Plant Cell
Cells are the structural and functional unit of life. All the living organisms are made up of the cells. It comprises of various cell organelles, which performs the function within the cell. The basic structure of a plant cell is given below:
The Various Cell Organelles of the Plant Cell are Given Below
Amyloplast
An organelle, found in some plant cells that stores starch. Amyloplasts is found in starchy plants, like tubers and fruits.
ATP
ATP stands for Adenosine Triphosphate. It is a high-energy molecule used for energy storage by organisms. In plant cell ATP is produced in the cristae of mitochondria and chloroplasts.
Cell Membrane
The thin layer of protein and fats that surrounds the cell from inside the cell wall, is called the cell membrane. It is selectively semipermeable and allows only some selective substances to pass into the cell through it, blocking others.
Cell Wall
It is a thick and rigid membrane that surrounds a plant cell. It is made up of cellulose fiber, which gives the cell most rigidity and support to the structure. The cell wall also helps to connect with other cell wall, to form the structure of the plant.
Centrosome
They are the small bodies located near the nucleus. It consists of a dense center containing radiating tubules. The centrosomes are made up of microtubules. During cell division (mitosis), the centrosomes divides into two parts, which move to the opposite sides of the dividing cell. Unlike the centrosomes in animal cells, the plant cell centrosomes do not have centrioles.
Chlorophyll
Chlorophyll is the molecules that can use light energy from sunlight to turn water and carbon dioxide gas into sugar and oxygen, during the process of photosynthesis. Chlorophyll is magnesium based and is usually green, which provides green colour to the plants.
Chloroplast
It is an elongated or disc-shaped organelle containing chlorophyll. Photosynthesis in plants takes place in the chloroplasts.
Christae
It is the multiple-folded inner membrane of a cell organelle. In mitochondria, it is a finger-like projections. The cell produces energy (ATP) on the walls of the cristae.
Cytoplasm
It is the jelly like material outside the more... 
Unicellular Organism
The organisms made up of single cell are called unicellular organisms. Most of the microorganisms, such as, bacteria is made up of single cell. The figure given below is of a cluster of Escherichia coli bacteria, which is magnified 10,000 times. Unicellular organisms are divided into two types:
(i) Prokaryotic
(ii) Eukaryotic cell
Unicellular Organism
The prokaryotic cells are those cells, whose nucleus is not bounded by nuclear membrane. The nucleus and cytoplasm cannot be differentiated. For example, Bacteria, Archaea etc.
The Eukaryotic cells are those cell, whose nucleus is bounded by the nuclear membrane. These cells are very complex and nucleus can be easily differentiated from the rest of the cell.
Drik went for a visit to a national park. He had not taken water bottle with him. Due to intense heat, he was feeling thirsty and could not resist himself from drinking water from the river. The very next day he was suffering from lose motion and vomiting. On consulting doctors, he was told that that, he was suffering from diarrhoea. Which organism was responsible for this?
(a) Virus
(b) Bacteria
(c) Plasmodium
(d) Flagella
(e) None of these
Answer: (b)
Explanation
Diarrhoea is caused due to the bacteria in the water and food.
We know that the milk can be changed into the curd. This conversion is done by the bacteria. Similarly, there are many such organisms, useful to us. The bacteria, which convert the milk into the curd is_______.
(a) Lactobacillus
(b) Salmonella
(c) E.coli
(d) L. monocytogenes
(e) None of these
Answer: (a)
Explanation
The bacteria which is found in milk is Lactobacillus. 
Introduction
What is biodiversity?
The term biodiversity is used to describe the variety of lives found on earth. It also refers to the wide varieties of animals and plants and their habitats. Biodiversity is the very foundation that is crucial for the functioning of ecosystem. There are basically two components of our ecosystem, biotic and abiotic. We are dependent on the ecosystem for our health, security, social life, freedom etc. It is very complex, dynamic and varied, as the features of earth.
Biodiversity Law
The efforts have been initiated long before to protect the wild fife from being extinct and endangered. It was in the Montreal meet of December 2003, the outlines of the role on the conservation of biological diversity, at international and national level, in creating awareness regarding the conservation of resources had been initiated. The laws regarding the biodiversity include environmental laws, rules and regulations for national biological diversity conservation activities. Like some other law, the impetus and mandate for this law is to spring up an international convention on biological diversity. The objective of CBD is biodiversity conservation, sustainable use of resources and equitable sharing of benefits from their uses.
The Draft Law on Biodiversity
The draft law on biodiversity stands as follows:
(i) The main objective of the Act is the conservation of biodiversity and sustainable use of resource.
(ii) The Act proposes to set up the governing bodies at three levels to carry out its functions. At national level NBD will screen the proposals for transfer of genetic recourses and advice the central government of the steps, necessary to prevent the violation of the Acts provision.
(iii) The second level is at state level, where the state biodiversity boards will see the use within the state Jurisdiction. It will also manage the state biodiversity funds.
(iv) The third level is the local level, managed by managing committee, which will look at the transferring, uses and conservation of resources at community level.
(v) The law also mandates the NBD to challenge the IPRs, and who ever found violating the rules and its community rights.
The provisions of the biodiversity law provide us the basic framework of achieving control over the access to the genetic resources, in the interests of conservation, sustainable use and assuring benefit sharing, from the use of resources. However, there are still certain aspects that need to be addressed and it is hoped that this would be taken care of in the rules, to be framed under the law. Rule making is an administrative act, which does not need to conform to the rigorous standards of debate and discussion as a law.
Provisions
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Conservation of Resources
The large scale deforestation has adverse effect on our environment. It had led to ecological imbalance and has destroyed the natural habitat of the animals, there by posing threat to their existence. The large scale killing of wild animals by hunters and poachers has disturbed the food chain in our ecosystem. We, therefore need to conserve these endangered species from being extinct, and maintain the ecological balance. The steps taken for the conservation of wild life:
(i) The relentless cutting of tree is strictly prohibited to stop the depletion of forest. Cutting of forest is punishable by law.
(ii) The natural habitats of animals are preserved in the form of national park and wild life sanctuaries.
(iii) There is strict law on hunting and poachers. Killing of animals is considered as a criminal offence.
The biosphere reserve is therefore, the conservation of forests and species of plants.
Biosphere Reserve
It is a large area of protected land for the conservation of wildlife, biodiversity and traditional life style of the people inhabiting the area. It is divided into three zones:
(i) Core zone
(ii) Buffer zone
(iii) Transition zone
The innermost zone of the reserve is known as core zone. It is mainly for the protection of wildlife, and no human activity is allowed in this zone. The middle zone is known as the buffer zone, in which limited humane activity is allowed. For example,research, environmental education and tourism. The outermost zone is known as the transition zone. In this zone, various human activities is carried out, such as, farming, housing, settlements, etc. Normally, the tribal people lives in this area and depends on the local natural resources for their requirement and necessities. No commercial exploitation of resources is allowed in the biosphere reserve. Some of the famous biosphere reserve in India are Andaman and Nicobar biosphere reserve, Kaziranga biosphere reserve, Sunderban reserve, Kanha reserve and Pachmarhi biosphere reserve.
Endemic Species
Endemic species are those, which are found in a particular region only. For example, the plant like Sal and wild mango are found in Pachmarhi biosphere reserve. The other species are giant squirrel, flying squirrel and bison are also the endemic species found in this reserve.
Endemic Species
There are some species, which are found in a specific region only and not else where naturally. Such species are known as:
(a) Endemic species
(b) Freshwater
(c) land species
(d) Coniferous plant
(e) None of these
Answer: (a)
Explanation
The species, which are found in some specific region are known as endemic species.
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Wild Life Conservation in India
The various steps taken to preserve the wildlife, which are on the verge of extinction, is called the wildlife conservation. Some of the Government initiative in this regard are, the Gir National Park for the protection of tiger in Gujarat, the Kaziranga Wild life Sanctuary in Assam is for saving Rhinocoers, the Periyar National Park in Kerela to preserve elephants and Dachigam National Park to preserve Kashmir! Stag.
Wild Life Conservation in India
Some of the Important Wildlife Sanctuaries in India are
(i) Bandhavgarh National Park in Madhya Pradesh
(ii) Corbett National Park in Utter Pradesh
(iii) Gir National Park & Sanctuary in Gujarat
(iv) Kanha National Park in Madhya Pradesh
(v) Kaziranga National Park in Assam
(vi) Periyar Wildlife Sanctuary in Kerela
(vii) Sariska Wildlife Sanctuary in Rajasthan
(viii) Sunderban National Park in West Bengal
(ix) Dachigam National Park in Jammu & Kashmir
(x) Manas Tiger Reserve in Assam
The wildlife sanctuary is meant for the preservation of different endangered species of animals. Which wild life sanctuary is famous for preserving tigers?
(a) Corbett National Park
(b) Sunderbans National Park
(c) Kaziranga National Park
(d) Bandhavgarh National Park
(e) None of these
Answer: (a)
Explanation
The different wild life century is meant for different animals and Corbett national park is famous for tiger.
Kaziranga national park is in Assam and is famous for preserving a particular type of animal. For which animal is it famous for?
(a) Deer
(b) Lion
(c) Rhinocoers
(d) Birds
(e) None of these
Answer: (c)
Explanation
Kaziranga wild life century is in Assam and is famous for Rhinocores.
List of National Parks
| Name State Established Area (in km2) |
| 1. Anshi National Park Karnataka 1987 250 |
2. Balphakram National Park more...
 Endangered Species
We can define the endangered species as those/ which are on the verge of extinction. They are either few in numbers or threatened by the environmental consequence or by the predators. According to the International Union for Conservation of Nature (IUCN), the percentage of endangered species is 40% of the all organism, based on the sample taken. The most endangered species is Dhole, which is on the verge of extinction. There is legal provision for protection of endangered species in many countries of the world. For example, the Pandas, Philippines Eagle, Javan Tiger, Passenger Pigeon, Caribbean Monk Seal, etc are some of the species, which are on the verge of extinction.
  
 There are many species, which are on the verge of extinctions. But, among them there are few species, which are considered as the most endangered one. Which one of the following is the most endangered species?
(a) Dhole
(b) Pandas
(c) Javan tiger
(d) Philippines Eagle
(e) None of these
Answer: (a)
Explanation
The species, whose population is very less, also there is a little chance of increasing their number in future, are known as endangered species. The most endangered species is Dhole, as the current world population of Dhole is estimated to be 2500.
In which one of the following states the Dalma Wildlife sanctuary is situated?
(a) UP
(b) Bihar
(c) Jharkhand
(d) Kerela
(e) None of these
Answer: (c)
Explanation
The Dalma wild life sanctuary is in the state of Jharkhand.
 Buoyancy
When an object is immersed in liquid an upward force acts on it, which is called buoyancy. The buoyant force does not depend upon the weight of the object or the shape of the object, it only depends on the weight of the liquid displaced by the object. This principle is applicable to all the object of any density. If the density of the object is more than the density of the liquid, the object will sink. But if the density of the liquid is more than the object, the object will float on the surface of the liquid. On the other hand, if the density of the liquid and objects are equal, the object will float with half part immersed in the liquid.
Buoyancy
When an object is immersed in liquid an upward force acts on it, which is called buoyancy. The buoyant force does not depend upon the weight of the object or the shape of the object, it only depends on the weight of the liquid displaced by the object. This principle is applicable to all the object of any density. If the density of the object is more than the density of the liquid, the object will sink. But if the density of the liquid is more than the object, the object will float on the surface of the liquid. On the other hand, if the density of the liquid and objects are equal, the object will float with half part immersed in the liquid.
 Find the weight of an object whose volume 45 m3 and density 2.4 gm/m3.
(a) 0.108kg
(b) 1.1 kg
(c) 2.4kg
(d) 3.2kg
(e) None of these
Answer: (a)
Explanation
Weight of an object is given by,
W = m x g
We can find the value of W by substituting the other parameters and we get the weight to be 0.108 kg.
Thomas throws a silver coin in the sea. The density of the coin is 0.985 gm/m3. Will the coin float on the surface of water or it will sink?
(a) Sink
(b) Float
(c) Float half immersed
(d) can't say
(e) None of these
Answer: (b)
Explanation
Since the density of the coin is less than the density of water, hence it will float on water.
 Amount of Buoyancy
The amount of buoyancy of a body is determined by the body's specific gravity. Specific gravity is the ratio of the weight of a body to the weight of the water it displaces. Pure water has a specific gravity 1. The specific gravity of other objects is determined by finding the ratio of the density of the object to the density of the water. Objects with the gravity of less than 1 will float and the object with a specific gravity greater than 1 will sink.
Archimedes' Principle
From the above figure, we can observe that when a weight is hanged with the help of a spring balance, the weight is more in air and less when it is dipped into the liquid. This is because, when the weight is immersed into the liquid, the buoyant force acts on it in upward direction, which reduces its weight. The decrease in the weight is equivalent to the weight of the liquid displaced by the object immersed in it.
more...  Archimedes Principle
Archimedes of Syracuse (circa 287 BC - 212 BC), was a Greek mathematician, astronomer, philosopher, physicist and engineer. He was killed by a Roman soldier during the sack of the city, despite orders from the Roman general, Marcellus, that he was not to be harmed. Some historians of Mathematics consider Archimedes as one of the greatest mathematicians in history, along with possibly Newton, Gauss and Euler. Also, St. Lucy was from Syracuse. She died because her eyes was taken out with forks by the violent people.
Archimedes Principle
The concept was put on around 212 B.C., by the Greek scientist Archimedes. According to this principle, an object immersed fully or partially in the liquid is acted upon by the upward force, which is equivalent to the weight of the liquid displaced by the object.
Mathematically, if M is the mass of the liquid, its weight is given by:
W= M x g
If V is the volume of the liquid, andp is the density of the liquid, its mass is given by:
M = pxV
Hence, W = px V xg..  Atmospheric Pressure
Our atmosphere contains large volume of mixture of gases. These gas exert pressure on the objects form all directions. This pressure is called atmospheric pressure. The atmospheric pressure is maximum at the sea level and minimum on the top of the mountains. This is because the air volume is maximum on the sea level and minimum at the top of the mountain. Thus, as we go up the pressure goes on decreasing. The air pressure on the surface of earth is 101.3 kPa and on the surface of sea-level is 760 mm of Hg.
We can demonstrate the existence of atmospheric pressure with the help of the following activity:
Take a glass jar and fill it with the water up to the brim. Place a sheet of paper on its brim so that no air molecule remains inside. Now keeping the paper in its position, invert the jar in downward direction. You will observe that, the paper does not fall off, though the jar is full of water and exerting pressure in downward direction. This is because of the fact that, the atmospheric pressure acting on the paper in the upward direction, holding the paper sheet in its position. The upward pressure on the sheet is more than the downward pressure, hence it is not falling.
 Pressure Inside Our Body
Our body contains liquid in the form of water and blood. These blood flow through the blood vessels and exert pressure on the wall of the vessels. This pressure is called blood pressure. Our body is balanced by the atmospheric pressure and blood pressure and hence we do not get crushed. Our body is so balanced by these pressures that we never feel discomfort. But if we go up high on the mountain where the pressure is very low, we start feeling uncomfortable and uneasy. Many people even start nose bleeding at higher altitude. This is because, due to the difference in the pressure at higher altitude the blood vessel in our body burst and bleeding starts.
Application of Atmospheric Pressure
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