2nd Part
Q Differentiate between essential and non- essential amino acids. Highlighting the measures you would adopt to improve the protein quality in a vegetarian diet. 8
A The proteins in plant food generally lack one or two essential amino acids and, therefore, are not of good quality. For example, cereals are poor in lysine and rich in methionine. On the other hand, pulses are poor in methionine and rich in lysine. When cereals are combined with pulses in the same meal then the quality of protein improves. Protein quality of-plant foods can be thus improved by the combination of one or more kinds of foods of plant origin. Some examples - a cereal-pulse combination as in dosa (rice, urad dal); dal-roti; rice-dal or (cereal-animal food combinations as in Dalia (milk, broken wheat); rice-fish). This is one of the ways of improving the quality of food proteins.
Food Sources:- nuts and oilseeds (groundnuts, almond, cashew nut, walnut) and pulses (Bengal gram, lentils, green gram, rajma, soybean). Among pulses, soybean is particularly rich in protein.
Q Name the amino acid lacking in pulses and the amino acid lacking in cereals. 2
A Pulses are poor in methionine and Cereals are poor in lysine.
Q Describe the process of digestion, absorption, and utilization of carbohydrates and proteins in our body. 10
A Digestion, absorption, and utilization of Proteins -
Digestion of proteins means the breakdown of these amino acid chains to their constituent amino acids.
Since saliva contains no proteolytic enzyme (enzymes which help in the breakdown of proteins), protein digestion mainly occurs in the stomach and the small intestine. Pepsin, a proteolytic enzyme, present in gastric juice breaks down proteins into smaller amino acid chains. But pepsin itself cannot complete the digestion of proteins. Partly broken down proteins from the stomach are released into the small intestine where further digestion takes place in two steps: I) Breakdown of partly digested proteins into smaller amino acid chains by proteolytic enzymes called proteases. ii) Finally, other kinds of proteolytic enzymes called peptidases act on amino acid chains and convert them to their constituent amino acids.
The metabolism of proteins is essentially the metabolism of amino acids as these are the end products of the process of digestion of proteins. After digestion, amino acids are carried by the blood to the liver. Here amino acids are used in three ways:
a) some of them are used for the building of blood proteins;
b) some are retained in the liver and
c) the rest enter the blood circulation as amino acids. Some of the amino acids remain in circulation and others are taken up by body tissues for protein synthesis whenever needed. It must be emphasized here that only proteins of good quality are maximally utilized by the body for protein synthesis.
Thus the amino acids present in proteins of good quality are used maximum for body protein synthesis. On the other hand, proteins of poor quality are less likely to be used for tissue protein synthesis. These proteins (amino acids) are more likely to be used for other purposes including the release of energy. Like glucose, amino acids can also be oxidized or burnt in the body to produce energy.
Digestion, absorption, and utilization of Carbohydrates -
The digestion of carbohydrates begins in the mouth itself. Saliva contains an enzyme called amylase which is capable of breaking cooked starch into smaller units. However, the time available for this enzyme to break down the starch in the mouth is too short to allow for any significant amount of digestion to take place. The longer one chews the food, the more is the digestion of starch. There are no carbohydrate-digesting enzymes in the stomach. Thus the principal site of carbohydrate digestion is the small intestine. The major carbohydrate-digesting enzyme present here is an amylase secreted by the pancreas. This enzyme is capable of acting on both raw and cooked starch and converts it into smaller units. The next phase of carbohydrate digestion takes place within the cells of the small intestine where three important enzymes complete the process of digestion. These enzymes act on sugars and partially digested starch and ultimately break them up into the simple basic units i.e. glucose, fructose, and galactose.
All the simple sugar units are taken to various body tissues and cells through the bloodstream and are ultimately converted to glucose. Some amount of glucose remains in the blood as blood sugar and is used by the body cells whenever needed to release energy. The process of burning of glucose to release energy can also be termed oxidation of glucose.
The extra glucose (which is not burnt to release energy) is converted to a substance called glycogen which is stored in the liver and muscles. Glycogen is made of long chains of glucose molecules. Glycogen can be broken down to release glucose whenever needed. But only a limited amount of glucose can be stored in the body as glycogen. Once the limit of glycogen storage is reached the remaining excess glucose is converted into fat and is stored in the body.
Q Define the terms of food, nutrient, nutrition, and health. Discuss the relationship between food, health, and disease. 6
A Food - Food refers to anything which nourishes the body. It includes solids, semi-solids, and liquids which can be consumed to sustain the body and keep it healthy. Food is a complex mixture of different nutrients and non-nutrients.
Nutrients - Food is essential because it contains substances that perform important functions in our body. These essential substances contributed by our food are called nutrients. If these nutrients are not present in our food in sufficient amounts, the result is ill health and in some cases, even death. There are over forty essential nutrients that are supplied by the food we eat. These nutrients can be classified into five major categories: proteins, carbohydrates, fats, vitamins, and minerals. Water is important as a nutrient as well as food. Food also contains many substances which are non-nutrients e.g. coloring and flavoring substances in food.
Nutrition - The processes by which the organism ingests, digests, absorbs, transports, and utilizes the nutrients and disposes of their end products is called nutrition. The various aspects of the study of nutrition include the social, economic, cultural, and psychological implications of food and eating.
Health - Health is a state of complete well-being and not just the absence of disease. There are 4 dimensions of health, these are -
Physical health - A person is physically healthy if he or she looks alert is responsive, energetic, attentive, and vigorous.
Mental Health - Mental health implies :
# freedom from internal conflicts
# no tendency of self-condemnation or pity
# ability to adjust to situations and people
# sensitive to the emotional needs of others
# capacity to deal with other individuals with consideration and courtesy
# good control over one's own emotions and doesn’t carry away by the strong feelings of fear, jealousy, anger, or guilt.
Social Health - An individual who recognizes his/ her obligations towards other members of society and is able to relate to other people around him/ her can be described as socially healthy.
Spiritual Health - Spiritual health is more a matter of attitudes and a way of looking at situations and people. Concern for others and a genuine desire to help or be of assistance.
Relationship between food, health, and disease -
Though good food is one of the important factors in ensuring good health, it is not the only one. The food eaten must not only be nutritious but it must be wholesome, clean, and free from harmful germs. If this is not so, the person eating the food would get ill even if the food is nutritious.
When food doesn’t contain the right kind of nutrients it leads to malnutrition. Malnutrition is an impairment of health that occurs because of deficiency,or, excess or imbalance of nutrients. In other words, malnutrition refers to both under-nutrition and over-nutrition. Undernutrition means a deficiency or lack of one or more nutrients and over-nutrition means the excess of one or more nutrients.
Both Under-nutrition and over-nutrition result in ill health. One prominent example of under- nutrition in our country is vitamin A deficiency. When young children do not consume enough vitamin A-rich foods, their eyes are affected and ultimately blindness results.
A disease-related to over-nutrition is extremely overweight or obesity. When a person takes in more energy than he is able to spend on his daily activities. he accumulates fat in the body and his weight increases. If the weight increases substantially, the person becomes obese.
Q a) Discuss the social, psychological & economic aspects of food & eating behavior. 6
Or ( Classification of food based on functions 5)
Or ( Briefly describe the functions of food in our body. 8)
(b) Describe the process of digestion and absorption of food. 6
(c) Explain the functions of proteins. List 2 sources of animal & vegetable proteins. 6
A. a) Classification of food based on functions -
Physiological Functions: - The physiological functions performed by food are the energy-giving, body-building, protective and regulatory functions. The energy-giving function of food is basically performed by two nutrient categories-carbohydrates and fats. The energy released by two nutrient categories is used to perform various activities like sitting, standing, running, beating of the heart, expansion, and contraction of the lungs, etc.
Bodybuilding function implies the growth of cells and tissues and the replacement of worn-out tissues. Proteins help in this process. The other major physiological functions performed by food are the protective and regulatory functions. Protective role implies preventing infection by ensuring the proper functioning of the body systems responsible for fighting infections. Even if a person does develop an infection or any other type of illness, food, and the nutrients it contains facilitate rapid recovery. The food is also responsible for performing regulatory functions which include the beating of the heart, maintenance of body temperature, and the contraction of muscles.
Social Functions:- Food and eating have significant social meanings. Sharing food with any other person implies social acceptance. Food also has important significance during festivities where special food is cooked and is an important means of bringing people together. Food also has religious importance where religious texts and practices strongly recommend some foods while rejecting others. Thus food plays an important role in society.
Psychological Functions: - Food also showcases the emotional gestures like love, security, affection, and attention. Food is also closely associated with our emotions. Food often serves as a reward. When a mother wishes to reward her child for doing well in a test, she may buy him a sweet or ice cream. In this manner, that particular food item brings pleasant feelings in the mind of the child.
b) Digestion of food - Digestion takes place in steps -
Mouth - The process of digestion begins in the mouth where food is chewed by the teeth and mixed with saliva. While the food is still in the mouth, it is acted upon by an enzyme, amylase, which acts only on cooked carbohydrates and partially digests them or breaks them up into smaller units.
Stomach:- The chewed food mixed with saliva then passes into the stomach through the tube-like structure called the esophagus. Here it gets mixed with the gastric juice present in the stomach. Besides enzymes and water, gastric juice also contains small amounts of an acid called hydrochloric acid which makes it acidic in nature. Mixing of food with gastric juice converts the food into a thin soup-like consistency. Gastric juice contains an enzyme Pepsin which acts on proteins and brings about their partial digestion. Other nutrients in food remain chemically unchanged.
Small intestine:- The next step in the digestive tract is the small intestine. The partially digested food passes from the stomach into the small intestine. The small intestine not only contains intestinal juice (which is secreted from the small intestine itself) but also secretions from the liver and pancreas. The secretion from the liver is called bile and from the pancreas is known as pancreatic juice. Bile aids in the digestion and absorption of fats. Both pancreatic and intestinal juices contain enzymes that break down fats, proteins, and carbohydrates into simpler substances. These simple substances ultimately reach the bloodstream.
Large intestine:- The food which is not absorbed in the small intestine along with a large amount of water passes on to the large intestine. Here most of the excess water is reabsorbed and the remaining water and solid matter are eliminated from the body as feces.
Absorption of food - The end products of digestion of food or the nutrients, present in the small intestine can be used by the body only when they enter the bloodstream. This process of movement of digested food or nutrients from the intestinal wall to the bloodstream is termed absorption of food. Most of the nutrients are absorbed from the upper part of the small intestine though some are absorbed from the lower portion.
(c) Functions of protein -
Body-building: Proteins supply amino acids whose main function is building new body tissues and the replacement of worn-out tissues. Thus they help in the growth and maintenance of the body. Even during adulthood worn-out body tissues are continuously replaced. Thus, proteins are required throughout life for the growth and maintenance of the body.
Regulatory and Protective substances: Proteins are also part of some chemical substances which are necessary for the regulation of vital body processes. All enzymes are proteins in nature. Like enzymes, hormones are also chemical substances that are essential for the regulation of some vital body processes. Some of the hormones (like insulin) are proteins. Antibodies that protect the body from illness are also proteins.
Proteins as carriers: Some of the proteins act as carriers and help to transport certain substances from one place to another. One prominent example of a protein carrier is haemoglobin, the red coloured protein-containing substance present in the blood. Haemoglobin carries oxygen from the lungs to various body tissues and carbon dioxide from body tissues to the lungs.
Energy-giving function: Proteins can also be broken down In the body to provide energy. Each gram of protein yields about 4 Kcal. This, however, is not the major function of proteins and only takes place when-the diet does not supply enough energy-giving nutrients such as carbohydrates and fats.
Animal - Meat, fish, poultry
Plant - Soybean, Groundnut, Rajmah
Q Why is dietary fiber important for us? Name four food sources rich in fiber. 7
Or (Why is it important to include dietary fiber in our diet ? 6)
A Fiber is important to us because -
Satiety value: Fibre cannot be broken down chemically in the body because of the unavailability of enzymes. However, in the digestive tract, some components of fiber absorb water. They swell up and make the food residue bulky which gives a feeling of fullness or satisfaction.
Elimination: Fibre also helps in the easy elimination of unabsorbed food in the form of stools or faeces from the body. Fibre present in stools holds water, makes them softer, and thus helps in its elimination. This is how fibre helps in preventing of constipation. Hence, it is advisable to include fibrous food items in our diet like cereals, pulses, and vegetables.
Prevention of diseases like cancer, diabetes, and heart disease: Research studies have indicated that fiber also helps in the prevention of diseases like heart disease, diabetes, cancer of the colon i.e. the large intestine.
Food Sources: Fibre is present in the outer covering of cereals and pulses. The wheat grain, whole wheat flour, and whole pulses (with outer husk) like black gram, rajma, lobia, contain appreciable amounts of fiber. some of the vegetables and fruits are particularly rich in fiber like - lotus stem, green leafy vegetables, ladies finger, peas, beans, brinjal, amla, guava.
Q Cereals and pulses together in a meal help to meet the protein requirement (justify) 5
A The proteins in plant food generally lack one or two essential amino acids and, therefore, are not of good quality. Cereals are poor in lysine and rich in methionine. On the other hand, pulses are poor in methionine and rich in lysine. When cereals are combined with pulses in the same meal then the quality of protein improves. Protein quality of-plant foods can be thus improved by the combination of one or more kinds of foods of plant origin. Cereal-pulse combination as in dosa (rice, urad dal); dal-roti; rice-dal are thus served to improve protein content in it.
Q Interrelationship between nutrition and health 5
Though good food is one of the crucial factors in ensuring the health, it is not the only one. The food eaten must not only be nutritious but it must be wholesome and clean and free from harmful germs. If this is not so, the person eating the food would get ill even if the food is nutritious.
If food doesn’t contain the right amounts of nutrients it leads to malnutrition. Malnutrition is an impairment of health resulting from a deficiency,or, excess or imbalance of nutrients. In other words, malnutrition refers to both under-nutrition and over-nutrition. Undernutrition means a deficiency or lack of one or more nutrients and over-nutrition means the excess of one or more nutrients.
Both Under-nutrition and over-nutrition result in ill health. One prominent example of undernutrition in our country is vitamin A deficiency. When young children do not consume enough vitamin A-rich foods, their eyes are affected and ultimately blindness results.
A disease that we easily relate to over-nutrition is extremely overweight or obesity.
When a person takes in more energy than he is able to spend on his daily activities. he accumulates fat in the body and his weight increases. If the weight increases substantially, the person becomes obese.
Q Carbohydrates 5 (Enumerate the food sources and functions)
A Food Sources - Cereals and millets are the main source of carbohydrates in Indian diets. All cereals like wheat, rice, and millets e.g. jowar, bajra, and ragi contain considerable amounts of starch. So do roots and tubers like potato, tapioca, sweet potato, yam, and colocasia. Fruits like mango, banana, sapota are, however, rich in carbohydrates in the sugar form. Cane sugar or cube sugar and other sweeteners like honey and jaggery are 95 percent to 100 percent carbohydrate (sugar form). Pulses also contain substantial amounts of carbohydrates. However, pulses are more important in our diet as sources of protein.
Functions of Carbohydrates -
Energy giving function: The chief function of carbohydrates is to produce energy for the working of the body. One gram of carbohydrate provides approximately 4 kilocalories (Kcal). Carbohydrate foods arc widely distributed in nature and are the cheapest sources of energy. They usually provide 60-70 percent of the total calories in our diets.
Protein sparing action - An insufficient amount of carbohydrates in the diet will force the body to break down proteins for releasing energy instead of using them for the body's growth and development. Carbohydrates, if taken in sufficient amounts to meet the energy needs of the body, spare proteins for their important basic role in the body i.e. supporting growth and bodybuilding. This particular act of carbohydrates of sparing proteins is termed as the protein-sparing action of carbohydrates.
Utilization of fat - The presence of carbohydrates in the diet prevents the body from breaking down the excess amounts of fat for energy. In case of deficiency of carbohydrates in the diet, more fat will be broken down to meet the energy requirements of the body. However, an excessive fat breakdown can lead to the accumulation of by-products of fat metabolism. This accumulation causes a problem and adversely affect health.
Q Define nutritional status. 2
A Nutritional status represents the health of an individual as influenced by the utilization of nutrients. Example - If a person does not consume enough vitamin C, its levels in the blood will drop and one can predict that the person is likely to get vitamin C
deficiency. This finding can be confirmed by looking at the diet which will reveal very few foods being eaten which are rich in this vitamin.
Q Differentiate between anabolism and catabolism. 2
A Metabolism refers to all the chemical changes that take place in the cells after the absorption of nutrients( end products of digestion). It is of two types- Anabolism represents all the chemical reactions by which simple substances are used to manufacture more complicated ones and catabolism represents all the chemical reactions by which complex substances are further broken down into simpler components.
Q Describe the process of digestion, absorption, and utilization of fats in our body. Functions and food sources . 8
A Food Sources: Food sources of fats and oils include all common fats and oils like ghee, vanaspati, mustard oil, groundnut oil, soya oil, coconut oil. They are almost 100 percent fat. The presence of fat is also evident in other foodstuffs like milk and milk products (curd, paneer, khoa), nuts and oilseeds (almond, groundnut, coconut, mustard seeds), eggs and flesh foods. These are known as fat-rich foods.
Functions - Fats as macronutrients play a crucial role in the body.
Source of energy: Fat is a concentrated source of energy. Each gram of fat provides approximately 9 Kcal. This is more than double the amount of energy supplied by a gram of carbohydrate or protein. Most of the excess fat is stored in the body in specific tissues called adipose tissue. Adipose tissue is present under the skin, and in the abdominal region among others.
Satiety Value: - Fats remain longer in the stomach and take more time to digest. Hence, like fiber, fats also give satiety value.
insulation and padding: Fat is stored in the body in adipose tissues at specific places. Layers of fat are stored under the skin act as an insulator and keep the body warm. A layer of fat is also present around the vital organs of the body like the kidney and the heart. This serves as padding and protects them against injury.
Source of essential fatty acids: Fats serve as sources of essential fatty acids that have important functions in our body.
Carrier of fat-soluble vitamins - Some of the vitamins are soluble in fats and are termed as fat-soluble vitamins. Fats serve as carriers of these fat-soluble vitamins and also aid in their absorption.
Digestion, absorption, and utilization: In the process of digestion, fats are broken down into their constituent components i.e. glycerol and fatty acids. The two enzymes which aid in the digestion of fats are gastric lipase present in gastric juice in the stomach and pancreatic lipase secreted by the pancreas in the small intestine. For the digestion of fats to take place by the action of enzymes a secretion from the liver called bile helps in fat digestion by breaking fat into small droplets. These fat droplets are then acted upon by enzymes. Since bile is not present in the stomach, the action of gastric lipase is not very significant. This is the reason, the main area of fat digestion in the small intestine where pancreatic lipase breaks, them into glycerol and fatty acids aided by the action of bile.
The end products of fat digestion i.e. glycerol and fatty acids which are present in the intestine move towards the intestinal cells. However, the fatty acids cannot enter the intestinal cells as such. Bile salts play an important role in fat absorption. It breakdown the fatty acids into small, tiny water-soluble units called micelles which can easily move into the intestinal cells.
Fatty acids and glycerol then get transported from the intestinal cells to blood circulation. They do not travel directly into the bloodstream but firstly enter the network of vessels (present in the villi of the small intestine) called lymph vessels. Then fatty acids from the lymph vessels enter the heart and from there move into the blood. Blood then carries them either to the adipose tissues where they are stored as concentrated sources of energy or to cells where they are broken down to provide energy.
Q What are fats and oils composed of ? 2
A The major constituent of all fats and oils are fatty acids and glycerol. A molecule of fat or oil has three fatty acids and a molecule of glycerol. This is called a triglyceride. Fats and oils are composed of many triglycerides or fat molecules.
The fatty acids are composed of a chain of carbon atoms with other elements like hydrogen and oxygen. The fatty acids can be classified in three categories on the basis of chain length. There are shorter chain fatty acids (10 or fewer carbon atoms), long-chain fatty acids (12 to 20 carbon atoms), and very-long-chain fatty acids (20 or more carbon atoms).
Q Available carbohydrate (explain) 2
A Carbohydrates like sugars and starches are digestible in the human digestive tract. The energy thus produced is available to perform body functions. These carbohydrates are termed as available carbohydrates.
Q Non-available Carbohydrates 2
A Cellulose and certain other large carbohydrate molecules that cannot be digested in
the human digestive tract is collectively referred to as fiber or non-available carbohydrates.
Q Amino acids (define) 2
A The basic building blocks of proteins are nitrogen-containing units called amino acids. Amino acids are joined or linked together in chains by linkages called peptide linkages. Several hundred or even thousands of amino acids are strung together in specific strands and coils to form proteins.
Q Differentiate between available and non-available carbohydrates highlighting their functions and food sources. 8
A Answered before
Q Enumerate the importance and role of water in our bodies.
A Role of water -
1. Water is a major component of our bodies. It makes up approximately 60 percent of the total weight of an adult and almost 75 percent in the case of the infant. It is the major and essential component of all cells and tissues, though the amount of water present in different body tissues varies.
2) Water is the medium of all body fluids including blood, saliva, digestive juices, urine, faeces, sweat, or perspiration.
3. Water plays an important role in the regulation of body temperature. The normal body temperature is maintained at 98.4* F or 37* C. As heat is produced in the body by the burning of carbohydrates, fats, and proteins. Water helps to distribute this heat throughout the body. Some amount of heat is used by the body for evaporation of water and thus cools down the body. Thus, the extra heat from the body is lost and body temperature is maintained.
4. Water is a universal solvent. It dissolves all the end products of digestion and carries them to various parts of the body via the blood. Similarly, it helps in the removal of waste products from the body. This property of water makes it essential for all the chemical reactions which are taking place in the body.
5) Water bathes the body cells and keeps them moist. Hence it acts as a lubricant. Water present in saliva and other digestive juices helps in the passage of food down the digestive tract. It also acts as a lubricant for the joints.
Sources -
1 The availability of water is in the form of drinking liquids like tea, coffee, milk, juices, etc.
2 Water is also present in various foodstuffs where it is available in hidden or invisible forms.
3. Water is also formed in the body due to the metabolism of nutrients. Some amount of water is formed in the body due to the metabolism of carbohydrates. Similarly, the metabolism of fats and proteins also contributes water to the body.
Q Discuss the physical, mental and social dimensions of health. Explain how these dimensions are inter-related. 6+2=8
A Health - Health is a state of complete well-being and not just the absence of disease. There are 4 dimensions of health, these are -
Physical health - A person is physically healthy if he or she looks alert. It is responsive, energetic, and vigorous.
Mental Health - Mental health implies :
# freedom from internal conflicts
# no consistent tendency to condemn or pity oneself
# a good capacity to adjust to situations and people
# sensitivity to the emotional needs of others
# # capacity to deal with other individuals with consideration and courtesy
# good control over one's own emotions without constantly giving in to strong
# feelings of fear, jealousy, anger, or guilt.
Social Health - An individual who recognizes his/ her obligations towards other members of society and is able to relate to other people around him/ her can be described as socially healthy.
Spiritual Health - Spiritual health is more a matter of attitudes and a way of looking at situations and people. What is important is a concern for others and a genuine desire to help and be of assistance.
A person may not be suffering from any disease and yet may not enjoy complete well-being. There are so many times when we feel tired or exhausted and incapable of concentrating on our work. At such times we are not enjoying complete well-being, even though at other times we do.
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