Medical brain notes 33

  Nutrition   The survival of all living organisms is due to several types of nutritive processes. The process of nutrition involves ingestion digestion, absorption and assimilation of food materials. The composition of nutrients vary in different types of feeding. However, for all living organisms, the nutrient comprises the following organic and inorganic components. They are carbohydrates, proteins, lipids, vitamins, minerals and water. Each component has a specific functional role. A well proportioned intake of nu-trients depends on several factors such as stage of growth, sex, health con-dition, bodily activities and environmental situations.   Carbohydrates (Poly hydroxyaldehydes (or) ketones.)   A carbohydrate is composed of carbon, hydrogen and oxygen in the ratio of 1:2:1 (CH 2 O)n. They are of three types namely monosaccharides, disaccharides and polysaccharides   Monosaccharides:   These are the simplest form of carbohydrates being comprised of a...

  Carbohydrates (Poly hydroxyaldehydes (or) ketones.)   A carbohydrate is composed of carbon, hydrogen and oxygen in the ratio of 1:2:1 (CH 2 O)n. They are of three types namely monosaccharides, disaccharides and polysaccharides   Monosaccharides:   These are the simplest form of carbohydrates being comprised of a single organic molecule. Depending on the number of carbon atoms they are classified into trioses, tetroses, pentoses, and hexoses.   The  trioses  (C 3 H 6 O 3 ) are common intermediary products in carbohydrate metabolic processes. They play an important role in inter con version of biomolecules. (eg. glyceraldehydes).  Pentoses  (C 5 H 10 O 5 ) like ribose and deoxyribose are the integral components of RNA and DNA molecules. The  Hexoses (C 6  H 12 O 6 ) such as glucose, fructose and galactose are food components commonly consumed.   Carbohydrates are commonly employed by the cells for providing energy. The energy m...

  Proteins(Polypeptides)   Proteins are nitrogenous compounds being made up of carbon, hydrogen, oxygen and nitrogen. Proteins also contain sulphur. In living systems proteins play an important role in the  structural  organisation eg., cell membrane, hairs, nails and muscles. Many of the proteins serve as enzymes. They are named as  functional  proteins.   The building blocks of proteins are aminoacids. There are approximately twenty different types of amino acids, such as glycine, alanine, serine, valine, leucin, proline etc. The amino acids are classified as essential and non essential amino acids. Essential amino acids can not be synthesised in our body. Hence they should be made available through food. The  essential amino acids  are arginine, valine, histidine, isoleucine, leucine, lycine, methionine, phenylalanine, threonine and tryptophan. The non-essential amino acids can be synthesized in our body from other compounds. Such amino ac...

  Lipids   Lipids are important cellular constituents. They are energy rich compounds. They form the most important storage food in the body. In our body, it serves as an insulating material. Cosmetically, the presence of limited amount of fat beneath the skin adds to beauty. Further, steroidal hormones are produced from certain lipids.   The most common type of lipids are the simple lipids (or) triglycerides. They are naturally occurring substances (vegetable oils). In animals it is a main constituent of adipose tissue. Chemically a triglyceride is formed of glycerol and fatty acids.   Fatty acids are of two types namely  saturated  and  unsaturated   fatty acids . The unsaturated fatty acids are capable of easier oxidative   breakdown, hence poly unsaturated fatty acids(PUFA) are favoured for persons having high blood pressure and other related ailments. These fatty acids are abundent in sunflower oil and safflower oil.   Each gram of ...

  Vitamins   Vitamins are complex organic compounds, whose presence in trace amount in the food is essential for growth and other physiological activities. Vitamins do not have any energy value. However they are essential for controlling energy yielding processes. The identified vitamins are classified as A , B , C , D , E  and  K . Of these, vitamin  B  and  C  are water soluble in nature. Vegetables and fruits containing these vitamins if washed in water as cut pieces would loose them easily. Vitamin  A , D , E  and  K , if consumed beyond required level may cause defects, commonly referred to as vitaminosis.   Of the various vitamins, vitamin  D  or calciferol on exposure to sunlight can be synthesised by our body through the lipid compound called ergosterol, found below our skin. Hence it is known as 'sunshine vitamin'.   The most important functions of vitamins include.   1.   Physiological process...

  Nutrition :   The survival of all living organisms is due to several types of nutritive processes. The process of nutrition involves ingestion digestion, absorption and assimilation of food materials. The composition of nutrients vary in different types of feeding. However, for all living organisms, the nutrient comprises the following organic and inorganic components. They are carbohydrates, proteins, lipids, vitamins, minerals and water. Each component has a specific functional role. A well proportioned intake of nutrients depends on several factors such as stage of growth, sex, health condition, bodily activities and environmental situations. Minerals   Along with complex organic substances, such as carbohydrates proteins and lipids, our body needs substances such as minerals, vitamins and water as accessory food factors.   Of the minerals certain elements are found in greater concentration. They are sodium, calcium, potassium, magnesium, phosphorus, sulphur and...