Category: Biology Second Paper

In the dehydration reaction, one molecule of glycerol and three molecules of fatty acid combine to form simple lipids called triglycerides. Triglyceride is an alcohol. It contains 3 carbon and 3 hydroxy groups. Fatty acids are hydrocarbon chains and contain carboxyl groups. Linkage of OH side group through dehydration reaction of carboxyl group is called ester linkage. There are two types of triglycerides. Saturated or unsaturated and unsaturated. Dr. Siddiq Publications

Triglyceride or Fatty acids : Definition, classification and function
In the dehydration reaction, one molecule of glycerol and three molecules of fatty acid combine to form simple lipids called triglycerides. Triglyceride is an alcohol. It contains 3 carbon and 3 hydroxy groups. Fatty acids are hydrocarbon chains and contain carboxyl groups. Linkage of OH side group through dehydration reaction of carboxyl group is called ester linkage. There are two types of triglycerides. Saturated or unsaturated and unsaturated. Dr. Siddiq Publications
1. Saturated
A fatty acid whose hydrocarbon chain is joined by a single bond (C-C) is called a saturated fatty acid. Its molecular symbol is CH3(CH2)nCOOH (n=18). It accumulates in the artery walls and stops blood flow. The result is heart disease. Such as lauric acid, palmitic acid, stearic acid, linoseric acid etc.
Properties of saturated fatty acids
(i) Carbon atoms of saturated fatty acids are joined by covalent bonds.
(ii) Its melting point is relatively high.
(iii) It is not an essential fatty acid.
(iv) It is high in animal fat.
(v) It remains solid at normal temperature (200C).
2. Unsaturated
Fatty acids that have a double or triple bond (C=C) in their hydrocarbon chain are called unsaturated fatty acids. Humans and mammals cannot form a double bond after the 9th carbon of a fatty acid. So we need to add some unsaturated fatty acids to our diet. This is why linoleic and linolenic acids are called essential fatty acids. Plant-derived unsaturated fatty acids are beneficial for human health. So the lack of nutrients in the body is fulfilled. For example, oleic acid, linoleic acid, linolenic acid etc.
Properties of unsaturated fatty acids
(i) Carbon atoms of unsaturated fatty acids are joined by divalent bonds.
(ii) Its melting point is relatively low.
(iii) It is an essential fatty acid.
(iv) It is high in phytonutrients.
(v) It is liquid at normal temperature (20°C).

Fat soluble vitamins are:
(i) Vitamin-A: Beta-carotene is converted into vitamin-A. Natural vitamin-A is available in liver, milk, ghee, eggs etc. Deficiency of vitamin-A causes dry skin, acne and stunted growth. It maintains the normal functions of the mucous membrane. Beta-carotene causes phototropism. Rhodopsin helps in normal vision of the eye.
(ii) Vitamin-D : Natural vitamin-D is found in liver, ghee, fish oil and eggs. It increases intestinal absorption of calcium and phosphorus. It affects bone mineral deposition. Lack of this causes bone disease.
(iii) Vitamin-E : Vitamin-E is an important antioxidant. Vitamin-E is found in vegetable oils, nuts, seeds, whole grains and wheat. Vitamin-E protects cells from the effects of oxidative damage. Dr. Siddiq Publications
(iv) Vitamin-K : Vitamin-K is found in dark green vegetables. It helps in blood clotting.

Carotenoids are yellow, orange and red lipid pigments. Most carotenoids are tetraterpenoids. About 700 types of carotenoids are found in plants. Humans consume 40-50 types of carotenoids from fruits and vegetables. Plants, algae, fungi and bacteria produce carotenoids. The major carotenoids are alpha-carotene, beta-carotene, beta-cryptoxanthin, G-xanthin, lutein, lycopene, carotene, xanthophyll etc. Beta-carotene is available in egg yolks, carrots, tomatoes, etc.
Functions of carotenoids : Carotenoids play a major role in the absorption of light energy in the process of photosynthesis. Carotenoids obtained from food are stored in the body. Beta-carotene causes phototropism. Rhodopsin gives vision. Dr. Siddiq Publications

Cholesterol is a monohydric secondary alcoholic compound. It is a white and crystalline substance. Cholesterol is insoluble in water, soluble in chloroform, benzene, ether and alcohol. Cholesterol content in plants is very low. Cholesterol is found in potato and potato. Cholesterol is the most abundant in the animal body.
Cholesterol function : It regulates cell membrane permeability. Helps in human blood flow. It reacts with fatty acids to form wax.

Isoprenoid compounds having 3000-6000 carbon atoms are called rubber. It is a type of polyterpene. Its molecular weight is about 3 lakh daltons. Artificial rubber is called gum rubber. It is involved in nearly 80% of the world’s industries. Rubber is found in the latex of tropical plants. Rubber is obtained from plants of the family Euphorbiaceae. Notable rubbers are Para rubber (Hevea brasiliensis), Indian rubber (Ficus elastica), Panama rubber (Castilla elastica), serum rubber (Manihot glaziovii), gutta (Palaquium gutta), chicle (Achras sp.) etc.
Function of Rubber
The importance of rubber is immense in our health, education, food, housing, industry etc. Toys, gloves, erasers, glue, rubber bands, insulators, tires etc. are made from rubber. Combs and buttons are made from gata. Chewing gum is made from gum.

Isoprenoid compounds having 10-40 carbon atoms are called terpenes. Two or more five-carbon isoprene units (C5H8) join to form terpenes (C5H8)n. Two, three, four, five, six, and numerous isoprene units join to form monoterpenes, diterpenes, triterpenes, tetraterpenes, pentaterpenes, hexaterpenes, and polyterpenes, respectively. Monoterpenes are volatile oils. The plant is fragrant due to its presence. Basil leaves, mint leaves (menthol), pinus cells (pinene), lemon (lemnin) etc. contain terpenes. Examples – geraniol, menthol, limonim, proline, camphor, thymol, systrol, pinene, limonene etc.
The action of turpentine
(i) Turpentine is used in the manufacture of varnishes.
(ii) It is used in the preparation of medicines.
(iii) Used in making soft drinks.
(iv) It has extensive use in the manufacture of perfumery and cosmetics.

Isoprenoid compounds having 27-29 carbon atoms are called steroids. Steroids with hydroxyl groups are called sterols. Animal sterols are called zoosterols and plant sterols are called phytosterols. Cholesterol is an important sterol present in the animal body. Important sterols present in plant body are Argosterol (Neurospora and Yeast), Stigasterol (Grape, Coconut and Soybean), Beta Citesterol (Grains), Spinesterol (Spinach and Cabbage), Cholesterol (Potato and Sweet Potato), Digitalin, Zymosterol, Mycosterol etc. Dr. Siddiq Publications
Biological importance of steroids
(i) Steroids act as cell signaling molecules.
(ii) It forms the cell membrane.
(iii) Cholesterol reduces the fluidity of the cell membrane.
(iv) It is a concentrated energy reservoir in the cell. But it does not provide any energy to the body.
(v) Malignant prostate cancer increases when steroid secretion is high.
(vi) Steroids act as sex hormones. Cortisol plays a role in sexual development.
(vii) Cortisol steroid digests carbohydrates and proteins and maintains water and salt balance.
(viii) Used as steroid medicine. Digitalis is used in the treatment of heart disease.
(ix) Argosterol is converted into vitamin-D by exposure to ultra-violet rays.

In the plant body, five-carbon isoprene units are repeatedly added to form compound lipids called terpenoids.

Lipids that are produced from compound lipids are called derived lipids. Such as monoglycerides, diglycerides, fatty acids, fatty alcohols, steroids, terpenes, ketone bodies, rubber, hydrocarbons, chlorophyll, carotenoids, etc.
1. Terpenoids
In the plant body, five-carbon isoprene units are repeatedly added to form compound lipids called terpenoids.
2. Steroids
Isoprenoid compounds having 27-29 carbon atoms are called steroids. Steroids with hydroxyl groups are called sterols. Animal sterols are called zoosterols and plant sterols are called phytosterols. Cholesterol is an important sterol present in the animal body. Important sterols present in plant body are Argosterol (Neurospora and Yeast), Stigasterol (Grape, Coconut and Soybean), Beta Citesterol (Grains), Spinesterol (Spinach and Cabbage), Cholesterol (Potato and Sweet Potato), Digitalin, Zymosterol, Mycosterol etc. Dr. Siddiq Publications
Biological importance of steroids
(i) Steroids act as cell signaling molecules.
(ii) It forms the cell membrane.
(iii) Cholesterol reduces the fluidity of the cell membrane.
(iv) It is a concentrated energy reservoir in the cell. But it does not provide any energy to the body.
(v) Malignant prostate cancer increases when steroid secretion is high.
(vi) Steroids act as sex hormones. Cortisol plays a role in sexual development.
(vii) Cortisol steroid digests carbohydrates and proteins and maintains water and salt balance.
(viii) Used as steroid medicine. Digitalis is used in the treatment of heart disease.
(ix) Argosterol is converted into vitamin-D by exposure to ultra-violet rays.
3. Terpins
Isoprenoid compounds having 10-40 carbon atoms are called terpenes. Two or more five-carbon isoprene units (C5H8) join to form terpenes (C5H8)n. Two, three, four, five, six, and numerous isoprene units join to form monoterpenes, diterpenes, triterpenes, tetraterpenes, pentaterpenes, hexaterpenes, and polyterpenes, respectively. Monoterpenes are volatile oils. The plant is fragrant due to its presence. Basil leaves, mint leaves (menthol), pinus cells (pinene), lemon (lemnin) etc. contain terpenes. Examples – geraniol, menthol, limonim, proline, camphor, thymol, systrol, pinene, limonene etc.
The action of turpentine
(i) Turpentine is used in the manufacture of varnishes.
(ii) It is used in the preparation of medicines.
(iii) Used in making soft drinks.
(iv) It has extensive use in the manufacture of perfumery and cosmetics.
4. Robert
Isoprenoid compounds having 3000-6000 carbon atoms are called rubber. It is a type of polyterpene. Its molecular weight is about 3 lakh daltons. Artificial rubber is called gum rubber. It is involved in nearly 80% of the world’s industries. Rubber is found in the latex of tropical plants. Rubber is obtained from plants of the family Euphorbiaceae. Notable rubbers are Para rubber (Hevea brasiliensis), Indian rubber (Ficus elastica), Panama rubber (Castilla elastica), serum rubber (Manihot glaziovii), gutta (Palaquium gutta), chicle (Achras sp.) etc.
Function of Rubber
The importance of rubber is immense in our health, education, food, housing, industry etc. Toys, gloves, erasers, glue, rubber bands, insulators, tires etc. are made from rubber. Combs and buttons are made from gata. Chewing gum is made from gum.
5. Cholesterol
Cholesterol is a monohydric secondary alcoholic compound. It is a white and crystalline substance. Cholesterol is insoluble in water, soluble in chloroform, benzene, ether and alcohol. Cholesterol content in plants is very low. Cholesterol is found in potato and potato. Cholesterol is the most abundant in the animal body.
Cholesterol function
It regulates cell membrane permeability. Helps in human blood flow. It reacts with fatty acids to form wax.
6. Carotenoids
Carotenoids are yellow, orange and red lipid pigments. Most carotenoids are tetraterpenoids. About 700 types of carotenoids are found in plants. Humans consume 40-50 types of carotenoids from fruits and vegetables. Plants, algae, fungi and bacteria produce carotenoids. The major carotenoids are alpha-carotene, beta-carotene, beta-cryptoxanthin, G-xanthin, lutein, lycopene, carotene, xanthophyll etc. Beta-carotene is available in egg yolks, carrots, tomatoes, etc.
Functions of carotenoids
Carotenoids play a major role in the absorption of light energy in the process of photosynthesis. Carotenoids obtained from food are stored in the body. Beta-carotene causes phototropism. Rhodopsin gives vision. Dr. Siddiq Publications
7. Vitamin
Fat soluble vitamins are:
(i) Vitamin-A: Beta-carotene is converted into vitamin-A. Natural vitamin-A is available in liver, milk, ghee, eggs etc. Deficiency of vitamin-A causes dry skin, acne and stunted growth. It maintains the normal functions of the mucous membrane. Beta-carotene causes phototropism. Rhodopsin helps in normal vision of the eye.
(ii) Vitamin-D : Natural vitamin-D is found in liver, ghee, fish oil and eggs. It increases intestinal absorption of calcium and phosphorus. It affects bone mineral deposition. Lack of this causes bone disease.
(iii) Vitamin-E : Vitamin-E is an important antioxidant. Vitamin-E is found in vegetable oils, nuts, seeds, whole grains and wheat. Vitamin-E protects cells from the effects of oxidative damage. Dr. Siddiq Publications
(iv) Vitamin-K : Vitamin-K is found in dark green vegetables. It helps in blood clotting.