Oct 042012
 

The word ‘lysosome’ is derived from two Greek words ‘lysis’ and ‘soma’ where the word ‘lysis’ means digestive and ‘soma’ means body. Hence, in simple words, we can say that lysosome is a structure which helps in digestion. Lysosomes were first discovered by de Duve in 1955 A.D. He found them in the liver cells of rats. These are present in all animal cells and in protists, fungi etc. They are more common in macrophages. They are mostly found in liver cells, White Blood Cells (W.B.C.), pancreas etc. which perform digestive functions.

Lysosomes are bound by single membrane. They contain many digestive enzymes which are known as acid hydrolases. These enzymes are capable of hydrolyzing or digesting all classes of macromolecules. Lysosomes are formed directly from Endoplasmic Reticulum (E.R.) and Golgi bodies (G.B.). The enzymes are synthesized by Endoplasmic Reticulum and transported to Golgi bodies. Then the enzymes are concentrated and then packed into vesicles which form primary lysosomes.

On the basis of morphological contents and functions, lysosomes can be categorized into four types which are listed and described below:

  1. Primary Lysosomes: Primary lysosomes are small bodies which are just pinched off or separated from Golgi bodies. They enclose enzymetic contents which are usually secreted by Endoplasmic Reticulum.
  2. Digestive Vacuoles or Phagosomes (Secondary Lysosomes): When the primary lysosome fuses with other vacuoles containing extracellular or intracellular materials, it is called secondary lysosome. Within secondary lysosome, the material is hydrolyzed by enzymes and then it is digested.
  3. Residual Lysosomes (Tertiary Lysosomes): In secondary lysosomes, food materials are digested. The digested food materials are absorbed into cytoplasm and undigested materials i.e., residue are left. The lysosomes having residue are called residual bodies or residual lysosomes. They move near to the cell surface membrane and they throw the contents by exocytosis process.
  4. Autophagic Vacuoles (Autolysosomes or Autophagosomes): When a lysosome contains a part of its one cell and digests it, it is called autophagic vacuole. It is a part of normal activity by which old, damaged and functionless organelles are digested.

Functions of Lysosomes
The major functions of Lysosomes are listed below:

  • Digestion of large extracellular particles like food materials, that enter the cell is done by lysosomes.
  • Digestion of intracellular substances like cell organelles during starvation to provide energy is carried out by lysosomes. This process is also known as autolysis. There can be self-destruction by the release of the contents of lysosomes within the cell. So, lysosomes are called the suicidal bags of the cell.
  • Digestion of harmful substances is done by lysosomes.
  • Lysosomes actively participate in the digestion of a cell as a whole during pathological conditions when the cells die due to attack of foreign bodies or lack of oxygen or poisoning etc. They digest damaged, old and functionless cells.
  • Lysosomes even help in the digestion of substances outside the cell. Lysosomes move near to the cell surface membrane and discharge their contents to digest the materials.
Oct 042012
 


The identity of any nation or community is determined by its custom, language and religion. Nepal is the only Hindu Kingdom of the world with religious tolerance. Nepal has given the shelter to many religious like Buddhism, Islam, Jainism and others beside Hinduism. All these religious sects have lived in peace, harmony and solidarity since ages.

They respect each other’s religions, customs and traditions. Unity in diversity is the major characteristic of Nepal and the Nepalese people. Religious faith and belief are the major values and norms of the society. They should be compulsorily followed by every person. If anybody doesn’t follow the traditional norms and values, he is regarded as a great sinner and a heretic. Though Nepalese are poor and there illiterate and are orthodox in their religious beliefs, religious salvation is regarded as their ultimate goal in life. Religion can play a significant role to eradicate traditional evils and launch social development activities.

But the religious belief sometimes has an adverse effect on the family planning programmes launched to reduce population growth.

A. Early marriage (child marriage)
From social and religious point of view, the Nepalese people follow a tradition of marrying their children at an early age. In rural areas, people still believe that if they can see the face of grandson at early age, then only they will go to the heaven. It is an auspicious act for them if they marry their daughter before her first menstruation. Due to such religious and social traditions, about 40 percent daughters are married before they reach the age of 16. As a result, several children are born before their mothers reach the age of thirty. Thus, having married at an early age, women in Nepal have a long period of fertility. This is one of the reasons for the rapid growth of population.

B. Preference to son
The wish to have sons rather than daughters is the result of religious belief and culture. In all societies in Nepal, a son is looked upon as a form of wealth. People cherish the belief that more sons earn more money and they can look after their parents in their twilight years. There still remains a belief that after the death of parents, their sons will open the gates to heaven for their departed souls. The materials of earthy life will be presented to them in the form of Shraddha ceremony, and if their sons actually carry out this act, they can enjoy eternal life in heaven. This belief is deep rooted in the minds of religious people. It is for this reason that even though there are four or five daughters already at home, the parents wish to have a son after them. The other reasons for greater preference to sons are son’s right to inherit parental property and continuation given to the family race by the sons.

 C. Children – the gift of god
In Nepal, whenever the elders bless the younger ones, it’s with the words, ‘may your children spread far and wide and be as numerous as the stars in the sky’. The person having more children is regarded the luckiest and richest person. So that, many couples want to earn good prestige by bearing more children.

Thus many programmes have been brought to bring change in traditional concept that gives priority to have more children. But, people, still have religious concepts deeply rooted. They have the faith that the more the god gives them the more prosperous they become. This has directly contributed to growth of population.