North America has been named after Amerigo Vespucci, an Italian explorer. However, Christopher Columbus is credited with the discovery of this continent.
The continent lies in the northern and the western hemispheres surrounded by the Arctic, the Atlantic and the Pacific oceans. The Isthmus of Panama joins North America to South America.
The United States of America and Canada occupy three fourths of North america.
NorthAmerica can be divided into four major physical divisions— the Canadian or Laurentian Shield, the Western Mountain System or Western Cordilleras, the Eastern Highlands or Appalachian Mountains and the Central Lowlands or Great Central Plains.
The Canadian Shield is composed of some of the oldest known hard rocks of the world. The surface of the Shield consists of many deep depressions formed by scraping and scouring out by moving ice. These depressions have been filled up with meltwater to form many freshwater lakes such as the five Great Lakes.
The Western Cordilleras are a series of young fold mountain ranges which have many active and extinct volcanoes, earthquake-prone regions and hot springs. The Cordilleras consist of several parallel ranges such as the Alaska Range and the Brooks Range. The highest point in North America, Mt McKinley, lies here. .
The Appalachians are lower than the Western Cordilleras. The eastern slopes of these highlands are very steep.
The edge of the Piedmont Plateau (located at the foot of the Appalachians or the Eastern Highlands) has many waterfalls along its length. It is referred to as the Fall Line.
The Great Central Plains have the largest river system in North America—the Mississippi-Missouri river system.
North America has several large rivers such as the Mississippi, Missouri, Mackenzie, Nelson, St Lawrence, Hudson, Yukon, Columbia and Rio Grande.
Lumbering is an important activity in the coniferous or taiga forests of Canada, carried out by lumbermen or lumberjacks.
Lumbering involves several stages of work such as cutting, skidding and hauling.
IMPORTANT TERMS
Gorge : A deep narrow valley with near vertical sides. Intermontane plateau: a plateau surrounded by mountains on all sides. Lumbering : The cutting down of trees and the processes leading to the manufacture of products like paper, newsprint, synthetic fibres, etc. Lumberjacks : Workers engaged in lumbering. Meltwater : Water derived from the melting of glacier ice and/or snow.
VALUES AND LIFE SKILLS
All occupations are important. Every job has dignity and deserves our respect.
The climate of South America is influenced by its location, presence of the Andes Mountains, prevailing winds, nearness to seas and oceans, and the impact of ocean currents.
The vast continent of South America has a climate that varies from the equatorial climate in most of Brazil, to the desert climate of the Atacama and Patagonian Deserts.
Some areas of Venezuela, Guyana, and Brazil also experience tropical climate. There is a small stretch of central Chile which experiences Mediterranean climate. Southern Chile has a maritime climate.
Different climates have influenced the natural vegetation found in South America. Forests exist in areas that receive heavy rainfall throughout the year such as the equatorial forests of the Amazon Basin. Grasslands predominate in regions that record maximum rainfall during the summers such as the grasslands in Guyana and Brazil. Deserts exist in areas that receive hardly any rainfall such as the Atacama and Patagonian Deserts. Mountain vegetation grows in the Andes and Mediterranean vegetation is found in central Chile.
The wildlife of South America includes several unusual species such as the anaconda, birds such as the egret, rhea, and condor, and animals such as the guanaco, vicuna, and llama.
Hardwood trees like mahogany, rosewood, and rubber are found in the selvas. Brazil nuts, balsa, cinchona for quinine, gum, resins, and dyes are other products obtained from these forests. Yerba mate is an important tree that grows in the Eastern Highlands.
Rivers like the Amazon, Orinoco, and Parana provide inland water transport. Brazil, Argentina, Paraguay, and Venezuela have developed hydroelectric power projects.
South America is rich in minerals ranging from crude oil, copper, diamond, gold to silver. This is what attracted the Europeans to settle in this continent.
IMPORTANT TERMS
Campos : the tropical grasslands in central Brazil. Gran Chaco : lowland alluvial plain in interior south-central South America. Armadillo : an animal found in South America with a hard shell made of pieces-Of bone. Lguana : a large tropical lizard found in South America
Chemistry is a fascinating science, full of unusual trivia. Chemistry is indeed in our everyday life. We find chemistry in the food we eat, the air we breathe, cleaning products, our emotions and literally every object we can see or touch.
Chemists use all kinds of equipment in their labs to run their experiments. In this topic, you will see some of the most common pieces of equipment and their uses and also precautions to be taken in the chemistry lab.
When performing experiments, taking accurate measurements is crucial. There are a wide variety of measurements that can be taken depending on the task at hand.
In this chapter, you will find a table which contains images of basic apparatus and how to use each piece of equipment in the laboratories.
Common laboratory apparatus and equipment
We must use our everyday experiences to understand various natural phenomena. In living beings, observation employs the senses. In science, observation can also involve the recording of data using instruments. It also refers to any data collected during the scientific activity. Careful observations help us to draw scientific conclusions.
A chemistry laboratory helps students to:
Observe and see for themselves.
Understand the difference between different compounds.
Learn the importance of observation and experiment.
Precautions to be taken in the chemistry lab
Safety is a key concern in any scientific enterprise, but particularly in the chemistry laboratory. There are many potential hazards when working with chemicals, but all of them can be avoided with the appropriate precautions.
Always wear an apron to protect your clothes.
Never work alone with chemicals.
Never touch or taste any substance.
Use small quantities of substances.
While heating substances, stand away from the burner and hold the tube away from yourself to avoid splashing.
Arrange apparatus and reagents in an orderly manner before starting the experiment
The cultivation methods depend upon the characteristics of the physical environment, technological know-how and socio-cultural practices. Farming varies from subsistence to commercial type. In different parts of India, the following farming systems are practised.
Primitive Subsistence Farming
It is a ‘slash and burn’ agriculture. Farmers clear a patch of land and produce cereals and other food crops. When the soil fertility decreases, the farmers shift and clear a fresh patch of land for cultivation. It is known by different names in different parts of the country. It is known as jhumming in north-eastern states.
Land productivity is low in this type of agriculture.
This type of farming depends on monsoon.
This farming is practised in a few parts of India.
Intensive Subsistence Farming
This type of farming is practised in areas of high population pressure on land.
It is labour-intensive farming, where high doses of biochemical inputs and irrigation are used for higher production.
Commercial Farming
This type of farming uses higher doses of modern inputs such as high yielding variety (HYV) seeds, chemical fertilisers, insecticides and pesticides to obtain higher productivity.
Plantation is a type of commercial farming in which a single crop is grown on a large area. Plantations cover large tracts of land, using capital intensive inputs, with the help of migrant labourers. All the produce is used as a raw material in industries.
Eg: Tea, Coffee, Rubber, Sugarcane, Banana.
Cropping Pattern
India has three cropping seasons:
Rabi
Kharif
Zaid
Rabi
Kharif
Zaid
Sowing Season
Winter from October to December
Beginning of the rainy season between April and May
In between the Rabi and the Kharif seasons, there is a short season during the summer months known as the Zaid season (in the months of March to July)
Watermelon, Muskmelon, Cucumber,Vegetables and Fodder crops
Major Crops in India
A variety of food and non-food crops are grown in different parts of India, depending upon the variations in soil, climate and cultivation practices. Major crops grown in India are:
Rice
Wheat
Millets
Pulses
Tea
Coffee
Sugarcane
oil seeds
Cotton
Jute
We will discuss all of these one by one, in detail.
Rice
It is a kharif crop.
It requires high temperature and high humidity with annual rainfall above 100 cm.
India is the second largest producer of rice in the world after China.
It is grown in the plains of north and north-eastern India, coastal areas and the deltaic regions.
Wheat
This is a rabi crop.
It requires a cool growing season and bright sunshine at the time of ripening.
It requires 50 to 75 cm of annual rainfall evenly distributed over the growing season.
The Ganga-Satluj plains in the north-west and black soil region of the Deccan are two main wheat-growing zones in India.
It is the second most important cereal crop and main food crop, in the north and north-western part of India.
Millets
Jowar, Bajra and Ragi are the important millets grown in India.
These are known as coarse grains and have very high nutritional value.
Jowar
Bajra
Ragi
3rd most important food crop with respect to area and production.
Grows well on sandy soils and shallow black soil.
It is a crop of dry regions.
It is a rain-fed crop mostly grown in the moist areas.
Grows well on red, black, sandy, loamy and shallow black soils.
Mainly produced in Maharashtra, Karnataka, Andhra Pradesh and Madhya Pradesh.
Major producing states are Rajasthan, Uttar Pradesh, Maharashtra, Gujarat and Haryana.
Major producing states are Karnataka, Tamil Nadu, Himachal Pradesh, Uttarakhand, Sikkim, Jharkhand and Arunachal Pradesh.
Maize
It is a Kharif crop.
It requires temperature between 21°C to 27°C and grows well in old alluvial soil.
It is used both as food and fodder.
Major maize-producing states are Karnataka, Madhya Pradesh, Uttar Pradesh, Bihar, Andhra Pradesh and Telangana.
Pulses
India is the largest producer and consumer of pulses in the world.
Pulses are the major source of protein in a vegetarian diet.
Major pulses grown in India are Tur (Arhar), Urad, Moong, Masur, Peas and Gram.
Pulses are mostly grown in rotation with other crops so that the soil restores fertility.
Major pulse producing states are Madhya Pradesh, Rajasthan, Maharashtra, Uttar Pradesh and Karnataka.
Food Crops other than Grains
Sugarcane
It is a tropical as well as a subtropical crop.
It grows well in hot and humid climates with a temperature of 21°C to 27°C and annual rainfall between 75cm to 100cm.
It can be grown on a variety of soils.
Needs manual labour from sowing to harvesting.
India is the second largest producer of sugarcane only after Brazil.
Sugarcane is the main source of Sugar, Gur (Jaggery), Khansari and molasses.
The major sugarcane-producing states are Uttar Pradesh, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh, Telangana, Bihar, Punjab and Haryana.
Oil Seeds
Different oil seeds are grown covering approximately 12% of the total cropped area of India. Main oil-seeds produced in India are:
Groundnut: is a Kharif crop and accounts for half of the major oilseeds produced in India. Gujarat is the largest producer of groundnuts.
Mustard: is a rabi crop.
Sesamum (til): is a Kharif crop in the north and rabi crop in south India.
Castor seeds: It is grown as both Rabi and Kharif crop.
Linseed: is a rabi crop.
Coconut
Soyabean
Cotton seeds
Sunflower
Tea
It is also an important beverage crop introduced by the British in India.
The tea plant grows well in tropical and sub-tropical climates with deep and fertile well-drained soil, rich in humus and organic matter.
Tea bushes require warm and moist frost-free climate all through the year.
Tea is a labour-intensive industry.
Major tea producing states are Assam, hills of Darjeeling and Jalpaiguri districts, West Bengal, Tamil Nadu and Kerala.
Coffee
Yemen coffee is produced in India and this variety of coffee is in great demand all over the world. Its cultivation was introduced on the Baba Budan Hills and is confined to the Nilgiri in Karnataka, Kerala and Tamil Nadu.
Horticulture Crops
India is a producer of tropical as well as temperate fruits. Major crops produced are pea, cauliflower, onion, cabbage, tomato, brinjal and potato. Some of the famous horticulture crops grown in India are:
Mangoes of Maharashtra, Andhra Pradesh, Telangana, Uttar Pradesh and West Bengal Oranges of Nagpur and Cherrapunjee (Meghalaya), bananas of Kerala, Mizoram, Maharashtra and Tamil Nadu.
Lichi and Guava of Uttar Pradesh and Bihar
Pineapples of Meghalaya
Grapes of Andhra Pradesh, Telangana and Maharashtra
Apples, pears, apricots and walnuts of Jammu and Kashmir and Himachal Pradesh
Non-Food Crops
Rubber
Fibre
Cotton
Jute
It is an equatorial crop.
Cotton, Jute, Hemp and Natural Silk are the four major fibre crops.
It is a Kharif crop.
It is known as the golden fibre.
It requires a moist and humid climate with rainfall of more than 200cm and temperature above 25°C.
Cotton, Jute and Hemp are grown in the soil.
It requires hightemperature, light rainfall, 210 frost-free days and bright sunshine for its growth.
It grows well on well-drained fertile soils in the flood plains. High temperature is required for its growth.
It is an important industrial raw material
Natural Silk is obtained from cocoons of the silkworms fed on green leaves
Cotton growswell in black cotton soil of the Deccan plateau.
It is used in making gunny bags, mats, ropes, yarn, carpets and other artefacts.
Mainly grown in Kerala, Tamil Nadu, Karnataka and Andaman and Nicobar islands and Garo hills of Meghalaya.
Rearing of silkworms for the production of silk fibre is known asSericulture.
Major cotton-producing states are Maharashtra, Gujarat, Madhya Pradesh, Karnataka, Andhra Pradesh,Telangana, Tamil Nadu, Punjab, Haryana andUttar Pradesh.
Major jute producing states are West Bengal, Bihar, Assam, Odisha and Meghalaya.
Technological and Institutional Reforms
Agriculture provides a livelihood for more than 60% of its population, so this sector needs some serious technical and institutional reforms. The Green Revolution and the White Revolution were some of the reforms initiated by people to improve agriculture.
Some Initiatives taken by the Government are:
Schemes introduced by Government such as Kissan Credit Card (KCC), Personal Accident Insurance Scheme (PAIS).
Special weather bulletins and agricultural programmes for farmers on the radio and television were introduced.
The government also announces minimum support price, remunerative and procurement prices for important crops to check the exploitation of farmers by speculators and middlemen.
Contribution of Agriculture to the National Economy, Employment and Output
In 2010-11 about 52% of the total workforce was employed by the farm sector.
The share of agriculture in the GDP is declining.
Indian Council of Agricultural Research (ICAR), agricultural universities, veterinary services and animal breeding centres, horticulture development, research and development in the field of meteorology and weather forecast, etc. are a few of the initiatives introduced by the government to improve Indian agriculture.
The transport system in the body is called as circulatory system.
Circulatory system in Human Begins:
The human circulatory is consist of heart, blood and blood vessels and lymphatic system. It is also called as circulatory system.
Human Heart:
The human heart is pinkish coloured about size of fist. It is located in between two lungs in rib cage. It has four hollow chambers with two thin walled auricles and two thick walled ventricles. These chambers mean to prevent the mixing of pure and impure blood. There interventricular septum which separates right and left ventricles.
Auricles: Also termed as atrium. Theses arte upper chambers of the heart with thin walls and receive blood from different parts of body. The right auricle revives impure blood while left auricle receives pure blood.
Ventricles: These are lower chambers of heart with thick walls as they have to pump the blood to outside. The right ventricle pumps impure blood while left ventricle pumps pure blood. The septum divided the heart into left and right sides. The Blood: Blood is red coloured fluid which as as connective tissue which supply nutrient as well remove waste from all body parts. Human body contain on average 5 litre of blood. ➢ Components of blood: Plasma : (60% In blood) It is liquid part of blood contains 90-92% of water , 7% protein 1% inorganic salts and about 0.1%glucose and traces of other substances. ➢ Blood cells: (40%) This is cellular part of blood. There are three types of cells in human blood such as red cells, white blood cells and blood platelets.
Red Blood Cells • Also called as erythrocytes. They are minute, biconcave circular structure, found about 5.5million/mm3 . • They contain more haemoglobin as they get mature and loses nucleus, ribosomes and mitochondria. • Oxygen combines with haemoglobin to form oxyhaemoglobin and when carbon dioxide combines with it forms carbaminohaemoglobin. • Red cells transport whole absorbed oxygen as they lack in mitochondria. • They are produce in long bone’s marrow and having the life span about 120 days White Blood Cells: • Called as leucocytes • They are large , irregular or oval colourless nucleated structure. They are found to be 7000/mm3 in an adult. • They are produced in red bone marrow and lymph nodes. • Leucocytes are of two types: (A)Granulocytes are subdivided into acidophil, Basophils and Neutrophils. (B)Agranulocytes : without granules and contain unlobed nuclei. Divided into lymphocytes and monocytes. Lymphocytes performed phagocytic action against infection causative agents. They have lifespan of about two weeks. • The lifespan of WBC’s ranges from 12 hours to 12 days Blood platelets: • They are termed as thrombocytes, found about 2,50,000/mm3 of blood. • They are oval, round or rod like cytoplasmic structure with only granules. • Blood clotting is the main function of platelets in order to prevent excessive blood loss Blood Groups: Karl Landsteiner discovered the blood grouping system Blood group are distinguished on the basis of presence of antigen and antibody. Antigens are foregn bodies which are capable of generating an immune responsein the body where as Antibodies are proteins that are produced by the body, as they work fight against the antigens. Four types of blood groups: A, B , AB, O in human beings on presence or absence of antigen and antibodies.
Blood vessels:
Blood vessels form network of tubes which carry blood away from the heart and towards heart.
They perform transportation and divided into following: o Arteries: Carries oxygenated blood from heart and transported to all body tissues (Except pulmonary artery which carries deoxygenated blood) They have thick and muscular wall and elastic to withstand the blood pressure Lumen of arteries is small and lack valves Smallest artery called as arterioles.
o Ventricles: Carries deoxygenated blood to heart (except pulmonary vein which carry oxygenated blood) The walls of veins are thin less muscular and non-elastic. They do possess valve and blood flows through it with little pressure. Small veins are called as venules . Vein collapse when empty..
o Capillaries: They are microscopic vessels They are terminal branches of artery and re-join to give rise to vein. Thin layer of it, enables for exchanging nutrients oxygen and carbon dioxide along with tissues.
Blood circulation:
• The pumping action of heart starts by initiation of heart contraction of its muscular walls • Alternate contraction and relaxation continues regularly • The right auricle receives blood rich in carbon dioxide from two major veins , vein lie in back and front of heart. • The blood the flows from right auricle to the right ventricle and then to the lungs through the pulmonary artery. • The gaseous exchange in the lungs turns the deoxygenated blood to pure blood ,makes it rich in oxygen. • This blood reaches to left auricle through the pulmonary veins. It then passes to the left ventricles • From the left ventricles, the oxygenated blood is pumped into aorta , which is largest artery in the body and is supplied to all the body parts.
Blood pressure:
The pressure exerted on wall of blood vessels is called as blood pressure. ▪ Upper limit of blood pressure is called systolic pressure , which ranges from 100-140 mm of Hg ▪ Lower limit of blood pressure called as diastolic pressure, which ranges from 60-80 mm of Hg When person having more than 140 mm systolic and 90mm diastolic is consider to be suffering from Hypertension or high blood pressure. Blood pressure is measured by Sphygmomanometer. The Heart Beat: The contraction of auricle and ventricles produce a sound called as Heart-beat The sequence of events taking place during one complete heartbeat is known as cardiac cycle. The contraction phase is systole followed by relaxation phase is diastole. Heart beat last for 0.85 seconds. During each heartbeat, two sounds are produced. The contraction of auricles produces weak sound which is followed by string sound produced by contraction of ventricles. Heartbeat can by listen by stethoscope.
Pulse:
The rhythmic beating of the arteries due to beating of the heart is called pulse. This rhythm or simply wave can be felt anf counted in the superfacial and radial arteries near wrist. This count represent the count of heart beat.
Respiration – The process, in which the energy is released by breaking down food for life activities, is called respiration.
Stages of Respiration – The process of respiration take place in two stages –
Breathing or external respiration – It involves the inhalation of oxygen rich air and exhalation of carbon dioxide rich air. Cellular or internal respiration – It causes breakdown of glucose with the help of oxygen into CO2, water and energy. C6H12O6 (Glucose) + 6O2 (Oxygen) 6CO2 (Carbon dioxide) + 6 H2O + Energy (38 ATP)
Site for respiration – This process partially takes place in cytoplasm and partially in mitochondria of the cell.
Types of Respiration –
Aerobic Respiration – This respiration results in the breakdown of glucose in the presence of oxygen. Anaerobic – This respiration results in the breakdown of glucose in the absence of oxygen. C6H12O6 2 C2H5OH + 2CO2 + 2ATP
Respiratory System in Humans – The passage through which the exchange of gases takes place is called respiratory tract. It involves various organs like nose, nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveolar sacs, and alveoli.
Exchange of gases – In this process, we inhale oxygen rich and exhale carbon dioxide rich air. Breathing – It is the process by which we take oxygen rich air in our body and air rich in carbon dioxide is taken out from our body. Breathing rate – breathing rate of a woman is faster than a man and it is not always constant. For an adult – 15 to 18 times in a minute
Mechanism of breathing – Breathing takes place in lungs. The air passes through nasal cavity and windpipe and reaches to lungs. Breathing involves the movement of ribcage and diaphragm.
It includes – Inspiration or inhalation – taking in oxygen Expiration or exhalation – giving our carbon dioxide
Common respiratory diseases –
Asthma – caused due to allergy and respiratory passage becomes swollen and constricted. Bronchitis – it is the swelling of lining of bronchial tube. It makes breathing difficult. Pneumonia – it is the inflammation of lungs tissue. Tuberculosis – it is the infectious disease that affects the lungs
Nutrition – It is a process which involves the utilization of food by an organism to give out energy for growth and development.
Stages of Nutrition in Humans –
Ingestion – process of taking food into the body
Digestion – breakdown of large insoluble food molecules into small water soluble molecules.
Absorption – the digested food is absorbed and passed through the intestinal wall into the bloodstream.
Assimilation – process of utilization of absorbed food
Egestion – elimination of undigested food. Human Digestive System – The digestive system is made up of two parts.
Alimentary canal – It is a muscular and tubular structure which starts from the mouth and ends at the anus. The important parts of alimentary canal are i. Mouth – the ingestion and digestion of food starts here. ii. Pharynx – it receives food from the mouth and air from the nose to throat. It is meant only for food to pass through. iii. Oesophagus – also known as food pipe. It connects pharynx to the stomach. iv. Stomach – it a muscular, J shaped, bag like structure. The food is churned and gets mixed well with the digestive juices. v. Small intestine – Most of the digestion and absorption of nutrients and minerals from the food takes place here. vi.Large intestine – It is mainly involved in absorption of water from the undigested food. vii.Rectum viii. Anus
Digestive glands – These are associated with alimentary canal. They secret enzymes that speed up the biochemical reaction and aid in digestion of food. In digestive system, there are –
i. salivary glands
a. submandibular
b. sublingual and
c. parotid
ii. Pancreas – It secrets pancreatic juices which are poured into small
intestine along with bile.
iii. Liver – It is the largest gland of the body. It secretes bile juice.
Process of Digestion – It involves the breakdown of complex food
molecules into simpler food particles. There are seven different stages of
process of digestion. These are –
In mouth – breakdown of carbohydrates
In the pharynx and oesophagus
In the stomach
Food in small intestine
Absorption of digested food in the small intestine
In the large intestine
Assimilation Enzymes and their functions – they are proteins which act as biological catalysts. Properties of enzymes –
They are more active at optimum temperature.
They are not destroyed during catalysis and can be reused.
They are sensitive to pH.
They are specific in their actions.
They are needed in small amount. Indigestion – it is a common condition which is related to upset stomach. It is also called dyspepsia. Symptoms –
Pain or discomfort in belly.
Bloating (Swelling of stomach)
Sense of uncomfortably full after eating.
Heartburn – it is caused due to the release of acid by stomach.
Healthy eating habits –
Eat healthy food like green leafy vegetables
Eat food slowly helps in detecting hunger.
Eat oats and other fibre rich grain.
Have a regular family meal.
Always turn the TV off while having meal. Unhealthy eating habits –
We should never skip breakfast as doing so drains out energy from our body.
Energy large amount of food in one sitting is also an unhealthy eating habit that should be avoided.
Eating food while watching TV, working, reading, even cooking food is also unhealthy eating behaviour.
Eating junk and oily food also sets you up for even gain.
Consuming sugar in large amount is also an unhealthy eating habit. Ways to keep oneself healthy –
Eating many small meals instead of two or three meals.
Avoiding snacks at last time.
Avoiding spicy food and coffee.
Avoiding smoking and chewing tobacco.
Avoiding laying down immediately just after eating food
Cell – it is the basic structural and fundamental unit of an organism. These are called building blocks of our body.
Discovery of Cell – The term cell is first coined by an English scientist Robert Hook in 1665. He used microscope to see a thin slice of dead cork. In this slice, he observed some honeycomb like structures and he named them cell.
Microscope – A device used to see very tiny objects that are not visible to naked ayes.
Cell theory – On the basis of remarkable findings, the basic features of modern cell theory states that – a. All living things are made up of one or more cells. b. Cells are the basic structural and functional unit of organisms. c. The chemical composition and metabolic processes of all the cells is same. d. All new cells are arises by the division of pre-existing cells.
Number, Shapes and Size of the Cell – Cells greatly differ in their shape, size and number like organism such as bacteria is made up of single cell. Hence, called unicellular and organism which are made up of multiple organism like humans are called multicellular organisms.
Cells can be irregular, oval, oblong, elongated and thread like in shape.
Mostly cells are microscopic. Cell – the structural unit of life Cells vary in their shape, size and number. However, the basic structural components are same. Every organism like plants, animals and humans are made up of cells. Cell – the functional unit of life All the life processes performed by our body are due to the activity of cells present in our body. Example – root cells of plant absorb water and mineral from the soil.
Basic structure of the cell –
The prime components of a cell are –
Cell membrane – It forms the outer boundary of the cell. It is known as plasma membrane in plant cell. It is living.
Cell wall – It is the outermost protective layer of a cell. It is non-living.
Nucleus – It is the small spherical mass present in the centre of cytoplasm. It has a surrounding membrane called nuclear membrane. It contains chromosomes. It regulates and controls various activities in a cell.
Cytoplasm – It is a semi-liquid substance enclosed by cell membrane.
Cell Organelles – Some of the main cell organelles present in cytoplasm are – i. Endoplasmic reticulum ii. Ribosome iii. Mitochondria iv. Golgi bodies v. Lysosome vi. Centrosome vii. Plastids viii. Vacuoles
Minerals are those in which individual crystals are composed of unit cells or basic unit layers of two or more types. Minerals are inorganic catalysts that function as regulators of metabolic activities in the body.
Isolation of elements in Chemistry class 12th aims to teach the students about the various processes of extraction of metals from ores. Very few metals such as the noble metals, i.e., Gold, Silver, Platinum, etc are present in their original metallic forms in nature.
Metallurgy is the field of science which deals with the extraction of metals from ores which are naturally found in the environment. Most of the elements especially metals are presently combined with other elements and these are called minerals.
An element may combine with a variety of other elements to make myriad minerals but out of them, only a few are viable sources of that metal. Such sources are called ores. Let’s have a brief look into some ores and minerals.
Aluminium
Bauxite Kaolinite (a form of clay)
AlOx(OH)3-2x [where 0 < x < 1] [Al2 (OH)4 Si2O5]
Iron
Haematite Magnetite Siderite Iron pyrites
Fe2O3 Fe3O4 FeCO3 FeS2
Copper
Copper pyrites Malachite Cuprite Copper glance
CuFeS2 CuCO3.Cu(OH)2 Cu2O Cu2S
Zinc
Zinc blend/Sphalerite Calamine Zincite
ZnS ZnCO3 ZnO
Extraction of Ores And Minerals
The process of extracting metal ores buried deep underground is called mining. The metal ores are found in the earth’s crust in varying abundance. The extraction of metals from ores is what allows us to use the minerals in the ground! Ores are very different from the finished metals that we see in buildings and bridges. They consist of the desired metal compound and the impurities and earthly substances called gangue.
The extraction of metals and their isolation occurs over a few major steps.
Concentration of Ore
Isolation of metal from concentrated Ore
Purification of the metal
Difference between Ores and Minerals
Here we have provided the major differences between Minerals and Ores.
Minerals
Ores
All the naturally occurring substances that are present in the earth’s crust are known as Minerals.
Ores are usually used to extract metals economically. A large number of metals are present.
All Minerals are not ores.
All ores are minerals.
Minerals are native forms in which metals exist.
Ores are mineral deposits.
FAQs
1. What is the difference between minerals and ores? Ans: Ore is the rock from which the metal is extracted in a convenient and economical way. Ore has a composition that is definite. Metals that occur naturally in the earth’s crust are called minerals. Minerals that can profitably be used to get the metal are called ores.
2. What are the different types of ores? Ans: Ores are the minerals from which metal is conveniently and profitably extracted. There are mainly four kinds of ores like Ores Oxides; Ores Carbonate; Sulphide Ores; Ores Halides.
3. What is mineral ore used for? Ans: Ore is a deposit of one or more precious minerals in the Earth’s crust. The most important ore deposits, such as copper, silver, and iron, contain metals that are essential to industry and trade. Copper ore is mined for a wide range of industrial applications. Copper, an exceptional electricity conductor, is used as an electrical wire.
4. What type of mineral is gold? Ans: Gold has almost always traced of silver in its natural mineral form, and it can also contain traces of copper and iron.
5. What are the main ores of zinc? Ans: Sphalerite (zinc blende), a mineral of zinc sulphide, is the most common zinc ore
Mesopotamia was one of the earliest river valley civilization, starting to form around 4000 BCE. The civilization was created after regular trading started relationships between multiple cities and states around the Tigris and Euphrates Rivers. Mesopotamian cities became self-run civil governments. One of the cities within this civilization, Ur, was the first literate society in history. Eventually, they constructed irrigation systems to exploit the two rivers, transforming their dry land into an agriculturally productive area, allowing population growth throughout the cities and states within Mesopotamia.
Egypt
Ancient Egypt also created irrigation systems from its local river, the Nile River, more complex than previous systems. The Egyptians would rotate legumes with cereal which would stop salt buildup from the freshwater[clarification needed] and enhance the fertility of their fields. The Nile River also allowed easier travel, eventually resulting in the creation of two kingdoms in the north and south areas of the river until both were unified into one society by 3000 BCE.[7]
Yellow River
The Yellow River became settled in 9500 BCE. Many tribes settled along the river, sixth-longest in the world, which was distinguished by its heavy load of yellow silt and its periodic devastating floods. A major impetus for the tribes to unite into a single kingdom by around 1700 BCE (Erlitou culture, a Yellow River civilization) was the desire to find a solution to the frequent deadly floods. The Yellow River is often called “The Cradle of Chinese Civilization”.
