Science Notes for CTET 2016
We are hoping that you are giving final touch to your preparations for CTET exam to be held in February 2016 as notified by Central board of secondary Education (the exam conducting body for CTET). Candidates are keen to qualify it to be eligible for being teachers (class I to class VIII) in government schools (state governments conduct their own TET exam). On the other hand, it is an opportunity to improve your performance for those who have already qualified. One of the elective subjects of paper II of CTET is Mathematics and Science (for Mathematics and Science teacher).
Science part of the subject has a weightage of 50 % (30 questions). One of the important topics of science is related to food. In the current article we are giving you few important notes on the topic “food” which may be helpful at the last minute preparations.
Food (carbohydrates, proteins, fats, vitamins, minerals):
Human body needs seven main classes of nutrients which are carbohydrates, proteins, fats, vitamins, minerals, fiber and water. The objective of the present article is to provide important notes on the sources, classification, importance and deficiency diseases of carbohydrates, proteins, vitamins and minerals in this unit.
Carbohydrates are the organic compounds made up of carbon, hydrogen and oxygen.The main sources of carbohydrates are plants, e.g., starch (storage forms carbohydrate of chlorophyll containing plants), sugars, cereals, potatoes, legumes, millets, roots and other vegetables. Sugars are found in fruits, juice, cane, honey, palm, milk, etc.
Carbohydrates may be classified into the following four major groups -
1.Monosaccharides (simplest form of carbohydrates): All carbohydrates are reduced to this state before absorption and utilization.
2.Disaccharide: Disaccharides Consist of two covalently joined monosaccharide units. They are produced as two molecules of the same or different monosaccharides on hydrolysis. Examples are lactose, sucrose, maltose etc.
3.Oligosaccaharides:These consist of few number (2-6) of monosaccharide units. The example is glycoproteins.
4.Polysaccharides: Polysaccharides are composed of many molecules of monosaccharides linked together. The example is Glycerole.
Importance and Functions:
•Glucose act as energy yielding compounds,
•Glycogen acts as important storage of food material of the organism.
•Play a key role in the metabolism of aminoacids and fatty acids.
•Act as protective function-mucosubstance.
•Act as intermediates in respiration and carbohydrates metabolism e.g., (trioses).
•Participate in lipid synthesis.
•Pentoses are used in synthesis of nucleic acid polysaccharides.
Carbohydrate deficiency diseases:
•Diarrhoea and flatulence
Proteins are macromolecules composed of amino acids linked by peptide bond. The elements constituting proteins are carbon (54%), hydrogen (7%), nitrogen (16%), oxygen (22%) and some may contain Sulphur (1%) or phosphorus (0.6%). Hemoglobin, albumin, globulin, enzymes, etc. are all proteins. The main sources of proteins are Peas, pulses,beans, cereals, lentils, milk, cheese, eggs, meat, nuts etc.
•Enzymes - accelerate the rate of metabolic reactions.
•Proteins provide mechanical support both within cells and outside.
•They are the transporters of substances from one part of the body to another.
•Hormones - perform regulatory functions and gene activators.
•Proteins form the machinery for biological movements.
•Act as the defense against infections by protein antibodies, service as toxins, form blood clots through thrombin, fibrinogen and other protein factors.
•Maintain colloidal osmotic pressure of blood.
•Proteins act as acid base balance.
•Hereditary transmission by nucleoproteins of the cell nucleus is done by proteins.
Protein Deficiency Diseases
•Kwashiorkor (Protein malnutrition)
•Marasmic - Kwashiorkor
Normally, Vitamins cannot be synthesized in the body but supplied by the diet to the human body and these are necessary for the growth and maintenance of good health in human beings.
Vitamins are classified into two groups.
1. Fat - soluble vitamins: Vitamin A, D, E and K.
2. Water -soluble vitamins: Have heterogeneous group (thiamine, riboflavin, pyridoxine, cyanoccobalamine, niacin, pantothenic acid, biotin, folic acid and ascorbic acid, para-amino benzoic acid, and choline).
Vitamin A (Retinol): The main sources of vitamin A aremilk, codliver oils, fishliver-oils, butter, eggs, carrots, cabbage, vegetables, green leaves, mangoes, potatoes tomatoes, spinach, papaya etc.
•Essential for growth and night vision
•Required for bone and teeth formation,
•Influence genetic expression, reproduction to manufacture R.B.C etc.
•Maintain the health and activity of epithelial tissues, and glands prevent infection, maintains nutrition and function of the nervous tissue.
•Controls the action of bone cells and formation, helps in normal fertility and glucose synthesis.
•Acts as antioxidant.
•Helps in RNA and protein metabolism.
Vitamin A Deficiency Diseases
•Night-blindness, Xerophthalmia, Keratinisation of skin and mucous membrane.
•Retardation of growth in children, defective growth of bone and teeth, skin lesions, Bitot's, sports etc.
•Abnormalities in respiratory, GU and GI epithelium, Kidney stone, bladder disorders, depression of immune reactions, anaemia,
Vitamins D (Cholecalciferol)
Source are Fish liver oils e.g., cod liver oil, halibut - liver oil etc. Butter, milk, eggs, liver. In sub coetaneous tissue, 7 dihydrocholesterol is conveted to vitamin D by UV light.
•Control calcium and phosphorus absorption from the small intestine, concerned with calcium metabolism, helps in the bone and teeth formation.
•Minimize the losses of calcium and increases phoshate excretion by the kidneys, affects insulin secretion in pancreases.
Causes Rickets (directive bone growth) in childless, osteomalacia in adults, disturbs calcium and phosphorous absorption.
Vitamin C (Ascorbic acid)
Sources are Guava, amla, green chilli, amaranth leaves, citrus fruits, green vegetables, potatoes, tomatoes, cheese, milk etc.
•Essential for formation of collagen present between cells, formation of osteoblasts and red blood cells.
•Helps to reduce the ferric iron (Fe3+) to ferrous iron (Fe2+) and is absorbed only in this form.
•Essential for the utilization of folic acid
•Acts as antioxidant. Takes part in oxidation and reduction reactions in the tissues.
•Prevents formation of free radical in the body.
•Scurvy, a disease characterized by sore, spongy gums, loose teeth, fragile blood vessels, swollen joints, and anemia.
•Delay in wound healing.
•Pain in bones.
•Skin becomes rough and dry.
•Pyrexia, rapid pulse and susceptibility to infection.
Vitamin B1 (Thiamine)
The main sources are Rice polishing, dried yeast and wheat germ, wheat, oats, legumes, oil seeds and nuts,
•Acts as a co-enzyme in carbohydrate metabolism
•Require for the synthesis of glycine
•It has a specific action on nerve tissue
•Requires for the maintenance of normal gastro-intestinal tone and motility
•Maintains normal appetite.
•Beriberi - nervous, system affected, muscles become weak and painful paralysis can occur.
•Heart failure, wet beriberi, dry beriberi, infantile beriberi, oedemia, children's growth is impaired, keto acids accumulate in the blood, wernicke’s-korsakoff’s syndrome etc.
•Loss of appetite, fatigue, irritability, depression and constipation occur.
Milk, liver, kidney, muscle, butter, chicken, fish, yeast, cheese, raw egg, white grains, green vegetable such as spinach, peanuts, fruits such as apple, orange etc. Functions
•Precursor of coenzymes (FMN and FAD) in oxidation-reduction reactions of electron transport chain, fatty acid synthesis etc.
•Essential for growth, essential for tissue oxidation related to carbohydrate, fat and protein metabolism.
•Maintain mucosal, epithelial and ocular tissues.
•Essential for normal vision.
•Tongue sore at the corner of the mouth.
•Loss of hair, skin becomes dry and scaly.
•Dermatitis around nose and lips, inflammation of tongue, angular stomatitis and cheilosis, photophobia, cataract etc.
•Scrotal or vulval dermatitis, intense itching etc.
Minerals are inorganic substances required in specific amounts. Some of the more important of these are calcium, phosphorus, sodium, potassium and iron.
Minerals may be divided arbitrarily into 2 groups.
1.Macro minerals: The minerals, which are required in amounts greater than 100 mg/ day.
•Calcium: The main sources of calcium are Milk, egg, leafy green vegetable, fish, meat soybeans etc. The functions are (i)Formation of bones and teeth structure. (ii) Activates ATP during muscular contraction, helps in blood clotting and capillary permeability.
•Phosphorus: The main sources of Phosphorus are milk, peas, meat, fish, eggs, cottage, cheese, almonds, wheat germ, soybeans, black beans etc. The important functions are (i) Synthesis of nucleic acid, ATP and some protein.(ii) Helps in calcification of bones, maintain buffer system in body and bone formation.
•Potassium: The main sources are Spinach, butter, beans, oranges, milk, peas, meat, fruits nuts, and vegetables. Involves transmission of nervous impulses chemical reactions and acid base balance in the body.
•Sodium: The main sources are Table salt, eggs. meat, milk, cheese, butter, margarine, bacon etc. The functions sodium are to form part of tissue fluids inducing blood, involves kidney functioning and transmission of nervous impulses, acid-base balance in body.
•Sulfur: The main sources of Sulfur areProtein e.g., meat, fish and milk.
•Manganese: Vegetables and most other foods. It is the constituent of bones and tooth structure, co-factor for many enzymes.
2. Micro minerals: The minerals, which are required in amounts less than 100 mg/ day.
•Iron: Sources are Liver, eggs, meat, dark and green vegetables, lentis, potatoes, soybeans, chick peas, black beans, spinach, etc. Forms part of haemoglobin, helps in electron transport in biochemical reactions.
•Fluorine: Found in Water, milk etc. Needed for strong enamel on teeth, as calcium deposit in bone
•Nitrogen: Found in Protein e.g., meat, fish and milk,Synthesis of protein NA and many other organic compounds, e.g., coenzymes and chlorophyll
•Manganese: Found in Vegetables and most other foods; Bone development (a growth factor)
•Cobalt: Liver and red meat; Red bloods cell development
•Copper: Most foods; Melanin production
•Zinc: Most foods; CO2 transport in vertebrate blood
•Molybdenum: Most foods; Hydrolysis of peptide bonds in protein digestion
•Boron: Most foods; Reduction of nitrate to nitrite during amino acid synthesis in plants.
•Iodine: Seafood’s, such as fish, shellfish and fish oil. Vegetables, spinach, fruits, and cereals.
Mineral Deficiency Diseases
•Sodium-muscular cramps, giddiness, anorexia, scanty urine, dry mouth, inelastic skin and disorientation.
•Chlorine-muscular cramps, renal disease etc.
•Calcium-poor skeletal growth, rickets in children, osteomalacea in adults.
•Manganese-poor bone development
•Iron-anemia, weakness, lethargy, brittle nails, koilonychia, palpitations, breathlessness etc.
•Zinc-poor appetite, mental lethargy and delayed wound healing etc.
•Iodine-goitre, cretinism in children
•Potassium-muscular weakness, paralysis, mental confusion, loss of appetite, nausea, abdominal distension.
•Phosphorus-rickets in children, osteomalacia in adults.
I hope above short notes will be valuable to candidates for last minute revision of this part (food) which is an important section as far as examinations is concern. Also, it is recommended that candidates should thoroughly study NCERT books for detailed discussion of the subject.