1.
Natural lipids are readily soluble in
a.
b.
c.
d.
2.
Which of the following is/are unsaturated fatty acids?
a.
b.
c.
d.
3.
Unsaturated fatty acids
Saturated fatty acids
*Saturated and unsaturated fatty acids
None of these
Which is a phospholipid
a.
b.
c.
d.
7.
Coagulation
*Saponification
Suspension
Colloidal
8. The fats and oils are respectively rich in
a.
b.
c.
d.
6.
*Oils
Solid
Fats
None of these
Hydrolysis of fats by alkalies into fatty acids and glycerol is called
a.
b.
c.
d.
5.
Linoleic acid
Oleic acid
Palmitoleic acid
*All of these
Liquid form of triglycerides at ordinary room temperature are called
a.
b.
c.
d.
4.
Oil
Mercury
Water
*None of these
*Lecithin
Cholesterol
Sterol
Steroid
The number of double bonds in Arachidonic acid
a. 1
b. 2
c. 3
d. *4
8.
Examples of monounsaturated fatty acids are:
a.
b.
c.
d.
*Oleic acid
Arachidonic acid
Palmitic acid
Linolenic acid
9.
Regarding fatty acids, the notation 20:4 indicates ____.( A 20 carbon fatty acid
containing 4 double bonds.)
10.
What are the main types of lipids?
a. The main types of lipids are triglycerides (fats and oils), phospholipids, waxes
and steroids
11.
What is the structural formula of glycerol? To which organic function do these
molecules belong?
a. Glycerol is a linear chain of three carbons; the central carbon is bound to one
hydroxyl radical and to one hydrogen and the two other carbons in the
extremities are bound to a hydroxyl radical and to two hydrogens. Spatial
sides of the hydroxyls are the same.
12.
How are triglycerides made?
a. Triglycerides, fats or oils, are made of three molecules of fatty acids bound to
one molecule of glycerol. Hydroxyls of each one of the three fatty acids and
each hydrogen of the hydroxyls of the glycerol bind to form three molecules of
water that are liberated.
13.
What are phospholipids?
a. Phospholipids are molecules made of glycerol bound to two long molecules of
fatty acids and to one phosphate group. Therefore, phospholipids are
amphipathic molecules, i.e., they have a non-polar portion, due to the long
fatty acid chains, and a polar portion, due to the group phosphate.
b. Phospholipids are the main component of cell membranes. Sphingomyelin,
the substance that forms the myelin sheath of axons in the nervous system, is
a phospholipid too.
14.
What are steroids? What are some examples of steroids with a biological function?
Steroids are lipids based in an angular combination of four carbon rings, three of
them made of six carbons and one ring made of five carbons in the extremity. The
union of each ring to the adjacent ring is made by the sharing of two adjacent
carbons belonging to both rings.
Bile salts, cholesterol, the sexual hormones estrogen, progesterone and testosterone,
the corticosteroids and the pro-vitamin D are examples of steroids.
15.
What are hydrophobic molecules (or hydrophobic molecular regions)? What are
hydrophilic molecules? How can they be characterized in relation to their polarity?
Hydrophobic molecules are those that have little or no tendency to dissolve in water
(hydro = water, phobia = fear). Hydrophilic molecules are those that have great
propensity to dissolve in water (philia = friendship).
Water is a polar substance. Remembering the rule that “equal dissolves equal” one
can conclude that hydrophobic substances are non-polar molecules while hydrophilic
molecules are polar molecules.
16.
Are organic solvents like benzene and ether polar or non-polar substances?
Benzene and the ethers are molecules without electrically charged portions and
thus they are non-polar substances.
17.
What is meant by saturation or unsaturation of oils and fats?
When it is said that a triglyceride is saturated it means that in its molecule the carbon
chain is bound in its maximum capacity to hydrogens, i.e., there are no double or
triple bonds between carbons. These saturated molecules are generally solid fats at
normal temperature.
Unsaturated triglyceride molecules are those in which there are double or triple
bonds between carbons and so they do not accomplish their maximum capacity of
hydrogenation. These unsaturated molecules in general are oils, liquid at normal
temperature.
The terms saturated or unsaturated refer then to the saturation of the carbonic chain
by hydrogen atoms.