Lipids and their function - class-XI
Description: lipids and their function | |
Number of Questions: 52 | |
Created by: Varsha Mane | |
Tags: bio-chemistry lipids biological molecule chemistry biology biochemistry |
Name the chemical formula.
C$ _{16}$H$ _{32}$O$ _2$
-
Palmitic acid
-
Stearic acid
-
Glycerol
-
Galactose
Palmitic acid or hexadecanoic acid was discovered by Edmond Fremy. It is commonly found in plants, animals and microorganisms.Its chemical formula is CH$ _3$(CH$ _2$)$ _{14}$COOH.It is a saturated fatty acid.
Which of the following is not an essential unsaturated fatty acid
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Oleic acid
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Linoleic acid
-
Linolenic acid
-
Stearic acid
What is a cholesterol?
-
Phospholipid
-
Wax
-
Steroid
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Triglyceride
Steroids are crystallisable lipids having four hydrocarbon rings consisting of three cyclohexane and one cyclopentane ring and a long hydrocarbon side chain. Fatty acids are absent. In animals, sterols are precursors of steroid hormones and vitamin D. Cholesterol is a sterol of animal systems which forms bile salts, is a component of plasma membrane and hormones.
Essential fatty acids were discovered by
-
Evans and Burr
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Bloor
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Sutherland
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Beevers
Essential fatty acids are those fatty acid which plays an important role in the biological process and they can be metabolized easily. These acts as a fuel rather getting deposited as fat in the body. The human body cannot synthesize essential fatty acids. Alpha-linolenic acid and linoleic acid are the two essential fatty acid. It was discovered by Evans and Burr.
Lanolin or wool fat is a
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Hard fat
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Oil
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Wax
-
Sterol
Lanolin is also known as wool fat, wool grease or wool wax. It is secreted by the sebaceous glands of wool-bearing animals. It is obtained by the sheep which has been raised specifically for wool. It helps the sheep to shedd water from their coats and protect them from changing environmental conditions. Wax is a long chain of sterol ester. It is also used in commercial production of lubricants, rust-preventive coatings, shoe polish.
Linoleic is unsaturated fatty acid whose content is highest in
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Cotton oil
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Sunflower oil
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Coconut oil
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Groundnut oil
Unsaturated fats are liquid at room temperature as they have double bonds. The essential fatty acids like alpha-linolenic acid and linoleic acid are unsaturated as they have double bonds. Sunflower oil is a non- volatile oil. It is a mixture of mostly oleic acid (omega-9)-linoleic acid (omega-6). The composition precisely comprises of 59% linoleic acid, oleic acid 30%, stearic acid 6%, and palmitic acid is 5%.
Match the columns:
$a$ | Biological pigments | $1.$ | Sodium chloride |
---|---|---|---|
$b$ | Chemical messengers | $2.$ | Steroids |
$c$ | Important constituent of blood | $3.$ | Prostaglandins |
$d$ | Four carbon rings | $4.$ | Terpenes |
-
$a - 2, b - 4, c - 3, d - 1$
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$a - 2, b - 1, c - 4, d - 3$
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$a - 3, b - 4, c - 2, d - 1$
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$a - 4, b - 3, c - 1, d - 2$
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$a - 3, b - 4, c - 1, d - 2$
Arachidonic acid gives rise to
-
Terpenes
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Prostaglandins
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Gangliosides
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Cerebrosides
A saturated fatty acid is
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Arachidonic acid
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Stearic acid
-
Oleic acid
-
Linoleic acid
Saturated fatty acids have 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 unsaturated fatty acids are reduced to saturated fatty acid. Stearic acid is a saturated fatty acid as it has single carbon bonds. It has eighteen carbon with chemical formula of C$ _{18}$H$ _{36}$O$ _2$. It can be produced by saponification of the triglycerides.
Which one is essential fatty acid?
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Linoleic acid
-
Linolenic acid
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Arachidonic acid
-
All the above
Arachidonic acid and palmitic acids have how many carbons in each of them.
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16, 16
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16, 20
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20, 16
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18, 16
Arachidonic acid contains 20 carbon. it is a polyunsaturated omega-6 fatty acid found in phospholipid of the membrane of cells liver, brain, and muscles.
A fatty acid is unsaturated if it
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Contains hydrogen
-
Contains double bonds
-
Contains an acidic group
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Bonds to glycogen
Unsaturated fat is a fat or fatty acid in which there is one or more double bond in the fatty acid chain. A fat molecule is monounsaturated if it contains one double bond, and polyunsaturated if it contains two or more double bonds.
Which of the following is not a type of fat?
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Polysaturated fat
-
Monounsaturated fat
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Saturated fat
-
Polyunsaturated fat
Answer is option A i.e. "Polysaturated"
Fats are one of the main macro-nutrients. Fats serve both structural and metabolic functions. There are four types of fats: saturated, monounsaturated, trans and polyunsaturated.
1) Saturated fats have no double bonds between the carbons in the chain.
2) Monounsaturated fats have one double bonded carbon in the chain
3) Polyunsaturated fats have multiple double bonds.
4) Trans fats are types of unsaturated fats formed by hydrogenation of oils.
$^{18}$C unsaturated fatty acid with three double bonds is
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Oleic aicd
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Linoleic acid
-
Linolenic acid
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Arachidonic acid
Linolenic acid 18 carbon containing unsaturated fatty acid with three double bonds. It is found in plants and required in the formation of prostaglandin.
Identify the incorrectly matched pair.
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Ferritin - storage protein
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Stearic acid - unsaturated fatty acid
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Tyrosine - aromatic amino acid
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Vinblastin - alkaloid
Fatty acids are of two types based on the single and double bonds in their hydrocarbon chain. The saturated fatty acids have only single bonds in their hydrocarbon chain. These are mostly obtained from an animal source. They exist as solids at room temperature. The unsaturated fatty acids have both the single and double bonds in their hydrocarbon chain. These are mostly derived from plant sources. They exist as a liquid at room temperature.
Omega 3 fatty acid is present in
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Sun flower oil
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Flax seed oil
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Ground nut oil
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Butter
Flaxseed oil contains alpha-linolenic acid (ALA), a form of omega-3 fatty acid that is only converted in small amounts to active forms of omega-3, like EPA and DHA. It is high in Omega-3 Fatty Acids.
Polyunsaturated fatty acid is
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Arachdionic
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Palmitic
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Stearic
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None of the above
Fatty acids with no carbon-carbon double bonds are said to be saturated those with at least one double bonds are unsaturated. Unsaturated fatty acids with more than one carbon-carbon double bond are referred to as polyunsaturated. Two essential polyunsaturated fatty acids are linoleic acid made up of 18 carbon atoms and having 2 double bonds and linolenic acid made up of 18 carbon atoms and having three double bonds. They cannot be synthesized by mammals and must be supplied in their diet. Arachidonic acid is made up of 20 carbon atoms and has four double bonds.
Sporopollenin is chemically a
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Homoplysaccharide
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Fatty substance
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Protein
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Heteropolysaccharide
The wall of the mature pollen grain is stratified. It comprises two principal layers the internal layer is called as intine and the outer layer is called as exine. The intine is pecto-cellulosic in nature. The exine is chiefly composed of a class of material called as sporopollenin. Chemical analysis has revealed that it is a mixture of biopolymers, containing long chain fatty acids, phenylpropanoids, phenolic compounds and carotenoids. It is derived from carotenoids by oxidative polymerization. Sporopollenin is resistant to physical and biological decomposition. Because of this property, the pollen grain walls are often preserved for long periods in fossil deposits.
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
-
Linoleic acid
-
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
-
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
-
Long chain dihydric alcohol
-
Trihydric alcohol
-
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
-
With no double bond
-
High melting point
-
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
-
Decreases with increase in double bonds
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Rises in some and falls in others
-
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.
-
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.
Number of double bonds present in arachidonic acid is
-
$4$
-
$3$
-
$2$
-
$1$
Arachidonic acid is a carboxylic acid which has 20 carbon and four double bonds in the cis configuration. It is a polyunsaturated fatty acid (PUFA). It is mainly present in the membrane phospholipids and in platelets. It is also found in liver, erythrocytes, skeletal muscle, cardiac muscle. Meat, egg, and fish are rich sources of arachidonic acid.
Essential fatty acids occur in
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Animal fat
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Plant oils
-
Fish and fowl
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Both B and C
Essential fatty acids are those fatty acids that body cannot produce on its own and therefore must be supplied from the diet. Two primary essential fatty acids are linoleic acid and alpha-linoleic acid. Linoleic acid (omega-6) occurs in plant oils like corn oil, palm oil, soybean oil, sunflower oil. Alpha-linoleic acid (omega-3) occurs in fowl and fish like salmon, sardines, tuna.
Content of unsaturated fatty acid linolenic acid is highest in
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Sunflower oil
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Cotton seed oil
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Groundnut oil
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Coconut oil
Unsaturated fatty acid is those which contain one or more double bond in their fatty acids. Generally, it is found in plants fats. It also lowers blood cholesterol. Linoleic is unsaturated fatty acid containing two double bonds. Sunflower oil contains highest linoleic acid. Thus, the correct answer is A.
Unsaturated fatty acids have
-
No double bonds
-
High melting point
-
One or more double bonds
-
Disulphide bonds
Number of fatty acid residues present in one molecule of fat is
-
$4$
-
$3$
-
$2$
-
$1$
Fat is stored reserve for the body which provides energy. These are triesters of glycerol. It is obtained from fatty acids and glycerol. It consists of one glycerol molecule and three fatty acid molecules. The carboxyl end of the fatty acid combines with the three -OH groups of the glycerol to form the ester. So, the correct answer is option B.
A fatty acid not synthesised in human body is
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Cholesterol
-
Linoleic acid
-
Glycerol
-
None of the above
The most essential of the fatty acids is
-
Arachidonic acid
-
Palmitic acid
-
Linoleic acid
-
Oleic acid
Fatty acids are of two types, the saturated fatty acids that have single bond across the carbon chain and the unsaturated fatty acids that have one or more double bond across the carbon chain. When there are more than one double bonds, they are called the polyunsaturated fatty acids. These are called the essential fatty acids as they cannot be synthesized in the body and must be supplied through the external source. Linoleic acid and linolenic acid are the essential fatty acids.
Which alcohol is present in fats?
-
Glycerol
-
Butanol
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Ethanol
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Octanol
Hydrolysis of lipids produces
-
Glycerine and glycerol
-
Fatty acids and trihydric alcohol
-
Glycine
-
All the above
Unsaturated fatty acids have
-
Palmitic acid
-
Stearic acid
-
Oleic acid
-
One or more double bonds
An unsaturated fat is a fat or fatty acid in which there is one or more double bond in the fatty acid chain. A fat molecule is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond. Where double bonds are formed, hydrogen atoms are eliminated.
An essential fatty acid is
-
Palmitic acid
-
Arachidonic acid
-
Stearic acid
-
Arachidic acid
Arachidonic acid is not one of
the essential fatty acids. Rather it is conditionally essential fatty acid
which, becomes essential if its precursor, linoleic acid is deficient thereby
resulting in the inability to convert linoleic acid to arachidonic acid.
However, some mammals lack the ability or have a very limited capacity to
convert linoleic acid to arachidonic acid, making it an essential part of their
diets. So, the correct answer is 'Arachidonic acid'.
Higher animals cannot synthesise a few essential fatty acids; these are typically
-
Saturated
-
Branched
-
Unsaturated
-
Cyclic
Higher animals cannot synthesize few fatty acids which are very essential for their growth and development. These fatty acids are typically
-
Saturated
-
Cyclic
-
Unsaturated
-
Branched
An essential fatty acid is
-
Arachidonic acid
-
Arachidic acid
-
Palmitic acid
-
Stearic acid.
Essential fatty acids are those compounds which cannot be synthesized by human and must be ingested externally. Examples of essential fatty acid include linoleic (omega-6 fatty acid) and alpha-linolenic acid (omega-3 fatty acid). Linoleic acid is converted to arachidonic acid. Arachidonic acid is an omega-6 unsaturated fatty acid required by proper functioning of body.
Number of fatty acid residues found in one molecule of fat is
-
1
-
2
-
3
-
4
Fatty acids are long, straight chain carboxylic acids. A fat (or oil) is formed when three fatty acid molecules react with a glycerol molecule to yield a triglyceride. Fats in the body are transported and stored as triglycerides.
Consider the following statements.
a. Cutin is a fatty acid polymer
b. Starch is composed only of glucose residues
Which of the statements given is/are correct?
-
$1$ only
-
$2$ only
-
Both $1$ and $2$
-
Neither $1$ nor $2$
Consider the following fatty acids.
a. Linolenic acid
b. Oleic acid
c. Palmitic acid
d. Stearic acid
Which of these is/are unsaturated fatty acids?
-
$1$ only
-
$1$ and $2$
-
$3$ and $4$
-
$2, 3$ and $4$
Which of the following statements concerning unsaturated fats is correct?
-
They have fewer fatty acid molecules per fat molecule
-
They have double bonds in the carbon chains of their fatty acids
-
They generally solidify at room temperature
-
They contain more hydrogen than do saturated fats having the same number of carbon atoms
When one or more double bonds are present between the carbon chains of the fatty acids it is known as unsaturated fats. They have a large number of fatty acid molecules per fat molecule. Due to the presence of double bonds they contain a lesser number of hydrogen bonds as compared to the saturated fatty acid molecules.
Select the correct option:
-
Oleic acid
-
Linoleic acid
-
Arachidonic acid
-
Palmitic acid
Fatty acids are two main types- saturated and unsaturated fatty acids are without double bonds in their carbon chains. They have higher melting points and are solids at room temperature. They have a general formula of $C _nH _{2n}O _2$,e.g., $C _{16}H _{32}O _2$ (palmitic acid), $C _{18}H _{36}O _2$ (stearic acid).
Which among the following is not a common saturated fatty acids encountered in nature?
-
Butyric acid
-
Palmitoleic
-
Acetic and palmitic
-
None of the above
Fatty acids are carboxylic acids with hydrocarbon chains of 4 to 36 carbons. In some fatty acids, this chain is fully saturated (meaning it cannot accept any more hydrogens) and unbranched; other fatty acids contain one or more double bonds (thus, they can be hydrogenated when the double bonds will get converted into single bonds).
Which one of the following is not an essential fatty acid?
-
Linoleic acid
-
Linolenic acid
-
Arachidonic acid
-
None of the above
Arachidonic acid is not an essential fatty acid because it can be synthesized by the cells in the body from linoleic acid. All the other three are essential fatty acids.
How many of fatty acids/ fats given below do you except to have low melting points and remain as liquids in waters?
Palmitic acid, gingelly oil, arachidonic acid, stearic acid, arachidic acid, tripalmitate
-
One
-
Two
-
Three
-
Four
Which one of the following oils is having maximum content of Polyunsaturated Fatty Acids (PUFA)?
-
Coconut oil
-
Cottonseed oil
-
Soyabean oil
-
Sunflower oil