1. CHAPTER 4 : CHEMICAL COMPOSITION OF THE CELL

2. L E A R N IN G
• To O U theCelementsEin
state
T OM S
lipids.
• To state the main types of
lipids.
• To state the components of fats
& oils.
• To explain the formation &
breakdown of fats & oils.
• To compare & contrast saturated
fats & unsaturated fats.

3. • E le m e nts : C , H & O
• Typ e s of lip id s : fats, oils, waxes,
phospholipids, steroids (cholesterol,
testosterone, oestrogen, progesterone)
• F ats & oils are p lace d in a cate gory
calle d triglycerides.
• 3 cate gorie s of lip id s : monoglycerides,
diglycerides, triglycerides

4. • Fats  solid in room
temperature (high
melting point)
• Oils  liquid in room
temperature (lower
melting point)
• Triglyceride  made up
of one glycerol & 3
fatty acids.

6. • 1 Glycerol + 1 fatty acid 
monoglyceride + 1 water
• 1 Glycerol + 2 fatty acids 
diglyceride + 2 water
• 1 Glyceride + 3 fatty acids
 triglyceride + 3 water
• The formation of fats & oils
involves the reaction of
condensation between
glycerol & fatty acids

7. • In the presence of enzymes, three fatty
acids become covalently bonded to one
glycerol & produces 3 molecules of
water.
• The breakdown of fats & oils 
hydrolysis + enzymes  glycerol & fatty
acids.

9. S A TU R A TE D &
U N S A TU R A TE D F A TS
• Saturated fats : contain
saturated fatty acids (do not
have any double bond between
the carbon atoms) SOLID FORM
AT ROOM TEMPERATURE, 27OC
(butter)
• Unsaturated fats : contain
unsaturated fatty acids (at
least one double bond between
the carbon atoms) LIQUID FORM
AT ROOM TEMPERATURE, 27OC
(corn oil, palm oil)

11. COMPARISON
S A TU R A TE D F A T U N S A TU R A TE D
S IM ILAR ITIE S F A T
BO TH are triglyce rid e & contain fatty acid s .
d iffe re nce s
C ontain s atu rate d fatty acid C ontain u ns atu rate d fatty acid
Its C arb on ch ain contains m ax. Its carb on ch ain is not
nu m . of h yd roge n s atu rate d with h yd roge n.
S ingle b ond b e twe e n carb on At le as t 1 D ou b le b ond
atom s b e twe e n carb on atom s
(-c-c-) (-c= c-)

12. COMPARISON
(cont.)
d iffe re nce s
S olid at room te m p e ratu re Liqu id at room te m p e ratu re
H igh m e lting p oint Low m e lting p oint
Incre as e th e le ve l of D e cre as e th e le ve l of
ch ole s te rol in th e b lood ch ole s te rol in th e b lood
Incre as e th e ris k of h e art D oe s not incre as e th e ris k of
d is e as e s h e art d is e as e s
E xam p le : anim al fats (lard , E xam p le : ve ge tab le oils
b u tte r) (p alm oil, corn oil)

13. YAHOOO!
!