REFERENCES

REFERENCES
http://www.google.tt/search?q=essential+fatty+acids&hl=en&source=lnms&sa=X&ei=hKppUaqzMsnk4APhtIGQBQ&ved=0CAYQ_AUoAA&biw=1440&bih=806
http://www.google.tt/search?q=essential+fatty+acids&hl=en&source=lnms&sa=X&ei=hKppUaqzMsnk4APhtIGQBQ&ved=0CAYQ_AUoAA&biw=1440&bih=806#hl=en&gs_rn=9&gs_ri=psy-ab&pq=essential%20fatty%20acids&cp=6&gs_id=1f&xhr=t&q=CARBOHYdrates&es_nrs=true&pf=p&sclient=psy-ab&oq=CARBOH&gs_l=&pbx=1&bav=on.2,or.r_qf.&bvm=bv.45175338,d.dmg&fp=b0dee5d54262d165&biw=1440&bih=806
http://www.google.tt/search?q=CELLS&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ei=sq9pUYy3K8Wp4APvpIGgBA&ved=0CEMQsAQ&biw=1440&bih=806
http://www.google.tt/search?q=CELLS&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ei=sq9pUYy3K8Wp4APvpIGgBA&ved=0CEMQsAQ&biw=1440&bih=806#hl=en&tbm=isch&sa=1&q=PROTEINS&oq=PROTEINS&gs_l=img.3..0l10.19427.23554.0.23734.12.11.0.1.1.0.302.1382.3j6j0j1.10.0…0.0…1c.1.9.img.Qit5W17CDlw&bav=on.2,or.r_qf.&bvm=bv.45175338,d.dmg&fp=f95e2fa89d3f2a5e&biw=1440&bih=806
http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/lipids.htm
http://www.google.tt/search?q=CELLS&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ei=sq9pUYy3K8Wp4APvpIGgBA&ved=0CEMQsAQ&biw=1440&bih=806#hl=en&tbm=isch&sa=1&q=AMINO+ACIDS&oq=AMINO+ACIDS&gs_l=img.3..0l10.997.11844.1.13106.30.20.7.3.7.1.253.2688.4j14j1.19.0…0.0…1c.1.9.img.G2qjLw9LGdc&bav=on.2,or.r_qf.&fp=f95e2fa89d3f2a5e&biw=1440&bih=806
MR.JASON MATTHEWS

ESSENTIAL FATTY ACIDS

Essential fatty acis are the acids that humans and other animals must ingest because the requires them for good health but cannot synthesize them. fatty acids are required for biological processes but does not include fat that act only as fuel.
The two essential fatty acids are:
-alpha linolenic acid( omega3 fatty acid)
-linoleic acid (omega 6 fatty acid)

FUNCTIONS OF LIPIDS

Structure
Composed of C, H and O and have a carboxyl – COOH group at
one end.
Saturated fatty acid e.g. Lauric acid
CH3(CH2)10COOH
Monounsaturated fatty acid e.g. Hexadecanoic acid
CH3(CH2)5CH=CH(CH2)7COOH
Glycerol + three fatty acids joined by an ester bond. (May be
three of the same fatty acids or may be different.) Contain many
C-H bonds
Similar to triglycerides but one fatty acid is replaced with a molecule
of phosphoric acid.
Cholesterol forms the basis of all steroids
e.g. oestrogen/testosterone.
Combination of carbohydrate and lipid
Combination of lipid and protein. Large, water-soluble molecules
Non polar, compact
Function
Energy source in most cells. Saturated fats contain more
energy than unsaturated fats because more H, therefore more
to reduce NAD/FAD during respiration. Precursors of all
other lipids. Energy reserve, e.g. in seeds
Form in which fatty acids are transported around the body
and stored (in adipose tissue)
Vital in, for example, desert animals, e.g. camel
Phospholipids form spontaneous bilayer and are therefore
essential components of cell and organelle membranes.
Phospholipids are also components of lung surfactants.
Cholesterol is only found in animals where it is a component
of and provides fluidity to the cell membranes and is a
precursor of bile salts and sex hormones (e.g. oestrogen).
Form hydrogen bonds with water molecules outside the cell
membrane, thus stabilising the membrane. Carbohydrate
portion may be ‘recognised’ by antibodies, hormones, etc.
Transport lipids in the blood. Low density lipoproteins
(LDLs) transport cholesterol from cells into the blood. Highdensity
lipoproteins (HDLs) remove cholesterol from the
blood.
No osmotic effect/cannot diffuse away therefore excellent
storage molecule. Excellent waterproofing, e.g. waxy cuticle
on plant leaf epidermis and in insect exoskeleton. Provide
buoyancy. Subcutaneous fat provides insulation – important
for endotherms.
Properties
May be saturated (no double bonds),
monounsaturated (contain a single double
bond), polyunsaturated (contain multiple
double bonds). Animal fats are mainly saturated
and solid at room temperature. Unsaturated
fats tend to be liquid.
Determined by nature of fatty acids. Animal
triglycerides tend to have (i) larger fatty acids
(ii) more saturated fatty acids than plant lipids.
Hydrolysis of triglycerides yields metabolic
water.
Phosphate-choline ‘head’ of molecule is polar
and hydrophilic. It therefore orientates itself
towards any aqueous medium. The fatty acid
‘tails’ are non-polar and hydrophobic and
therefore orientate themselves away from any
aqueous layer.
Has a hydrophilic (polar) component and a
hydrophobic (non-polar) part and therefore
contributes to the membrane bilayer.
Carbohydrate portion provides cell ‘signature’
allowing recognition.
Polarity confers solubility.
Insoluble in water
Less dense than water
Conduct heat poorly