It is observed that in 9th Std Homi Bhabha Exam, some questions are often asked from SSC board science textbooks. These are not significant from the perspective of learning science. (In fact, the information is mostly useless from the point of view of understanding concepts.) But from exam perspective, they might be very useful!
So, we have compiled some points from 8th and 9th std SSC textbooks. Do go through them in the last few days before the exam.
8th std Text book points
- Carl Linnaeus (1735) 2 kingdoms – Vegetabilia and Animalia.
- Haeckel (1866) – 3 Kingdoms- Protista, Plants and Animals.
- Chatton (1925) two groups Prokaryotes and Eukaryotes
- Kopland (1938)- 4 kingdoms-Monera, Protista, Plants and Animals.
- Protista: Euglena, Volvox contain chloroplast.
- Fungus: Cell wall made up of Chitin’.
- Aspergillus (Fungus on corn)
- Vibrio (Comma shaped) baceria. Vibrio cholerae gives Cholera
- Bacetria can double their number in 20 minutes.
- Protozoa (size – approximately 200 mm)
- Entamoeba histolytica – causes amoebiasis.
- Dengue: spread by Aedes aegypti. This disease is caused by DEN-1 – 4 virus belonging to the type- flavivirus.
- Malaria-Anopheles; Dengue-Aedes (Both clean water); elephantiasis-Culex (dirty water);
- Swine flu is caused by the virus influenza A (H1N1)
- AIDS (Acquired Immuno Deficiency Syndrome) : This disease is caused by HIV (Human Immunodeficiency Virus) – ELISA test
- Rutherford took a very thin gold foil (thickness : 10-4mm)
- The radioactive isotopes are used for detection of cracks (leakage) in the underground pipes. eg. Sodium -24.
- Iodine -131 is used in the treatment of goiter, disease of thyroid gland.
- Moderator : Graphite or heavy water is used as moderator for reducing the speed of neutrons. Controller : To reduce the number of neutron by absorbing them rods of boron, cadmium, beryllium etc.
- ‘Apsara’ at Bhabha Atomic Research Centre in Mumbai is the first nuclear reactor in India
- Indian scientists have developed a future plan for nuclear reactors based on production of the isotope U – 233 from Th – 232.
- Chlorophyll that contains magnesium, hemoglobin that contain iron, cyanocobalamine (vitamin B-12) that contain cobalt are some examples of complex compounds.
- Heterogeneous mixture of a liquid and a solid is called a suspension. The diameter of the solid particles in a suspension is larger than 10-4m. light cannot transmit through. it can be filtered.
- Colloid(particles is around 10-5m.) : water + milk. Light is partly transmitted and partly scattered. cannot be separated by filtration.
- Colloid solutions: ‘solid in gas’ (for example, smoke), ‘liquid in gas’ (for example, fog,cloud), etc.
- A cheap variety of stainless steel is made by using copper instead of nickel. Vertical cracks observed in some stainless steel vessels are due to this
- Delhi iron pillar in the premices of Kutubminar is alloy of carbon,silicon and phosphorus mixed in iron
- Large number of tanning centers are present in Tamilnadu. Waste water from those centers is released into Palar river. Hence that river is referred as Puzzar (Gutter river).
- To get prior intimation about earthquake, modern equipments like laser ranging very long baseline, geiger counter, creep meter, strain meter, tide gauge, tilt meter, volumetric strain gauge etc. are used.
- Stirrup pump is the best device to put off small fires. It sprays water in all directions around the fire.
- plasma membrane – Protein molecules are embedded in two layers of phospholipids.
- If any changes occur outside the cell, the celllular environment does not change due to plasma membrane. This condition is called homeostasis.
- The part of cytoplasm other than organelles is the cytosol.
- Except nucleus and chloroplast, all other organelles can be seen only with electron microscope.
- Due to the loss of nucleus of sieve tubes of the plant phloem, they become hollow and thereby transportation of food becomes easy.
- These sacs in Golgi Complex are called ‘cisternae’. Camilio Golgi described the Golgi complex for the first time. He developed the staining technique called ‘Black reaction’
- During starvation, lysosomes digest stored proteins, fats.
- Mitochondria= The outer membrane is porous and the inner membrane is deeply folded. These folds are called ‘cristae’. Synthesis of proteins, carbohydrates, lipids etc. by using the energy in ATP.
- Mitochondria are absent in RBCs. Due to this, the oxygen which is carried by them is not used for themselves.
- Vacuoles in amoeba it stores food before digestion.
- Plastids = Leucoplasts – White or colourless plastids synthesis and storage of food like starch, oils and proteins., Chromoplasts – Coloured plastids. give different colours to flowers and fruits.
- Raw green tomatoes turn red due to breakdown of chlorophyll and synthesis of lycopene.
- Mitochondria and plastids can produce proteins as well as replicate themselves, as they have their own DNA and ribosomes.
- Each lung has double layered covering. It is called as pleura.
- RBCs are produced in red bone marrow and live for about 100 – 127 days.
- 5 types of WBCs are present – basophils, eosinophils, neutrophils, monocytes & lymphocytes.
- Body temperature is maintained constant at 37 0C by vasodilation and vasoconstriction.
- Blood pressure of a healthy person is about 120/80 mm to 139/89 mm of Hg. It is measured with the help of sphygmomanometer’.
- A, B, O blood groups were discovered by Carl Landsteiner Blood group AB was discovered by Decastello and Sturli
- Branch of medical science that deals with the study of blood, hematopoietic organs and blood diseases is called as hematology
- The plastic that can be molded as per our wish is called as thermoplastic. eg. Polythene, PVC are used for manufacturing the toys, combs, plates, bowls etc.
- once a specific shape is given with the help of mold, its shape cannot be changed on heating. It is called as thermosetting plastic. eg. Electric switches, coverings over the handles of cookers, etc.
- Thermocol is a form of a complex material called polystyrene
- Being carcinogenic ingredients in styrene, the person in contact with thermocol for long duration may have the possibility of blood cancer like leukemia and lymphoma.
- For glass produroduced by heating the mixture of sand and soda. As this glass is soluble in water, it called as ‘water glass’.
- The position of any living organism in context to other living organisms and the role it is playing is called ‘Niche’.
- Biotic community’ is another name for ‘ecosystem.’
- Dudhwa forest was the habitat for single horned Rhino
- The Great Himalayan National park is the largest sanctuary where white panther, a rare species is conserved.
- Dysentery Bacteria, virus, Shigella, bacilli, Entamoeba, histolytica
- Silicosis happens due to dust
- Deodorants contain parabens (methyl, ethyl, propyl, benzyl and butyl) and also alcohol in large proportions. Aluminium compounds and silica are also used.
- Aluminium – Zirconium compounds are the most harmful chemicals in the deodorant.
- There is a possibility of various skin disorders and also skin cancer due to the aluminium chlorohydrates.
- Bryophyta =amphibians plans. Examples – Examples are Moss (Funaria), Marchantia, Anthoceros, Riccia,
- Pteridophyta = Nephrolepis, Marsilea, Pteris, Adiantum, Equisetum, Selaginella, Lycopodium
- Pteridophyta These plants reproduce asexually by spore-formation and sexually by zygote formation. They are called cryptogams as their reproductive organs cannot be seen. (cryptos: hidden, gams: reproductive organs).
- Gymnosperms Examples Cycas, Picea (Christmas tree), Thuja (Morpankhi), Pinus (Deodar),
9th Std Textbook points
- Nitrogen fixation: Conversion of nitrogen into nitrates and nitrites through atmospheric,industrial and biological processes.
- Ammonification: Release of ammonia through decomposition of dead bodies and excretory wastes of organisms.
- Nitrification: Conversion of ammonia into a nitrite and then nitrate.
- Denitrification: Conversion of nitrogen compounds into gaseous nitrogen.
- Zinc oxide reacts with sodium hydroxide to form sodium zincate (Na2ZnO2) and water. Similarly, aluminium oxide reacts with sodium hydroxide to form sodium aluminate (NaAlO2) and water
- The lactobacilli convert lactose, the sugar in the milk, into lactic acid. This process is called fermentation. As a result, the pH of milk decreases causing coagulation of milk proteins. The low pH destroys harmful microbes present in the milk.
- Useful microbes like lactobacilli are added to these eatables. Such eatables are healthy because they kill the harmful bacteria like clostridum in the alimentary canal and help to improve our immunity.
- Lactobacilli fermentation is useful for large scale production of cider, cocoa, pickles of vegetables, etc.
- Leavened fodder offered to domestic cattle like cows and buffalos, is fodder fermented with the help of lactobacilli.
- Nowadays, seeds are coated with rhizobial solution or powder before sowing. After sowing, rhizobia enter the plantlets. This is called ‘rhizobial inoculation’. This experiment has helped in the supply of nitrogen to cereal and other crops, besides leguminous crops.
- Molasses produced from sugarcane juice is fermented with the help of the yeast called Saccharomyces. Makes ethanol as primary and ester and other alcohols as secondary products
- A yeast, Yarrowia lipolytica is used to absorb the toxins released during the production of palm oil and the heavy metals and minerals released in some other industrial processes. Saccharomyces cereviceae is used for absorption of a pollutant, arsenic. Oil spills in oceans are cleaned with the help of Alcanivorax bacteria.
- Broadspectrum antibiotics. Examples are ampicillin, amoxicillin, tetracycline
- narrow-spectrum antibiotics are used. Examples are penicillin, gentamycin, erythromycin,
- Penicillium (discovered by Alexander Fleming ), and is used for diseases like pneumonia and scarlet fever. infections caused by bacteria like Staphylococci, Clostridia, Streptococci, and ear, nose, throat and skin infections
- fungi release mycotoxins and so we can not eat such food. Clostridium. spoil cooked food. These bacteria are rod-shaped and produce bottle-shaped endospores cannot withstand the normal oxygen
- Types of Clostridium= Clostridium tetani Clostridium Perfringens Clostridium botulinum Clostridium difficile
- Van Ermengem proved that the anaerobic bacterium Clostridium botulinum, is responsible for food poisoning
- Ida Bengston research on the toxin responsible for gas gangrene and the antitoxin useful for treating it. Studied typhus,. So Got ‘Typhus Medal’ in 1947.
- Bird Flu (H7N9) Swine Flu (H1N1)
- Vasantrao Govarikar in the decade of the 1990’s a monsoon model based upon 16 Worldwide climatic parameters was developed. Mathematical model (Dynamic) to Forecasts – Param supercomputer. Vijay Bhatkar- Statistical model. Nowadays, predictions declared by IMD are the collective outcome of various models. This is called a holistic model.
- Pyrolysis (energy production by burning of waste at high temperature Ex. Biogas, Bioelectricity)
- America is the largest producer of electricity from solid waste
- Japan makes threads, paper from banana peelings.
- cardio-pulmonary rescucitation (CPR) = the heart should by pressed down hard by pressing the chest with both the palms.
- For injuries like sprains, twisting and contusion, the ‘RICE’ remedy should be applied : Rest Ice Compression Elevate
- ENIAC = first generation computers. Used Valves
- C-DAC, the welknown Centre for Development of Advanced Computing.
- ISCII code for writing different language scripts. (Indian Script Code for Information Interchange)
- Borelli and Viviani, in the 1660s, first measured the speed of sound.
- The velocity sound is inversely proportional to the square root of molecular weight of the gas. The molecular weight of oxygen gas (O2) is 32 while that of hydrogen gas So the velocity of sound in hydrogen is four times that in oxygen.
- Ultrasonic sound to sterilize liquids like milk by killing the bacteria
- The German chemist Wohler synthesized an organic compound urea from an inorganic compound ammonium cyanate. NH4+CNO– — >NH2CONH2
- tissue culture = ‘Ex vivo growth of cells or tissues in an aseptic and nutrient-rich medium’. A liquid, solid or gel-like medium prepared from agar supplies nutrients energy for tissue culture
- Frederick Campion. shown that cells and tissues can be grown ex vivo. he isolated the cells from carrot root and proved that entire plant can be produced from single cell.
- In a bioreactor, cells can be grown in a more nutritive medium and protected from pathogens
- Application of biotechnology in floriculture, nurseries and forestry
- Local Indian varieties of cows like sahiwal, sindhi, gir, lal kandhari, devni, khillari, dangi, etc. and exotic varieties like jersey, brown Swiss, Holstein, etc. are kept for their milk. Required for animals: fibre-rich coarse food, fodder, and sufficient water
- Poultry farming. Indian varieties like Aseel. exotic varieties like leghorn. Rhode Island Red, New Hampshire, Plymouth Rock, Black Rock are varieties of chicken reared for eggs as well as meat.
- Layers. For eggs: Leghorn, Minorca, Ancona, Lehman.
- Broilers. For meat: Brahma, Long, Cochin, Aseel
- Silkworms = Bombyx mori. Stages: egg, larva, pupa and adult
- Our eyes can see only that light which has wavelengths between 400 nm to 800 nm
- The images formed by lenses have erorrs of colours. This is called chromatic aberration
- The reflecting telescopes are mainly of two types: Newtonian and Cassegrain. .it is easier to make large mirrors as compared to making large lenses.
- Giant Meterwave Radio Telescope (GMRT) at Narayangaon near Pune
- Astrosat satellite has ultraviolet and X-ray telescopes and detectors
- Sulphamic acid (H3NSO3) is a solid inorganic acid.
- Sodium bicarbonate is formed on passing CO2 through an aqueous solution of sodium carbonate. (sodium bicarbonate = baking soda) Chemical equation of the reaction
Na2CO3 + H2O + CO2 — > 2NaHCO3
- Liquid CO2 is used as solvent in modern eco-friendly dry cleaning.
- Methane and chlorine gases react with each other at the temperature of 250 deg C to 400 deg C in presence of ultraviolet light and form mainly methyl chloride (chloromethane) and hydrogen chloride. This reaction is called chlorination of methane.
CH4 +Cl2 (Light) — > CH3Cl + HCl
- Electrolysis of salt water: 2NaCl + 2H2O — > 2NaOH + Cl2 + H2
- The 25% aqueous solution of salt is called saturated brine. When 1/5 of this solution is evaporated the dissolved salt gets crystallized and salt gets separated from the solution.
- Chlorine is inconvenient to handle because of its gaseous state. Instead, the solid bleaching powder which has the same effect is more convenient to use. Bleaching powder undergoes slow decomposition due to the carbon dioxide in air and chlorine gas is released. Bleaching powder gets its property because of this release of chlorine gas.
Bleaching powder (Calcium Oxychloride CaOCl2)
CaOCl2 + CO2 — > CaCO3 + Cl2
- Bleaching powder is obtained by the reaction of chlorine gas with slaked lime.
Ca(OH)2 + Cl2 — > CaOCl2 + H2O
- Dilute sulphuric acid and dilute hydrochloric acid react rapidly with bleaching powder to release chlorine gas completely.
CaOCl2 + H2SO4 — >CaSO4 + Cl2 + H2O
- Washing soda reacts with hard water to form insoluble carbonates:
MgCl2 (aq)+ Na2CO3 (s) — > MgCO3(s) + 2 NaCl (s)
- Crystaline soda. Loses water to form powder soda
Na2CO3 .10 H2O (crystalline soda) — > Na2CO3 .
H2O white powder (washing soda)
- Washing soda hygroscopic, that is, it absorbs moisture if left exposed to air.
- Borax (Na2B4O7.10H2O)
- Sodium sulphate (Glauber’s salt Na2SO4.10 H2O)
- When oil or animal fat is boiled with an aqueous solution of sodium or potassium hydroxide, sodium or potassium salts of carboxylic acids (fatty acids) are formed. These salts are called soap. When soap is mixed with hard water calcium and magnesium salts of fatty acids are formed. These being water insoluble they form a precipitate and that is why lather is not formed.
- Tetrazene, sunset yellow are artificial food colours used extensively
- Lipstick contains a dye named carmine. It does not affect lips but causes stomach disorders.
- Deodorants contain parabens (methyl, ethyl, propyl, benzyl and butyl) and also alcohol in large proportions. Aluminium – Zirconium compounds are the most harmful chemicals in the deodorant.
- In 1608, spectacle maker and researcher, Hans Lippershey discovered that seeing through two lenses kept one behind the other, seems to brings objects closer to us. He thus made the first telescope. Galileo made a telescope in 1609
- The images formed by lenses have errors of colours. This is called chromatic aberration.
- Biggest optical telescope in India, having a mirror of 3.6 m diameter is situated in the Aryabhatt Research Institute of Experimental Sciences, Nainital.
- Giant Meterwave Radio Telescope (GMRT) has been erected at Narayangaon near Pune.
- JL Proust showed law of constant proportion. Elements are in proportion in a compound
- Rhizobium is useful for nitrogen fixation on roots of legumes. Seeds of cereals and other plants (other than legumes) are soaked in rhizobia (solution or powder) before sowing, this is rhizobial inoculation.
- Alcanivorax bacteria cleans oil spill in ocean.
- Yeast Saccharomyces is used to make Alcohol ethanol C2H5OH and biodiesel.
- Yeast Saccharomyces cereviceae absorbs pollutant arsenic.
- Yeast Yarrowia lipolytica absorbs heavy metals in industry and toxins produces while making palm oil.
- Broad spectrum antibiotics : are useful against many bacteria. e.g. ampicillin, amoxicillin, tetracyclin.
- Narrow spectrum antibiotics : against a particular bacteria. e.g. penicillin, gentamycin, erythromycin. Penicillin controls infections of staphylocoocus , clostridia, streptococci bacteria,diseases like pneumonia, scarlet fever.
- Alexander Fleming observed (3rd sept 1928) staphylocoocus bacteria were destroyed by fungus Penicillium.
- Fungi causes dandruff in hair, ringworm, scabies as skin diseases. fungi produce harmful chemicals called mycotoxins and spoils food.
- Ants grow fungus in ant hill (termitarium) to use as food. Wasps and other insects lay eggs in fugus colony.
- National Institute of Virology is in Pune.
- Harmful microbes: Clostridium botulinum (Van Ermengem proved food poisoning. Spoilt cooked food causes food poisoning. rod shaped bacteria produce bottle shaped endospores. they are anaerobic.
- Ida Bengston herself infected due to Typhus while doing research. She was honoured ‘typhus medal’. Her research was on antibiotics for gas gangrene.
- Indian Institute of Ecology and Environment, Delhi
- Lindeman in 1942 studied food chain and energy flow through it. Charles Elton proposed ecological pyramid In 1927. It is also called Eltonian pyramid. He studied Tundra Ecosystem of Beer islands in England.
- Biogas contains about 55% to 60% methane and the rest is carbon dioxide. Production of biogas is an anaerobic process. It takes place in two stages.
- Production of acids. The microbes act on the biodegradable complex organic compound and produce organic acids.
- Methane gas production The methanogenic bacteria act on the organic acids to produce methane gas CH3COOH — > CH4 + CO2
- Proper co-ordination between various systems of an organism helps to maintain a state of equilibrium called ‘homeostasis’ which is necessary for the optimal efficiency of the body.
- Some cells in the body of living organisms are ‘totipotent’, that is if provided a proper environment, a new organism can grow from these cells.
- Layers for egg production: Leghorn, Minorca, Ancona, Lehman
- Broilers for meat: Brahma, Long, Cochin, Aseel
- Bombyx mori is variety of silk worm
- GM crops. For example,
Maize : MON 810, MON 863.
Potato : Amflora
Rice : Golden Rice
Soybean : Vistive Gold
Tomato : Vaishali
Cotton : BT cotton
•Basicity of acids : The number of H+ ions obtainable by the dissociation of one molecule of an acid is called its basicity. •Acidity of bases : The number of OH- ions obtainable by the dissociation of one molecule of a base is called its acidity.