Category: Biology Second Paper

(i) Wax acts as a water resistant layer on the stem, leaves, fruits and flowers of plants.
(ii) Wax acts as a preservative in plant organs.
(iii) Candles are made from wax.
(iv) It is used in cosmetic industry.
(v) Waxy feathers and feathers are water resistant.
(vi) Reduces waxy sensation on leaves and young stems.
(vii) Cutin and suberin coat are formed in the cell wall. Cutin and suberin are waxy substances.
(viii) It is used in fruit preservation.

(i) Wax is colorless and odorless.
(ii) Waxes are insoluble in water, but soluble in organic solvents.
(iii) It is chemically inert.
(iv) Wax remains solid at normal temperature.
(v) It contains saturated fatty acids.
(vi) It is water repellent.
(vii) Its melting point is higher than fat.

Ester of fatty acid and monohydric alcohol with high molecular weight is called wax. Carbon numbers of fatty acids are 14-36 and carbon numbers of alcohols are 16-36. Waxes are insoluble in water, but soluble in organic solvents. It is chemically inert. Remains solid at normal temperature. The stems, leaves, flowers and fruits of plants contain wax. Carnoba wax is produced from the Brazilian palm tree. Different types of wax are – lanolin, beeswax, feather wax, hair wax, bewax, carnoba, sebum, cerumen, suberin etc.

(i) Oils and fats are concentrated sources of energy. They act as a source of energy in the absence of sugar supply.
(ii) Fat cells present in adipose tissue prevent heat loss and maintain normal body temperature.
(iii) Vitamins A, D, E and K are fat soluble vitamins. All these vitamin needs are met by consuming oil-like food.
(iv) Oils and fats are the main sources of fatty acids in the body. It has metabolic and structural functions.
(v) The fat stored in the fruits and seeds of plants is stored as food.
(vi) The oils and fats stored in the seeds are converted into sugars and provide nourishment to the growing embryo.
(vii) Fat increases the risk of heart disease by increasing LDL levels in the body.
(viii) The oil reduces the risk of heart disease by reducing the level of LDL in the body.

Those composed of triglycerides containing saturated fatty acids and solid at normal temperature (20°C) are called fats. Their melting point is high, 70 0C. close to Such as fish oil, butter, ghee, coconut oil, animal fat, olive oil, palm oil and chocolate.

Triglycerides which are composed of unsaturated fatty acids and are liquid at normal temperature (200C) are called oils. Their melting point is very low, 50C. close to Vegetable fats and palm oil have high melting points. Coconut oil coagulates at low temperatures.

Esters of fatty acids and glycerol are called fat solute. It is composed of three molecules of fatty acid and one molecule of glycerol. Hence it is called triglyceride. Excess triglycerides cause atherosclerosis, a disease that causes heart attacks and strokes. Triglycerides are divided into two parts.
(i) Oils: Triglycerides which are composed of unsaturated fatty acids and are liquid at normal temperature (200C) are called oils. Their melting point is very low, 50C. close to Vegetable fats and palm oil have high melting points. Coconut oil coagulates at low temperatures.
(ii) Fats: Those composed of triglycerides containing saturated fatty acids and solid at normal temperature (20°C) are called fats. Their melting point is high, 70 0C. close to Such as fish oil, butter, ghee, coconut oil, animal fat, olive oil, palm oil and chocolate.
Function: Fruits and seeds of plants contain oils and fats as stored food. During germination, oils and fats are converted into carbohydrates and provide food for the growing embryo.

Those lipids which, when broken down or analyzed, yield no other constituents other than fatty acids and glycerol, are called simple lipids.

Those lipids which, when broken down or analyzed, yield no other constituents other than fatty acids and glycerol, are called simple lipids. It is of two types. These are-
1. Triglycerides or Sneha Drovia: Esters of fatty acids and glycerol are called Sneha Drovia. It is composed of three molecules of fatty acid and one molecule of glycerol. Hence it is called triglyceride. Excess triglycerides cause atherosclerosis, a disease that causes heart attacks and strokes. Triglycerides are divided into two parts.
(i) Oils: Triglycerides which are composed of unsaturated fatty acids and are liquid at normal temperature (200C) are called oils. Their melting point is very low, 50C. close to Vegetable fats and palm oil have high melting points. Coconut oil coagulates at low temperatures.
(ii) Fats: Those composed of triglycerides containing saturated fatty acids and solid at normal temperature (20°C) are called fats. Their melting point is high, 70 0C. close to Such as fish oil, butter, ghee, coconut oil, animal fat, olive oil, palm oil and chocolate.
Function: Fruits and seeds of plants contain oils and fats as stored food. During germination, oils and fats are converted into carbohydrates and provide food for the growing embryo.
Functions/importance of oils and fats
(i) Oils and fats are concentrated sources of energy. They act as a source of energy in the absence of sugar supply.
(ii) Fat cells present in adipose tissue prevent heat loss and maintain normal body temperature.
(iii) Vitamins A, D, E and K are fat soluble vitamins. All these vitamin needs are met by consuming oil-like food.
(iv) Oils and fats are the main sources of fatty acids in the body. It has metabolic and structural functions.
(v) The fat stored in the fruits and seeds of plants is stored as food.
(vi) The oils and fats stored in the seeds are converted into sugars and provide nourishment to the growing embryo.
(vii) Fat increases the risk of heart disease by increasing LDL levels in the body.
(viii) The oil reduces the risk of heart disease by reducing the level of LDL in the body.
2. Wax: Ester of fatty acid and monohydric alcohol with high molecular weight is called wax. Carbon numbers of fatty acids are 14-36 and carbon numbers of alcohols are 16-36. Waxes are insoluble in water, but soluble in organic solvents. It is chemically inert. Remains solid at normal temperature. The stems, leaves, flowers and fruits of plants contain wax. Carnoba wax is produced from the Brazilian palm tree. Different types of wax are – lanolin, beeswax, feather wax, hair wax, bewax, carnoba, sebum, cerumen, suberin etc.
Properties of wax
(i) Wax is colorless and odorless.
(ii) Waxes are insoluble in water, but soluble in organic solvents.
(iii) It is chemically inert.
(iv) Wax remains solid at normal temperature.
(v) It contains saturated fatty acids.
(vi) It is water repellent.
(vii) Its melting point is higher than fat.
Functions/importance of wax
(i) Wax acts as a water resistant layer on the stem, leaves, fruits and flowers of plants.
(ii) Wax acts as a preservative in plant organs.
(iii) Candles are made from wax.
(iv) It is used in cosmetic industry.
(v) Waxy feathers and feathers are water resistant.
(vi) Reduces waxy sensation on leaves and young stems.
(vii) Cutin and suberin coat are formed in the cell wall. Cutin and suberin are waxy substances.
(viii) It is used in fruit preservation.

1. Neutral lipids
2. Phospholipids
3. Glycolipids
4. Terpenoids
5. the wax