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Class X
Chemistry
Chemical Reaction and Equation
Objectives:
Students will learn about the basic concept of chemical reaction and equation.
They will learn different types of chemical reaction. They will understand how to balance a chemical reaction. They will learn the concept of Corrosion and rancidity and understand the
methods of prevention of corrosion and rancidity.
Topic DescriptionPhysical change *In which no new substance is formed.
e.g. . Melting of Ice. Evaporation of water.
Chemical change *In which substance lose their identity and nature.i.e., form a new substance.e.g.
Rusting of iron. Burning of coke in air.
Chemical reaction *Involves a chemical change.*Rearrangement of atoms.e.g.
Burning of Mg ribbon in air. Zn + H2SO4--------------->ZnSO4 + H2
Reactant *Originally taken substance.Product *Newly formed substance.Exothermic reaction *In which heat is evolved from the system.
*Temperature increases.e.g.
ZnSO4 + H2SO4 ---------->ZnSO4 + H2 (Reaction mixture become hotter.)
Endothermic reaction *In which heat is absorbed from the system.*Temperature falls.se.g.
Ba (OH) 2 + 2NH4Cl---------->BaCl2 +2NH4OH (Reaction mixture become colder).
Chemical Equation *Representation of a reaction in terms of Symbol and formula.
Balanced chemical Equation
*Which involves equal number of atoms of each element on two sides.
Steps Involving in balancing chemical reaction
*Step: To Write Word equation. Write skeletal equation. Enclose the formula in boxes. To list the number of atoms of different
element on L.H.S. or R.H.S. To start balancing of different elements. To check the correctness of the balanced
equation.e.g.
Iron + steam--------> Magnetic oxide of iron + Hydrogen
Fe + H2O ------>Fe3O4 + H2
Balanced equation: 3Fe + 4 H2O-------->Fe3O4 + 4H2
Thermo chemical Equation *In which absorbed or released heat is represented.e.g.
C(S) + O2 --------->CO2 + 395.4KJ mol-
*Which takes place in the presence of sun light.e.g.
H2 + Cl2 2HClCatalyst *Substance which increases the speed of a
reaction without being consumed.Types of Chemical reaction Types:
Combination reaction Decomposition reaction Displacement reaction. Double displacement reaction Precipitation reaction Neutralisation reaction.
Oxidation -reduction reaction.Combination reaction *Two or more element combine together to form
a single product.A +B-------------->C
2Mg + O2 ----------->2MgO CaO + H2O----------->Ca(OH)2
NH3 + HCl---------->NH4ClDecomposition reaction *Single compound breaks down to give two or
more simpler substance. A----------->B + C
Types of Decomposition reaction
Types: Thermal decomposition Electrolytic decomposition Photo decomposition
Thermal decomposition *In which heat is absorbed.e.g.
2Pb(NO3)2--------------->2PbO + 4NO2 + O2
FeSO4.7H2O-------------->FeSO4 + 7H2O 2FeSO4---------------->Fe2O3 + SO2 + SO3
(green) (reddish brown) Electrolysis *Reaction takes place when current is passed
through the compound in molten/solution phase.e.g.
2H2O------------>2H2 +O2
Photolysis *which take place on absorption of light.e.g.
2AgCl----------->2Ag + Cl2
(white) (grey) 2AgBr------------->2Ag + Br2
These reactions are used in black and white photography because photographic film is coated with these salts.
Displacement reaction *More reactive element displaces a less reactive element from its compound.
It depends upon reactivity of metals.Reactivity series *Arrangement of metals in a vertical column in
order of their decreasing reactivity from top to bottom.
Reactivity series Highly reactive
Potassium KBarium BaCalcium CaSodium NaMagnesium Mg Aluminium AlZinc ZnIron FeNickel NiTin SnLead PbHydrogen HCopper Cu Less reactive
Mercury Hg than hydrogen
Silver AgPlatinum Pt Gold Au
Gold and platinum are noble metals i.e.,non reactive towards acid, base & other substance.
Displacement reaction *Types: Metal displacement. Non metal displacement.
Metal displacement *More reactive metal displaces a lesser reactive metal from its solution.e.g.
Fe + CuSO4-------->FeSO4 + Cu Cu + FeSO4------------>No Reaction
Because Cu is less reactive than Fe.Non metal displacement *Metal reacts with acid & liberates hydrogen gas.
e.g. Mg + 2HCl--------->MgCl2 + H2
Double displacement reaction
*Reaction in which two ionic compounds in the solution phase react by exchange of their ions.e.g.
BaCl2 + Na2SO4--------->BaSO4 + 2NaCl (white p.p.t)
Precipitation reaction *Two compounds on mixing react to form an insoluble compound (ppt).e.g.
Ca(OH)2 + CO2-------->CaCO3 (milky suspension)
Double displacement reaction is also considered as a precipitation
reaction.Neutralisation reaction *Acid reacts with base to form salt and water.
e.g. NaOH + HCl------->NaCl + H2O
Oxidation –Reduction reaction
*Oxidation Addition of oxygen. Removal of hydrogen. Oxidation number increases. Loss of electron.
e.g. 2Cu +O2-------> 2CuO In this reaction Cu loses 2 e- and convert
into Cu+2.
Cu gain O2 and form CuO. Oxidation no. of Cu Changes from 0 to +2.
*Reduction Addition of Hydrogen. Removal of Oxygen. Oxidation number decreases. Gain of electron.
e.g. CuO(s) + H2(g)----------->Cu(s) + H2O(g) In this reaction Cu gain 2 e- and convert into
Cu. CuO remove O2 and convert into Cu. Oxidation number of Cu Changes from +2 to
O.Redox reaction *Reaction in which both oxidation and reduction
takes place simultaneously.e.g. ZnO+ C----------->Zn + CO
Zn O.NO. Changes from +2 to O.i.e., Reduction.
C Oxidation. No. O to +2, i.e., Oxidation.Oxidising Agent *Substance undergoes reduction.
* Oxidises others and itself reduces. Reducing Agent *Substance undergoes oxidation.
* Reduces others and itself oxidises. Substance which loses e- i.e. gets oxidized, act as a reducing agent and
which gain e- i.e., gets reduced, acts as an oxidising agent.
Corrosion *Slowly eating up of the metal surface due to attack of O2, H2S, CO2 and water vapour.*Due to attack of these gases metal convert into corresponding oxides, sulphide, and carbonate.
Rusting of Iron.2Fe + 3/2 O2 + XH2O------>Fe2O3.XH2O (rust)
(hydrated ferric oxide) Cu object lose their lustre due to corrosion.
2 Cu + CO2 + O2 + H2O------->CuCo3. Cu(OH)2
(green)(basic copper carbonate)
Ag gets tarnished due to corrosion. 2Ag + H2S------->Ag2S + H2
(black)
Prevention By painting. By greasing and oiling. By Galvanisation: Coating the surface of
iron object with a thin layer of Zinc.Rancidity *Oxidation of oil and fat.
*Resulting in bad smell and bad taste.Method to Prevent Rancidity
*By adding anti Oxidant: Which slow down the process of oxidation.e.g. B.H.T. (Butylated hydroxy toluene)*Vacuum packing.*Replacing air by nitrogen.e.g.
Bags of chips are flushed with nitrogen to prevent from oxidation.
*Refrigeration: Due to low temperature, oxidation is slowed down.
Extra point : All decomposition reactions are endothermic in nature i.e., heat is
absorbed. Combination and decomposition reactions are opposite to each other. Corrosion of Aluminium metal is an advantage because it prevents the
metal from further damage.When Al is exposed to moist air, its surface is covered with a thin non penetrable layer of Al2O3 . Aluminium oxide does not allow moist air to come in contact with the metal .Hence protect a metal from further damage.Al is a common metal which is highly resistant to corrosion.
H2O2 is always kept in coloured bottles because it is highly reactive towards light and decomposes into water and oxygen.
Activities: To study the reaction between Magnesium and oxygen to form
Magnesium Oxide. To study the reaction between lead nitrate solution and potassium
iodide solution. To study the reaction between Zinc and dilute sulphuric acid. To study the decomposition of ferrous sulphate on heating. To study thermal decomposition of lead nitrate. To study displacement of Cu from Copper sulphate solution by Iron. To study Double displacement reaction between Barium chloride
solution and sodium sulphate solution.
CLASS X (BIOLOGY)
SA-1 notes
Chapter – 6. (Life Processes)
Topic - Nutrition in plants and animals
S.No.
Main points Explanation
1 Nutrition Process of obtaining and utilizing of food is known as nutrition.
2 Mode of nutrition Mode of Nutrition
Autotrophic Nutrition Heterotrophic Nutrition
(All green plants) (Animals, Man ,Non green plants)
Saprotrophic Nutrition Parastic nutrition Holozoic Nutrition
(Dodder)
(Amoeba,Man)
(Fungi, Mushroom, Bread mould)
3 (AutoTrophs - Auto-Self, Trophs-Food)
It is mode of nutrition in which organism can make their own food from simple raw material. Example – All green plants.
4 Heterotrophs-
Hetero-other, trophs-food
It is mode of nutrition in which organism cannot prepare their food on their own and depend on others. Example-animals
5 Saprotrophic Nutrition Saprotrophic nutrition is the process by which the organism feed on dead and decaying matter.
Rhizopus, Mucor, Yeast
6 Photosynthesis
Photo-light, Synthesis- to combine
Photosynthesis is the process by which green plants prepare their own food.
Sunlight
Carbon dioxide +Water Glucose +
chlorophyll Oxygen
7 Raw materials for photosynthesis
1. Water and Minerals -These are absorbed by the roots from the soil
2. Carbon dioxide - Carbon dioxide enters the leaves through tiny pores called stomata
3. Sunlight- Energy from the sun is called solar energy
4. Cholorophyll- Chlorophyll pigment helps leaves to capture solar energy.
8 Products of Carbohydrate-glucose. It is converted to starch.
Photosynthesis
9. Symbiotic relationship
(greek word symbion-to live together)
Two organism live in close association and develop a relationship that is beneficial to both this is called symbiotic relationship
Exam. Lichen is a living partnership between a fungus an an alga. Fungus absorbs water and provides shelter and alga prepare food by photosynthesis
10 Insectivores plant Pitcher plant- plants feed on insects for their nitrogen requirements.
1 Holozoic nutrition It means feeding on solid food. Organism takes complex organic food into body , E.g. Man, Amoeba, dog, etc.
2 Herbivores Animals which feed on plants only. E.g. deer, cow.
3 Carnivores Animals which feed on flesh or meet. E.g. tiger
4 Omnivores Animals which feed on both plant and flesh. E.g. Man, dog
5 Steps of Holozoic nutrition 1. Ingestion: taking food into mouth.2. Digestion: break down of large insoluble food into small
water soluble molecule by enzymes.3. Absorption: digested food absorbed through intestinal wall
into blood.4. Assimilation: absorbed food is taken by body cells for
releasing energy, growth and repair.5. Egestion: eliminating undigested food from body.
6 Phagocytosis It means cell feeding. It is a process of obtaining food by amoeba.
7 Pseudopodia Pseudo- (False) Podia- (Feet)
8 Holozoic nutrition in amoeba.
Amoeba ingest the food which float in water by help of pseudopodia and digest it food vacuole by enzymes present in it, then absorbed it in body and use it for growth of body , at last undigested food egested from body by contractile vacuole.
9 Digestive organ of human being
Mouth, oesophagus, stomach, small intestine and large intestine with glands like salivary, liver, pancreas .
10 Teeth An organ which breaks down the complex food and help in chewing the food.
11 Milk –Teeth The first set of 20 small teeth when baby is 6-7 months old.
12 Permanent-Teeth The second set of 32 larger teeth, when child is 6-7 years old. And comes by replacing milk- teeth.
13 Enamel A white, Strong, Shining, Protective Material covering on teeth.
14 Different Types of teeth 1. Incisors- It is used for cutting food.2. Canines- It is used for tearing food.3. Premolar and Molar- It is used for grinding the food
15 Tongue A mascular organ attached to the floor of buccal cavity which helps in tasting and mixing the food with saliva for digestion.
16 Ruminants These are grass eating animals. Example- Cow, goat, horse etc.
17 Rumen The part of ruminant animals, stomach, which has some microbes that helps in partial digestion of cellulose of plant material.
Topic:- Transportation in plants and animal
Main points Explanation
1.Vascular tissue A plant tissue which helps in transportation
2. Xylem tissue It helps in transporting water and mineral in plants.
3.Phloem It helps in transporting food in plants
4. Translocation The process of transporting food from leaves to other part of plants
5. Transpiration A loss of water from stomata in leaves
6. Blood A red colour fluid with circulates in body of animals.
7. plasma Fluid part of blood which consist of nutrients , hormones, and waste products.
8. Erythrocytes RBC which provide red pigment hemoglobin to blood.
9. Leucocytes It provides protection to body from pathogens.
10. Thrombocytes Helps in clotting of blood during injuries
11 Blood vessel Tube like structure present in body for carrying blood in.
12. Artery It carry oxygenated blood from heart to body parts.
13 veins It carry deoxygenated blood from body part to heart.
14. Capillary A thin walled narrow tube which connect artery and vein.
15 Heart A muscular organ present in thoracic cavity and helps in pumping blood in body.
16. Double circulation A circulatory system in which blood travel twice through heart in one complete cycle.
17. Heart beat One complete contraction and relaxation of heart (72 times in a minute)
18. Stethoscope Instrument which measures heart beat.
19. Systolic pressure Maximum pressure at which blood flows during contraction of heart.(120mmHg)
20 Diastolic Pressure Minimum pressure at which blood flows during relaxation of heart.(80mmHg)
21 Sphygmomanometer Instrument which measures blood pressure
22 lymph A light yellow liquid flowing from body tissue to blood circulatory system and provides immunity
23 bicuspid valve It protect back flow of blood from left ventricle to left atrium.
24 Tricuspid valve It protect back flow of blood from right ventricle to right atrium.
Topic:- Excretion in plants and animals
Main points Explanation
1.Excretion Process of removing waste product from body
2. Excretory products of plants CO2, O2, water vapour , peel of bark , fruits , leaves , gum , raisin etc.
3.Raphides Plant waste stored in form of solid body
4. Excretory products of human Carbon dioxide , urea, etc
5. Kidney Organ which remove toxic substance urea from blood and filter it.
6. Urine A yellowish liquid which contain water an urea.
7. Dialysis The procedure used for cleaning blood of person in case of kidney failure.
8. Nephron Functional unit of excretory system present in kidney for filtering blood.
9. Renal Artery Blood vessels which bring blood from heart to kidney
10. Renal vein Blood vessel which bring blood from kidney to heart.
Chapter -: 7 (control and coordination)
Topic :- Control and coordination in plants
Main points Explanation
1. Stimuli The change in environment to which organism respond
2. Co-ordination Working together of various organ of an organism in a systematic manner to produce a proper response.
3.Phyto hormones These are plant hormones
4. Auxin A hormone in plant which promote cell enlargement and growth in plants.
5. Gibberellins A hormone in plant which promote cell differentiation and breaking dormancy of seed and buds
6. Cytokinin A plant hormone which promote cell division and opening of stomata
7. Abscisic Acid It helps in inhibiting growth of plant and promotes wilting and falling of leaves and food.
8. Tropism A growth movement of plant which determines direction with stimulus
9. Nastism A growth movement of plant which do not determine direction with stimulus
10. Phototropism Movement of plants toward light
11 Geotropism Movement of plants toward gravity of earth
12. Chemotropism Movement of plants toward chemical
13 Hydrotropism Movement of plants toward water
14. Thigmotropism Movement of plants towards response to touch of an object
Topic :- control and coordination in animals
Main points Explanation
1. Stimuli The change in environment to which organism respond
2. Co-ordination Working together of various organ of an organism in a systematic manner to produce a proper response.
3. Neuron Functional unit of nervous system
4. Synapse A microscopic gap between a pair of adjacent
neurons
5. Receptor A cell in a sense organ which is sensitive to stimuli
6. Motor nerves It carry message from brain to body parts for action
7. Sensory nerves It carry message from body to brain
8. Olfactory receptor It detects smell by nose
9. Gustatory receptor It detects taste by tongue
10. Thermoreceptor It detects heat and cold by skin
11 Photoreceptor It detects light by eye.
12. Reflex action Simplest form of response in nervous system which perform automatically.
13 Brain An organ present in skull which control and regulate activity of whole body and known as president of body.
14. Cerebrum Main thinking part of brain present in fore brain area which control all voluntary actions.
15. Cerebellum It is present in hind brain area and helps in maintaining posture and balance of body.
16 Medulla It is present in hind brain area and helps in controlling in voluntary actions of brain.
17. Spinal chord A 31pair cylindrical structure enclosed in vertebral column which helps in conduction of nerve impulses to and from brain.
SA- 2 Notes
Chapter- 14 Management of natural resources
Management of natural resources is needed for conservation of natural
resources.
There are national and international laws and Acts to protect the environment. Ganga Action Plan : Multi Crore Project came in 1985 to improve the quality of Ganga Accordingly a survey was conducted and a data was collected of total coliform ( a group of bacteria found in human intestine) between 1993-1994
National Award for wildlife conservation – In the memory Amrita Devi
Bishnoi who lost her life in the protection of Khejri trees in Rajasthan
alongwith 363 other people.
Chipko Andolan – Movement originated in Garhwal in early 1970S that was the result of a grassroot level effort to end the alienation of people from their forest.
?Protection of Sal forest in West Bengal in 1972.
?Three R’s to save the environment
Reduce means use less Save the resource
by not wasting them
Recycle Segregate the waste that can be recycled and use to make required things.
Reuse use the things again and gain.
Reuse is better than recycling as it saves energy.
Management of Natural Resources is necessary so that these may last for the
generations to come and are not exploited for short term gains. Also see the
damage they cause to the environment when they are used or mixed.
?Forest and wild life conservation – Forests are biodiversity hot spots
Biodiversity of an area is the number of species of different life forms like
bacteria, fungi, powering plants insects, birds etc.
?Hotspot means an area full of biological diversity.
– loss of diversity may lead to a loss of ecological stability/ecological
imbalance
Stake holders
A person having interest or concern for some thing called as stake holder.
Stakeholders : their dependence on forests
?Sustainable management – Management of forest resources Wisely to make it
available for future generations.
water as a Resource
Water is a basic necessity for all terrestrial forms of life.
Regions of water scarcity are closely correlated to the regions of acute
poverty.
Failure to sustain water availability has resulted in loss of vegetation cover,
diversion for high water demanding crops and pollution from industries and
urban wastes and less rain.
Irrigation methods like dams, tanks and coals have been used in various part
of India.
Dams
Advantages of Dams – Ensures of adequate water for irrigation.
Generate electricity.
Continuous supply of water in regions.
Disadvantages :
No equitable distribution of water.
Large no. of people displaced without compensation.
Involves huge amount of Public money without giving proper benefits.
Causes deforestation and loss of biological diversity.
Water Harvesting – Aim is to develop primary resources of land and water
and to produce secondary resources of plants and animals for use in a manner
which will not cause ecological imbalance.
Various ancient methods of water harvesting
These techniques are locale specific to ensure the mismanagemen t and
over-exploitation of these resources
Advantages of Khadin System :
– Water does no evaporate
– Recharge wells and moisture for vegetation.
– does no provide breeding ground for mosquito
– Ground water is protected from human and animal waste.
Coal and Petroleum
Generally called fossil fuel.
Formed from the disintegration of bio-mass millions of years ago.
They will get exhausted in the future no matter how carefully we use them.
Petroleum will last us for about 40 years and the coal resources will last for
another two hundred years.
These contain hydrogen, nitrogen and sulphur.
Why to use fossil fuels judiciously?
– By using public transport enstead of private one, by using C.F.L. tubes, by
using stairs instead of lift, by saving electricity as much as possible.
Chapter:15 - Environment
Environment: The combination of all the physical and biological conditions affecting the responses of living organisms is called environment.
Biodegradable wastes: The wastes which are broken down by the activity of microorganisms and enter into the biogeochemical cycle are known as biodegradable wastes.
Non-biodegradable wastes: The wastes which cannot be broken down by the enzymes produced by microorganisms into simpler and harmless products in nature are called non-biodegradable wastes.
Garbage: Domestic wastes including the kitchen waste are termed as garbage.
Incineration: Destruction of waste materials by burning at high temperature is called incineration.
Biotic Community: A group of various populations of organisms living in a gegion is called biotic community.
Ecosystems: The self-contained and distinct functional unit capable of independent existence made by the interaction of living and non-living components is called an ecosystem.
Ecosystem component consists of two components- Abiotic and biotic
Abiotic Components consist of inorganic and organic substances and climatic factors.
Biotic components consist of living organism.
Autotrophs: Those organisms which can produce their own food are called autotrophs or producers. All green plants are producers.
Consumers: Those organisms which are unable to synthesis their food themselves and consume the food produced by producers or eat other organism as food, are termed as consumers.
Decomposers: Bacteria and fungi which break down the complex organic compouinds present in the dead plants and animals and their products into simpler substances are known as decomposers.
Food Chain: The sequence of consumption of one organism as a food by another organism is known as food-chain
Trophic levels: Different steps or levels of food-chain at which the transfer of food(energy) takes place from one organism to another are called trophic levels.
Food Web: The web formed by interconnection of food-chains of the various trophic levels is called a food web.
Biomagnification: The increase in concentration of the harmful chemicals in the body of an organism per unit its mass at each successive trophic level in a food-chain is known as biomagnifications.
Ozone Depletion: The thinning of ozone layer is called ozone depletion.
Ozone depleting substances: Cholorofluorocarbons(CFCs), oxides of nitrogen, methane, carbon tetrachloride and chlorine are the ozone depleting substances.
CHAPTER- 9
HEREDITY AND EVOLUTION
Genetics: Branch of science that deals with Heredity and variation.
Heredity: It means the transmission of features/ characters/ traits from one generation to the next generation.
Variation: The differences among the individuals of a species/ population are called variations.
MENDEL AND HIS WORK ON INHERITANCE
Gregor Johann Mendel (1822&1884) : Started his experiments on plant breeding and hybridisation
Mendel was known as Father of Genetics
Plant selected by Mendel : Pisum sativum (garden pea). Mendel used a number of contrasting characters for garden pea.
Sex Determination
Phenomenon of decision or determination of sex of an offspring
FACTORS
Responsible for Sex Determination
Environmental In some animals the temperature at which the fertilised eggs are kept decides the gender.
eg. in Turtle
Genetic
In some animals like humans gender or individual is determined by a pair of chromosome called sex chromosome
XX – Female
XY – Male
Sex Chromosomes : In human beings there are 23 pairs of chromosome. Out of these 22 chromosomes pairs are called autosomes and the last pair of chromosomes that help in deciding gender of that individual are called sex chromosome.
XX – female
XY – male
The cross done shows that half the children will be boys and half will be girls. All children will inherit an X chromosome from their mother regardless whether they are boys or girls. Thus sex of children will be determined by what they inherit from their father, and not from their mother.
Acquired and Inherited Traits
Acquired Traits
1. These are the traits which are developed in an individual due to special conditions
2. They cannot be transferred to the progeny
3. They cannot direct evolution
eg. Low weight of starving beetles.
Inherited Traits
1. These are the traits which are passed from one generation to the next.
2. They get transferred to the progeny.
3. They are helpful in evolution.
eg. Colour of eyes and hair
Speciation
Micro evolution : It is the evolution which is on a small scale. eg. change in body
colour of beetles.
Speciation : it is the process of formation of new species.
Species : A group of similar individuals that along to a population that can interbreed and produce ferrite off spring.
Gene flow: It is exchange of genetic material by interbreeding between populations of same species or individuals
WAYS BY WHICH SPECIATION TAKES PLACE
Speciation takes place when variation is combined with geographical isolation.
Gene flow: occurs between population that are partly but not completely
Separated
Genetic Drift
It is the random change in the frequency of alleles (gene pair) in a population over successive generations.
*Natural Selection: The process by which nature selects and consolidate those organisms which are more suitably adapted and posesses favorable variations
Genetic drift takes place due to
a) Severe changes in the DNA
b) Change in number of chromosomes
Evolution and classification
Both evolution and classification are interlinked.
1. Classification of species is reflection of their evolutionary relationship.
2. The more characteristic two species have in common the more closely they are related.
3. The more closely they are related, the more recently they have a common ancestor.
4. Similarities among organisms allow us to group them together and to study their characteristic
Tracing Evolutionary Relationships
(Evidences of Evolution)
I. Homologous Organs : (Morphological and anatomical evidences. These are the organs that have same basic structural plan and origin but different functions.
Example :
Forelimb of Horse (Running) Same basic
Winds of bat (flying) plan,
Paw of a cat (walk/scratch/attack) different functions
II. Analogous Organs: These are the organs that have different origin and structural plan but same function example :
Wings of bat elongated fingers with skin folds
Wings of bird Feathery covering along the arm
III. Fossils : (Palaeontological evidences) The remains and relics of dead organisms of the past.
Example :
i) Fossil of wooly mammoth
ii) Archeopteryx (fossil bird)
iii) Dead insect caught in hot mud.
Artificial Selection:
Humans have been a powerful agent in modifying wild species to suit their own requirement throughout ages by using artificial selection. eg (i) Wild cabbage the dissimilar looking structures have evolved from a common ancestral design. (ii)
Wheat (many varieties obtained due to artificial selection)
Chapter- 8 HOW DO ORGANISMREPRODUCE
– Reproduction is the process by which living organisms produce new individuals similar to themselves.
– Reproduction ensured continuity of life on earth.
– Reproduction - A bridge to hereditary transmission.
– It involves continuation of characters from the parents to daughter cells by
Copying of DNA (Deoxyribose Nucleic Acid) molecules present in the chromosomes of the cell.
– Copying of DNAs is also not a foolproof exercise, even minute changes bring about Variation in the blue print of the offsprings.
– The useful variations are retained while the harmful one does not go beyond.
– Actually variations help the species to withstand drastic environmental changes, thus save the species from becoming extinct and promotes its survival for a longer time.
– This inbuilt tendency of variation is the "fuel" for Evolution.
Asexual Reproduction is extremely useful as a mean of rapid multiplication.
It is common in lower plants and animals.
– Different form of Asexual Reproduction.
1. FISSION : the parent cell divides/splits into two daughter cell-Binary
Fission; splits into many cells-multiple Fission
2. BUDDING : A new organism is produced as an outgrowth of the parent
body part.
3. Spore Formation : Spores are small, bulb like structure develops at the top of the erect hyphae of the fungus plant, released into the air and ge rmina t e , into new individuals after landing into food or soil.
4. FRAGMENTATION : It is the accidental process when the broken pieces
of an organism (fragments) grows into a complete organism.
eg. fragmentation in spirogyra
5. REGENERATION : When the simple animals like Hydra Planaria develop a new individual from their broken older part it is known as regeneration. It is carried out by specialised cells which grow large numbers of cells.
VEGETATIVE PROPAGATION :
A mode of reproduction in which part like the stem, root, leaves develop into new plant under favourable conditions.
Benefits
1. Plants can bear flowers, fruits earlier than those produced from seeds.
2. Growing Banana, orange, rose, jasmine that have lost the capacity to produce seeds.
3. Genetical similarity is maintained in the plants.
eg. Sugarcane, rose, grapes by layering or grafting.
SEXUAL REPRODUCTION
When reproduction takes place as a result of fusion between two gamets, one from each parent, it is called sexual reproduction.
– This process of fusion between two gamets is called fertilization.
– The formation of gamets involves exchange of chromosomal (genetic) fragments between homologous chromosomes causing genetic recombination which leads to variation.
SEXUAL REPRODUCTION IN PLANTS
It occurs mostly in flowering plants. In fact flowers are the reproductive organ of plants.
Egg cell (ovule) [n]
– Pollen grains of a flower transfer to stigma of the carpel of the same flower
(Self-Pollination) or to the carpel of the another flower (Cross-Pollination).
– This transfer of pollens is achieved by agent like wind, water or animals.
– After Pollination, the pollen grains reach to the egg cell in the form of a pollen tube.
– Fertilization : The fusion between the pollen grain and female egg cell. It occurs inside the ovary. Zygote is produced in this process.
– Zygote divides several times to form an embryo within the ovule. The ovule develops a tough coat and is converted into a seed.
– Ovary grows rapidly and ripens to forms a fruit, while the seed contains the future plant or embryo which develops into a seedling under suitable condition. This process is known as Germination.
REPRODUCTION IN HUMAN BEINGS
– Humans use a Sexual Mode of reproduction.
– It needs sexual maturation which includes creation of the germ cells i.e, egg (ova) in the female and sperm in the male partner & this period of sexual maturation is called Puberty.
– Human beings have a well developed male and female reproductive system.
– The formation of male germ cell (sperms) takes place in the testes (male reproductive organ)
– Actually a pair of testes are located inside scrotum situated outside the abdominal cavity. It is meant to keep relatively a low temperature needed for the production of sperms by testes.
– Moreover testes release a male sex hormone called testosterone whose
function is to:
1. Regulate the production of sperm
2. Brings about changes in appearance seen in boys at the time of puberty.
– The sperms along with the secretion of prostate gland and seminal vesicle, together constitute semen, which is released and made to enter into the female genital tract during Copulation.
FEMALE REPRODUCTIVE SYSTEM
The female germ cells or eggs are made in the ovaries, a pair of which is located in both side of abdomen.
When a girl is born, the ovaries already contain thousands of immature eggs.
At the puberty, some of these Eggs start maturing. One egg is produced every month by one of the ovaries.
-The Egg is carried from the ovary to the womb through a fallopian tube.
-These two fallopian tube unite into an elastic bag like structure known as Uterus
-The Uterus opens into the vagina through the cervix.
-Fertilization occurs in the fallopian tube of female genital tract.
-The fertilized egg also called zygote (2n) gets implanted in the lining of the Uterus, and start dividing. Actually uterus is richly supplied with blood to nourish the growing embryo.
-If zygote is not formed, the inner wall of uterus breaks which causes bleeding through vagina. This process is called MENSTRUATION. It occurs at a regular interval of 28 days.
-The Embroyo gets nutrition from the mother's blood with the help of a special tissue called PLACENTA.
-It provides a large surface area for glucose and oxygen to pass from the mother to the embryo. Similarly the wastes from developing embryo are removed to mother's blood through placenta.
-The child is born as a result of rhythmic contractions of the muscles in the uterus after nine months (36 weeks) of development inside mother's womb, called Gestation Period.
-The sexual cycle in a woman continues upto the age of 45 to 50 years. After
that the ovary do not release egg. This stage is called Menopause. It a also
marks the end of menstruation in the woman.
REPRODUCTIVE HEALTH
Reproductive Health means a total well-being in all aspects of reproductive,
ie., physical emotional, social and behavioral.
Contraception : It is the avoidance of pregnancy.
Chapter- 16
Management of natural resources
Management of natural resources is needed for conservation of natural
resources. There are national and international laws and Acts to protect the environment. Ganga Action Plan : Multi Crore Project came in 1985 to improve the quality of Ganga Accordingly a survey was conducted and a data was collected of total coliform ( a group of bacteria found in human intestine) between 1993-1994
National Award for wildlife conservation – In the memory Amrita Devi
Bishnoi who lost her life in the protection of Khejri trees in Rajasthan
alongwith 363 other people.
Chipko Andolan – Movement originated in Garhwal in early 1970S that was the result of a grassroot level effort to end the alienation of people from their forest.
?Protection of Sal forest in West Bengal in 1972.
?Three R’s to save the environment
Reduce means use less Save the resource
by not wasting them
Recycle Segregate the waste that can be recycled and use to make required things.
Reuse use the things again and gain.
Reuse is better than recycling as it saves energy.
Management of Natural Resources is necessary so that these may last for the
generations to come and are not exploited for short term gains. Also see the
damage they cause to the environment when they are used or mixed.
?Forest and wild life conservation – Forests are biodiversity hot spots
Biodiversity of an area is the number of species of different life forms like
bacteria, fungi, powering plants insects, birds etc.
?Hotspot means an area full of biological diversity.
– loss of diversity may lead to a loss of ecological stability/ecological
imbalance
Stake holders
A person having interest or concern for some thing called as stake holder.
Stakeholders : their dependence on forests
?Sustainable management – Management of forest resources Wisely to make it
available for future generations.
water as a Resource
Water is a basic necessity for all terrestrial forms of life.
Regions of water scarcity are closely correlated to the regions of acute
poverty.
Failure to sustain water availability has resulted in loss of vegetation cover,
diversion for high water demanding crops and pollution from industries and
urban wastes and less rain.
Irrigation methods like dams, tanks and coals have been used in various part
of India.
Dams
Advantages of Dams – Ensures of adequate water for irrigation.
Generate electricity.
Continuous supply of water in regions.
Disadvantages :
No equitable distribution of water.
Large no. of people displaced without compensation.
Involves huge amount of Public money without giving proper benefits.
Causes deforestation and loss of biological diversity.
Water Harvesting – Aim is to develop primary resources of land and water
and to produce secondary resources of plants and animals for use in a manner
which will not cause ecological imbalance.
Various ancient methods of water harvesting
These techniques are locale specific to ensure the mismanagemen t and
over-exploitation of these resources
Advantages of Khadin System :
– Water does no evaporate
– Recharge wells and moisture for vegetation.
– does no provide breeding ground for mosquito
– Ground water is protected from human and animal waste.
Coal and Petroleum
Generally called fossil fuel.
Formed from the disintegration of bio-mass millions of years ago.
They will get exhausted in the future no matter how carefully we use them.
Petroleum will last us for about 40 years and the coal resources will last for
another two hundred years.
These contain hydrogen, nitrogen and sulphur.
Why to use fossil fuels judiciously?
– By using public transport instead of private one, by using C.F.L. tubes, by
using stairs instead of lift, by saving electricity as much as possible.
CHAPTER- 9 HEREDITY AND EVOLUTION
Genetics: Branch of science that deals with Heredity and variation. Heredity: It means the transmission of features/ characters/ traits from one
generation to the next generation. Variation: The differences among the individuals of a species/ population are
called variations.
MENDEL AND HIS WORK ON INHERITANCE Gregor Johann Mendel (1822&1884) : Started his experiments on plant
breeding and hybridisation Mendel was known as Father of Genetics Plant selected by Mendel : Pisum sativum (garden pea). Mendel used a
number of contrasting characters for garden pea. Sex Determination Phenomenon of decision or determination of sex of an offspring FACTORS Responsible for Sex Determination Environmental In some animals the temperature at which the fertilised eggs
are kept decides the gender. eg. in Turtle Genetic In some animals like humans gender or individual is determined by a pair of
chromosome called sex chromosome XX – Female XY – Male Sex Chromosomes : In human beings there are 23 pairs of chromosome. Out
of these 22 chromosomes pairs are called autosomes and the last pair of chromosomes that help in deciding gender of that individual are called sex chromosome.
XX – female XY – male The cross done shows that half the children will be boys and half will be girls. All
children will inherit an X chromosome from their mother regardless whether they are boys or girls. Thus sex of children will be determined by what they inherit from their father, and not from their mother.
Acquired and Inherited Traits Acquired Traits 1. These are the traits which are developed in an individual due to special
conditions 2. They cannot be transferred to the progeny 3. They cannot direct evolution eg. Low weight of starving beetles. Inherited Traits 1. These are the traits which are passed from one generation to the next. 2. They get transferred to the progeny. 3. They are helpful in evolution. eg. Colour of eyes and hair Speciation Micro evolution : It is the evolution which is on a small scale. eg. change in
body colour of beetles. Speciation : it is the process of formation of new species. Species : A group of similar individuals that along to a population that can
interbreed and produce ferrite off spring. Gene flow: It is exchange of genetic material by interbreeding between
populations of same species or individuals WAYS BY WHICH SPECIATION TAKES PLACE Speciation takes place when variation is combined with geographical isolation. Gene flow: occurs between population that are partly but not completely Separated
Genetic Drift It is the random change in the frequency of alleles (gene pair) in a population
over successive generations. *Natural Selection: The process by which nature selects and consolidate those
organisms which are more suitably adapted and posesses favorable variations Genetic drift takes place due to a) Severe changes in the DNA b) Change in number of chromosomes Evolution and classification Both evolution and classification are interlinked. 1. Classification of species is reflection of their evolutionary relationship. 2. The more characteristic two species have in common the more closely they
are related. 3. The more closely they are related, the more recently they have a common
ancestor. 4. Similarities among organisms allow us to group them together and to study
their characteristic Tracing Evolutionary Relationships (Evidences of Evolution) I. Homologous Organs : (Morphological and anatomical evidences. These are
the organs that have same basic structural plan and origin but different functions.
Example : Forelimb of Horse (Running) Same basic Winds of bat (flying) plan, Paw of a cat (walk/scratch/attack) different functions II. Analogous Organs: These are the organs that have different origin and
structural plan but same function example : Wings of bat elongated fingers with skin folds Wings of bird Feathery covering along the arm III. Fossils : (Palaeontological evidences) The remains and relics of dead
organisms of the past. Example : i) Fossil of wooly mammoth ii) Archeopteryx (fossil bird) iii) Dead insect caught in hot mud. Artificial Selection: Humans have been a powerful agent in modifying wild species to suit their own
requirement throughout ages by using artificial selection. eg (i) Wild cabbage the dissimilar looking structures have evolved from a common ancestral design. (ii)
Wheat (many varieties obtained due to artificial selection) Chapter- 8 HOW DO ORGANISMREPRODUCE – Reproduction is the process by which living organisms produce new
individuals similar to themselves. – Reproduction ensured continuity of life on earth. – Reproduction - A bridge to hereditary transmission.
– It involves continuation of characters from the parents to daughter cells by Copying of DNA (Deoxyribose Nucleic Acid) molecules present in the
chromosomes of the cell. – Copying of DNAs is also not a foolproof exercise, even minute changes bring
about Variation in the blue print of the offsprings. – The useful variations are retained while the harmful one does not go beyond. – Actually variations help the species to withstand drastic environmental
changes, thus save the species from becoming extinct and promotes its survival for a longer time.
– This inbuilt tendency of variation is the "fuel" for Evolution. Asexual Reproduction is extremely useful as a mean of rapid multiplication. It is common in lower plants and animals. – Different form of Asexual Reproduction. 1. FISSION : the parent cell divides/splits into two daughter cell-Binary Fission; splits into many cells-multiple Fission 2. BUDDING : A new organism is produced as an outgrowth of the parent body part. 3. Spore Formation : Spores are small, bulb like structure develops at the top
of the erect hyphae of the fungus plant, released into the air and ge rmina t e , into new individuals after landing into food or soil.
4. FRAGMENTATION : It is the accidental process when the broken pieces of an organism (fragments) grows into a complete organism. eg. fragmentation in spirogyra 5. REGENERATION : When the simple animals like Hydra Planaria develop a
new individual from their broken older part it is known as regeneration. It is carried out by specialised cells which grow large numbers of cells.
VEGETATIVE PROPAGATION : A mode of reproduction in which part like the stem, root, leaves develop into
new plant under favourable conditions. Benefits 1. Plants can bear flowers, fruits earlier than those produced from seeds. 2. Growing Banana, orange, rose, jasmine that have lost the capacity to produce
seeds. 3. Genetical similarity is maintained in the plants. eg. Sugarcane, rose, grapes by layering or grafting. SEXUAL REPRODUCTION When reproduction takes place as a result of fusion between two gamets, one
from each parent, it is called sexual reproduction. – This process of fusion between two gamets is called fertilization. – The formation of gamets involves exchange of chromosomal (genetic)
fragments between homologous chromosomes causing genetic recombination which leads to variation.
SEXUAL REPRODUCTION IN PLANTS It occurs mostly in flowering plants. In fact flowers are the reproductive organ of
plants. Egg cell (ovule) [n] – Pollen grains of a flower transfer to stigma of the carpel of the same flower (Self-Pollination) or to the carpel of the another flower (Cross-Pollination). – This transfer of pollens is achieved by agent like wind, water or animals.
– After Pollination, the pollen grains reach to the egg cell in the form of a pollen tube.
– Fertilization : The fusion between the pollen grain and female egg cell. It
occurs inside the ovary. Zygote is produced in this process. – Zygote divides several times to form an embryo within the ovule. The ovule
develops a tough coat and is converted into a seed. – Ovary grows rapidly and ripens to forms a fruit, while the seed contains the
future plant or embryo which develops into a seedling under suitable condition. This process is known as Germination.
REPRODUCTION IN HUMAN BEINGS – Humans use a Sexual Mode of reproduction. – It needs sexual maturation which includes creation of the germ cells i.e, egg
(ova) in the female and sperm in the male partner & this period of sexual maturation is called Puberty.
– Human beings have a well developed male and female reproductive system. – The formation of male germ cell (sperms) takes place in the testes (male
reproductive organ) – Actually a pair of testes are located inside scrotum situated outside the
abdominal cavity. It is meant to keep relatively a low temperature needed for the production of sperms by testes.
– Moreover testes release a male sex hormone called testosterone whose function is to: 1. Regulate the production of sperm 2. Brings about changes in appearance seen in boys at the time of puberty. – The sperms along with the secretion of prostate gland and seminal vesicle,
together constitute semen, which is released and made to enter into the female genital tract during Copulation.
FEMALE REPRODUCTIVE SYSTEM The female germ cells or eggs are made in the ovaries, a pair of which is
located in both side of abdomen. When a girl is born, the ovaries already contain thousands of immature eggs. At the puberty, some of these Eggs start maturing. One egg is produced every
month by one of the ovaries. -The Egg is carried from the ovary to the womb through a fallopian tube. -These two fallopian tube unite into an elastic bag like structure known as
Uterus -The Uterus opens into the vagina through the cervix. -Fertilization occurs in the fallopian tube of female genital tract. -The fertilized egg also called zygote (2n) gets implanted in the lining of the
Uterus, and start dividing. Actually uterus is richly supplied with blood to nourish the growing embryo.
-If zygote is not formed, the inner wall of uterus breaks which causes bleeding through vagina. This process is called MENSTRUATION. It occurs at a regular interval of 28 days.
-The Embroyo gets nutrition from the mother's blood with the help of a special tissue called PLACENTA.
-It provides a large surface area for glucose and oxygen to pass from the mother to the embryo. Similarly the wastes from developing embryo are removed to mother's blood through placenta.
-The child is born as a result of rhythmic contractions of the muscles in the uterus after nine months (36 weeks) of development inside mother's womb, called Gestation Period.
-The sexual cycle in a woman continues upto the age of 45 to 50 years. After
that the ovary do not release egg. This stage is called Menopause. It a also marks the end of menstruation in the woman. REPRODUCTIVE HEALTH Reproductive Health means a total well-being in all aspects of reproductive, ie., physical emotional, social and behavioral. Contraception : It is the avoidance of pregnancy.
Chapter Physics Electricity and its heating effectsTopics Key Points
Free Electron
Conductor
Insulator
Electric Current
Unit
Direction
Electric Potential
Note
Potential difference
Electric circuit Ohm’s Law
Last orbit electron or loosely bounded electron of atom is called free electron .
The material which can allow the flow electron through itself is called conductor . It have large no free electron . It offer low opposition in the flow of current.
The material which can not allow the flow electron through itself is called conductor.
It have less or no free electron . It offer high opposition in the flow of current.
The amount of flow charge through any cross sectional area of conductor in unity time is called electric Current.It is represented by ‘I’ I=Q / t where Q is amount of current.Unit of Electric Current is CS-1 (coulomb per second) or Ampere (A) Electric Current is scalar quantity. It is measured by ammeter
The direction of conventional current (or practical current) is opposite to the flow of electron .
Electric Potential at any point in the electric field is define as the amount of work done to bring the unit positive charge from infinity (from out side the electric field ) to that point. V=W/q S.I. unit of Electric Potential is JC-1 or volt (V) It is scalar quantity.The +ve charge flow from higher to lower potential. The -ve charge flow from lower to higher potential . Difference of electric potential between any two point in the electric field is called electric Potential difference. VAB= VA-VB = WAB/q A . .B Electric Potential difference is measured by voltmeter. Close and continuous path for the flow of electric charge is called electric circuit. According to this law “ Under the constant physical condition the potential difference across the conductor is directly proportional to the current flowing through the conductor” V ὰ I V=IR Where R is proportionality constant called resistance of conductor. It depend upon nature, geometry and physical condition of conductor
Chapter Electricity and its heating effectsTopics Key pointsResistance Ratio of applied voltage to the current flowing in the conductor is called resistance
of conductor.
Physical Meaning
Specific resistance
Series Combination of resistance
Parallel combination
R=VI
S.I. Unit of resistance is VA-1 or ohm (Ω).
Resistance is the opposition offered by the conductor in the flow of current.Practically it is— R α L ( L is length of conductor ) R α 1/A (A is area of conductor) So R α L/A R =ρ L/A Where ρ is proportionality constant called specific resistance of conductor. It only depend upon nature (material) and Temperature of conductor .Specific resistance or Resistivity ρ = RA /L S.I. Unit of ρ is Ωm Combination of resistance---
In this combination the current across every component is sameBut potential across every component is different.
If resistance R1 ,R2,and R3 are connected in series with a battery of Potential VThen equivalence resistance of combination R= R1+R2+R3
Parallel combination of resistance---*In this combination the current across every component is differentBut potential across every component is same.
If resistance R1 ,R2,and R3 are connected in parallel with a battery of Potential VThen equivalence resistance of combination.
1/R= 1/R1+1/R2+1/R3
Chapter Electricity and its heating effectsTopics Key points
Electric Energy
S.I. Unit
Electric Power
Electric Energy is amount of work done to maintain the continuous flow of electric current in the circuit. W= Vit W=E E= Vit = I2Rt = V2t/RIts SI units is joule (J)
The electric energy consumed by an electric appliances in unit time is called its
S.I. Unit
Current Rating
Misconception
Activity
electric Power P =w / t = E/t = V I = V2/R = I2R
Watt (W) , 1W = 1 JS-1
The max. value of electric current that can pass through an electric appliance without damaging electric appliance is called current rating of electric appliance.
1. In series combination the current across every component is sameBut potential across every component is different.
2. In parallel combination the current across every component is different But potential across every component is same.
1-To determine the resistance of wire by ohm’s law.2- To verify the law of combination of resistance.
Chapter Magnetic effect of electric currentTopics Key WordsMagnetic Field
Magnetic Field lines
Property of Magnetic Field lines
Oersted’s Experiment
The area around a Magnet in which other magnet feel force of attraction or repletion is called Magnetic field.
The closed curved imaginary line in the magnetic field which indicate the direction of motion of a north pole in magnetic field. if magnet is free to do so.
1. Magnetic Field lines originate from north pole of a magnet and end at its south pole.
2. Magnetic Field lines are denser near the poles but rare at other places.3. The magnetic Field lines do not intersect one another.
(Result) According to this experiment –A current carrying wire create a magnetic field around it .The direction of magnetic field depend on the direction of current in conductor .
Right hand thumb rule.
Magnetic field pattern due to circular current carrying loop
Solenoid
Magnetic field due to current carrying solenoid
Electromagnet
Magnetic field pattern due to straight current carrying conductor are concentric circles whose center lie on the wire.
Direction of Magnetic field due to straight current carrying can be determine by Right hand thumb rule.
According to this rule “ if current carrying conductor hold in right hand in such a way that thumb indicate the direction of current ,then the curled finger indicate the direction of magnetic field lines around conductor .’’(Right hand thumb rule)
The pattern of magnetic field due to circular loop The Magnetic field line is circular near the current –carrying loop.As we move away from loop field line form bigger and bigger circle. At the center of the circular loop ,the magnetic field line are straight .
B = µ0 /4π (2I/r)where—I is current in conductor, r is radius of loop
Solenoid is a insulated and tightly wounded long circular wire having large no of turn ,whose radius is small in compression to its length .
Magnetic field produce by a solenoid is similar to the magnetic field produce by a bar Magnet.
B= µ0nIWhere — n no of turn per unit length in conductor
I current in conductor µ0 permeability of medium
Current carrying solenoid is called electromagnet.
Chapter Magnetic effect of electric currentTopics Key Words Force
Direction
Note
Electromagnetic Induction
Faraday’s Law of EMI
Force on current carrying wire placed in a magnetic Field— F = IBLSinӨ
Where I current in conductorB Magnetic field inductionL length of conductor
Ө Angle b/w L & BFleming Left -Hand Rule for the direction of force “ If three finger(thumb ,fore and central ) of left hand arrange mutual perpendicular in such a way that forefinger indicate magnetic field, central indicate current then thumb will indicate the direction force on conductor. ’’
Electric motor work on same principle.
This is a process of production of electricity (electric current) by the variation of magnetic field across the conductor is called Electromagnetic Induction .
First law -Whenever magnetic line of forces change across conductor ,an e.m.f. is induce in it .This induced e.m.f. last so long as the change in magnetic field continues.Second law-
Direction of induced current
Activity
The magnitude of the induced e.m.f. is directly proportional to the rate of change of Magnetic flux linked with the conductor (or coil). Fleming Right -Hand Rule – It use to determine the direction of induced current .According to this rule : “if three finger of right hand arrange mutual perpendicular in such a way that thumb points in the direction of motion of conductor, forefinger points direction of magnetic field, then middle finger indicate direction of induced current .”
To draw magnetic line of forces by a bar magnet. To show force on a current carrying conductor place in magnetic field.
