11th Class Biology Nutritional Requirements

Nutritional Requirements

Category : 11th Class

(1) Food : All living organism needs food, animal are unable to synthesize their own food hence they obtain it from outside sources. Animals require food for three main purposes, such as food as a fuel which provides energy and material for body maintenance, food for movement of body includes muscles contraction etc., food for growth as well as for the synthesis of body substances.

(2) Components of food : These are following types -

(i) Carbohydrates : They are made up of \[C:H:O,\]having H and O in the ratio of 2 : 1 and the general formula is \[{{(C{{H}_{2}}O)}_{n}}.\]

They are the chief source of energy. The source of carbohydrates in our food is cereals and pulses.

Types and examples of carbohydrates

Types of carbohydrate	Examples
Monosaccharides	Glucose (the main blood sugar) Fructose (found in fruits) Galactose (in milk sugar) Deoxyribose (in DNA) Ribose (in RNA)
Disaccharides	Sucrose (table sugar) = glucose + fructose Lactose (milk sugar) = glucose + galactose Maltose = glucose + glucose
Polysaccharides	Glycogen, the stored form of carbohydrate in animals Starch, the stored form of carbohydrate in food Cellulose, part of cell walls in plants; not digested by humans but aids movement of food through intestines

Specific features

(1) Storage amount : 900 gm approx.

(2) Storage site : Chiefly liver and muscles.

(3) Daily requirement : 500 gm approx.

(4) Source : Chiefly cereals (rice, wheat, maize), pulses, potato, fruits, sugarcane, milk, honey, sugar etc.

(5) Caloric value : \[4.1\,\,k\text{ }cal./gm\]

(6) Physiological value : \[4.0\,\,k\text{ }cal./gm\]

Functions of carbohydrates

(1) Carbohydrates, especially glucose, are the main respiratory fuels.

(2) Ribose and deoxyribose sugars are components of nucleic acids (DNA and RNA). Galactose is a structural component of medullary sheath.

(3) Monosugars act as monomers for the formation of disaccharides and polysaccharides.

(4) Starch and glycogen, serve as reserve fuel.

(5) Excess of glucose may also be changed into fats (lipogenesis) and stored in liver, adipose tissue and mesenteries.

(6) Glucose has antiketogenic role as it prevents the incomplete oxidation of fats and formation of ketonic bodies in the blood.

(7) Glucose spares the amino acids for protein synthesis.

(8) Sucrose is the major form in which sugar is transported in the plant body. Sucrose is storage sugar of sugarcane and sugar beet.

(9) Cellulose, hemicellulose etc. are the main components of cell wall of plants.

(10) Chitin is main component of cell wall of fungi and exoskeleton of crustaceans.

(11) Heparin prevents the blood clotting inside the blood vessels (Anticoagulants).

(12) Glycoproteins form a protective layer, glycocalyx, on intestinal cells.

(13) Hyaluronic acid acts as a lubricating fluid in the synovial joints between the limb bones.

(14) Blood antigens like A, B and Rh-factor are glycoproteinaceous and provide immunity to the individual.

(15) Sugars are also important components of some glycoproteinaceous hormones like FSH (Follicular stimulating hormone), LH (Luteinizing hormone) etc. FSH controls gametogenesis while LH controls the ovulation and formation of corpus luteum.

(16) Carbohydrates may be changed into amino acids.

(17) Oligosaccharides of cell membrane help in cellular recognition.

(18) Cellulose forms roughage of food which stimulates the secretion of digestive juices. It also helps in peristalsis.

(19) Cellulose nitrate is used in explosives.

(20) Carboxy-methyl cellulose is used in cosmetics and medicines.

(21) Cellulose acetate is used in preparing cellulose plastics, shatter-proof glass, fabrics etc.

(ii) Lipids and fats : Fats and all fat like substances are called lipids. They are composed of C, H and O. They are insoluble in water but soluble in ether, alcohol, chloroform etc.

Types of lipids in the body

Types of Lipid	Functions
Triglycerides (fats and oils)	Protection, insulation, energy storage.
Phospholipids	Major lipid component of cell membranes.
Steroids
Cholesterol	Minor component of all animal cell membranes; precursor of bile salts, vitamin D, and steroid hormones.
Bile salts	Needed for absorption of dietary lipids.
Vitamin D	Helps regulate calcium level in the body; needed for bone growth and repair.
Adrenocortical hormones	Help regulate metabolism, resistance to stress, and salt and water balance.
Sex hormones	Stimulate reproductive functions and sexual characteristics.
Elcosanodis	Have diverse effects on blood clotting, inflammation, immunity, stomach acid secretion, airway diameter, lipid breakdown, and smooth muscle contraction.
Other Lipids
Fatty acids	Catabolized to generate adenosine triphosphate (ATP) or used to synthesize triglycerides and phospholipids.
Carotenes	Needed for synthesis of vitamin A. which is used to make visual pigments in the eyes.
Vitamin E	Promotes wound healing, prevents tissue scarring, contributes to the normal structure and function of the nervous system, and functions as an antioxidant.
Vitamin K	Required for synthesis of blood-clotting proteins.
Lipoproteins	Transport lipids in the blood, carry triglycerides and cholesterol to tissues, and remove excess cholesterol from the blood.

Specific features

(1) Source : Butter, ghee, liver oil, vegetable cooking oil etc.

(2) Daily requirement : 50 gm.

(3) Storage site : Subcutaneous fat, adipose cells.

(4) Caloric value : 9.45 k cal/gm.

(5) Actual value : 9.0 k cal/gm.

Functions of lipids

(1) The fats acts as concentrated fuel. The caloric fuel value of 1 gm of fats is 9.45 kcal, while the physiological fuel value of 1 gm of fats is 9.0 kcal (37 kJ), which is about 2.25 times more than the energy provided by same amount of glucose.

(2) The fats are also highly suitable for storage as the reserve food material. It is mainly stored in the liver, beneath the skin, in the brown deposits and in the fat bodies. Normally, the fats constitute about 4% of liver by weight.

(3) Fats stored in the subcutaneous tissue insulate the body against the loss of heat energy, so conserve the body heat. Thus, fats help in homeothermy.

(4) Medullary sheath is formed of white fatty substance, myelin, which insulates the nerve fibres and prevents the loss of energy.

(5) Fats from the protective shock absorbing cushions around a number of organs like the eye balls, kidneys (renal fat), ovaries, etc.

(6) These help in the absorption of fat-soluble vitamins like A, D, E and K.

(iii) Proteins : They are composed of C. H. O. N and some of in addition contain S and P. They are complex, versatile, macromolecules with very high molecular weight. Their unit is amino acids. Out of the 20 amino acids, required in human to build proteins, half of them are essential and rest are non-essential amino acid. Essential amino acids are those, not synthesized by human body and are present in food. The non-essential amino acids are those which can be synthesized by human body.

Types of amino acids

Dispensable or Essential amino acids	Non-dispensable or Nonessential amino acids
Arginine	Glycine
Histidine	Alanine
Isoleucine	Serine
Leucine	Aspartic acid
Methionine	Asparagine
Phenylalanine	Cysteine
Threonine	Glutamic acid
Tryptophan	Glutamine
Lysine	Proline
Valine	Tyrosine

Arginine and histidine are considered semi indispensable amino acids. These two are not essential in the adult organisms.

Classification of proteins : They are following types –

(1) On the basis of structure of molecules

(i) Fibrous : Examples - Collagen, myosin, keratin, fibrin of coagulated blood etc.

(ii) Globular : Examples - Albumin, globulin, haemoglobin, enzymes, snake venom etc.

(2) On the basis of their chemical nature : The proteins are divided into three categories -

(i) Simple proteins : These are formed of peptide chains and yield only amino acids on hydrolysis. On the basis of shape, these may be fibrous proteins e.g. collagen of white fibres, elastin of yellow fibres, keratin of exoskeletal structures like nails, horns, hoofs, hair, feather etc.; globular proteins e.g. albumins and globulin of blood plasma, protamines, histones, glutelins etc.

(ii) Conjugated proteins : These are formed of a proteinaceous and a non-proteinaceous prosthetic group. These include nucleoproteins (of chromosomes-DNA and proteins; and ribosomes-RNA and proteins), glycoproteins (of blood-antigens), phosphoproteins (casein of milk), lipoproteins (lipovitellin of egg-yolk), chromoproteins (haemoglobin of RBCs), haemocyanin, rhodopsin (visual purple), iodopsin (visual violet), cytochromes), metalloproteins (carbonic anhydrase enzyme with\[Z{{n}^{2+}}\]) etc.

(iii) Derived proteins : These are formed by the partial hydrolysis of simple proteins and include peptones, proteoses etc.

Specific features

(1) Source : Chief source is pulses, egg, milk, meat, fish, leafy vegetables, soyabean, groundnut etc.

(2) Daily requirement : \[70-100gm.\]

(3) Caloric value : \[5.6k\text{ }cal/gm.\]

(4) Physiological caloric value : \[4k\text{ }cal/gm.\]

Types and functions of protein

Types of Protein	Functions
Structural	Form structural framework or various parts of the body. Examples : Collagen in bone and other connective tissues, and keratin in skin, hair, and fingernails.
Regulatory	Functions as hormones that regulate various physiological processes; control growth and development; as neurotransmitters, mediate responses of the nervous system. Examples : The hormone insulin, which regulates blood glucose level, and a neurotransmitter known as substance P, which mediates sensation of pain in the nervous system.
Contractile	Allow shortening of muscle cells, which produces movment. Examples : Myosin and actin.
Immunological	Aid responses that protect body against foreign substances and invading pathogens. Examples : Haemoglobin, which transports most oxygen and some carbon dioxide in the blood.
Catalytic	Act as enzymes that regulate biochemical reactions. Examples : Salivary amylase, sucrase and ATPase.

(iv) Nucleic acids : These are compounds of carbon, hydrogen, oxygen, nitrogen and phosphorus. These occur in all body cells and transmit coded informations of all morphological and functional hereditary characteristics from one generation to the next. The molecules of nucleic acids are long-chain polymers of nucleotide monomers. These megamolecules are called polynucleotides. These are the largest and most complex molecules of nature.

Nucleic acids are of two types - Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Only nine types of nucleotide monomers occur in cells; only four of these link by “phosphodiester bonds” forming polynucleotide chains (megamolecules) of DNA and another four of RNA. Each nucleotide is itself a complex molecule formed by linking of a nitrogenous base, a pentose sugar and a phosphate group. “Phosphodiester bonds” are also dehydration or condensation linkages. Hence, in digestion, nucleic acids of food are hydrolysed first into nucleotides. Then the nucleotide molecules are further degraded to their component nitrogenous bases, pentose sugars and phosphate groups.

(v) Water : Water is an essential constituent of protoplasm, which forms the physical basis of life, though it does not yield any energy. The water is an inorganic compound, composed of hydrogen and oxygen in the ratio of 2 : 1. Protoplasm has nearly about 70-90% water, but the human body has approximately \[6070%\] of water.

Specific features

(1) Sources : Metabolic water, liquid food and drinking water.

(2) Daily requirement : \[5-6\]

glasses (4-5 litre).

Functions

(1) Water act as a best solvent.

(2) Involve in so many metabolic process.

(3) Act as temperature stabilizer.

(4) Remove excess of body heat through sweating.

(5) It also act as dispersion medium ioniser, diffusion medium.

(vi) Vitamins

Historical review

I. Lunin (1881) discovered vitamins. The term ‘vitamin’ was first used by Funk in 1912. Hopkins and Funk (1912) propounded a ‘vitamin theory’.

Definition : Vitamin are complex organic compounds needed daily in minute quantities and act as growth and metabolic regulatory substances.

Sources : Vitamins can only be synthesized by green plants, hence animals depend for their vitamin requirement upon the plants. Human body manufactures vitamin D using ultraviolet rays of sunlight and can store A, D, E, K and \[{{B}_{12}}.\]

The chemical compositions of vitamins are known and it is possible to synthesize them.

Importance : The vitamins are not a sources of energy. They regulate the various metabolic processes. They mostly act as the constituents of coenzymes in the cells.

Types : Vitamins are divided into two groups –

(a) Fat soluble vitamin : A, D, E and K.

(b) Water soluble vitamin : B complex and C.

Fat soluble vitamins

Name of vitamins and chemical formula	Discovery	Sources	Daily requirement per day	Functions	Name of Deficiency Disease	Symptoms	Other Features
Vitamin A or Retinol or anti xero-phthalmic or anti infection vitamin	Mc-Collumn and Davis (1913)	Butter, liver oils, egg yolk, mango and orange, carrot, yellow, green vegetables.	2 mg	Part of visual pigment, maintenance of epithelia and prevention of keratinization of epithelium. Beta carotene act as Antioxidants.	Xerophthalmia Night blindness or nyctalopia Keratomalacia. Dermatosis	Drying of eyeball Unable to see in dim light Epithelium keratinised Dry scaly skin	Synthesized and stored in the liver. Destroyed by - strong light.
Vitamin D or Ergocalciferol or sunshine vitamin or anti richitic vitamin	Steenbock and Hess 1924)	Cod liver oil, butter, fish, eggs, milk, brain, lung, and spleen.	0.01 mg	Facilitates absorption of calcium and phosphorus by intestine and their retention in body and deposition in bones.	Rickets in children Osteomalacia in adults.	Deformities of bones like bowlegs, pigeon chest Weak bones liable to easy fracture	Synthesized in the body on exposure of skin (7-hydroxy cholesterol) to light. Destroyed by ? oral contraceptives
Vitamin E or a Tocopherol or anti sterility vitamin	Evan and sore (1922)	Fresh green vegetables, meat, yolk, vegetable oils, butter and cheese, peanuts wheat germs.	20 mg	Antioxidant and some role in ETS. DNA / RNA/RBC formation promote wound healing.	Anaemia Sterility Muscular atrophy	Destruction of RBC. In male causes sterility and in female abortion may occur of offspring. Effect not proved in man. Degeneration of muscles	Destroyed by UV ? rays. It is also used for curing tumour and cancer
Vitamin K or Phylloquinone or anti haemorrhagic vitamin	Dam and Droisy (1935)	Fresh green vegetables. tomatoes, liver, soyabean, cheese, egg.	0.07 ? 0.14 mg	Synthesis of prothrombin for normal clotting of blood.	Haemorrhage	Reduced ability of blood to clot and also leads to haemorrhages.	Vitamin K is synthesised by intestinal microbes present in the intestine. Destroyed by?prolonged use of antibiotics.

Water soluble vitamins

Name of Vitamins and Chemical Formula	Discovery	Sources	D.R.	Function	Name of Deficiency Disease	Symptoms	Other Features
Vitamin or Thiamine or anti neuritic or antiberiberi	C. Funk (1926)	Branrice, whole wheat flour, egg, meat, liver yeast etc.		Act as an enzyme in cellular respiration, role in nutrition of nerve cells. Essential for carbohydrate metabolism, protein synthesis and control water balance in body. Major component of co-enzyme carboxylase.	Beri- beri or Dry beri - beri (man) Polyneuritis or wet beri ? beri (animals) Cardiovascular atrophy	Loss of appetite and weight, retarded growth, muscular dystrophy. Nerves to become extremely irritable. Heart enlargement	Beri-beri disease was discovered by Eijkman Destroyed by ? cooking
Vitamin or G or yellow enzyme or Riboflavin or Lactoflavin or ovaflavin or hepatoflavin	Warburg and Christain	Cheese, egg, yeast, meat, liver, cereals, green, vegetable.		Required for cell growth. Form pair of coenzyme (FMN, FAD).	Cheilosis Glossitis Keratitis	Cracking of skin at corners of mouth Inflammation of tongue Inflammation of skin	Stored in liver, Excess of this is eliminated in urine. It is associated with the physiology of vision
Vitamin Yeast factor or pantothenic acid or anti graying factor on chick antidermatitis factor	Williams (1933)	All foods, more in yeast, kidney, liver, egg, meat, milk, ground nut		Part of co-enzyme A. needed for cell respiration, necessary for normal skin and nerves.	Burning feet syndrome, Nervous disorder	Nerve degeneration	It occurs in all types of plants and animal tissues. Its deficiency cause graying of hair
Vitamin or Niacin or Nicotinic acid or pellagra preventing factor	Goldberger (1912)	Fresh meat, liver, fish, milk, cereals, pulses, yeast etc.		It is an essential component of NAD and NADP thus form coenzymes, metabolism of carbohydrates, functioning of gastrointestinal tract and nervous system	Pellagra, Dermatitis, Diarrhoea Dementia Death (4-D syndrome)	Rough skin Inflammation of skin which becomes scaly and papillated Dehydration Neural deterioration which may lead to madness	It is characterised by 3D?s i.e. dermatitis diarrhoea and dementia Destroyed by ? cooking Pellagra preventing factor Goldberger also called Goldberger?s p-p factor It is also synthesized by colon bacteria
Vitamin or pyrido-xine or anti dermatities factor	Gyorgyi (1928)	Brewer?s yeast, liver, egg, yolk, kidney, milk, and vegetables.	2 mg	It is essential component of coenzyme pyridoxal phosphate. It promotes growth in rats used for curing tuberculosis.	Anaemia Dermatitis, paralysis & death of rats. Mental disorder Dermatitis	Nausea, lack of RBC (blood) Disturbance of central nervous system Skin leisons	Term was coined by Gyorgy. Destroyed by ? cooking and oral contraceptives
Vitamin H or or Biotin or coenzyme R or Avidin	Bateman and Allison (1916)	Yeast, vegetables and egg yolk	150-300 mg	It acts as coenzymes and essential for fat synthesis and energy production.	Dermatitis	Scaly and itchy skin	It is synthesized by intestinal bacteria Destroyed by ? prolonged use of antibiotics
Folic Acid or Vitamin M or folacin or Anti anaemic factor	Day (1935)	Green vegetable (spinach) Banana, orange and Liver.	0.4 mg	It forms coenzymes and play essential role in cell metabolism, Necessary for erythropoiesis, required for DNA synthesis.	Megaloblastic anaemia. Sprue	Enlarged RBCs Ulceration of mouth	It is also synthesized by intestinal bacteria Destroyed by - cooking
Vitamin or Cyanocobalamine or Animal protein factor (APF) or Intrinsic factor of castle	Rickets (1948)	Meat, egg, liver, fish, synthesized by intestinal bacteria.	0.003 mg	Required for chromosome duplication and formation of blood corpuscles.	Pernicious anaemia	Reduced formation of erythrocytes in bone marrow	It is also known as anti pernicious factor Also synthesized by intestinal bacteria in human colon Destroyed by ? excessive heat
Vitamin C or Ascorbic Acid	Szent Gyorgyi (1928)	Citrus fruits such as lemon, mango, amla, plumes, guava.	40-60 mg	Functions as part of oxidation-reduction system. Helps in secretion of collagen cement dentine. Helps body to develop resistance to diseases. Helps in absorption of Ca and Fe in the intestine. Wound healing.	Scurvy.	Spongy and bleeding gums, fragile blood vessels and bones.	Required by primates, all other vertebrates and some other invertebrates can synthesize vitamin C. It is the earliest known vitamin. It is wound healing vitamin. Destroyed by heating

Other Types of vitamins, functions and deficiency symptoms

Name of Vitamin	Function	Symptoms of deficiency
Inositol or mouse antialopecia factor	Stimulate growth of mice. Spectacle-eye condition in rat can be treated keep a limit on the cholesterol level in the blood of man.	Causes reduced growth and alopecia (loss of hair) in the mice. Also causes hemorrhagic degeneration of the adrenal gland.
Choline	It is an important lipotropic factor which prevent excessive development of fatty liver. It takes part in the formation of acetylcholine which involved conduction of nerve impulse.	Chronic deficiency causes cirrhosis in the liver also causes haemorrhagic changes in kidney.
Vit.P or citrin	Control the permeability and fragility of the capillary wall to plasma protein works as the co-factor with vitamin C.	Its deficiency causes subcutaneous bleeding due to break down of capillary walls.

(vii) Mineral elements : They forms approximately 4% of body weight. They are essential to regulate the various metabolic activities of the animals. The various types of mineral are group into two categories as minor element. Examples :\[-\,\,\,Ca,\text{ }S,\text{ }P,\]

Na etc. and trace element examples :\[\,\,Cu,\text{ }Zn,\text{ }Mn\]

etc. Some of these minerals are described as follows –

Chart of important minerals required in animal bodies

Mineral elements	Sources	Significance	Effects of deficiency
Minor elements (1) Calcium-Ca	Milk, Cereals, Cheese, Green Vegetables, Pods.	Required for formation of teeth and bones, blood clotting, functions of nerves and muscles.	Weak teeth and bones; retarded body growth.
(2) Phosphorus-P	Milk, Meat, Cereals.	Required for formation of teeth and bones and acid-base balance; component of ATP, DNA, RNA.	Weak teeth and bones; retarded body growth and physiology.
(3) Sulphur-S	Many proteins of food.	Component of many amino acids.	Disturbed protein metabolism
(4) Potassium-K	Meat, Milk, Cereals, Fruits and Vegetables.	Required for acid-base balance; water regulation and function of nerves.	Low blood pressure, weak muscles; risk of paralysis.
(5) Chlorine-Cl	Table Salt.	Required for acid-base balance; component of gastric juice.	Loss of appetite; muscle cramps.
(6) Sodium-Na	Table Salt.	Required for acid-base and water balances and nervous functions.	Low blood pressure, loss of appetite; muscle cramps.
(7) Magnesium-Mg	Cereals, Green Vegetables.	Cofactor of many enzymes of glycolysis and a number of other metabolic reactions dependent upon ATP.	Irregularities of metabolism, principally affecting nervous functions.
(8) Iron-Fe	Meat, Eggs, Pods, Cereals, Green Vegetables.	Component of haemoglobin and cytochromes.	Anaemia weakness and weak immunity.
(9) Iodine-I	Milk, Cheese, Seafood, Iodized salt.	Important component of thyroxin hormone and regulate metabolism of cell.	Goitre, cretinism.
Trace Elements (10) Fluorine-F	Drinking water, Tea, Seafood	Maintenance of bones and teeth.	Weak teeth, Larger amount causes mottling of teeth.
(11) Zinc-Zn	Cereals, Milk, Eggs, Meat, Seafood	Cofactor of digestive and many other enzymes.	Retarded growth, anaemia, rough skin, weak immunity and fertility.
(12) Copper-Cu	Meat, Dry fruits, Pods, Green Vegetables, Seafood.	Cofactor of cytochrome oxidase enzyme. Necessary for iron metabolism and development of blood vessels and connective tissues.	Anaemia, weak blood vessels and connective tissue and damage to central nervous system.
(13) Manganese-Mn	Dry fruits, cereals, Tea, Fruits and Green Vegetables.	Cofactor of some enzymes of urea synthesis and transfer of phosphate group.	Irregular growth of bones, cartilages and connective tissues.
(14) Cobalt-Co	Milk, Cheese, Meat.	Important component of vitamin	Anaemia.
(15) Selenium-Se	Meat, Cereals, Sea food.	Cofactor of many enzymes; assists vitamin E.	Muscular pain; weakness of cardiac muscles.
(16) Chromium-Cr	Yeast, Seafood, Meat, Some vegetables.	Important for catabolic metabolism.	Irregularities of catabolic metabolism and ATP production.
(17) Molybdenum-Mo	Cereals, Pods, Some Vegetable	Cofactor of some enzymes.	Irregular excretion of nitrogenous waste products.

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