Nutrition in animals Class 12 Notes | EduRev

Class 12 : Nutrition in animals Class 12 Notes | EduRev

 Page 1


1 
 
NUTRITION IN ANIMALS AND PLANTS (Nutrition in animals) 
Class VII 
Modes of Nutrition: 
 Autotrophic Nutrition Heterotrophic Nutrition 
Definition It is the mode of nutrition in which the organisms 
manufacture their own food by photosynthesis 
using inorganic raw materials like carbon dioxide 
and water in the presence of light and chlorophyll. 
It is also called holophytic nutrition. The 
organisms are called autotrophs or producers.  
E.g. all green plants. 
It is the mode of nutrition in which organisms 
cannot manufacture their own food and depend on 
others for their food. It is also called holozoic 
nutrition since the organisms feed on solid food. 
The organisms are called heterotrophs or 
consumers.  
E.g. all animals and the non-green plants. 
Types of heterotrophs: 
? The animals who feed on plants directly are called herbivores. E.g. Deer, Cow, Goat, Rabbit. 
? The animals who eat the flesh of other animals by killing them are called carnivores. E.g. Lion, Tiger, snakes. 
? The animals who feed on both plants and animals are called omnivores. E.g. Man, Bear, Crow. 
? Heterotrophs that obtain food  by decomposing dead plant and animal matter are called saprophytes or 
decomposers and this mode of heterotrophic nutrition is called saprophytic nutrition. E.g.most fungi, 
bacteria,protozoans and certain plants. 
? Heterotrophs that feed on the flesh of dead animals are called scavengers. E.g. Vultures. 
? The organisms that draw food from other living organisms called hosts by living on or inside their bodies are 
called parasites and this mode of nutrition is called parasitic nutrition. E.g. Malarial parasite, several fungi 
and bacteria. 
Explain: 
Nutrient: Substances in our food that gives us energy or materials needed for growth and development are called 
nutrients. Carbohydrates, Fats,  Proteins, Vitamins and Minerals are the nutrients found in our food. 
Sugars: They are the simple water soluble carbohydrates which have a sweet taste e.g. glucose and fructose. 
Polymer: A very large molecule made up of several units of a small molecule is called a polymer e.g.starch and 
cellulose, which are polymers of glucose. 
Deficiency diseases: Diseases caused due to deficiency of nutrients in our diet are called deficiency diseases 
e.g.Anaemia caused due to deficiency of iron. 
Amino acids: The simplest units of which all proteins are made are called amino acids. 
Roughage: The indigestible form of carbohydrate i.e.cellulose, found in fruits and vegetables is called roughage. It 
adds bulk to the food and  prevents constipation. 
Calorific value of food: The amount of heat released when food is oxidised in the body is called its calorific value. It 
is measured in‘kilocalorie’.(1 kilocalorie = 1000 calories) 
1 calorie: The heat required to raise the temperature of 1gram of water by 1°C is called 1 calorie. 
Food fads: Ideas relating to food that have no scientific basis and which arise out of lack of knowledge are called 
food fads.e.g. ‘An apple a day keeps the doctor away’; ‘Fish is good for the brain’. 
Adulterants(Food additives): The cheap substances or chemicals that are added to the food by the manufacturer or 
supplier to increase its weight or to make it more attractive are called adulterants and the food containing the additives 
is said to be adulterated. E.g. unpermitted colours are added to food items like haldi, edible oil, sweets and pulses. 
Prevention of Food Adulteration Act has been passed by the government to set proper standards for mantaining the 
quality of food being sold. 
Complex carbohydrates are those which are made up of many molecules of glucose. When digested, they break 
down to form glucose e.g.starch. 
CARBOHYDRATES: 
Composition: They are made up of carbon, hydrogen and oxygen. 
Functions: Their main function is to provide energy. Most of the energy in our food comes from carbohydrates. 
Sources: Wheat, rice, maize, potato(sources of starch); Table sugar, ripe mango, grapes(sources of sugars) 
Types of carbohydrates:  (1) Simple carbohydrates e.g. sugars  (2) Complex carbohydrates e.g. starch and cellulose 
Simple sugars are glucose(in grape juice); fructose(in ripe fruits); lactose(in milk); sucrose(in sugarcane). 
Page 2


1 
 
NUTRITION IN ANIMALS AND PLANTS (Nutrition in animals) 
Class VII 
Modes of Nutrition: 
 Autotrophic Nutrition Heterotrophic Nutrition 
Definition It is the mode of nutrition in which the organisms 
manufacture their own food by photosynthesis 
using inorganic raw materials like carbon dioxide 
and water in the presence of light and chlorophyll. 
It is also called holophytic nutrition. The 
organisms are called autotrophs or producers.  
E.g. all green plants. 
It is the mode of nutrition in which organisms 
cannot manufacture their own food and depend on 
others for their food. It is also called holozoic 
nutrition since the organisms feed on solid food. 
The organisms are called heterotrophs or 
consumers.  
E.g. all animals and the non-green plants. 
Types of heterotrophs: 
? The animals who feed on plants directly are called herbivores. E.g. Deer, Cow, Goat, Rabbit. 
? The animals who eat the flesh of other animals by killing them are called carnivores. E.g. Lion, Tiger, snakes. 
? The animals who feed on both plants and animals are called omnivores. E.g. Man, Bear, Crow. 
? Heterotrophs that obtain food  by decomposing dead plant and animal matter are called saprophytes or 
decomposers and this mode of heterotrophic nutrition is called saprophytic nutrition. E.g.most fungi, 
bacteria,protozoans and certain plants. 
? Heterotrophs that feed on the flesh of dead animals are called scavengers. E.g. Vultures. 
? The organisms that draw food from other living organisms called hosts by living on or inside their bodies are 
called parasites and this mode of nutrition is called parasitic nutrition. E.g. Malarial parasite, several fungi 
and bacteria. 
Explain: 
Nutrient: Substances in our food that gives us energy or materials needed for growth and development are called 
nutrients. Carbohydrates, Fats,  Proteins, Vitamins and Minerals are the nutrients found in our food. 
Sugars: They are the simple water soluble carbohydrates which have a sweet taste e.g. glucose and fructose. 
Polymer: A very large molecule made up of several units of a small molecule is called a polymer e.g.starch and 
cellulose, which are polymers of glucose. 
Deficiency diseases: Diseases caused due to deficiency of nutrients in our diet are called deficiency diseases 
e.g.Anaemia caused due to deficiency of iron. 
Amino acids: The simplest units of which all proteins are made are called amino acids. 
Roughage: The indigestible form of carbohydrate i.e.cellulose, found in fruits and vegetables is called roughage. It 
adds bulk to the food and  prevents constipation. 
Calorific value of food: The amount of heat released when food is oxidised in the body is called its calorific value. It 
is measured in‘kilocalorie’.(1 kilocalorie = 1000 calories) 
1 calorie: The heat required to raise the temperature of 1gram of water by 1°C is called 1 calorie. 
Food fads: Ideas relating to food that have no scientific basis and which arise out of lack of knowledge are called 
food fads.e.g. ‘An apple a day keeps the doctor away’; ‘Fish is good for the brain’. 
Adulterants(Food additives): The cheap substances or chemicals that are added to the food by the manufacturer or 
supplier to increase its weight or to make it more attractive are called adulterants and the food containing the additives 
is said to be adulterated. E.g. unpermitted colours are added to food items like haldi, edible oil, sweets and pulses. 
Prevention of Food Adulteration Act has been passed by the government to set proper standards for mantaining the 
quality of food being sold. 
Complex carbohydrates are those which are made up of many molecules of glucose. When digested, they break 
down to form glucose e.g.starch. 
CARBOHYDRATES: 
Composition: They are made up of carbon, hydrogen and oxygen. 
Functions: Their main function is to provide energy. Most of the energy in our food comes from carbohydrates. 
Sources: Wheat, rice, maize, potato(sources of starch); Table sugar, ripe mango, grapes(sources of sugars) 
Types of carbohydrates:  (1) Simple carbohydrates e.g. sugars  (2) Complex carbohydrates e.g. starch and cellulose 
Simple sugars are glucose(in grape juice); fructose(in ripe fruits); lactose(in milk); sucrose(in sugarcane). 
2 
 
Glucose breaks down easily in our body to release energy. Thus, sportsmen and patients are given glucose directly. 
Form of carbohydrate that is absorbed and used by our body is glucose. 
Simplest sugar/carbohydrate/basic unit of all carbohydrates is glucose. 
Form of carbohydrate that is stored in the plants is starch. 
Form of carbohydrate that is present in the cell wall of plants is cellulose. Herbivores can digest cellulose while 
human beings cannot. 
FATS : 
Composition: They are made up of carbon, hydrogen and oxygen. However, the proportion of oxygen is less as 
compared to carbohydrates.  
Functions:  
(1) They are the richest source of energy and give us more energy than cabohydrates. 
(2) They act as an insulator by preventing loss of heat from the body.  
(3) They are stored in our body as a reserve source of energy for future use. 
Sources: All vegetable oils, butter, ghee, oil seeds and nuts. Our body can also synthesise fats from nonfatty foods. 
 FATS OILS 
Physical state at room temperature Solids Liquids 
Sources Obtained from animal sources Obtained from plant sources 
Examples Butter, ghee Vegetable oils grounduts,oil seeds 
? Animals living in cold countries face shortage of food in winters. Therefore, they store fats in the body to meet 
their winter requirement of energy. 
? Camels store fat in their humps since they have to go without food for several days.  
? Plants store oils, mostly in their seeds e.g. mustard, groundnut, coconut. 
? Animals and humans use only a part of the fats that they consume. They store the rest for future use in their 
body under their skin and around various organs. When our body falls short of energy, the body uses this store 
to provide energy. 
? One molecule of fat/oil is made up of 3 molecules of fatty acids and 1 molecule of glycerol. 
PROTEINS: 
Composition: They are made up of carbon, hydrogen,  oxygen and nitrogen. Some proteins may also contain sulphur 
and phosphorus. 
Basic/Simplest unit of proteins are the amino acids. There are 20 types of amino acids which form thousands of 
different types of proteins. 
Sources: Meat, fish, eggs, milk and milk products(animal sources); Pulses, nuts, grams, peas, soyabean(plant sources) 
Functions: 
1. Growth(making new cells) and development;  repair and healing of damaged cells and tissues 
2. Form the main structural substance of animal and plant cells- our skin, muscles, nails and hair are made up of 
proteins. 
3. Haemoglobin is a kind of protein that helps to transport oxygen in our blood. 
4. As enzymes they help in digestion of food. 
5. Help in muscle contracion and clotting of blood 
 
Casein is the protein found in milk; Albumin is the protein found in egg-white. 
VITAMINS: 
Functions: They are needed in small quantities for the metabolic activities of the body. 
Sources: Fruits and vegetables. Our body can synthesise ‘Vitamin D’. It is synthesised by the action of sunlight on 
the fat stored under our skin. 
Types of vitamins:  
 Fat- Soluble Vitamins Water- Soluble Vitamins 
Solubility Soluble in fats , insoluble in water Soluble in water, insoluble in fats 
Examples Vitamin A, Vitamin D, Vitamin E, Vitamin K Vitamin B complex, Vitamin C 
 
 
Page 3


1 
 
NUTRITION IN ANIMALS AND PLANTS (Nutrition in animals) 
Class VII 
Modes of Nutrition: 
 Autotrophic Nutrition Heterotrophic Nutrition 
Definition It is the mode of nutrition in which the organisms 
manufacture their own food by photosynthesis 
using inorganic raw materials like carbon dioxide 
and water in the presence of light and chlorophyll. 
It is also called holophytic nutrition. The 
organisms are called autotrophs or producers.  
E.g. all green plants. 
It is the mode of nutrition in which organisms 
cannot manufacture their own food and depend on 
others for their food. It is also called holozoic 
nutrition since the organisms feed on solid food. 
The organisms are called heterotrophs or 
consumers.  
E.g. all animals and the non-green plants. 
Types of heterotrophs: 
? The animals who feed on plants directly are called herbivores. E.g. Deer, Cow, Goat, Rabbit. 
? The animals who eat the flesh of other animals by killing them are called carnivores. E.g. Lion, Tiger, snakes. 
? The animals who feed on both plants and animals are called omnivores. E.g. Man, Bear, Crow. 
? Heterotrophs that obtain food  by decomposing dead plant and animal matter are called saprophytes or 
decomposers and this mode of heterotrophic nutrition is called saprophytic nutrition. E.g.most fungi, 
bacteria,protozoans and certain plants. 
? Heterotrophs that feed on the flesh of dead animals are called scavengers. E.g. Vultures. 
? The organisms that draw food from other living organisms called hosts by living on or inside their bodies are 
called parasites and this mode of nutrition is called parasitic nutrition. E.g. Malarial parasite, several fungi 
and bacteria. 
Explain: 
Nutrient: Substances in our food that gives us energy or materials needed for growth and development are called 
nutrients. Carbohydrates, Fats,  Proteins, Vitamins and Minerals are the nutrients found in our food. 
Sugars: They are the simple water soluble carbohydrates which have a sweet taste e.g. glucose and fructose. 
Polymer: A very large molecule made up of several units of a small molecule is called a polymer e.g.starch and 
cellulose, which are polymers of glucose. 
Deficiency diseases: Diseases caused due to deficiency of nutrients in our diet are called deficiency diseases 
e.g.Anaemia caused due to deficiency of iron. 
Amino acids: The simplest units of which all proteins are made are called amino acids. 
Roughage: The indigestible form of carbohydrate i.e.cellulose, found in fruits and vegetables is called roughage. It 
adds bulk to the food and  prevents constipation. 
Calorific value of food: The amount of heat released when food is oxidised in the body is called its calorific value. It 
is measured in‘kilocalorie’.(1 kilocalorie = 1000 calories) 
1 calorie: The heat required to raise the temperature of 1gram of water by 1°C is called 1 calorie. 
Food fads: Ideas relating to food that have no scientific basis and which arise out of lack of knowledge are called 
food fads.e.g. ‘An apple a day keeps the doctor away’; ‘Fish is good for the brain’. 
Adulterants(Food additives): The cheap substances or chemicals that are added to the food by the manufacturer or 
supplier to increase its weight or to make it more attractive are called adulterants and the food containing the additives 
is said to be adulterated. E.g. unpermitted colours are added to food items like haldi, edible oil, sweets and pulses. 
Prevention of Food Adulteration Act has been passed by the government to set proper standards for mantaining the 
quality of food being sold. 
Complex carbohydrates are those which are made up of many molecules of glucose. When digested, they break 
down to form glucose e.g.starch. 
CARBOHYDRATES: 
Composition: They are made up of carbon, hydrogen and oxygen. 
Functions: Their main function is to provide energy. Most of the energy in our food comes from carbohydrates. 
Sources: Wheat, rice, maize, potato(sources of starch); Table sugar, ripe mango, grapes(sources of sugars) 
Types of carbohydrates:  (1) Simple carbohydrates e.g. sugars  (2) Complex carbohydrates e.g. starch and cellulose 
Simple sugars are glucose(in grape juice); fructose(in ripe fruits); lactose(in milk); sucrose(in sugarcane). 
2 
 
Glucose breaks down easily in our body to release energy. Thus, sportsmen and patients are given glucose directly. 
Form of carbohydrate that is absorbed and used by our body is glucose. 
Simplest sugar/carbohydrate/basic unit of all carbohydrates is glucose. 
Form of carbohydrate that is stored in the plants is starch. 
Form of carbohydrate that is present in the cell wall of plants is cellulose. Herbivores can digest cellulose while 
human beings cannot. 
FATS : 
Composition: They are made up of carbon, hydrogen and oxygen. However, the proportion of oxygen is less as 
compared to carbohydrates.  
Functions:  
(1) They are the richest source of energy and give us more energy than cabohydrates. 
(2) They act as an insulator by preventing loss of heat from the body.  
(3) They are stored in our body as a reserve source of energy for future use. 
Sources: All vegetable oils, butter, ghee, oil seeds and nuts. Our body can also synthesise fats from nonfatty foods. 
 FATS OILS 
Physical state at room temperature Solids Liquids 
Sources Obtained from animal sources Obtained from plant sources 
Examples Butter, ghee Vegetable oils grounduts,oil seeds 
? Animals living in cold countries face shortage of food in winters. Therefore, they store fats in the body to meet 
their winter requirement of energy. 
? Camels store fat in their humps since they have to go without food for several days.  
? Plants store oils, mostly in their seeds e.g. mustard, groundnut, coconut. 
? Animals and humans use only a part of the fats that they consume. They store the rest for future use in their 
body under their skin and around various organs. When our body falls short of energy, the body uses this store 
to provide energy. 
? One molecule of fat/oil is made up of 3 molecules of fatty acids and 1 molecule of glycerol. 
PROTEINS: 
Composition: They are made up of carbon, hydrogen,  oxygen and nitrogen. Some proteins may also contain sulphur 
and phosphorus. 
Basic/Simplest unit of proteins are the amino acids. There are 20 types of amino acids which form thousands of 
different types of proteins. 
Sources: Meat, fish, eggs, milk and milk products(animal sources); Pulses, nuts, grams, peas, soyabean(plant sources) 
Functions: 
1. Growth(making new cells) and development;  repair and healing of damaged cells and tissues 
2. Form the main structural substance of animal and plant cells- our skin, muscles, nails and hair are made up of 
proteins. 
3. Haemoglobin is a kind of protein that helps to transport oxygen in our blood. 
4. As enzymes they help in digestion of food. 
5. Help in muscle contracion and clotting of blood 
 
Casein is the protein found in milk; Albumin is the protein found in egg-white. 
VITAMINS: 
Functions: They are needed in small quantities for the metabolic activities of the body. 
Sources: Fruits and vegetables. Our body can synthesise ‘Vitamin D’. It is synthesised by the action of sunlight on 
the fat stored under our skin. 
Types of vitamins:  
 Fat- Soluble Vitamins Water- Soluble Vitamins 
Solubility Soluble in fats , insoluble in water Soluble in water, insoluble in fats 
Examples Vitamin A, Vitamin D, Vitamin E, Vitamin K Vitamin B complex, Vitamin C 
 
 
3 
 
 
MINERALS: 
Functions: 
? They are required in very small quantities for regulating growth and development of our body. 
? Minerals like sulphur and phosphorus may be found in some proteins. 
? Minerals are also found in cell membrane, protoplasm and chromosomes. 
? Chlorophyll, the green pigment needed for photosynthesis, also contains minerals. 
WATER: 
? It is the most important constituent of our cells. 
? It accounts for 70% of our body weight and 90% of our blood. 
? It is a universal solvent and therefore all chemical reactions in our body take place in the medium of water. 
Sources: Drinking water, tea, milk, juices, fruits like watermelon and melon. 
ROUGHAGE: 
Sources: Fruits and vegetables, since the cell wall of plants is made up of cellulose that acts as roughage(fibre) for 
our body. 
BALANCED DIET:  A diet which contains all the nutrients i.e. carbohydrates, fats, proteins, vitamins and minerals 
in the right proportion is called a balanced diet. It should include a good amount of water and roughage also. 
Dependance of balanced diet on various factors: 
? People who do physical labour need more carbohydrates than those involved in mental work because they are 
rich in energy. 
? Growing children need more carbohydrates and proteins for extra energy and growth and development of the 
body. 
? A male uses more energy than a female of the same age and therefore needs to consume more calories than the 
female. 
? A pregnant woman requires more nutrients as she has to nourish both herself and the growing embryo. The 
embryo needs amino acids for overall growth, calcium for growth of bones, and iron for blood formation. 
? A nursing mother needs more nutrients because her baby obtains all the necessary nutrients from her milk. The 
baby needs amino acids for overall growth, calcium for growth of bones, and iron for blood formation. 
? People suffering from serious illness need more proteins and vitamins to help them recover from the illness. 
A balanced diet should include the following four categories of food everyday along with water: 
1. Cereals which provide mostly carbohydrates. 
2. Milk or milk products that provide mainly fats and smaller quantities of proteins, minerals and vitamins. 
3. Meat, eggs and pulses that give mainly proteins along with fats and minerals. 
4. Fruits and vegetables which provide carbohydrates, vitamins and minerals. 
Calorie requirement of a 12 year old: 1900 calories per day(girls); 2100 calories per day(boys). 
OBESITY: When the intake of energy rich foods like carbohydrate and fats exceeds the amount of energy used, the 
unutilised food changes to fat and gets deposited in the body. This leads to unnecessary gain in weight and causes 
obesity. 
Risks associated with obesity: High blood pressure, blockage of arteries that could lead to heart attack, diabetes, 
joint pains etc. 
 
 
NOTE: This hand-out covers pg.29 to pg.35(upto nutrition of plants). The following have to be learnt from the book 
itself: 
1. Test for starch(pg.30) 
2. Test for fats(pg.31) 
3. Test for proteins(pg.31) 
4. Table 4.2 and table 4.3(pg.32) 
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