Tag: lipids
Questions Related to lipids
Long chain molecules of fatty acids are formed by
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Polymerisation of 2 carbon compounds.
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Decomposition of fats.
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Polymerisation of glycogen.
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Conversion of glycogen.
Long chain molecules of fatty acids are formed by polymerisation of 2 carbon compounds. A fatty acid is a carboxylic acid with a long aliphatic tail (chain), which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids that have carbon-carbon double or triple bonds are known as unsaturated. Fatty acids without double bonds are known as saturated. They differ in length as well. Long-chain fatty acids (LCFA) are fatty acids with aliphatic tails 13 to 21 carbons.
Which among the following is a main component of plant cuticle and a fatty acid polyester?
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Agar
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Lignin
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Suberin
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Cutin
Cutin is a polymer which is the main component of the plant cuticle, which covers all aerial surfaces of plants. Cutin consists of $\omega$-hydroxy acids and their derivatives, which are interlinked via ester bonds, forming a polyester polymer of indeterminate size. There are two major monomer families of cutin, the C16 and C18 families. The C16 family consists mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-di hydroxy palmitic acid. The C18 family consists mainly of 18-hydroxy oleic acid, 9,10-epoxy-18-hydroxy stearic acid, and 9,10,18-trihydroxystearate.
Essential fatty acids are
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Arachidonic acid
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Linolenic
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Linoleic acid
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All of the above
- Animals that cannot synthesize fatty acids in the body de novo are called as an essential fatty acid. These (arachidonic acid, linolenic, linoleic acid) are polyunsaturated fatty acids essential for growth and health but are not synthesized in the animal body.
- Linoleic acid is abundant in corn, peanut, cottonseed and soyabean oil and gives rise to other two in the body.
- The deficiency of these fatty acids causes sterility, kidney failure, and skin lesions.
Neutral fat are
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Glycerol
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Fatty acids
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Both A and B
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None of the above
Triglycerides or neutral fats or true fats are the esters of three molecules of fatty acids and one molecule of trihydric alcohol glycerol. Hence, they are also called triglycerides. Oils are liquid at room temperature. They possess either small or unsaturated fatty acid.
What are glycerides of fatty acids?
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Lecithin
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Phospholipids of plasma membrane
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Vegetable oils
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All of the above
Which of the following fatty acid is not synthesized in the human body?
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Glycerol
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Cholesterol
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Linoleic acid
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Both A and B
Linoleic acid (LA) is an essential fatty acid but is not synthesized in the human body. LA is a polyunsaturated fatty acid used in the biosynthesis of arachidonic acid (AA) and thus some prostaglandins, leukotrienes (LTA, LTB, LTC), and thromboxane (TXA). It is found in the lipids of cell membranes. It is abundant in many vegetable oils, comprising over half of poppy seed, safflower, sunflower, corn, and soybean oils.
Wax is ester of fatty acid with
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Long chain dihydric alcohol
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Trihydric alcohol
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Long chain monohydric alcohol
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Short chain monohydric alcohol
Wax is ester of fatty acids with long chain monhydric alcohol. Cholesterol is the type of alcohol found in wax. It is not easily hydrolyzed like fat. It gives protection. It prevents excessive drying. It also provides water resistance. Beeswax, carnuba wax are examples of wax.
A saturated fatty acid is
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With no double bond
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High melting point
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Low melting point
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Both A and B
Saturated fatty acids are the fats that do not contain a double bond between the carbon atoms. Fatty acids chain are straight. Saturated fats are mostly found in animal fats and animal product. It is solid at room temperature e.g., butter. Saturated fatty acids are high melting than unsaturated fatty acids(low melting point and liquid at room temperature). Thus, the correct option is D.
The melting point of unsaturated fatty acids
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Increases with increase in double bonds
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Decreases with increase in double bonds
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Rises in some and falls in others
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There is no relationship between unsaturation and melting point
Unsaturated fats are liquid at room temperature as they have double bonds. Saturated fatty acids have the single bond and are solid at room temperature. Hydrogenation is the process which involves the addition of hydrogen in the presence of nickel, palladium or platinum. On addition of hydrogen, the double bonds of fatty acids are reduced.
Fat is hydrolysed by enzyme lipase to yield
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Fatty acid and amino acids.
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Glycerol and fatty acids.
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Glycerine and water.
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Glycerol and amino acids.
Lipase is a type of enzyme known as hydrolse and is resposible for catalysing the hydrolysis of triglycerides into fatty aids and glycerol.