12th Zoology

Proteins (Polypeptides)

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.

Types of Protein

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.

Essential Amino Acids

The essential amino acids are arginine, valine, histidine, isoleucine, leucine, lycine, methionine, phenylalanine, threonine and tryptophan. The nonessential amino acids can be synthesized in our body from other compounds. Such amino acids need not be added in the diet.

A protein (or) a polypetide chain is formed of several amino acids
linked with each other by peptide bonds. This linear arrangement is termed
as primary organisation of a protein. However in most of the proteins, the
straight chain structure gets complicated, into secondary, tertiary or quaternary
stages.

These levels are due to several other chemical bonds. The complicated
nature of a particular protein is specifically required for its prescribed function.
The amino-acids sequence and level of ogranisation is determined genetically.
Hence the genome gets its importance due to its capability to produce, specific
types of protein for bringing out genetical characteristics.

The daily requirement of protein, according to the Nutrition experts
committee of ICMR (Indian Council for Medical Research) and WHO (World
Health Organisation) is 1 gm per kg body weight. Reduction in the intake of
protein leads to protein malnutritions, such as marasmus and kwashiorkar.
In marasmas the child loses weight and it also causes severe diarrhoea and
the body muscles get wasted.

It will appear as though the bones are covered by the skin. In kwashiorkar there is a wastage of muscles. Face and feet will have oedema. The belly region will appear enlarged.

Related Topics in Zoology:

Bio Zoology All Important Topics


  1. Human Physiology Introduction

  2. Nutrition

  3. Carbohydrates Poly hydroxyaldehydes (or) ketones

  4. Proteins (Polypeptides)

  5. Lipids

  6. Vitamins – Functions Of Vitamins

  7. Deficiency of Vitamin

  8. Minerals – Water – Role of water

  9. Balanced diet

  10. Obesity

  11. Digestive System

  12. Dental Caries (Tooth decay)

  13. Root Canal Treatment

  14. Peptic ulcer

  15. Hernia and Types

  16. Appendicitis (Appendix)

  17. Gall Stones

  18. Hepatitis

  19. Fractures – Types of fractures

  20. Mechanism of fracture

  21. Dislocation of joints

  22. Arthiritis

  23. Rickets and Osteomalacia – Orthopedics

  24. Muscles

  25. Mechanism of muscle contraction

  26. Types of muscle contraction

  27. Myasthenia Gravis

  28. Respiration – Process of pulmonary respiration

  29. Mechanism of Breathing

  30. Regulation of Respiration

  31. Pneumonia Tuberculosis Symptoms Treatment

  32. Bronchitis – Acute bronchitis, Chronic Bronchitis Causes

  33. Circulatory System – Functioning of Human heart

  34. Cardiac Cycle

  35. Coronary blood vessel and its significance

  36. Myocardial infarction

  37. Angina pectoris

  38. Angiogram – Angioplasty

  39. Atherosclerosis

  40. Heart block Echo cardiography Heart Valves

  41. Rheumatic Heart Disease (RHD), ICCU – (Intensive Coronary Care Unit)

  42. Blood Pressure

  43. Heart transplantation

  44. Pulse rate

  45. Cardio Pulmonary Resuscitation (CPR)

  46. Blood – Composition of plasma – Blood cells

  47. Clotting of Blood or Haemostasis

  48. Thrombosis

  49. Nervous system Co-ordination systems

  50. The Brain – Fore Brain, Midbrain, Hindbrain

  51. Memory

  52. Sleep – Types of sleep

  53. Stroke – Brain haemorrhage

  54. Alzheimer – Meningitis (Brain fever)

  55. Conditioned reflex

  56. Electroencephalography EEG

  57. Right and Left brain concept

  58. Spinal cord functioning

  59. Chemical co-ordination – Functions of Endocrine glands

  60. Hypothalamus

  61. Pituitary gland – hormone

  62. Hormones of Neurohypophysis – vasopressin

  63. Thyroid gland

  64. Parathyroid Gland

  65. Pancreas

  66. Adrenal gland

  67. Gonads

  68. Receptor Organs – Eye

  69. Photochemistry of Retinal visual Pigments

  70. Errors of refraction

  71. Optometry – Retinopathy

  72. Cataract – Lens Replacement – Glaucoma – Nyctalopia

  73. Eye Infections and Eye Care

  74. Ear

  75. Mechanism of hearing

  76. Defects of the ear

  77. Hearing Aid – Noise pollution

  78. Skin and functions of skin

  79. Melanin functions

  80. Effects of solar radiation / UV radiation – Skin grafting

  81. Dermatitis

  82. Tongue – Mechanism of Stimulation

  83. Excretion Ureotelism Nephron

  84. Mechanism of urine formation

  85. Renal Failure, Dialysis, Kidney Machines

  86. Kidney stone – Kidney transplantation

  87. Diabetes mellitus

  88. Functioning of male reproductive system

  89. Functioning of female reproductive system

  90. Ovulation and fate of the ovum – Menstrual cycle

  91. Fertilization

  92. Birth control

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