain 2 monosaccharides e.g. lactose
(galactose+glucose); maltose (glucose+glucose);
sucrose (glucose+fructose)
• Oligosaccharides – 3 to 12 monosaccharides units
e.g. glycoproteins
• Polysaccharides – more than 12 monosaccharides
units e.g. glycogen (homopolysaccharide) having
hundreds of sugar units; glycosaminoglycans
(heteropolysaccharides) containing a number of different
monosaccharides species.
Section 3
DISACCHARIDES
AND
OLIGOSACCHARIDES
DISACCHARIDES AND
OLIGOSACCHARIDES
Configurations: alfa or beta ( 1,4, glycosidic bonds or
linkages; other linkages 1,1; 1,2; 1,3; 1,6)
Digestion of disaccharides and other carbohydrates
aided by enzymes. Defficiency of any one enzyme
causes unpleasant symptoms. The undigestible
dissacharide sugar pass into large intestine and digested
by bacteria (fermentation) in colon produces gas
[bloating of cramps].
Most common defficiency, an ancestoral disorder,
lactose intolerance caused by reduced synthesis of
lactase
Important sugars of Disaccharides
LACTOSE
(milk sugar) disaccharide found in milk; composed of one
molecule of galactose (OH group in C-1) and glucose (OH
group at C-4) linked through beta(1,4) glycosidic linkage
(anomeric C of galactose is in β-configurations); because of
the hemiacetal group of the glucose component, lactose is a
reducing sugar
Lactose intolerance
Lactose (milk sugar) in infants is hydrolyzed by
intestinal enzyme lactase to its component
monosacch for absorption into the bloodstream
(galactose epimerized to glucose).
Most adult mammals have low levels of betagalactosidase. Hence, much of the lactose they
ingest moves to the colon, where bacterial
fermentation generates large quantities of CO2,
H2 and irritating organic acids.
These products cause painful digestive upset
known as lactose intolerance and is common
in the African and Asian decent.
MALTOSE ( malt sugar)
An intermediate product of starch hydrolysis; it is a disaccharide with an alfa(1,4)
glycosidic linkage between two D-glucose molecules; in solution the free
anomeric carbon undergoes mutarotation resulting in an equilibrium mixture of
alfa and beta – maltoses; it does not occur freely in nature
SUCROSE
common table sugar: cane sugar or beet sugar produced
in the leaves and stems of plants; it is a disaccharide
containing both alfa-glucose and beta-fructose residues
linked by alfa,beta(1,2)glycosidic bond.
CELLOBIOSE
degradation product of cellulose
containing two molecules of glucose linked
by a beta (1,4) glycosidic bond; it does not
occur freely in nature
OLIGOSACCHARIDE SUGARS
Oligosaccharides are small polymers often
found attached to polypeptides in
glycoproteins and some glycolipids.
They are attached to membrane and
secretory proteins found in endoplasmic
reticulum and Golgi complex of various
cells
Two classes: N-linked and O-linked
Section 4
POLYSACCHARIDES
4.1. Intro to Polysaccharides
4.2. Classification of Polisacharides
4.2.1. Homosacharides
4.2.2. Heteropolysacharides
4.1. Intro to Polysaccharides
Composed of large number of monosaccharide units
connected by glycosidic linkages
Classified on the basis of their main monosaccharide
components and the sequences and linkages between
them, as well as the anomeric configuration of linkages,
the ring size (furanose or pyranose), the absolute
configuration (D- or L-) and any other substituents
present. (http://www.lsbu.ac.uk/water/hypol.html)
Polysaccharides are more hydrophobic if they have a
greater number of internal hydrogen bonds, and as their
hydrophobicity increases there is less direct interaction
with water
Divided into homopolysaccharides (e.g.Starch, glycogen,
cellulose, and chitin) & heteropolysaccharides
(glycoaminoglycans or GAGs, murein).
4.2. Classification of Polisacharides
4.2.1.HOMOPOLYSACCHARIDES
Found in abundance in nature
Important examples: starch, glycogen, cellulose,
and chitin
Starch, glycogen, and cellulose all yield Dglucose when they are hydrolyzed
Cellulose - primary component of plant cells
Chitin – principal structural component of
exoskeletons of arthropods and cell walls of
many fungi; yield glucose derivative N-acetyl
glucosamine when it is hydrolyzed.
STARCH (Homopolysaccharide)
A naturally abundant nutrient carbohydrate, (C6H10O5)n, found
chiefly in the seeds, fruits, tubers, roots, and stem pith of
plants, notably in corn, potatoes, wheat, and rice, and varying
widely in appearance according to source but commonly
prepared as a white amorphous tasteless powder.
Any of various substances, such as natural starch, used to
stiffen cloth, as in laundering.
Two polysaccharides occur together in starch: amylose and
amylopectin
Amylose – unbranched chains of D-glucose residues linked
with alfa(1,4,)glycosidic bonds
Amylopectin – a branched polymer containing both alfa(1,4,)
and alfa(1,6) glcosidic linkages; the alfa(1,6) branch points
may occur every 20-25 glucose residues to prevent helix
formation
Starch digestion begins in the mouth; alfa-amylase in the
saliva initiates hydrolysis of the gycosidic linkages
Amylose
amylopectin
GLYCOGEN (Homopolysaccharide)
Glycogen is the storage form of glucose in animals and humans
which is analogous to the starch in plants.
Glycogen is synthesized and stored mainly in the liver and the
muscles.
Structurally, glycogen is very similar to amylopectin with alpha
acetal linkages, however, it has even more branching and more
glucose units are present than in amylopectin.
Various samples of glycogen have been measured at 1,700600,000 units of glucose.
The structure of glycogen consists of long polymer chains of glucose
units connected by an alpha acetal linkage.
The branches are formed by linking C # 1 to a C # 6 through an
acetal linkages.
In glycogen, the branches occur at intervals of 8-10 glucose units,
while in amylopectin the branches are separated by 12-20 glucose
units.
STRUCTURE OF GLYCOGEN
CELLULOSE
(Homopolysaccharide)
Cellulose is found in plants as microfibrils (2-20 nm diameter and
100 - 40 000 nm long). These form the structurally
strong framework in the cell walls. The microfibrils are held together
by hydrogen bonding and may contain 12,000 glucose units each.
Cellulose is mostly prepared from wood pulp
Cellulose is a linear polymer of β-(1 4)-D-glucopyranose units in 4C1
conformation. The fully equatorial conformation of β-linked
glucopyranose residues stabilizes the chair structure, minimizing its
flexibility
Cellulose has many uses as an anticake agent, emulsifier, stabilizer,
dispersing agent, thickener, and gelling agent but these are
generally subsidiary to its most important use of holding on to water.
Water cannot penetrate crystalline cellulose but dry amorphous
cellulose absorbs water becoming soft and flexible.
Purified cellulose is used as the base material for a number of
water-soluble derivatives e.g. Methyl cellulose, carbomethycellulose
The ability to digest cellulose is found only
in microbes that possess enzyme
cellulase.
Certain animal species (termites and
cows) use such organisms in their
digestives tracts to digest cellulose.
The breakdown of cellulose makes
glucose available to both the microbes and
their host.
Cellulose also make up the dietary fibre.
Cellulose as polymer of β-D-glucose
Cellulose in 3D
CELLULOSE
CHITIN (Homosaccharide)
Chitin is a polymer that can be found in anything from
the shells of beetles to webs of spiders. It is present all
around us, in plant and animal creatures.
It is sometimes considered to be a spinoff of cellulose,
because the two are very molecularly similar.
Cellulose contains a hydroxy group, and chitin contains
acetamide.
Chitin is unusual because it is a "natural polymer," or a
combination of elements that exists naturally on earth.
Usually, polymers are man-made. Crabs, beetles, worms
and mushrooms contain large amount of chitin.
Chitin is a very firm material, and it help protect an insect
against harm and pressure
Structure of the chitin molecule, showing two of the Nacetylglucosamine units that repeat to form long chains in
beta-1,4 linkage.
CHITOSAN
A spinoff of chitin that has been discovered by the
market is chitosan. This is a man-made molecule that is
often used to dye shirts and jeans in the clothing
industry.
Chitosan can be used within the human body to regulate
diet programs, and researchers are looking into ways in
which it can sure diseases.
Chitin, the polysaccharide polymer from which chitosan
is derived, is a cellulose-like polymer consisting mainly of
unbranched chains of N-acetyl-D-glucosamine.
Deacetylated chitin, or chitosan, is comprised of chains
of D-glucosamine. When ingested, chitosan can be
considered a dietary fiber.
CHEMICAL STRUCTURE OF CHITOSAN
http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/chi_0067.shtml
4.2.2.HETEROPOLYSACCHARIDES
Are high-molecular-weight carbohydrate
polymers more than one kind of
monosaccharide
Important examples include
glycosaminoglycans (GAGs) – the
principle components of proteoglycans
and murein, a major component of
bacterial cell walls.
Glycoaaminoglycans (GAGs)
GAGs are linear polymers with
disaccharides repeating units. Many of
their sugar residues are amino derivatives.
The repeating units contain hexuronic acid
(a uronic acid contain 6-C atoms) except
for keratan sulphate – contains galactose.
Usually N-acetylglucosamine sulphate is
also present except in hyaluronic acid
which contain N-acetylglucosamine.
Many disacharide units contain both
carboxyl nd sulfate functions groups.
GAGs are classified according to their
sugar residues, the linkages between
residues and the presence and location of
sulphate groups.
5 classes has been distinguished:
hyaluronic acid, chondroitin sulfate,
dermatan sulfate, heparin and keratan
sulfate
THE SPECIFIC GAGs OF PHYSIOLOGICAL
SIGNIFICANCE
Hyaluronic acid
Occurence : synovial fluid, ECM of loose
connective tissue
Hyaluronic acid is unique among the GAGs
because it does not contain any sulfate and is
not found covalently attached to proteins. It
forms non-covalently linked complexes with
proteoglycans in the ECM.
Hyaluronic acid polymers are very large (100 10,000 kD) and can displace a large volume of
water.
Hyaluronic acid (D-glucuronate + GlcNAc)
Dermatan sulfate (L-iduronate + GlcNAc sulfate)
Occurence : skin, blood vessels, heart valves
Chondroitin sulfate (D-glucuronate +
GalNAc sulfate)
Occurence : cartilage, bone, heart valves ;
It is the most abundant GAG.
Heparin and heparan sulfate (D-glucuronate
sulfate + N-sulfo-D-glucosamine)
Heparans have less sulfate groups than heparins
Occurence :
Heparin :component of intracellular granules of mast cells lining the
arteries of the lungs, liver and skin Heparan sulfate : basement
membranes, component of cell surfaces
Keratan sulfate ( Gal + GlcNAc sulfate)
Occurence : cornea, bone, cartilage ;
Keratan sulfates are often aggregated with chondroitin
sulfates.
MUREIN (Peptidoglycan)
Peptidoglycan, also known as murein, is a polymer consisting of
sugars and amino acids that forms a mesh-like layer outside the
plasma membrane of eubacteria.
The sugar component consists of alternating residues of β-(1,4)
linked N-acetylglucosamine and N-acetylmuramic acid residues.
Attached to the N-acetylmuramic acid is a peptide chain of three to
five amino acids.
The peptide chain can be cross-linked to the peptide chain of
another strand forming the 3D mesh-like layer.
Some Archaea have a similar layer of pseudopeptidoglycan.
SUMMARY
Monosaccharides, the simplest carbohydrates, are
classified as aldoses or ketoses.
The cyclic hemiacetal and hemiketal forms of
monosacchs have either alfa or beta configuration at
their anomeric carbon.
Monosacch derivatives include aldonic acids, uronic
acids, deoxy sugars, amino sugars, alfa & beta
glycosides.
Disaccharides simplest polysaccharides occuring as
hydrolysis products of larger molecules e.g.
Lactose,sucrose
Oligosaccharides play important roles in determining
protein structure and in cell-surface recognition
phenomena. Oligosacchs with 3 or more sugar residues
are mostly found in plants.
Summary contd. -1
POLOYSACCHARIDES consist of monosacchs
linked by glycosidic bonds.
Cellulose and chitin are structural polysacchs
with beta(1-4) linkages that adopt rigid and
extended structures.
The storage polysacchs starch and glycogen
consist of alfa-glycosidically linked glucose
residues
Glycosaminoglycans are unbranched
polysacchs containing uronic acids and amino
sugars that are often sulfated
END NOTES
The destiny of a nation depends on the
manner in which it feeds itself.
We eat to live, NOT, live to eat.
Lower your carbohydrate consumption, but
balance it with the right amount of protein
and fat.