Introduction to Carbohydrates
one of the three major classes of biological molecules.
most abundant biological molecules.
carbohydrates
Functions of Carbohydrates
1) Energy
2. Provides dietary Fiber
3. Structural
4. Intercellular Communication
-glucose fuels the work of most of the body’s cells
-preferred fuel of NERVOUS TISSUE (the brain, nerves) and RED BLOOD CELLS (RBC)
-excess glucose is stored as GLYCOGEN in liver and muscle tissue
energy
-Found in plants
-increase fecal weight and soften stool to ease passage
-reduces risk of hemorrhoids, diverticulitis, appendicitis and colon cancer
-beneficial for weight control by contributing to satiety & delay gastric emptying
-soluble fibers lower blood cholesterol to help reduce risk of cardiovascular disease
Provides dietary Fiber
(components of nucleotides, plant and bacterial cell walls, arthropod exoskeletons, animal connective tissue etc.)
Structural
(component of the cell surface/membrane-- molecular recognition)
Intercellular Communication
Carbohydrates Contain the Elements:
-Carbon
-Hydrogen
-Oxygen
The formula for a carbohydrate is:
(CH2O)n
The __ represents the number of times the CH2O unit is repeated.
n
All carbohydrates can be classified as:
1. Monosaccharides
2. Disaccharides
3. Oligosaccharide
4. Polysaccharides
-one unit of carbohydrate
Monosaccharides
-carbohydrate form used by the body; referred to as “blood sugar”
-basic sub-unit of other larger carbohydrate molecules
-found in fruits, vegetables, honey
glucose
-sweetest of the sugars
-occurs naturally in fruits & honey, “fruit sugar”
Fructose
It combines with glucose to form lactose, “milk sugar”
Galactose
Two units of carbohydrates joined by glycosidic bond.
Disaccharides
fructose + glucose (also known as “table sugar” ) =
Sucrose
galactose + glucose (also known as “milk sugar”) =
Lactose
glucose + glucose (also known as “malt sugar”, maltose is in beer) =
Maltose
Anywhere from three to ten monosaccharide units joined by glycosidic bonds. found in legumes and human milk
Oligosaccharide
are much larger, containing hundreds of monosaccharide units joined by glycosidic bonds.
Polysaccharides
-plant storage form of carbohydrate
-long branched or unbranched chains of glucose
starch
-animal storage form of carbohydrate
-highly branched chains of glucose units
-found in LIVER and MUSCLE
-Humans store ~ 100g in liver; ~ 400g in muscle
glycogen
-consisting of a linear chain of several hundred to many thousands of β(1→4) linked glucose units commonly found in plant’s cell wall.
-This β-1,4 bonds cannot be broken by human enzymes; hence it is a non-digestible carbohydrates found in all types of plant foods
-Often referred to as “Dietary fiber”
cellulose
Carbohydrates also can combine with lipids to form _________
With proteins to form ___________.
glycolipids
glycoproteins
carbohydrates joined by __________.
glycosidic bond
Monosaccharides examples:
-glucose
-fructose
-galactose
Disaccharides examples:
-sucrose
-lactose
-maltose
Oligosaccharide examples:
-raffinose
-stachyose
Polysaccharides examples:
-starch
-glycogen
-cellulose
Carbohydrates are chemically characterized as:
-aldose
-ketose
-Sugars that contain an aldehyde group.
-Examples of aldoses are Glucose, Galactose, and Mannose. They are also known as aldohexose.
aldose
-Sugars that contain a keto group.
-Examples of ketos is fructose. It is also known as ketohexose.
ketose
Aldose
-Sugars that contain an aldehyde group.
-Examples of aldoses are Glucose, Galactose, and Mannose. They are also known as _________.
aldohexose
Ketose
-Sugars that contain a keto group.
-Examples of ketos is fructose. It is also known as _______.
ketohexose
Examples of aldoses are:
Glucose, Galactose, and Mannose
Examples of ketos is:
fructose
are molecules that have the same molecular formula, but have a different arrangement of the atoms in space.
isomers
Examples of isomers:
-Glucose
-Fructose
-Galactose
-Mannose
epimers
are sugars that differ in configuration at ONLY 1 POSITION.
(of course, they are also isomers)
Examples of epimers :
D-glucose & D-galactose (epimeric at C4)
D-glucose & D-mannose (epimeric at C2)
TRIOSE
number of carbons:
formula:
-3
-C3H6O3
TETROSE
number of carbon:
formula:
-4
-C4H8O4
PENTOSE
number of carbon:
formula:
-5
-C5H10O5
HEXOSE
number of carbon:
formula:
-6
-C6H12O6