12th Zoology

Carbohydrates Poly hydroxyaldehydes (or) ketones

Carbohydrates (Poly hydroxyaldehydes (or) ketones.)

A carbohydrate is composed of carbon, hydrogen and oxygen in the
ratio of 1:2:1 (CH2O)n. They are of three types namely monosaccharides,
disaccharides and polysaccharides


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 (C3H6O3) are common intermediary products in
carbohydrate metabolic processes.

They play an important role in inter con
version of biomolecules. (eg. glyceraldehydes). Pentoses (C5H10O5) like
ribose and deoxyribose are the integral components of RNA and DNA

The Hexoses(C6H12O6) such as glucose, fructose and
galactose are food components commonly consumed.
Carbohydrates are commonly employed by the cells for providing

The energy metabolism happens through glycolytic
processes involving oxidative, citric acid cycle. The energy liberated is stored
in the form of ATPs (Adenosine triphosphate).

Each gram of carbohydrate is capable of yeilding energy equivalent
of 4.1 calories.


These are the carbohydrates formed by condensation of two
monosaccharide monomers. These are found in common food substances
such as milk and sugar.

There are three common disaccharides namely maltose,
sucrose and lactose. They have the following composition
Maltose à glucose + glucose
(In germinating cereals)
Sucrose (cane sugar) à glucose + fructose
Lactose (milk) à glucose + galactose


These are complex carbohydrates formed by polymerisation of a large
number of monosaccharides. Nature abundantly produces various types of

Several of them are structural components in the living world
eg. chitin, cellulose. Starch molecules serve as storage food materials trapping
enormous amount of energy. In food grains, starch is available as pectin
and amylopectin molecules. Glycogen, a polysaccharide is found in liver and

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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