Lipid:
- The lipids are important constituents of the diet because of their high energy value and also because of the fat-soluble vitamins and the essential fatty acids found with the fat of the natural foodstuff.
- Definition: the lipids are a heterogeneous group of compounds related to fatty acid and include fats, oil, waxes, and other related substances. these are oily or greasy organic substance, relatively insoluble in water, and considerably soluble in organic solvents like ether, chloroform, and benzene. they are, thus hydrophobic in nature, this is called lipoids or lipids.
- The lipid was first used by the German biochemist Bloor in 1943 for a major class of tissue components.
- so let see its the basic classification
Classification of lipids:
- Simple lipids or Homolipids
- Compound lipids or Heterolipids
- Derived lipids
A) Simple lipids: These are esters of fatty acids with some alcohols
- Fats and oils (triglycerides, triacylglycerols): These are esters of fatty acids with trihydroxy alcohol, glycerol. a fat is solid at ordinary room temperature whereas oil is liquid.
- Waxes: These are esters of fatty acids with high molecular weight monohydroxy alcohols.
B) Compound lipids or Heterolipids: These are esters of fatty acids with alcohol and possess additional groups also.
- phospholipids(phosphatides): These are compounds containing, in addition to fatty acids and glycerol, a phosphoric acid, nitrogen bases, and other substituents.
- Glycolipids (cerebrosides): these are the compound of fatty acids with carbohydrates and contain nitrogen but no phosphoric acid. the glycolipids also include certain structurally-related compounds comprising the groups, gangliosides, sulfolipids, and sulfatides.
C) Derived lipids: These are the substances derived from simple and compound lipids by hydrolysis. these include fatty acids, alcohols, mono- and diglycerides, steroids, terpenes, and carotenoids.
- Glycerides and cholesterol esters, because of their uncharged nature, are also called as neutral lipids. however, Cann and Stumpf 1976 have traditionally classified lipids into following 6 classes 1) Acyl glycerol 2)waxes 3) Phospholipids 4) sphingolipids 5) Glycolipids 6) Terpenoid lipids including carotenoids and steroids
1. This molecule acts as molecular chaperones to assist the folding of proteins
(a) Vitamins
(b) Carbohydrates
(c) Amides
(d) Lipids
Answer: (d)
2. Which of these is not a lipid?
(a) Fats
(b) Oils
(c) Proteins
(d) Waxes
Answer: (c)
3. The abundantly distributed enzyme in germinating seeds and adipocytes is
(a) Lipase
(b) Proteases
(c) Cellulase
(d) Nuclease
Answer: (a)
4. Beta-oxidation of fatty acids occurs in
(a) Peroxisome
(b) Peroxisome and Mitochondria
(c) Mitochondria
(d) Peroxisome, Mitochindria and ER
Answer: (C)
5. An example of ____________ is Carnauba wax
(a) Soft wax
(b) Liquid wax
(c) Hard wax
(d) Archaebacterial wax
Answer: (c)
6. In fats, the number of OH groups can be expressed as
(a) Reichert-Meissil number
(b) Polenske number
(c) Iodine number
(d) Acetyl number
Answer: (d)
7. Rancidity of lipids of lipid-rich foodstuff is because of
(a) Reduction of fatty acids
(b) Hydrogenation of unsaturated fatty acids
(c) Dehydrogenation of saturated fatty acids
(d) Oxidation of fatty acids
Answer: (d)
8. This is an example of derived lipids
(a) Terpenes
(b) Steroids
(c) Carotenoids
(d) All of the above
Answer: (d)
9. The degree of unsaturation of lipids can be measured as
(a) Iodine number
(b) Saponification number
(c) Reichert Meissel number
(d) Polenske number
Answer: (a)
10. The specific gravity of lipid is
(a) 1.5
(b) 1.0
(c) 0.8
(d) 0.2
Answer: (c)
11. Which of the following macro-molecules can be most structure diverse among living world
(a) Carbohydrates
(b) Proteins
(c) Nucleic Acids
(d) Lipids
Answer: (d)
12. Fat storing cells of vertebrates are called.... .
(a) Hepatocytes
(b) Asterocytes
(c) Adipocytes
(d) Melanocytes
Answer: (c)
13. Main function of preen glands in birds is
(a) Hormone Secreation
(b) Fatty acid degradation
(c) Wax secretion
(d) Pigment Synthesis
Answer: (c)
14. 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 are not undergo oxidative rancidity
(d) Oxidative rancidity can be effectively checked by dehydrogenation of fatty acids
Answer: (a)
15. Number of miligrams of KOH required to neutralize fatty acid present in 1g of fat is called
(a) Potassium number
(b) Acid number
(c) Saponification
(d) Iodine Number
Answer: (b)
16. Saponification number is the number of miligrams of KOH required to saponify 1g 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
Answer: (a)
17. The degree of unsaturation of lipid can be measured as...
(a) Saponification number
(b) Iodine Number
(c) Polenske Number
(d) Reichert Meissil Number
Answer: (b)
18. The number of OH group in fats can be expressed as...
(a) Polenske number
(b) Reichert- Meissil number
(c) Acetyl Number
(d) Iodine Number
Answer: (C)
19. 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.
Answer: (d)
20. Which of the following is an example for derived lipids?
(a) Steroids
(b) Terenes
(c) Carotenoids
(d) All of these
Answer: (d)
21. Naturally occuring fats are....
(a) L- type
(b) D- type
(c) An Equi-molar mixture of L&D types
(d) Symmetric
Answer: (a)
22. Generally fats with unsaturated fatty acid are........ at room temperature (25').
(a) Solid
(b) Liquid
(c) Liquid in the presence of oxygen
(d) Liquid in the absence of oxygen
Answer: (b)
23. Carnauba wax is an example for...
(a) Liquid wax
(b) Soft wax
(c) Hard Wax
(d) Archaebacterial Wax
Answer: (c)
24. 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
Answer: (c)
25. Dietary fats are transported as ..
(a) Chylomicrons
(b) Liposomes
(c) Lipid Globules
(d) Oil droplets
Answer: (a)
26. Beta- oxidation of fatty acids takes place as
(a) peroxisome
(b) mitochondria
(c) mitochondria and Peroxisome
(d) Mitochondria, Peroxisome and ER
Answer: (b)
27. Which among the following is not a lipid?
(a) Oils
(b) Proteins
(c) Fats
(d) Waxes
Answer: (b)
28. Unsaturated lipid fats are usually derived from which source out of the options given?
(a) Plant species
(b) Human beings
(c) Aquatic animals
(d) None of the above
Answer: (a)
29. What are the components of a triglyceride molecule
(a) One glycerol and one cholesterol
(b) One Glycerol and two fatty acids
(c) One cholesterol and two fatty acids
(d) One glycerol and three fatty acids
Answer: (d)
30. Which of the following is a characteristic of lipids:
(a) They are composed of nitrogenous chains
(b) They are not soluble in water
(c) They are either fats or oils
(d) They are polar molecules
Answer: (b)
31. Which of the following occurs when hydrogen is reacted with vegetable oil?
(a) The hydrogenated vegetable oil, will contain fewer trans fats
(b) The hydrogenated vegetable oil will become solid at room temperature
(c) The hydrogenated vegetable oil will become polorized
(d) The hydrogenated vegetable oil will become a saturated fat.
Answer: (b)
32. How are triglycerides formed:
(a) Triglycerides are formed through dehydration synthesis, which results in the addition of H2O molecules.
(b) Triglycerides are formed through hydrolysis which results in the production of H2O molecules?
(c) Triglycerides are formed through dehydration sysnthesis, which results in the loss of H2O molecules.
(d) Triglycerides are formed through hydrolysis, which results in the loss of H2O molecules.
Answer: (c)
No comments:
Post a Comment
problem related comment