MCQ on Lipids, Fats & Waxes
Biochemistry MCQ 008
(Multiple Choice Questions in Biology / Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT BET JRF, GATE, ICAR NET, PG Entrance)
(1). Which of the following molecule can act as molecular chaperons for assisting the folding of proteins?
(2). Which of the following macro-molecule can be most structurally diverse among living world?
c. Nucleic acids
(3). Fat storing cells of vertebrates are called
(4). The enzyme abundantly distributed in adipocytes and germinating seeds are
(5). Rancidity of lipids of lipid rich food stuffs is due to:
a. Hydrogenation of unsaturated fatty acids
b. Reduction of fatty acids
c. Oxidation of fatty acids
d. Dehydrogenation of saturation fatty acids
(6). Main function of preen glands in birds is
a. Hormone secretion
b. Fatty acid degradation
c. Wax secretion
d. Pigment synthesis
(7). Which of the following statement is true
a. Oxidative rancidity is observed more frequently in animal fats than vegetable fats
b. Oxidative rancidity is observed more frequently in vegetable fats than animal fats
c. Plants fats ado not undergo oxidative rancidity
d. Oxidative rancidity can be effectively checked by dehydrogenation of fatty acids
(8). Number of milligrams of KOH required to neutralize fatty acid present in 1 g of fat is called
a. Potassium number
b. Acid number
c. Saponification number
d. Iodine number
(9). Saponification number is the number of milligrams of KOH required to saponify 1 g fat. Which of the following statement is true about saponification number?
a. The shorter is the chain length of fatty acids the higher is the saponification number
b. The shorter is the chain length of fatty acids, the lower will be the saponification number
c. The higher the chain saturation of fatty acid, the lower will be saponification number
d. The lower is the saturation of fatty acid, the higher will be saponification number
(10). The degree of unsaturation of lipid can be measured as ____________.
a. Saponification number
b. Iodine number
c. Polenske number
d. Reichert Meissil Number
(11). The number of OH group in fats can be expressed as _____________.
a. Polenske number
b. Reichert-Meissil number
c. Acetyl number
d. Iodine number
(12). Polenske value of fatty acid indicates __________.
a. How much unsaturation is there in the fatty acid
b. Level of saturation in the fatty acid
c. Indication of branching of fatty acid in the fat
d. How much volatile fatty acid can be extracted through saponification
(13). Which of the following is an example for derived lipids?
d. All of these
(14). Naturally occurring fats are ______
a. L types
b. D types
c. An equi-molar mixture of L and D types
(15). Generally fats with unsaturated fatty acids are ____________ at room temperature (25oC)
c. Liquid in the presence of oxygen
d. Liquid in the absence of oxygen
(16). Carnauba wax is an example for __________
a. Liquid wax
b. Soft wax
c. Hard wax
d. Archaebacterial wax
(17). Specific gravity of lipid is________.
(18). Greater the number of carbon atom in chain of fatty acid __________
a. The boiling point will be higher
b. The boiling point will be lesser
c. The melting point will be higher
d. The melting point will be lower
(19). Dietary fats are transported as
c. Lipid globules
d. Oil droplets
(20). Beta-oxidation of fatty acids takes place at
c. Mitochondria and Peroxisome
d. Mitochondria, Peroxisome and ER
Answer key and explanation
1. Ans. (c). Lipids
Chaperons are the biomolecules which assists the folding of proteins. Proteins are the common chaperons in the cells. Very rarely some lipids also acts as molecular chaperon
2. Ans. (d). Lipids
3. Ans. (c). Adipocytes
There are two types of adipocytes: white adipocytes which store white fat and brown adipocytes which stores brown fat. White adipocytes are large and univacuolar containing a single large droplet of lipid surrounded by a thin layer of cytoplasm. The brown adipocytes are plurivauolar containing many lipid droplets and plenty of cytoplasm.
4. Ans. (b). Lipase
Lipase enzyme hydrolyzes the ester bond between glycerol and fatty acid in a fat (lipid) and yield free fatty acids and glycerol. The liberated fatty acid can enter in the beta-oxidation and can yield Acetyl Co-A. Acetyl Co-A can enter into Kreb’s cycle and can yield ATP (energy). Germinating seeds and adipocytes contains fat as reserved food materials.
Human Pancreatic Lipase (HPL) is the lipase enzyme which catalyze the hydrolyze of dietary lipids.
5. Ans. (c). Oxidation of fatty acids
Oxidative breakdown of fats (fatty acids) by the atmospheric oxygen cause rancidity of lipids. The oxidation of lipids generates volatile short chain aldehydes and ketones which have very offensive smell.
6. Ans. (c). Wax secretion
Preen gland is also called as uropygial gland or oil glands, which are found in birds. Preen glands secrete oil called preen oil which is used to coat over the feathers, beaks and body parts.
7. Ans. (a). Oxidative rancidity is observed more frequently in animal fats than vegetable fats
8. Ans. (b). Acid number
9. Ans. (a). The shorter is the chain length of fatty acids the higher is the saponification number
10. Ans. (b). Iodine number
11. Ans. (c). Acetyl number
12. Ans. (d). How much volatile fatty acid can be extracted through saponification
13. Ans. (d). All of these
Derived lipids are lipids derived from simple or compound lipids by hydrolysis.
14. Ans. (a) L-type
15. Ans. (b). Liquid
Unsaturation of fatty acid cause a kink in the chain which disturb the compact packing of molecules and thus fats containing unsaturated fatty acids will be liquid at room temperature
16. Ans. (c). Hard wax
Carnauba wax is also called as Brazil wax and palm wax, is a wax obtained from a palm namely Copernicia prunifera
17. Ans. (b). 0.8
Density of water is 1 (exactly 0.9982). Since the density of fat is less than water, fats float over the water.
18. Ans. (c). The melting point will be higher
19. Ans. (a). Chylomicrons
20. Ans. (b). Mitochondria
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