Tissue Culture | Biotechnology

Tissue culture is a test tube  method used to create and clone novel plant varieties. A method in which whole plants grow by cultruing small pieces of tissues cute from the parent or even single parenchyma cells on an artificial medium containing nutrients plant cells are totipofient (a small cell with full genetic potential of organism). In 1950 carrot was produced from a single carrot phloem cells the cultured cells divided to form undifferentiated callus. This test tube plant can than be transferred to soil where they continue their growth plant tissue culture can fasehtate genetic engineering in plants.

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Gene Sequencing | DNA molecules

Gene sequencing is a method of determining nucleotide sequence of a gene (DNA molecules). This gene sequence can provide great deal of information. It is fastest way to determine amino acid sequence of its polypeptide. It provides location of restriction site with in a gene which can be manipulated further later on. Man's phases of gene friquencing are firstly to cut genes into specific small pieces, then each fragment is individually sequenced. Most sequences, that are determined are being collected in computer data bank that are valuable for biotechnology with the help of computers long sequences can be scanned for shorter segments known to be control sequences such as promotes or enhances. It is also possible to scan a DNA sample to know sequences in other genes or organisms.

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Incomplete Dominance - Biotechnology

F1 offspring of Mendel's classic pea crosses always looked like one of the two parental varieties because of the complete dominance of one allek - over another. Many characteristics in a variety of organisms show this mode of inheritance. But many others do not. They may show another phenomenon of inheritance called incomplete dominance or intermediate inheritance. It is a phenomenon of inheritance in which dominant - alleles of contrasting characters are not completely dominant over other resulting that heterozygous individuals have phenotypes in between two contrasting or blending of characters occurs in heterozygous condition.

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Test Cross | How it Performs - Botany

All plants produced in F2 generation may either have TT 01 IT genotypes. Mendel devised simple way to distinguish the genotype. It is known as lest cross. The oigantsins of dominant phenolype (tall) hut unknown genotype is crossed to homozygous recessive individual eg. a tall plant is crossed with a dwarf plant. It tall plant is homozygous (IT) and F1 plants would he tall (Tt) and one half dwarf (Tt) exhibiting a ration 1:1. This ratio is called test cross ratio.

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Ionic Bonding - Chemical Bonding

An ionic bond is formed when a metal atom transfers one or more electrons to other atom. 

Na ---> Na (positive) + e (Negative)

F  + e -----> F (Negative)

The Oppsitely charged ions get attraction through electrostatic force of attraction to form an ionic Bond.

    If the electronegativity  difference between the atoms is equal to or greater than 1.7 the bond forms between the atoms have more than 50 % ionic character.

• In the solid each cation surrounds itself with anions and each anion with cations. In this way a very large number of ions are arranged in an ordinary network called ionic crystals.
• They are good conductors of electricity in fused state or aqueous solution.
• They are soluble in polar solvents and insoluble in non-polar solvents.
• Have high melting point and boiling point.
• Have strong force of attraction between cation and anion (Columbic force).

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Hydrogen Bonding - Second Year Chemistry Topic

Hydrogen bonding is said to be formed when slightly acidic hydrogen attached to a strongly electronegativity atom such as F, O and N is held with weak electrostatic forces by the non-bonded pair of electrons of another atom. That is, it is a dipole-dipole interaction.

• Of all the electronegative donor atoms, only F, O and N enter into stable H-bond formation.
• Greater the electronegativity difference between the bonded atoms, stronger is the Hydrogen bonding.

For example: The electronegativity difference between F and H is greater than that of between Cl and H, therefore HF is more polar than HCl.

Intramolecular Hydrogen bonding: This type of Hydrogen bonding occurs between polar H and electronegative atom present in the same molecule.

Intermolecular Hydrogen Bonding: This type of Hydrogen bonding takes place between hydrogen and electronegative element present in the different molecules of the same substance (H2O and H2O) or different substances (H2O and NH3).

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Law of Conservation of Angular Momentum - Artificial Satellite & Critical Velocity

The law of conservation of angular momentum states that the angular momentum about any axis of a given rotating body or a system of bodies is constant, if no external torque acts about that axis.

       L(total) = L1 + L2 + L3 + ........ = Constant

        The axis of rotation of an object will not change its orientation unless an external torque causes it to do so.

Rotational Kinetic Energy: 

        If a body is spinning about an axis with constant angular velocity, each point of the body is moving is a circular path and therefore has some K.E.

         To determine the total K.E of a spinning body we imagine it to be composed of tiny pieces. The rotational K.E of the whole body is the sum of the kinetic energies of all the parts.

       K.Erot = 1/2 I

Artificial Satellite: 

       Satellites are objects that orbit around the Earth. They are put into orbit by rockers and are held in orbits by the gravitational pull of the Earth. The low flying Earth satellites have acceleration 9.8 ms towards the center of the Earth. If they do not they would fly off in a straight line tangent to the Earth. When the satellite is moving  in a circle, it has an acceleration. In a  circular orbit around the Earth, the centripetal acceleration is supplied by gravity and we have g = v2/R.

Critical Velocity: 

        7.9 km s-1 is the minimum velocity necessary to put a satellite  into the orbit and called critical velocity.

        The higher the satellite, the slower will the required speed and longer it will take to complete one revolution around the Earth. Close orbiting satellites orbit the Earth at a height of about 400 km. Twenty four such satellites form the Global Positioning System.

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Geo-stationary & Communication Satellite

Geo-stationary Orbits:

     Geo-stationary satellite is the one whose orbital motion is synchronized with the rotation of the Earth. In this way the synchronous satellite remains always over the same point on the equator as the Earth spins on its axis. Such a satellite is very useful for worldwide communication, weather observations, navigation and other military uses 4.23 X 104 km is the orbital radius measured from the center of the Earth, for Geo-stationary satellite. A satellite above a particular point on the surface of the Earth. This height above the equator comes to be 36000 km.

Communication Satellite: 

       A satellite communication system can be set up by placing several geostationary satellites orbiting over different points on the surface of the Earth. One such such satellite covers 120 degree of longitude, so that whole of the populated Earth's surface can be covered by three correctly positioned satellites. The energy needed to amplify and retransmit the signals is provided by the large solar cell panels fitted on the satellites. There are over 200 Earth stations, which transmit signal to satellites and receive signals via satellite from other countries. The largest satellite system is managed by 126 countries, International Telecommunication Satellite Organization (INTELSAT). An INTELSAT VI operates at microwave frequencies of 4, 6, 11 and 14 GHZ and has a capacity of 30,000 two way telephone circuits plus three TV channels.

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Genetic Coding brief Explanation

The sequence of nucleotide in DNA and RNA directs, the oriler of amino acid in a protein. There is code of each 20 amino acid found in Protein. Each code word is called carbon and is made up of 2 bases such as AG; there would be only 16 codons not enough to code for 20 amino acids. If each codon were made up of 3 bases, such as AGC, there would be 64 colons, more than enough to code for 20 different amino acids. There genetics code is triplet code and each codon has 3 nucleotide bases.

1. Genetic code is degenerate i.e. most amino acids have more than one codon e.g: leucine, serine and arginine have different codons.
2. This helps code against harmful effect of mutations.
3. Genetic code is unanbiguous Each triplet code has only one meaning.
4. The code has 'Start' and ''Stop'' signals. There is only one start signal but 3 stop signals.

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Battle of Hunain

Before the Holy Prophet (P.B.U.H) could leave Makkah for Madinah, he received reports that the Hawazin and Saqeef, the two very strong and warring tribes of Taif, had collected a large army for attacking the Muslims. The Holy Prophet (P.B.U.H), therefore, postponed his departure for Madinah and made preparations for meeting this new challenge. He proceeded against them with an army of 12,000 Muslims, ten thousand of which had come from Madinah and two thousand were the new converts to Islam.

    Probably the enemy had received reports of the route to be followed by the Muslim army. So they posted archers in secret places and made a surprise attack on the Muslims while they were passing through the narrow valley near Hunain. As a result, Muslims began to retreat in disorder. The Holy Prophet (P.B.U.H) and his companions called the retreating men to return. The Muslim army responded to the call and the Holy Prophet (P.B.U.H) rallied his forces. Thus within no time the defeat was changed into victory. The Quran says:

    "Assuredly Allah did help you in many battlefields and on the day of Hunain: Behold! your great numbers elated you, but they availed you naught; - and ye turned back in retreat. But Allah did pour His calm on the Messenger and on the Believers and sent down forces which ye saw not:-" (9: 25,26)

      In this battle, the Muslim army took six thousand prisoners of war, twenty-four thousand camels and forty thousand goats.

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Forest Ecosystem

Forest occupies roughly 35-40% of the land surfaces of the earth. In Pakistan the forest occupy about 6% of the total land area. The forest of the world have been classified into three kinds as coniferous, temperate and tropical forest. Coniferous forests are confined to Northwern Hemisphere where summer is short and winter is long and very cold. The temperature forest found in USA. Western Europe and East Asia, have mild temperature and moderate rain fall. The tropical rain forest grows in equatorial region where humidity is high, rainfall is heavy and annual average temperature is about 28 C. The fauna and flora of different kinds of forest varies from each other. Among all, the tropical rain forests are most rich, s sprites composition.

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Some Outstanding Qualities of the Prophet Mohammad (P.B.U.H)

The Holy Prophet was totally different from the people among whom he was born and with whom he lived as a child and adult. He never a lie and was known as Sadiq and Amin --- The Truthful and Trustyworthy. He talked politely and never used abusive language. In his dealings with people, he always followed the principal of justice. He remained engaged in trade for many years, which he conducted with honesty and intregity. Those who dealt with him in business had the fullest confidence in his intregity. Even his enemies deposited their valuables with him for sale custody.

      He caused harm to no one; rather he suffered hardships for the sake of others. He kept away from tribal feuds and rivalries and was foremost in bringing about reconciliation among enemies. Thus, the personality of the Holy Prophet may be  compared to a beacon of light in the midst of dark and dismal surroundings.

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Nitrogen Cycle - How works nitrogen ?

Nitrogen is indespensible in nature, it is essential for chlorophyll and amino acids which form proteins. It constitutes main bulk of atmosphere, where it is present in about 78% in ratio. The atmospheric nitrogen is insert and does not readily participate in any reaction. However it is cycled from environment to organisms and back to environment by several paths. Nitrogen is fixed from atmosphere through different sources and is absorbed by the plants in the form of nitrates.

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Appoaches To Ecology

There are several factors, which interact in a particular locality due to this this there are several approaches to undertake ecological investigations. Each approach has its own merits and demerits. Thus ecologists use one of the suitable approach to understand ecological phenomenon. These approaches are population approach or autecology, community approach or synecology, ecosystem approach, habitat approach, evolutionary and historical approach.

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What is Test Cross - Test Cross Notes

Cross fertilization of a phenotypically dominant individual with a hemozygous recessive individual is called a test cross. It helps in determining the homozygosity or heterozygosity of the dominant parent. When dominant homozygous parent is crossed with recessive, all the offspring will be dominant phenotypically. But when cross is between heterozygous dominant with recessive then half will be dominat and half recessive offspring are produced.

       The result are shown diagrammatically in figure.

4

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Short Note on Meiosis

Meiosis or reduction is a rather complicated type of cell division occurring in the reproduction of germ cells at the time of gamete formation. The process of meiosis occurs both in plants and animals.

     In animals it occurs during gametes formation whereas in plants, it occurs during spores formation. It has already been stated that every species of animals and plant has a definite number of chromosomes and that this number remains constant in its somatic cells, generation after generation. To keep the number constant, the chromosome number in gametes is reduced to half. When male and female gametes and their nuclei fuse, the normal number of chromosomes characteristic of each species is restored. The somatic or vegetative cells having the complete number of chromosomes are called diploid (2n). While gametes containing half of the original number of chromosomes are called haploid (n) or monopoloid.

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How works perform Diakinesis In the cell division - Mitosis & Meosis

The diakinesis is characterized by the disappearance of the nuclear membrane, nucleolus and completion of spindle apparatus. The separation of bivalents is completed by the process called terminalization in which the movement of the chiasmata from the centromere towards the ends of the chromosome arms take place like a zipper and at the end of diakinesis the two chromatids and held together only at their ends by the centromeres. Now the bivalents become more thickened contracted and prominently visible. Prophas I ends here.

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Terrestrial OR LIthospheric Ecosystem

The ecosystem present on land or soil is called terrestrial or lithosopheric ecosystem. Terrestrial ecosystem receives plenty of light and the soil provides ecosystem nutrients water, however is limited and very unevenly distributed both in place and in time.

Factors Affecting Life On Land:

          Factors which influence life on land are given below:

a) Temperature: Like water, favourable temperatures are very unevenly distributed on land in place and time.

      On poles, the average temperature is below freezing. While in temperature zones only during certain seasons of the year it is quite favourable but in tropic zones uniformly warm, moist climate is present.

b) Air: In terrestrial ecosystem air is in constant motion so its composition is more uniform. The amount of O2 and CO2 in air is much constant and most beneficial for terrestrial ecosystem.

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Division of Terrestrial Ecosystem

It can be divided into following main types such as:

1-   Forest Ecosystem.

      It is further sub-divided into:

(a)  Tropical rain forests

(b)  Temperature deciduous forest

(c)   Coniferous alphine and boreal forests

2-   Grass Land Ecosystem.

3-   Desert Ecosystem.

4-   Tundra Ecosystem.

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Intervention of Man in Aquatic Ecosystem

Human activities may greatly accelerate. The process of eutrophication, because nutrients are carried into lakes from farm feedlots and sewage.

          Even if solid wastes are removed, water discharges from sewage treatment plant is often rich in phosphate and nitrates dissolved from wastes and detergens.

         Excessively enriched water also washes off fertilizers from fields where the mature of thousands of cattle is accumulated. These added nutrients support excessive growth of phytoplankton. Produces like blue-green algae form a scum on the lake surface, depriving the submerged plant of sunlight, as a result they die. The dead plant bodies are decomposed by bacteria, utilizing oxygen present in the water, deprived of oxygen, fish, snails and insect larva die and their decaying bodies fuel, snails more bacterial growth, further, depleting that oxygen. 

        Even without oxygen, certain bacteria that produced foul smelling gases thrive. Although it is full of life and nutrients, polluted lake smells.

         Most of the trophic levels including the fish eliminate and the bacteria and blue, green, alga, dominate the community.

           Few organisms can with stand the low Ph of acidified lakes.

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Reading Comprehension - Passage about the Pakistan food Conditions

The public distribution system, which provides food at low prices, is a subject of vital concern. There is a growing realization that though Pakistan has enough food to feed its masses three square meals a day, the monster of starvation and food insecurity continues to haunt the poor in our country. 

     Increasing the purchasing power of the poor through providing productive employment leading to rising income, and thus good standard of living is the ultimate objective of public policy. However, till then, there is a need to provide assured supply of food through a restructured more efficient and decentralized public distribution system (PDS).
       Although the PDS is extensive - it is one of the largest such systems in the world - it has yet to reach the rural poor and the far off places. It remains an urban phenomenon, with the majority of the rural poor still out of its reach due to lack of economic and physical access. The poorest in the cities and the migrants are left out, for they generally don't posses ration cards. The allocation of PDS supplies in big cities is larger than in rural areas. In view of such deficiencies in the system, the PDS urgently needs to be streamlined. In addition, considering the larger food grains production combined with food subsidy on one hand and the continuing slow starvation and dismal poverty of the rural population on the other, there is a strong case for making PDS target group oriented. 
       The growing salaried class is provided job security, regular income, and percent insulation against inflation. These gains of development have not percolated down to the vast majority of our working population.
          If one compares only dearness allowance to the employees in public and private sector and looks at its growth in the past few years, the rising food subsidy is insignificant to the point of inequity. The food subsidy is a kind of D.A to the poor, the self - employed and those in the unorganized sector of the economy. However, what is most unfortunate is that out of the large budget of the so called food subsidy, the major part of it is administrative cost and westages. A small portion of the above budget goes to the  real consumer and an even lesser portion to the poor who are in real need.
            If is true subsidies should not become a permanent feature, except for the destitute, disabled widows and the old. It is also true that subsidies often create a psychology of dependence and hence is habit-forming, killing the general initiative of the people.  By making PDS target group oriented, not only the poorest and neediest would be reached without additional cost, but it will actually cut overall costs incurred on large cities and for better off localities. When the food and food subsidy are limited the rural and urban poor should have the priority in the PDS supplies. The PDS should be closely linked with programs of employment generation and nutrition improvement.

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Productivity of Quatic Ecosystem

The productivity, can be indicated by consumption of CO2 and evolve oxygen of photosynthesis. The productivity of aquatic ecosystem is basically determined by the light and nutrients.

   Light intensity and quality varies with the water depth so, the primary productivity also varies with light.

    The amount of nutrients forms also changes with season. Productivity also varies from zone to zone.

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Relations between the Prophet (P.B.U.H) and the Jews - 7th Year of Hijrat

When the Holy Prophet (P.B.U.H) came to Madinah, he had made agreements with the Jewish tribes of Madinah to defend the city from foreign invaders and to maintain peace and order. But instead of defending it from its enemies, they organized a campaign of slander against Islam and its followers. They first tried to create disruption between the two man tribes of Madinah i.e. the Aus and the Khazraj. Then they incurred the displeasure of Muslims by their contacts with the Quraish of Makkah.
     At the time of the Battle of Badr, they did not help the Muslims according to the treaty signed with the Holy Prophet (P.B.U.H). After the Battle, Ka'ab, the leader of the Jews propagated against Muslims and maintained a secret communication with Abu Sufyan. He even tried to murder the Holy Prophet (P.B.U.H).
      Among the three tribes of the Jews - the Banu Qainuqa, Banu Nazir and Banu Quraiza - the Banu Qainuqa, were the first to break the treaty that was signed earlier and fought with the Muslims in the periods  between the Battles of Badr and Uhad. Attempts made by the Prophet (P.B.U.H) to come to terms with the Jews were unsuccessful. Thereupon, a siega was enforced against the Banu Qainuqa, the result of which was their expulsion from Madinah. In the third year of the Hijrat, Ka'ab was executed for his activities against Madinah and the Muslims.
     In the 4th year of the Hijrat, the Banu Nazri tribe of the Jews plotted to murder the Prophet (P.B.U.H) and at the instigation of the Quraish planned to rise against the Muslims. The Prophet (P.B.U.H) sent a message to leave Madinah within ten days. By the rejected it and shut themselves up in their fortresses. At this the Prophet (P.B.U.H) led an army against them and laid siega to their forts. After a siega of two weeks, the Jews surrendered. They were exiled from Madinah.
       The third tribe of the Jews - Banu Quraiza, opently joined the Quraish in the Battle of Ditch. After the battle, they were told to leave the city. But on their refusal, the Prophet (P.B.U.H) besieged their settlements. At last they also surrendered to him and agreed to abide by the decision of Sa'ad bin Mu'az who decided their fate according to the Jewish law of the Old Testament. Their men were slain, the women sold as captives and their lands properties were divided among the Muslims.
      Most of the Jews expelled from Madinah took shelter at Khyber, near the border of Syria. Here they began to plot against the Muslims in co-operation with the Bedouin tribes. In 5 A.H, the fortresses at Khyber were besieged and captured by the Muslims. The Jews were allowed to remain there by contributing a share of their produce to the Muslim government. 
        But the Jews did not refrain altogether from enemy towards the Muslims and the Holy Prophet (P.B.U.H). Once again, they plotted to murder the Prophet (P.B.U.H) by poisoning him but fortunately, the Prophet (P.B.U.H) was saved. The Jews continued to cherish evil designs against the Muslims up to the reign of the second Khalifa Hazrat Umar when they were asked to leave Syria. After that incident, the whole of Arabia was feed from the Jews.

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Reasons for Change in the relationship between the Holy Prophet and the Jews

When the Holy Prophet migrated to Madinah, he sought to develop friendly relations with the Jews. For this purpose, he signed a treaty of peace and friendship with them.

     The relations were cordial at the beginning, but as more and more people joined Islam, and the Holy Prophet's position grew stronger, the Jews became apprehensive of his growing and power and considered it a threat to their own dominant position in the area. Some of their learned rabbis had embraced Islam. The Jews, therefore began to deny his prophethood and ridicule his teachings.

     The Jews were mainly money lenders who would charge heavy interest on loans. The teachings of Islam forbid usury and the charging of interest. The Jews did not like this as it hurt their economy and affected their business.

       The Jews used to exploit the rivalry between two tribes of Madinah - Aus and Khazraj to their advantage. With the establishment of brotherhood by the Holy Prophet, this rivalry ceased and Jews could no longer use it to their advantage.

        After the Qiblah was changed from Jerusalen to Makkah, in the second year of Hijrat, the Jews began to organize constant intrigues with the hypocrities and the Quraish of Makkah. They sent deputations to the Quraish and the Arab tribes to attack Madinah and even offered them financial help. They also started a slander compaign against the Holy Prophet and the Muslims. They even tried to murder him.

       These actions were a violation of the terms of the agreement which they had made with the Holy Prophet who was now forced to take practical steps against them. He decided that the Jews should not be allowed to remain in Madinah and they were expelled from the city.

Performance of Umrah:

        According to the treaty of Hudaibiya, signed in 6 A.H., Muslims could perform Umrah the next year. They were also entitled to stay for three days in Makkah. The Holy Prophet (P.B.U.H), therefore, undertook the journey to Makkah. Before leaving he asked his Companions not to take any arms with them. They were allowed to enter Makkah where they performed Umrah. After three days, the Holy Prophet (P.B.U.H) left Makkah with his followers.

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Balltle of Trench - 5th Year of Hijrat

After the battle of Uhad, the Muslims were able to regain their former position. The Quraish could not reconcile themselves with the growing power of the Muslims because they felt it was a threat to their social and religious position as well as their commercial prosperity.

    The Jewish tribe of Banu Nazir who had settled at Khybaer kept on plotting against the Muslims. Their chiefs went to Makkah and asked for help against the Muslims which the Quraish agreed to give. Then they went to Ghatafan tribe and obtained their support too. Some other tribes also agreed to give full support against the Muslims. With an army of ten thousand men under the command of Abu Sufyan, they marched to Madinah.

     When the news came to the Holy Prophet (P.B.U.H), he consulted his companions Hazrat Salman Farsi advised to dig a trench. Madinah was safe on three sides on account of population oasis. The fourth side that was on the Syrian route was unsafe. The Holy Prophet (P.B.U.H), therefore, decided that a trench be dug on the side that was open to attack. Three thousand companions worked along with the Holy Prophet (P.B.U.H) in digging the trench.

      At first, the Banu Qurauza had refused to support the unbelievers. But later they also came out against the Muslims and broke their treaty with the Holy Prophet (P.B.U.H). Thus there was a mighty attack on Muslims from all sides. For this reason, the battle is also called Battle of Ahzab or the "Battle of Allies". The Holy Quran says:

      "Behold! they came on you from above you and from below you, and behold the eyes became dim and the hearts gaped upto the throats, and ye imagined various thoughts about Allah! In that situation were the Believers tried: they were shaken as by a tremendous shaking." (33: 10-11)

       The hypocrites among the Muslim army, finding the situation dangerous, asked permission from the Holy Prophet (P.B.U.H) to return to their homes on the excuse that their homes were not safe. In this connection, the Quran says:

        "Behold! a party among them said: "Ye men of Yasrib! ye cannot stand (the attack)! Therefore go back! And a band of them asked for leave of the Prophet, saying, Truly our houses are bare and exposed,' though they were not exposed: they intended nothing but to run away." (33: 13)

        The siega lasted for a month, during which the Muslims had to face hunger, cold and constant attacks from the enemy. Allah, however, came to the help of the Holy Prophet (P.B.U.H) and the Muslims. One night there was a piercing blast of cold wind, the enemy's tents were torn up, their fires were extinguished, the sand and the rain beat in their faces. The enemy, stricken by cold and terror from the severe storm, withdrew in utter confusion.

         The Holy Quran mentions this in the following words:-

         "O ye who believe! Remember the Grace of Allah (bestowed) on you, when there came down on you hosts (to overwhelm you): but We sent against them a hurricane and forces that ye saw not. But Allah sees (clearly) all that ye do." (33: 9)

        Islam emerged successful from the trial and was more family established than ever. This was the end of the aggressive power of the chiefs of Makkah. After the Battle of Trench the strength of the enemy was broken forever.

Banu Quraiza

     The Jewish tribe of Banu Quraiza, in violation of the agreement signed with the Holy Prophet (P.B.U.H), had helped the enemies of Islam in the battle of Ahzab. The Holy Prophet (P.B.U.H), therefore, advanced against their fortresses and surrounded them. The siega continued for about a month after which the Banu Quraiza surrendered. The agreed to accept the decision of Sa'ad Bin Mu'az regarding their fate. Sa'ad bin Mu'az was the chief of the Aus tribe with whom the Jews had been in alliance. Sa'ad applied the Jewish law of the Old Testament. According to this law the men Quraiza were killed, the women and children taken as captives of war and their lands and properties divided among the Muslims.

      The Holy Quran refers to this incident in these words: 

       "And those of the people of the book, who aided them - Allah did take them down from their strongholds and cast error terror into their hearts, (so that) some ye slew, and some ye made prisoners. And He made you heirs of their lands, their houses and their goods---." (33: 26-27)

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Battle of Badr - Second Year of Hijrat

Causes and Events

      During the first thirteen years of his mission, the Holy Prophet (P.B.U.H) had only one enemy to deal with in Makkah, the pagan Quraish, who eventually forced him to leave Makkah. But in Madinah, he had to face opposition from three quarters. First, were the Quaish of Makkah who were determined to crush the Holy Prophet (P.B.U.H) and his followers. The increasing strength of the Muslims was seen by them as a threat both to their prestige as custodians of the Ka'abah and to their social and economic leadership.

      Secondly, there were the Jews who had entered into  a treaty with the Holy Prophet (P.B.U.H), yet they began to intrigue, and their various tribes began to break treaties with the Muslims.

     Apart from these two enemies there were the hypocrites or the Munafiqin who had accepted Islam, but were working against the interests of the Muslims.

     The Holy Prophet (P.B.U.H) had hardly settled down in Madinah when the Quraish of Makkah sent word to the people of Madinah to hand over the Holy Prophet (P.B.U.H) and the emigrants to them, or kill them. The Ansar who had themselves, invited the Holy Prophet (P.B.U.H) to Madinah refused to do so.

     At the time Abu Sufyan, a rich and influential leader of the Quraish, was returning from Syria with a caravan carrying merchandise. He asked the Quraishto send an armed expedition to escort him home safely as he did not want to take the risk of interference from the Muslims on his way. The Quraish, despatched an army to join Abu Sufyan in Syria. When Abu Sufyan reached Makkah safely he asled the army to return but they refused to do so. Some of the leaders, like Abu Jahl, insisted on advancing towards Madinah.

     In month of Safar 2 A.H, Allah already given permission to fight against the unbelievers, "Fight in the cause of Allah those who fight you." (2: 190)

     When the Holy Prophet (P.B.U.H) learnt that the Quraish were advancing towards Madinah with the intention to attack, he immediately called the Muslims to take necessay steps. The Muhajirin and the Ansar got together to defend themselves. They were three hundred and thirteen men in all with only two horses and a few camels.

      The Quraish stopped at Badr, which is a village at a distance of about eighty miles from Madinah. They had come with a huge quantity of food supply with them. Since they had arrived at Badr first, they occupied all important positions. They were about one thousand in number with all their best warriors and arms and a large number of horese and camels.

      When the Holy Prophet (P.B.U.H) and his companions reached Badr, they were illequipped with arms and the place which they occupied had no water. Before the battle started, the Holy Prophet (P.B.U.H) prayed to Allah to help them against the enemies of Islam. The prayer was accepted and heavenly assistance was promised in these words of the Quran: 

       "Remember ye implored the assistance of your Lord, and He answered you: " I will assist you with a thousand of the angels, ranks on ranks." (8:9)

       Meanwhile, there was heavy rain and the Muslims collected sufficient water for their use. Ultimately, the two armies met and the battle started. While the battle was going on, the Holy Prophet (P.B.U.H) prostrated, before Allah and prayed: 

      "O Allah! If this small band of men perish, there will be no one alive to worship you, and your faith will be destroyed forever."

        Regarding these two ill-matched armies, the Quran Says: 

   "There has already been for you a sign in the two armies that met (in combat): one was fighting in the cause of Allah, the other resisting Allah: there saw with their own eyes twice number. But Allah doth support with His aid whom He pleaseth ---."(3: 13)

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Year of Grief - Life In Makkah

In the 10th year of Prophet, Hazrat Khadija died. In the same year the Prophet's uncle Abu Talib too, passed away. The Holy Prophet (P.B.U.H) was so deeply grieved by the deaths of his wife and his loving uncle that this year was called Am-ul-Hazn, "the Year of Grief."

      The death of Abu Talib, provided on opportunity to the enemy, to harm and persecute the Holy Prophet. The Muslims shared in his sorrow, but they were too weak to stand up against the Quraish or provide the kind of protection that he had lost due to the death of Abu Talib.

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Pledges of Aqabah First & Second Pledge

On his return to Makkah from Taif, the Holy Prophet (P.B.U.H) resumed his preaching concentrating more on strangers, who came to Makkah for the pilgrimage. In the eleventh year of Prophethood, six pilgrims from the tribe of Khazraj in Yasrib came to Makkah. The Holy Prophet (P.B.U.H) invited them to Islam. After hearing the teachings of Islam, they embraced the faith. When they returned to Yasrib, they introduced Islam to their friends and relatives.

     In this way, the message of Islam reached Yasrib. Next year, that is, the 12th year of the Prophethood, twelve persons from Yasrib met the Holy Prophet (P.B.U.H) at Aqabah, accepted the faith and agreed to abstain from idol worship, cruelly and falsehood, to lead a righteous life and to believe in One God. This is called the First Pledge of Aqabah. These Muslims promised to spread Islam in Yasrib, and the Holy Prophet (P.B.U.H) sent two persons with them to preach Islam to the residents of that city.

     In the 13th year of the Prophethood, a deputation consisting of seventy-five persons came from Yasrib to take the same pledge. This is called the Second Pledge of Aqabah. They also invited the Holy Prophet (P.B.U.H) to Yasrib and pledged full support for him and his followers. On the return of his deputation, Islam began to spread rapidly in Yasrib.

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Migration to Yasrib - Life in Makkah

a) Causes   

      It was after the pledges of Aqabah that the idea of migrating to Yarib was born in the heart of the Holy Prophet, but there were also strong reasons, which compelled him to leave Makkah for Yasrib.

     The people of Makkah were generally hard and ill tempered. On the other hand, the people of Yasrib were tender hearted and considerate, so Islam could find a more suitable ground in Yasrib then at Makkah in its early period of expansion.

     The Holy Prophet was hated and despised by his own people in Makkah, but he was invited by the people of Yasrib to come to their city.

     The priests of Makkah opposed Islam from the very beginning, because the success of Islam meant their own destructions, as Islam is opposed to idol, worship. In Yasrib, however, there was no priest class, so it was easier to preach Islam there.

       In Yasrib the two tribes of Aus and Khazraj, who had been at war with each other looked for a strong leader who could establish peace in their land, so they invited the Holy Prophet to come to their city.

       The Jews, who were living at Yasrib, had been informed of the coming of the Holy Prophet as a supporter of their scriptures, so they were eager to receive him.

        The aggressive attitude of the Quraish and their persecution was an important factor in the migration to Yasrib, specially the death of Abu Talib who had been his protector from the very beginning.

       After the pledges of Aqabah, the Muslims realized that the people of Yasrib were ready to welcome them and there was a place where they could seek refuge. 

b) Event of Migration

       When the unbelievers came to know of these development, they redoubled their persecution of the Holy Prophet (P.B.U.H) and his followers. The Prophet (P.B.U.H), therefore, advised them to emigrate to Yasrib secretly. Thereafter family after family left in this manner. By and  by, all the companions of the Holy Prophet (P.B.U.H) except Hazrat Abu Bakr and Hazrat Ali Succeeded in migrating to Yasrib.

         The Quraish held a meeting in the council hall, Dar-un-Nadwa, when it was decided that one person from each tribe should be selected who would simultaneously attack the Holy Prophet (P.B.U.H) and kill him. This way their object would be achieved and the Banu Hashim would not be able to take revenge.

         The Holy Prophet (P.B.U.H) was informed of this plan of his enemies by Allah and was told to leave Makkah that same night:

  "Remember how the unbelievers plotted against thee, to keep thee in bonds or slay thee, or get thee out (of thy home). They plot and plan, and Allah too plans, but the bast of planners is Allah." (8:30)

         They Holy Prophet (P.B.U.H) asked Ali to sleep on his bed, and to return the valuables entrusted to the Prophet (P.B.U.H) by various people. Then quietly, he left the house unnoticed by anyone. Accompanied by Abu Bakr, he made his way to Yasrib. As his enemies were looking for him everywhere, he stayed in the cave of Saur for three days and nights.

         Next morning, when the chiefs of Makkah found Ali in Hazrat Muhammad's (P.B.U.H) bed they were furious. Determined more than ever to find him, they offered a huge reward of one hundred camels for his capture, dead or alive.

         Many young men of the Quraish went out in search of the Holy  Prophet and came close to the cave. Hazrat Abu Bakr trembled with fear and exprected them to break into the cave. He said to the Holy Prophet, "If anyone of them looks down, he will find us." To this, the Holy Prophet answered: "O Abu Bakr, how can you fear for two men whose constant companion is Allah Himself?"

         This incident is mentioned in the Quran in the following words: ".....for Allah did indeed help him, when the unbelievers drove him out: he had no more than one companion: the two were in the cave, and he said to his companion, 'Have nor fear, for Allah is with us.' (9: 40)

c) Important of Migration

       The important of migration can be judged from the fact that the Muslim calender starts from this event and not from any other incident in the life of the Prophet.

           The migration not only completely altered the prevailing conditions of Arabia, but it changed the entire course of human history. Those who embraced Islam before migration used to pray secretly for fear of the unbelievers. As they were weak and in minority and the unbelievers were powerful and strong, it was not possible for them to fight for their faith or to defend themselves from the torture and persecution. It was after migration that Muslims became strong enogh to stand against injustice and persecution.

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Biosphere

Biosphere is a thin layer of earth in which all living organism exist. Organisms within the biosphere not only adapt to the environment but also interact to modify and control chemical and physical conditions of the biosphere. An organism lives in a habitat.

     Biosphere is spread out over the surface of planet earth extending about 8/10 kilometers in the upper reaches of atmosphere and also in same distance into the depths of oceans.

     An organism responds to a variety of environment factors, and only when all of them are within the range of tolrance, it can inhabit a location. The actual location of place where an organism lives is called its habitat.

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Ecological Niche

In 1917, Joseph Grinnell an American ornithologist first proposed the term niche in ecology.

      Niche is defined as the ultimate distributional unit within a species is restrained by the limitations of its physical structure and its physiology. The habitat and niche the basic are closely related. Charles Eton, considered the niche, the basic role of an organism in the community what it does in and for living community, its relationship to its food and enemies. In order words he denied the niche as the species occupation.

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Migration to Abyssinia

The hardships and suffering of the Muslims increased. The Holy Prophet therefore, gave permission to a group of Muslims to migrate to Abyssinia. Accordingly in the fith year of prophethood, a group of eleven men and four women secretly left Abyssinia. These included Hazrat Usman and his wife Ruqayya, daughter of the Holy Prophet (P.B.U.H). Then followed another group of seventy-nine men and seven women including Hazrat Jafar, son of Abu Talib. 

       Najashi, the Christian king of Abyssinia treated the Muslims with kindness and respect and the Muslims found a safe place to live.

       When the Quraish came to know of this, they sent a deputation with some gifts to the king to request him to hand over the emigrants to them.

'       Najashi was a kind and just man. He said in reply that he could not hand over the Muslims to them until he found out the truth about their religion. He called the Muslims to his court and after hearing the speech of Hazrat Jafar who explained the principles of Islam and what the Holy Prophet (P.B.U.H) had taught them, Najashi refused to send them back.

         It is said that Najashi asked Jafar to recite some ayats from the Holy Quran and Jafar recited a portion of Surah Maryam. After hearing it, Najashi said: "By God this and the Gospel are the lights of one candle".

          Thereafter Najashi returned the gifts brought by the leaders of Makkah. Thus the mission failed and the Quraish returned totally disappointed.

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The Meselson Stahl Experiment - Biology

 The three hypothesis of Dna replication were evaluated by Mathew Meselson and Franklin Stahl of the California Institute of Technology in 1958.

       The grew bacteria in a medium containing heavy isotope of nitrogen, N15 which became incorporated into the bases of the bacterial DNA.

       After several generations, the DNA of these bacteria denser than that of bacteria grown in a medium containing the isotope of nitrogen, N14

        Meselson and Stahl then, tranferred the bacteria from the N15 mediun to the N14 medium and collected the DNA at various intervals.

       They dissolved the DNA in Cesium Chloride and then spunt it at a very high speed in an ultra-centrifuge.

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Reasons for Opposition - Islam

The Quraish were leading tribe in the Arabian Paninsula. They were used to idol worship that the Holy Prophet openly condemend. They took the teachings of Islam as an insult to their religion and the ways of their forefathers.

   The location of the Ka'abah in Makkah gave them an important position as the custodians of the House. It was a source of income for them, particularly the priests, as the pilgrims to the Ka'abah would being rich gifts for their idols. In the rise of Islam, they saw the danger to their dignity and prestige and the loss of the important position which they had held for centuries. Apart from idol worship, adultery, drinking, gambling, murder and plunder were common among the Arabs, Islam condemned all these. Embracing Islam meant discaring these evil practices and adpoting a new mode of life. The Quraish were not at all ready to do that.

     The chiefs, particularly those belonging to the Banu Umayyah, Could not bear that anybody from among the Banu Hashim, the tribe to which the Holy Prophet belonged, should have supremacy over them. They were also of the view that the Quran should have been sent down to some influential person. The Quran says: "Also, they say: why is not this Quran sent down to some leading man in either of the two (chief) cities." (43: 31)

       The Quraish were proud of their chiefs, against whom they were not ready to accept the supremacy of the Holy Prophet (P.B.U.H) who neither had wealth nor sons nor any other sign of worldly power. The Quraish used to say: "Is this the one whom Allah has sent as a messenger?" (25:41)

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Reaction of early Muslims towards persecution

The Muslims of early days although limited in number, had very strong faith and belief in Allah and His prophet. They maintained this faith, regardless of the cosequences. For instance, the Muslim slaves who were tortured mercilessly by their masters never renounced their religion, and at times, lost their lives when given an alternative between idol worship and Islam.

        The Muslims were always united under the leadership of the Holy Prophet (P.B.U.H). Even when persecutions were at their peak, instructions set out by him were followed. When he advised them to migrate to Abyssinia, they migrated with the confidence that the advice of the Holy Prophet can only have a good outcome.

       The Muslims displayed the most amazing qualities of courage, discipline and patience in face of this persecution. It was borne patiently without complaints. The Muslims were forced to live in a valley for three years with women and children without any means of food and water for days at a time but they waited patiently for Allah's help. Although the believers were a very small group of people, they opposed the pagan ideas, defied the idol worshippers and followed a different religion.

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Preaching By The Holy Prophet (P.B.U.H)

The revelations stopped for some time. The Holy Prophet passed this time in restlessness and anxiety, until one day, he saw angel Jibrael again, in the sky seated on a chair. The Holy Prophet became frightened and rushed home. He asked Khadija to cover him up. She covered him up, after which he received another revelation which said:

     "O thou wrapped up (in a mantle)!

Arise and deliver thy warning!

And thy Lord do thou magnify." (74: 1-3)

    In obedience to the command of Allah, the Holy Prophet invited his friends and relatives to the religion of Islam. He preached to them the Oneness of Allah and warned them of the consequences of following their evil ways. But he did not, at this stage, make any public announcement. He confined his message only to those of his close friends and relatives that he thought would give a favourable response. The first person to believe in him was his wife, Khadija, who accepted his message without any hesitation. This was followed by the acceptance of Islam by ten year old, Ali, son of Abu Talib.

     The first freed slave to accept Islam was Zaid bin Haris. The first person to become a Muslim outside the Prophet's immediate family was his close friend, Hazrat Abu Bakr.

       Within a period of three years, while the Holy Prophet was preaching his message in secret, about forty righteous and God-fearing people accepted Islam. Among them were Usman, Talha, Zubair, Abdur Rehman bin Auf, Sa'ad bin Abi Waqas and Abdullah bin Masud.

         The early converts were the people who had witnessed the prophet's private and public life very closely and had arrived at the conclusion that such a gentle and honest person could not mislead the people.

         The came another revelation that said:

"And admonish thy nearest kinsmen." (26: 214)

         In order to carry out this command, the Holy Prophet invited his relatives to his house and said to them: "Allah has ordered me to call you to Him, so who amongest you will help me in this affair and be my friend, my adviser and may deputy?" No one responded to the message except Ali, who said: "O Prophet of Allah! I shall be your helper. I will fight him who fights you." The people laughed and dispersed making fun of the Holy Prophet.

         Soon afterwards he received another revelation through which the Holy Prophet was give the order to: "Expound openly what thou art commanded, and turn away from those who join false gods with Allah." (15: 94)

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Call to Prophethood - Life of Makkah

 With age and growing understanding Hazrat Muhammad became more aware of the corrupt society around him and it disturbed him greatly. He could not believe the polytheistic ideas of the pagans of Makkah and often thought of God of his forefathers, Ibrahim and Ismail. He did not follow any particular method of worship, beacuse he was not aware of any, but he realized that there is a force of truth beyond this world which must have power and control over the whole universe.

    A few years before the conferment of prophethood, he became more and more fond of solitude. He started retiring for days with a supply of dates, oatmeal and water into a cave in a nearby mountain, known as Hira. There he pondered and meditated over the condition of his people. These spells of loneliness and meditation because more frequent as he approached the age of forty.

    One day towards the end of Ramazan, he was at the mount of Hira, when angel Jibrael appeared before him and asked him to read. This was so sudden and unexpected that startled by the strange voice, he answered: " I cannot read ". Then he felt that he was being hugged and squeezed so hard that he thought that he would die of suffocation. He was then released and the request to read was repeated. "I cannot read", said Muhammad (P.B.U.H) again. The angel hugged him and asked him to read. Muhammad (P.B.U.H) was afraid of being squeezed a third time, So he asked: "What shall I read?" The angel the recited the following verses:

Proclaim (or read) in the name of thy Lord and Cherisher,

Who created

Created man, out of a (mere) clot of congealed blood.

Proclaim! And thy Lord is Most Bountiful,

He who taught (the use of) the pen.

Taught man that which he knew not" (96: 1-5)

      Muhammad recited these verses after the angel and the words were imprinted on his mind. This was the first revelation and the beginning of prophethood of Hazrat Muhammad. He was then forty years old.

       Muhammad (P.B.U.H) was greatly shaken by this experience and he ran out of the cave. Suddendly, he heard a voice and raising his head in the sky, he saw the same angel in the form of a man filling the whole horizon and saying: "O Muhammad (P.B.U.H), you are the messenger of Allah and I am Jibrael." Whichever may he looked, he saw the same vision and heard the same voice. He stood there until the angel disappeared.

       After the experience, he came home a bit shaken at his selection for this great and noble mission. He feared the thought of the huge and tremendous task of this mission. He narrated the incident to Hazrat Khadija. She comforted him and assured him that no harm could come to a man of his nature and the Allah would perotect him from all evils. Then she look him to her cousin. Warqa in Naufal, who was a scholarlyn person and had embraced Christianity.

         After hearing what had happened to her husband at the mount of Hira, he said that it was the Angel Jibrael who had always brought revelations to previouse messengers of God. He also informed her that his enemies would turn the new Prophet out of his city.

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Fruit Set & Fruit Ripening

Germinating pollen grain is not only in important structure for safe transfer of gametes and insurance for fertilization but also a rich source of auxis as well as commonly stimulating the tissues of the style and ovary to produce move auxin. This auxin is necessary for fruit set i.e. retention of the ovary, which becomes the fruit after fertilization. Without it abscission of flowers normally occurs, leading to low fruit yields.

Fruit Ripening: 

     After fertilization the ovary and the ripe seeds continue to produce auxins which stimulate fruit development.

       Developing seeds are not only a rich source of auxins and gibberellins but also of cytokinins. These growth substances are mainly associated which development of the embryo and accumulation of food reserves, in the seed and sometimes in the pericarp (Fruit Wall).

Climatric: 

       Fruit ripening is often accompanied by a burst of respiratory activity called climatric. This is associated with ethane production, which helps in ripening of the fruit.

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