MOLECULES OF LIFE:
THERE ARE FOUR
MAIN CLASSES OF
ORGANIC COMPOUNDS
ESSENTIAL TO LIFE
1.
2.
3.
4.
CARBOHYDRATES
LIPIDS
PROTEINS
NUCLEIC ACIDS
SEVERAL OF THESE
MOLECULES
ARE CONSIDERED
TO BE
MACROMOLECULES.
A. CARBOHYDRATES:
1.ARE ORGANIC
COMPOUNDS MADE
OF ELEMENTS –
C,H,O
2. EXIST AS
MONOSACCHARIDES,
DISACCHARIDES
AND
POLYSACCHARIDES
3. MONOSACCHARIDES :
HAVE CHEMICAL
FORMULA
C6H12O6
a.ARE SIMPLE SUGARS
INCLUDING:
(1)GLUCOSE –
MAIN SOURCE
OF ENERGY FOR CELLS
(2) FRUCTOSE –
IN FRUIT
3) GALACTOSE –
IN MILK
. SINCE MANY MONOSACCHARIDES HAVE
THE SAME CHEMICAL
FORMULA, THEY ARE
DIFFERENT
STRUCTURALLY.
MOLECULES
WITH THE SAME
FORMULA BUT
DIFFERENT STRUCTURAL
ARE CALLED:
ISOMERS
c. GENERAL CHEMICAL
FORMULA
FOR CARBOHYDRATES
IS
(CH2O) N
4. DISACCHARIDES
a. DOUBLE- SUGAR
b. MADE OF TWO SIMPLE
SUGARS
JOINED THROUGH
A CONDENSATION
REACTION
c. INCLUDES:
(1)LACTOSE: A
COMBINATION
OF GLUCOSE +
GALACTOSE
(2) SUCROSE: A
COMBINATION OF
GLUCOSE +
FRUCTOSE
(3) MALTOSE: A
COMBINATION
OF
GLUCOSE +GLUCOSE
5. POLYSACCHARIDES:
a.COMPLEX MOLECULES
OF THREE OR MORE
MONOSACCHARIDES
b. INCLUDES
(1)GLYCOGEN –
GLUCOSE STORAGE
IN ANIMALS, FOUND
IN THE LIVER
AND IN MUSCLES
– QUICK ENERGY
(2) CELLULOSE – FOUND
IN PLANT CELL WALLS
GIVES STRENGTH AND
RIGIDITY, PEOPLE CANNOT
DIGEST CELLULOSE, YET IT
IS AN IMPORTANT PART
OF A HEALTHY DIET. WHY?
(3) STARCH –
PLANT
STORAGE OF
GLUCOSE
(4) CHITIN – MAKES
UP
EXOSKELETONS
OF
ARTHROPODS
6. Building and breaking down
carbohydrates: both reactions involve
enzymes and water
a. Building – called condensation or
dehydration synthesis:
b. Breaking a disaccharide into two
monosaccharides is called hydrolysis