Importance Of English In Modern Age

8:07 AM


English is an old language. It come into the sub-continent India with the English rulers. Since then, the people of sub-continent have been under the influence of English. It was Sir Syyed Ahmed Khan who urged the Muslims to study English. His efforts in this context are praiseworthy. Under his advice, the Muslim learnt English and began to compete with the Hindus in every field of life. Had they not learnt English, they would have remained backward. The importance of English in the modern world can be studies under the following topics:

English is almost an international language: 
It is spoken and read in almost every country of the world. It has linked various parts of the world and has promoted understanding among people of different countries. Its knowledge is essential for the promotion of international understanding. Pakistan is a country where people love to speak and study in their mother tongue. They like to speak Punjabi, Urdu, Sindhi, Balouchi and Pushto. English is the only language which can foster unity among the people of our provinces.

English has become a language of knowledge and learning:
All our scientific and technical knowledge is present in this language. It deals with commerce and trade. All our foreign trade is done through this language. The knowledge of medicine, engineering, technology, surgery and military equipment is communicated to us in this language. The best in poetry, drama and other branches of literature is found in English. No other language of the world gives us standard terminology and symbols in various branches of science and technology. Knowledge of English is compulsory for getting employment at home and abroad. English has played a very important role in our struggle for independence. All the activities in this respect we carried through the medium of English.
We cannot do away with English. It has its roots very deep in our society. It has been an official language for more than two centuries in the sub-continent India. It is used in the working of our executive and judiciary. It is taught in our schools and colleges and universities. The doctors, engineers, teachers and other educated people use this language for communication of ideas. Our educated people have great love for it. The importance of Urdu language cannot be underrated, but it is still in its infancy. It cannot compete with English as regards its vocabulary and scope. We can say that the future of English in Pakistan is quite safe. We cannot do away with it. 
Importance Of English In Modern Age Importance Of English In Modern Age Reviewed by SaQLaiN HaShMi on 8:07 AM Rating: 5


7:15 AM


co-education means educating the boys and girls in the same institution. It is a modern concept. It was first introduced in Switzerland but later on it become very popular in every country. It was adopted by other countries of the West like Germany, France, Canada, Russia and America. In the Eastern countries this concept of co-education is making headway slowly. In our country, it is popular only in vocational institutions.
There exists two school of thoughts who differ sharply in their views about co-education. One group of people favors Co-education. It includes the people who are educated in the western traditions. They put forward the following points:
1: First, they say that we should adopt co-education in our school and colleges because our country is poor and under-developed. We cannot open separate schools and colleges separately both for boys and girls. This difficulty becomes very great in case of vocational and technical institutions. It is very difficult for the Government to open separate vocational colleges both for the boys and girls and equip them with necessary scientific apparatus and library.
2: Second, there is a great dearth of skilled teachers on technical subject in our country. That is why, it is desirable to educate the boys and girls in the same institution.  
3: Third there is another advantage of co-education, the boys and girls have to play an important part in their practical life in the national progress of their country. They begin to have an understanding of each other at the college level. Co-education also produces in both the sexes a healthy competition in their studies. The boys also become more civilized and polished in the presence of girls. They try to approach the girls like sensible and civilized human being. The girls also stand  to gain something in the presence of boys. A mystery seems to spread round both sexes if they are kept separated from each other. If they are allowed to mix with each other, it is bound to produce in them a spirit a good will, trust and mutual understanding.

1: First, in a hot country, like Pakistan , co-education makes the boys and girls alive to sex matters. The boys begin to run after girls. The girls also feel proud of their boy friend. Thus, this tendency make them neglect their studies. Moreover, the girls lose their feminine qualities. They lose feminine charm as well.
2: Second, the period of youth is characterized by irresponsibility and immaturity. They fear that free mixing both the sexes will lead to terrible consequence. This free contact will result in laxity of morals. The youth of both the sexes will be corrupted by free mixing. Colleges will be converted into romantic arbors. Cupid will have a free rein. There would be Romeos  and Juliet's in the colleges. Ugly sense would be a common occurrence. Chastity is the greatest ornament of women. If they once lose it, they lose their place in society permanently. That is why our, religion forbids the free mixing of men and women at any stage of life. Therefore, it is false rationality to teach them in the same institution.  
The boys and girls in our country have to play different roles in their life. The girls has to run her home. Man has to earn his living. The courses taught to the girls should be different from those taught to the boys. Co-education does not encourage this tendency.
We should not introduce it at the university level, because it has many harms. However, we can continue it at the primary stage. 

Co-Education Co-Education Reviewed by SaQLaiN HaShMi on 7:15 AM Rating: 5

Role of Information Technology

9:15 PM


We live in a highly scientific and industrial world. Modern inventions in the field of communication have revolutionized every field of life. Information technology has undergone a revolution at a faster speed than any other branch of human advancement.
Radio and T.V, have been eclipsed before the new advancement of information system. The old information system of the world relied on the libraries. Book, magazines and newspapers were the major source of information in the past.

Then came wireless, radio and T.V. Now computer have conquered the market. Practically the information technology has been changing everyday.
Information technology consist of three things; transmission, recording of memory and processing on information. Computers form a major segment of new information technology. Now different countries of the world are interlinked with one another. 

Internet connections are very popular. Internet clubs are connecting the world in the social, political and economic fields. There have been a tremendous bombardment of information from all sides. Now information are being collected about goods, marketing, politics and other affairs of the life from all over the world.


1: All the paper knowledge has been transferred to the C.D (computer disk) of computers. We can get information and knowledge of all important books on medicine, engineering, arts, science and commerce on our computers. We do not have to wait for days and weeks to collect the information about ant topic of knowledge from abroad. The internet connection are becoming very popular now a days. Through the E-mail, Fax or internet phones it is possible to get information on time. With the help of phones we get any information from abroad in a moment and at a very cheap rate.

2: In the advanced countries of world, the students are gaining a lot of knowledge about language, art and science through their computers. Mass education can also be given to illiterate and uneducated people of our country through this electronic media. Soon there will be available personal computers to everybody in the country. They can fight ignorance, backwardness and illiteracy.

3: Recent development in the field of information technology system are a gift of modern science to mankind but its free use has also given rise to some serious social problems.

4: The entertainment programs presented by computers, internet, phones and other electronic media are very harmful to the students. The divert their attention from studies. They are absorbed and lost in the attractive and charming music and songs programs. Then they have a free hand to see and watch vulgar and sex dominated films. These vulgar films with the dance of half naked girls and obscene songs are bound to produce a negative influence on the morals, and manners of the students.
Role of Information Technology Role of Information Technology Reviewed by SaQLaiN HaShMi on 9:15 PM Rating: 5

Mobile phones and its drawback

3:55 AM


This is an age of science and technology. The recent development in the field on technology has given birth to many ❛wonders❜ in our life. The progress in the field of communication has surprised everybody. The mobile phone is a wonderful invention of science. It looks incredible that a man should talk or converse with another man while he is travelling or he is on his way to work. Such a thing was impossible a few years ago. Mobile phone have become very popular in the modern life. They have become a friend and companion to every man and woman. In the modern age, they have become professional necessity. Even in private life, they have established their utility. Now people cannot do away with them.

In the beginning of 20th century, the short range mobile car phones were developed. They were later on developed into into long range mobile phones. In the U.S, many small broadcast towers were set up. The phone calls travels from tower to tower. By 1981, a cellular radio phone system was fully available in the U.S. Later on, the same was developed into mobile phones whose range of communication was limitless. The messages were now transmitted without the aid of any wire. The communication through mobile phones is now carried through satellite.


1: Firstly they are the most rapid and quickest means of communication. We are connected with another man all the time without losing a second. They have increased our volume of business and trade. The money exchange of different countries can promote their business through mobile phones. The rates of different currencies in all countries are communicated to the customers readily. The flow of money from one country to the other is made smooth and easy through this instrument. In this way, many business failure are avoided. Timely information about the rates of a commodity from a trader in one city to another trader in the other city may save him from heavy loss.

2: Secondly the mobile phones have helped the travellers, explorers, hunters and passengers a lot. Now the hunters and travellers of all kind may explore any place of value or interest. They may explore the inner depths of a cove or the heights of a mountain. in time of crisis, they can make contact with their friends or with the government agencies and seek help from them.

3: Thirdly mobile phones may save us from the attack of criminals or terrorists. If we use them wisely and intelligently, we can contact the police before we are attacked. Many cases have been reported where the mobiles phones has saved the life of a car traveller.
Surely, wrong doubts of different kind can be removed readily through cellular talk. Even was and disputes can be avoided without losing a fraction of a second.


1: The mobile phone is a double edged weapon. It is of great utility but at the same time, it has its harms. The mobile phone is a great friend and companion of a criminal or a terrorist. Criminals and terrorists make use of this device to make contact with one another. They plan or make a plot to attack a building, hijack a person or commit a robbery in a bank through the mobile phone. Many outlaws and hardened criminals escaped from the prison homes with the aid of this instrument.

2: It has shattered the nervous system of many of its users. Its frequent users suffer from nervous ailments. It effect our memory. Our too much dependence on it has resulted in the loss of memory.

It has discouraged true learning. Now the students spend more of their time on mobile phones than or their books. Its excessive use results in the loss of time and money.
Mobile phones and its drawback Mobile phones and its drawback Reviewed by SaQLaiN HaShMi on 3:55 AM Rating: 5

Science in the service of man

9:12 PM


We live in the age of science. science has entered every field of life. It has added many comforts to our life. The impossibilities of the past have been made possible. New miracles are happening everyday. It has given man a new seance of confidence and power. Man has conquered the force of nature. It has helped man to explore the hidden treasures of the earth. Man has now learnt to land on the moon. He is in search of new worlds. A great writer Emerson says ❝ Science surpasses the old miracles of mythology ❞.

Science has brought a revolution in the matter of transportation and communication. It has shortened the distance. In the past, travelling was a difficult and dangerous matter. It took weeks and months to reach from one place to another. People bade farewell to their relatives and friends with a heavy heart , while they set out on a journey. Now those days have gone. We can now travel from one part of the world to the other in a few hours. There are rocket planes that travel at the speed of seven or eight hundred miles per hour. They travel faster than sound.

Telephone, Wireless, Radio, and Television and Computer are a wonderful inventions of science. They connect us with the world within the twinkling of an eye. The radio and T.V are the most powerful means of information and education for us. They make a record of everything which happen in the world. T.V., with its plays, entertaining features and educational programs enlightens and delight us. Its influence on men, women and children stand undefeated. Massages are flashed. Direct conversation can be carried on. Internet has brought the countries close together. The world has shrunk in size. science has established and strengthened the bonds of friendship and love between the people of different countries. It is no doubt a great service of science.

Electricity is perhaps the most wonderful invention of science. It is used as a source of light, heat and power. With the help of power, we can now change the course of rivers, level the mountain and cultivate our barren lands. Without it, the whole progress of industry would come to a stand still. Had it not been invented, the entire world would have plunged into darkness. It moves trains and trams. It heats our rooms in winter and cools them in summer. It cools our food and iron our clothes.

It has also done wonders in the world of medicine. Treatment by X-ray and radiation is one of the greatest wonder of science. Difficult surgical operations have become a routine matter. Vaccination has made small pox a thing of past. Many other diseases like cholera, plague and T.B have been fully controlled. Quinine has finished malaria.

Science has made us open minded and rational. We analyse everything before we believe it. We do not have faith in ghosts and spirits. Now-a-days science has made us practical minded.
Science in the service of man Science in the service of man Reviewed by SaQLaiN HaShMi on 9:12 PM Rating: 5

The Value of advertisment

7:54 AM


We live in age of competition. In this age, advertising has gained a great importance. The business activity in the country mainly depends on advertisements. Only those goods are accepted as popular which put up a brave show. By means of advertisement, the manufacturer of a product introduces it in market. Without advertisement, we shall not know the range of products available in the field.
Advertisement has age-long history. In the past, the things were advertised and made popular by the beating of drums. But in the modern age, the mean of advertising have changed. By modern mean of mass media , we introduce our products in the market. We can say that advertising is a means to communicate to public the merits of different products and goods. It is done by mean of newspapers, placards, posters, handbills, radio and television.
There are many agencies which promote advertisement:
First, T.V. is the most modern mean of promoting advertisement. The products display on T.V. conquer our sense of sight and hearing. They sweep us away with them. We are forced to form favorable opinion about the things so advertised.
Second, the newspaper also advertise things which facilities a communication between buyer and seller. Advertisements related to the sale of cars, houses, shops, factories no doubt produce great facility for the buyer and the seller. It is through advertisement that the eligible bachelors get their brides and unemployed get jobs.
Thirdly, there are advertising agencies in big cities. They aim at boosting up an article by clever methods. Even substandard products find their way in the market. Sometimes they go to a ridiculous length while praising a thing. Advertisements dealing with after shave lotion, oil turning the hair dark, perfumes, cosmetics and shampoos turn out mere trash when actual product is bought.
The advertiser makes his product attractive and popular by means of regular propaganda. He knows human psychology and goes on introducing one modern product after the other. A modern man is a great friend of advertiser. An advertiser is well versed in the art of judging human nature. He exploits our sense of taste. He also exploits the knowledge of modern science to make his advertisement popular and effective.
Advertisement has many advantages, First, it produces an urge for better standard of living. It sets up before a person the goal of a better home, better clothing and better food.
Secondly, it brings the producer and the consumer close together. Thirdly, it boosts up business and promotes business activity.
The Value of advertisment The Value of advertisment Reviewed by SaQLaiN HaShMi on 7:54 AM Rating: 5

Water Crisis

5:19 AM

Water is a great endowment and blessing of God to man. Without water, life in this world is impossible. Water gives life and energy to everything. It is essential for the life and survival of human being, birds, beasts, plants and trees. It is the main source of energy and power. We use it for cooking our food and quenching our thirst. It is the main source of irrigating our field. Without it we can not conceive of life on the earth.
Unfortunately, this great gift and blessing of God has been wasted and ill used by the people of  world and especially in Pakistan people no care about water and waste huge amount of water every day. We have never paid any attention to preserve and save this great treasure of Nature. There are many areas in Pakistan where people do not get water for drinking purpose. In the interior Sind, and Baluchistan, there are many towns and villages where people have to carry water from as far as thirty or forty kilometers away from their homes. The women, children, and old men have to undertake long journey to carry water for their daily use. This is a very sad spectacle . The sources of getting water are very few and limited. Water is present in the subsoil of earth. It is brought to earth by the operation of tube wells and electric motors. The other source of water is the rivers, lakes and streams. Water comes into rivers and streams by the melting of massive icebergs and glaciers.
This source of getting water is quite doubtful and uncertain. Sometimes, the summer season beings late and these icebergs and glaciers are not melted in time. Consequently, the rivers and lakes become dry and barren. The country falls a victim to the shortage of water.
In 1960, a treaty between ❝Pakistan and India❞ was signed with World Bank Meditation. The treaty is known as the Indian Basin Treaty. According to it, the control of waters of Ravi, Bias, and Sutleg was given to India. It was decided that the India Govt. would help Pakistan in the construction of two large dams on the Indus and the Jhelum. But this was never fulfilled. Indian Govt. often stopped the flow of water in our rivers when it liked, out sheer enmity.
The only way to overcome water crisis is to build dams on the rivers banks. The earliest dams were built to store water for domestic and agriculture. Hydro power became a major reason t build new dams.
The construction of Kalabagh Dam is the need of the time. If it is not built in time, our country is going to face severe starvation and famine.

Water Crisis Water Crisis Reviewed by SaQLaiN HaShMi on 5:19 AM Rating: 5

Paratonic movement in plants and kinds of paratonic movement

1:21 AM


The plant movement due to external causes are called paratonic movements. These are following types.

  • Tropic Movement (Directional + Respond to External Stimuli)
  • Nastic Movement (Non-directional + Respond to External stimuli)

(1) Tropic Movement (Directional + Respond to External Stimuli): It is the kind of paratonic movement in which curvature or turning of whole organ occurs due to external stimuli like light, gravity or touch. It is directional movement. Following are common tropic movements:

(i) Photorpism: The tropic movement of the organ of plant in response to light is photorpism roots and stems show phototropism. Actually, differential growth is reason of movement.

(ii) Thigmotropism: The tropic movement in response to stimulus of touch is known as thigmotropism. Climbing vines are coiled by thigmotropic movement. When vines come in contact with sonic solid object, in this situation, the growth on the opposite sides of contact increases and the tendrils coils around the support.

(iii) Chemotropism: The tropic movement in response to stimulus of chemicals is called chemotropism.
The hyphae of fungi respond to certain chemicals.

(iv) Hydrotropism: The tropic movement of plant parts in response to stimulus of water is termed as hydrotropism.
The growth of roots toward water due to ❝positive hydrotropism❞.
The growth of shoots away from the water is ❝negative hydrotropism❞ or negative hydrotropic.

(v) Geotropism: The tropic movement of plant parts in response to gravity is called geotropism.
Roots show positive geotropism and shoots display negative geotropism.

(2) Nastic Movement: (Non-directional + Respond to External stimuli)  The non-directional movement of plant parts in response to external stimuli are called nastic movement.

(i) Nyctinasty: The nastic movement in response to external stimuli in which differential growth take place is known as Nyctinastic movement or nyctinasty.
These are due to turgor and growth changes. It has two types.

(a) Photonasty: Opening and closing of flowers due to photonasty. The nyctinastic movement in response to light is called photonasty.

(b) Thermonasty: In this case the growth is respond to temperature.
For example the flower of Tulip close at night due to rapid growth in lower sides in the petals. Thus petals move upward and inward.

(ii) Haptonastic Movement: The non-directional movement of plant parts in response to contact is called haponasty or haponastic movement.
Venus fly trap has haponastic condition.

Paratonic movement in plants and kinds of paratonic movement Paratonic movement in plants and kinds of paratonic movement Reviewed by SaQLaiN HaShMi on 1:21 AM Rating: 5

Growth movements in plants

10:11 PM


The kind of plant movement which occurs due to unequal growth on two sides of plant organ like stem, roots, tendrils, buds etc., is known as growth movement. These are three general types of growth movements.

  • Epinasty
  • Hyponasty
  • Nutation

(i) Epinasty: The growth movement in which upper side or surface of leaf shows more growth as compared with the lower surface is called epinasty.

(ii) Hyponasty: If growth in the lower surface of the leaf in bud condition is more than that the upper surface then the bud will remain closed.

(iii) Nutation: Zigzag movement of growing tip of young stem due to alternate change in growth on opposite side of the apex is termed as nutation.

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Turgor movements in plants

9:54 PM


The movements which occur due to differential changes in turgor and cell size as a result of gain or loss of water are called turgor movements. Turgor movements are divided into further classes.

Sleep Movement
Rapid Movement

(i) Sleep Movement: The lowering of leaves in the evening and raising in the morning is termed as sleep movement.

Example: Bean plans of legume family (fabaceae) show this movement.

Reason of Lowering of Leaves: When turgor pressure decrease on the lower side of pulvinus, the leaves lower and go to ❝Sleepping❞ position, pulvinus is a swollen portion with parenchyma cells at the base of petiole.

Reason of Rising of Leaves: When turgor pressure increase on the lower side of pulvinus, the leaves rise and become horizontal.

(ii) Rapid Movement: The folding of the compound leaves due to rapid loss of turgor by cells at the base of petioles is known as rapid movement. It takes place in Mimosa plant when it is touched. It is reported that kᐩ ions more first, which causes water to leave the cell by exosmosis. Mimosa takes about the ten minutes to region the turgor and restore turgidity in cell of the leaves.

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Tactic movements in plant

9:26 PM


 The movement by which an entire cell or organisms change their position in response to external stimuli.
The movement will be positive if organism moves towards the stimulus.
It is negative if organism move away from the stimulus.
Tactic movement are dived into further kinds on the basis of the nature of the stimulus.

  •  Phototactic Movements 
  • Chemotactic Movements

(i) Phototactic Movements: The tactic movement in response to stimulus of light is called phototactic movement.

Example: The movement of chloroplast due to cyclosis (movement of cytoplasm within cells) is the best example of positive tactic movement.
It is the passive movement of chloroplast. In this way, chloroplast absorbs maximum light for CO₂ fixation.
The direction of light and intensity of light both effect the intracellular distribution of chloroplast.

(ii) Chemotactic Movement: The tactic movements in response to stimulus of chemical is known as chemotactic movement.

Example: Sperms of liverworts, mosses and ferns toward archegonia in response to stimulus of nucleic acid.
Nucleic acid is released by the ovum.

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Secondary Growth, Meristematic Activities in Growth

7:22 AM

❝ The growth in which plant girths is increased due to the activity of the vascular cambium (lateral meristem) in the woody plants, is called secondary growth.❞

During primary growth, stems increase in length while somates and sunflower also increase in diameter. The result of secondary growth is most evident in woody perennial plants like tree, shrubs and Vine.
The lateral thickening involves the activity of a secondary meristem, the Vascular cambium. Secondary growth occurs due to cell division in:

(i) Vascular cambium (ii) Cork cambium.

(a) Vascular Cambium as a Cylinder:
Firstly, cambium is restricted to the vascular bundles. It appears as a cylinder.

(b) New Tissue Formation:
Later, it forms a continuous cylinder with in the stem between the cortex and pith.
Its cell divide in such a way as to make new xylem cells on the inside and new phloem cells on the outside.

(c) Increase the Thickness of Stem:
The continuous division of cambium cells add new cell to the stem and it increase in thickness i.e., secondary thickening.
In such woody stems the epidermis is often replaced by dead corky layer, Bark, which itself is made by separate, layer of Cork Cambium.
Cork cambium is found beneath the epidermis.

(d) Right Formation:
Cambium produces layers upon layers of secondary xylem. These layers visible as rings. Since one growth ring is formed in one year, a count of the rings at the base of trunk indicate the age of trees at the time it was cut.

(e) Limitations of Secondary Xylem:
In older trees, only few annual growth rings are active in conduction at one time.

(i) Heart Wood:
After, a tree or branch is several year o;d, the inner part of the stem usually becomes inactive and filled with resins, gums, oils and tannins.

(ii) Sap Wood:
Outside the heartwood is a light-coloured, less dense region of active wood called sapwood.

(f) Callus Formation:
Callus is a mass of parenchymatous cells tht forms at a wounded surface. It produced by cambium. Where a branch has been cut off a tree. The callus tissue forms a ring of thickening (wound wood) around the wood. Evebtually, it may completely cover the exposed wood.

Secondary Growth, Meristematic Activities in Growth Secondary Growth, Meristematic Activities in Growth Reviewed by SaQLaiN HaShMi on 7:22 AM Rating: 5

Role of Xylem Phloem, Sclerenchyma, Collenchyma

11:56 PM


Collenchyma and sclerenchyma have lignified cell.This lignification becomes the reason of hardness.

  • Collenchyma is present in cortex ans sclerenchyma in xylem tissues.
  • The stems of land plants resist against wind.
  • Bending is checked by xylem.
  • Xylem tissues play role like steel road.

In short, the arrangement of vascular bundles in the rings provides resistance to wind stress, and weight bearing ability.


  • Generally, these cells are non-living.
  • Sclerenchyma cells provide support to the plant parts.
  • They are rigid due to secondary cell walls.
  • Lignin makes the wall tough ang rigid.

There are three types of sclerenchymatous cell:
(i) Fiber
(ii) Sclerids (Stone cells)
(iii) Vessels (Trachea)

FIBERS: These are long and cylindrical. They are found in solid bundles in xylem or as bundle caps. Fibers are common in plant stems.

SCLERIDS (Stone cells): There are common in shells of nuts and seed coats.
Sclerids are shorter than fiber. They give strength.

VESSELS (Trachea): These are long tubular structures.
These structure are joined end to end and form long water conducting pipe in xylem.


 (i)_The outer most cells of the cortex of young stems, lying just beneath the epidermis,often constitute a tissue known as collenchyma.
(ii)_The walls of collenchyma cells are composed of layers of pectin and cellulose.
The cell walls are thickened at the corner.
(iii)_These thickenings are flexible these tissues form complete cylinder.
(iv)_Collenchyma cells provide support to herbaceous parts of the plants.
(v)_Cells are also found in petioles of leaves.
(vi)_Protoplasm remains alive.
(vii)_These cells are without secondary wall.
Role of Xylem Phloem, Sclerenchyma, Collenchyma Role of Xylem Phloem, Sclerenchyma, Collenchyma Reviewed by SaQLaiN HaShMi on 11:56 PM Rating: 5

Chapter 1 (Measurement) Numerical Problem 1.1

10:36 PM


A light year is the distance light travels in one year. How many meters are there in one light year: (speed of light=3.0x10⁸ms⁻¹)


Given data:
                       time= t =1 year = 365 days.
                                  t = 365 x 24 x 60 x 60 s
                                    = 31536000 s
                                    = 3.154 x 10⁷s
Speed of light  =     v = 3.0 x 10⁸ ms⁻¹
To determine:
                   Distance= S = ?
we know that:
                    S  = vt
Here            V = c
                     S = ct
Now substituting the value we have;
                      S = 3.0 x 10⁸ ms⁻¹ x 3.154 x 10⁷s
                      S = 9.5 x 10¹⁵  m      Ans.
Chapter 1 (Measurement) Numerical Problem 1.1 Chapter 1 (Measurement) Numerical Problem 1.1 Reviewed by SaQLaiN HaShMi on 10:36 PM Rating: 5

Dialysis, Hemodialysis and Peritoneal Dialysis

11:22 PM


'' The filtering of the blood by an artificial way due to failure of kidney is called dialysis''.
When kidney do not perform its function, the amount of nitrogenous wastes, particularly urea is increased in the blood.In this case,patient is treated by dialysis. This artificial method cleans the blood. The wastes and extra water are removed by dialysis.

There are two types of dialysis: Hemodialysis and Peritoneal Dialysis.

(i) Hemodialysis
Hemodialysis means ''cleaning the blood''. In this procedure an artifical kidney is used.
Artifical kidney is used in hemodialysis is called dialyzer.


  • Blood is circulated through a machine which contains a dialyzer. Dialyzer has two spaces separated by thin membrane.
  • Blood passes from one side of the membrane and dialysis fluid on the other.
  • The wastes and extra water pass from the blood through the membrance into the dialysis fluid.

(ii) Peritoneal Dialysis:

In hemodialysis an artificial membrane is used in a dialysis while in method of peritoneal dialysis the peritoneum is used in dialyzer.

  • Perioneum is a natural membrane in the patient's own body.
  • Peritoneal dialysis can be carried out is hospital.
  • A thin plastic tube is inserted into the abdominal cavity through a small slit in the abdomen wall and can be left permanently.
  • The peritoneal membrane, or perioneum, which lives in the the abdominal cavity is the dialysing membrane and it is partially permeable.
  • Dialysis fluid is added to the abdominal cavity down the tube and left the several hours before removal.
  • The fluid can be replaced regularly 3 or 4 times of a day meanwhile the patient can be mobile and free to live relatively normal life.
  • It is used after kidney failure and dialysis is done repeatidly until the transplant of kidneys.

Dialysis, Hemodialysis and Peritoneal Dialysis Dialysis, Hemodialysis and Peritoneal Dialysis Reviewed by SaQLaiN HaShMi on 11:22 PM Rating: 5

What is Renal Failure

9:28 PM


''The decline of the performance of kidney due to malfunctioning of nephrons particularly glomerulus by which nitrogenous wastes increase in blood, is known as kidney failure.''

  • The increase of urea causes high blood pressure and anemia.
  • Kidney failure may be chronic and acute.
  • Chronic failure means increase of abnormality gradually, while acute means stopage of kidney function.

What is Renal Failure What is Renal Failure Reviewed by SaQLaiN HaShMi on 9:28 PM Rating: 5

Hypercalcemia, Kidney Problems & their Cures

5:49 AM


The processes of kidney may be disturbed due to physiologic, morphologic and hormonal disturbances.


(a)Hyper Calcemia (Calcium Stone Formation): An excess of calcium in the blood is called hypercalcemia.

  • Excess amount of calcium deposits as a stone.
  • Excessive PTH secretions and excessive vitamin D ingestion may cause hyper-calcemia.
  • The stone formation is metabolic disease.
  • Materials like stones etc in the kidney become the reason of urinary obstruction and complications due to infections.
  • Several kinds of cancer also cause hypercalcemia is the result of abnormal homeostasis of calcium.
(b) Hyperoxaluria (Calcium Oxalate Stone): An excess of oxalates gives the result of calcium oxalate stones.So extra oxalates is the reason of abnormal homeostasis.
★ Green vegetable and tomatoes may be the reason hyperoxaluria.
In patients, there are 70% calcium oxalate types stones in kidneys.

(c) Stones Of Calcium Phosphate: The incidence of calcium of calcium phosphate stones is 15%.

(d) Stones Of Uric Acid: The stones of uric acid are found 10% in kidneys of patient.

(e) Stones Formation: When salt are precipitated out during urine formation and accumulate later to form stone.

The stones of kidneys may be removed by following ways:

(a)Surgery: The kidneys stones may be removed by kidney surgery.It is general technique.

(b)Lithotripsy: Now a day, a non surgical technique is used to remove the stones from kidneys, ureter or gall bladder.This technique is famous as lithotripsy. 
  • In lithotripsy different kinds of wave shocks are utilized to remove stones.
  • The most common lithortripsy is extra-corporeal shock wave lithortripsy.
  • The shock waves break the stones in tiny pieces or into sand.
  • Ultimately, these tiny pieces are passed out through the urine body in urine.
  • High concentrations of X-ray or Ultrasound are directed from a machine outside the body to stone inside.
Hypercalcemia, Kidney Problems & their Cures Hypercalcemia, Kidney Problems & their Cures Reviewed by SaQLaiN HaShMi on 5:49 AM Rating: 5

Differentiate between Osmoconformers and Osmoregulators

3:49 AM

(i)  Osmoconformers : 

Those organisms in which osmotic potential of body fluid fluctuates with environment called osmoconformers .
In osmoconformers, the body fluid remains isotonic to the external environment even in massive (sea water) environment.

(ii)  Osmoregulators : 

Those organisms which are capable of controlling internal osmotic potential and keeping it constant inspite of environment variations, are called osmoregulators. 
In other words, for regulation of internal osmotic balance, discharge of water in hypotonic condition of salts in hypertonic condition. 
Differentiate between Osmoconformers and Osmoregulators Differentiate between Osmoconformers and Osmoregulators Reviewed by SaQLaiN HaShMi on 3:49 AM Rating: 5

Adaptation Of Plants In Different Habitats

2:43 AM

Plant grow in differnt kinds of habitat(living area).In each habotat plant cells and tissue osmoregulate themselves for normal biological activites and survival.


        Few living areas (habitats) are discussed below:
        (i)   Hydrophytes are aquatic plants.
        (ii)  Plants grow in moderate condition are celled Mesophytes.
        (iii) Plants of dry soil are known as xerophytes.


(i)    Adaptations Of Aquatic Plants (Hydrophytes):
  • Large surface area of leaves and extensive stomata increase transpiration.
  • This process of transpiration prevents turgidity of cell.
  • No flooding takes place in cells because large leaves and so much stomata promote loss of water.

(ii)   Adaptations Of Mesophytes:

  • Opening and closing of stomata become the reason of osmoregulation.
  • In case of water shortage stomata remains close while in sufficient amount of water, stomata remains open. e.g. Rose, Mango, Brassica etc.

(iii)  Adaptations Of Xerophytes:

Reduced transpiration is necessity of xerophytes.Due to water shortage in habitat.they cannot afford loss of water.Xerophytes store water only in rainy season xerophytes have the following adaptation.
  • Small and thick leaves to reduce water loss.
  • They posses thick, waxy and leathery cuticle.
  • Short number of stomata, generally on lower surface of leaves.
  • Stems are photosynthetic.
  • They store water in stems in rainy season and use in dry condition.
Adaptation Of Plants In Different Habitats Adaptation Of Plants In Different Habitats Reviewed by SaQLaiN HaShMi on 2:43 AM Rating: 5

Hypotonic, Hypertonic and Isotonic environments

11:43 PM

Environments :

Each cell of a body has water in specific amount. Water acts as a solvent of solutes. For the normal performance, each cell maintains the quantity of water. The concentration of water in the cell is adjusted by homeostasis.
Cells are always busy to maintain themselves in changing extra cellular environment. Cells generally face the following extra cellular environments.

(i) Hypotonic Environment (Hypo = Deficient) :
The surrounding of cell with diluted solution compared to the cell concentration is called hypotonic environment.

In the case , endosmosis takes place and cell becomes turgid. More than enough intake of water becomes the reason of swelling and bursting.

(ii) Hypertonic Environment (Hyper = Extra) :

The surrounding of cell with more concentrated solution compared to the cell cytoplasm is known as hypertonic environments.

In This way, exosmosis takes place in the cell. Plasmolysis occurs due to shrinkage of protoplasm.

(iii) Isotonic Environment  (Iso = similar) 

The surrounding of cell with similar concentration of solution compared to the cell is called isotonic environment. In this case neither endosmosis nor exosmosis occurs.
Hypotonic, Hypertonic and Isotonic environments Hypotonic, Hypertonic and Isotonic environments Reviewed by SaQLaiN HaShMi on 11:43 PM Rating: 5

Osmoregulation, Thermoregulation, Excretion, Homeostasis

6:58 AM

(i) Osmoregulation :

The adjustment of internal osmotic pressure of a body in relation to that of the environment is called osmoregulation.


The regulation of gain and loss of water and solute in an organism in response to environment factors is known as osmoregulation.

(ii) Thermoregulation :

The adjustment of temperature of body in changing temperature of environment is called thermoregulation.

(iii) Excretion :

The process of removal of waste products or nitrogenous wastes which are formed during metabolism, and not needed in the body.

(iv) Homeostasis

The self regulating process which maintains a steady internal condition or physiology with a constantly changing environment is called homeostasis.
Osmoregulation, Thermoregulation, Excretion, Homeostasis Osmoregulation, Thermoregulation, Excretion, Homeostasis Reviewed by SaQLaiN HaShMi on 6:58 AM Rating: 5
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