Carbohydrates (also called carbs) are a type of macronutrient found in certain foods and drinks. Sugars, starches and fiber are carbohydrates. Other macronutrients include fat and protein. Your body needs these macronutrients to stay healthy.
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Carbohydrates Carbohydrates are a major
source of energy from our diet. composed
of the elements C, H and O.
They are also called saccharides, which
means “sugars.”
Carbohydrates are produced by
photosynthesis in plants such as glucose
are synthesized in plants from CO2, H2O,
and energy from the sun but are oxidized in
living cells to produce CO2, H2O, and energy
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Formerly, carbohydrates were defined as a group of
compounds composed of Carbon, Hydrogen and Oxygen.
The later 2 elements are in the same proportion as in
water and were expressed by a formula Cn(H₂O)n.
The word carbohydrates can be traced back to Germans,
who called them “Kohlenhydrates”. It was then termed
Carbohydrates in English.
The definition is not valid as it was misleading few
compounds like Acetic acid (C₂H₄O₂), lactic acid
(C₃H₆O₃) which are not carbohydrates.
To accommodate a wide variety of compounds, the
carbohydrates are now-a-days broadly defined as
polyhydroxy Aldehydes or Ketones.
Carbohydrates are much abundant in plants, rather than
in animals.
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Another type of classification scheme is based
on the hydrolysis of certain carbohydrates to
simpler carbohydrates i.e. classifications
based on number of sugar units in total chain.
Monosaccharides: single sugar unit
Disaccharides: two sugar units
Oligosaccharides: 3 to 10 sugar units
Polysaccharides: more than 10 units 10
6. Monosaccharides
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The general formula CnH2nOn with one of the carbons being
the carbonyl group of either an aldehyde or a ketone.
The most common monosaccharides have three to eight
carbon atoms.
The suffix-ose indicates that a molecule is a carbohydrate, and
the prefixes tri-, tetr-, pent-, and so forth indicate the number of
carbon atoms in the chain.
Monosaccharide containing an aldehyde group are classified
as aldoses; those containing a ketone group are classified as
ketoses.
A ketose can also be indicated with the suffix ulose; thus, a
five- carbon ketose is also termed a Pentulose. 9
10. POLYSACCHARIDES
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Formula(C6H10O5)n
On hydrolysis it produce Indefinite no. of
Monosaccharide's molecules called as Glycans.
Common Polysaccharides of biological significance
are Starch , Glycogen(Animal starch),Cellulose ,
Inulin.
Starch-Glucose units joined by α-1,4& α-1,6 linkages.
Cellulose-Glucose units joined by β -1,4 linkages.