BPSC Prelims Past Year Paper- 2020 - BPSC (Bihar) MCQ

Important Points

• Milk is a nutrient-rich liquid food.
• It is an emulsion of fat in water.
• It is a colloidal suspension of proteins.
• It is produced by the mammary gland of mammals.
• It is composed of:
  • Water = 87.5%.
  • Fat = 3.9%.
  • Protein = 3.4%.
  • Lactose & Minerals = 5.2%.
• It comprises the following components:
  • Protein, Calcium, Magnesium, Water, Fat, Phosphorus, Vitamin D, Potassium, Vitamin B12, Zinc & some amount of Carbohydrate.
  • Lactose is the main Carbohydrate.
  • Lactose is a disaccharide found only in milk and dairy products.
  • The fermentation of lactose produces lactic acid, which causes a sour taste.
    • The molecular mass of lactose: C₁₂H₂₂O₁₁.
• Milk contains a variety of proteins.
  • Casein protein is the main among them.
  • These protein form micelles which causes scattering of light ultimately causing milk to appear as white.
• Function:
  • To provide nutrient to the body for the growth of tissue, bones & muscles.
• Lactic acid is found in it.

Electromagnetic waves:

• The waves which do not require any medium to propagate are termed electromagnetic waves.
• They can travel even through a vacuum.
  • E.g: Cathode ray, Alpha ray, Beta ray, Gamma-ray, Ultraviolet rays etc.
• They propagate in a perpendicular direction to each electric field & magnetic field.
• These waves are composed of oscillating magnetic and electric fields.
• These waves travel with a constant velocity of 3 x 10⁸ ms^-1 in a vacuum.
• They are deflected neither by the electric field nor by the magnetic field. 
• Electromagnetic wave spectrum:

• Gamma rays:
  • Discovered by: Becquerel & Curie in 1896.
  • Wavelength: 10^-14 to 10^-10m.
  • Used in cancer treatment.
• X-rays:
  • Discovered by Roentgen in 1895.
  • Wavelength: 10^-12 to 10^-8 m.
  • Used in detecting fracture in bones, hidden bullet, needle or metals etc. inside the body.
• Ultraviolet rays:
  • Discovered by: Ritter in 1801.
  • Wavelength: 10^-9m to 4 x 10^-7m.
  • Used in preserving foodstuffs.
    • In detecting invisible writing, forged documents.
    • In capturing fingerprints in the laboratory.
• Visible light:
  • First studied by Newton in 1666.
  • Wavelength: 4 x 10^-7 to 7 x 10^-7 m.
• Infrared waves:
  • Discovered by Herschel in 1800.
  • Wavelength: 7 x 10^-7 m to 10^-3 m.
  • Uses:
    • In greenhouses to keep plants warm.
    • In revealing secret writings.
    • For looking through a fog, mist during wartime.
    • In Tv remotes.
• Microwaves:
  • Discovered by Hertz in 1888.
  • Wavelength: 10^-4 m to 1 m.
  • Uses:
    • Mainly used in RADAR & long-distance communication.
      • RADAR: Radio Detection & Ranging.
    • In fixed traffic speed cameras.
    • In remote sensing.
    • Wireless networks.
    • For cooking food in microwave ovens.
    • Cancer treatment.
    • Collision avoidance systems.
    • Garage door openers & keyless entry systems. 
• Radio waves:
  • ​Discovered by Marconi in 1895.
  • Wavelength: 0.1 m to 10⁵ m.
  • Used in radio & TV.

Key Points

• On July 16, 1969, Apollo 11 blasted off to the moon from Cape Kennedy Space Centre, Florida.
• Apollo 11's mission: To land two men on the moon & come back to Earth safely.
• Crew: Neil Armstrong (Commander), Edwin "Buzz" Aldrin (Lunar Module Pilot) and Michael Collins (Command Module Pilot).
• On 20th July 1969, Armstrong and Aldrin landed on the moon.
  • They landed on the moon in the Lunar Module named "The Eagle".
  • The lunar site where they landed is named "Sea of Tranquility".
• Collins stayed in orbit around the moon & performed experiments and took pictures.
• On July 20, 1969, Neil Armstrong became the first human to step on the moon.
  • He and Aldrin walked there for three hours.
  • They performed experiments.
  • They picked up the moon's dirt and rocks for further study of the origin of the moon.
• They left a plaque on the moon.
• The plaque on the moon says, "Here men from the planet Earth first set foot upon the moon July 1969, A.D. We came in peace for all mankind."
• They put a U.S. flag on the moon.
• On July 24, 1969, all three astronauts came back to Earth safely.

The correct answer is Infrared.

• Infrared rays are used for the treatment of muscles ache, and tension.
• It is also used in cookers for cooking food, in short-range communications, in thermal imaging cameras etc.

The correct answer is 4.70 kilo-ohm.

Solution: 

• Total Resistance (R) = 1.403 kilo-ohm.
  • R₁ = 2.0 Kilo-ohm.
  • R₂ =?
    • 1 kilo-ohm = 10³ ohm.
    • 1.403 kilo-ohm = 1403 ohm.
    • 2 kilo-ohm = 2000 ohm.
• Now, for parallel combination: 
  • 1/R = 1/R1 + 1/R2
  • On putting the values;   1/1403 = 1/2000 + 1/ R₂
    • 1/1043 - 1/2000 = R₂
    • 2000 - 1403 / 1403 x 2000 = 1/R₂
    • 597/ 1403 x 2000 = 1/R₂
    • R₂ = 1403 x 2000 / 597 = 2806000 / 597 = 4700.16
    • R₂ = 4700.16 ohm
    • If 10³ ohm = 1 kilo-ohm
      • then, 4700 ohm = 4.7 kilo-ohm
• Therefore, R₂ = 4.7 kilo-ohm. 

Key Points

• On heating, bonds between the electrons of semiconductors break because of the energy gained due to heating.
  • Electrons become free & help in the conduction of electric current if there is a potential difference applied across the semiconductor.
  • Hence the resistance decreases on heating. 

Resistance:

• ​It is the ability of the material to oppose the flow of current through the conductor.
• It depends on the following factors:
  • Length.
  • Area.
  • Temperature.
  • Type of material.
• R = p L / A.
  • Where p = resistivity of the material.
  • L = length of the conductor.
  • A = cross-sectional area of the conductor.
• SI Unit = Ohm.
• In the case of a conductor, resistance increases on heating.

Resistivity:

• It is the electrical property of a material that determines the resistance of a conductor.
• It depends upon the nature & temperature of the material.
• SI unit: Ohm- metre.

Semiconductor:

• ​It is the type of material having conductance lesser than conductor & resistance lesser than insulators.
• They do not have free electrons at normal temperatures.
  • On heating, the electrons get free & they behave like a conductor.
• The entire electronic system is based on semiconductor devices.
• Materials like Si, Ge, As etc are semiconductors.
• A pure semiconductor is neither n-type nor p-type.
  • Both p-type & n-type semiconductor is electrically neutral.
• It is of two types:
  • Intrinsic:
    • It is a semiconductor in pure form.
    • E.g: Germanium (Ge), Silicon (Si) etc.
  • Extrinsic:
    • It is a semiconductor mixed with a suitable impurity to increase its conductivity.
    • It is further classified into two groups:
      • n-type: It is mixed with pentavalent impurity like As, Sb etc. in which negatively charged electrons work as charge carriers.
      • p-type: It is mixed with trivalent impurity like Al, B etc. in which positively charged holes work as charge carriers.

Faraday:

• When an electric current passes up to 1 second due to 96485 C, through an electrolyte then the equivalent weight of electrolyte deposited is one & this amount of electric current is called 1 Faraday.
• Faraday constant (F) = 96485C mol⁻¹
• The constant is named after the British physicist Michael Faraday.
• It is a universal constant.
• It is the amount of electric charge carried by 1 mole of electrons.
• Represented by F & its measuring unit is Coulombs per mole (C.mol^-1 ).
• Faraday's laws of electrolysis:
  • First law:
    • The total mass (m) deposited at an electrode in the process of electrolysis is directly proportional to the total charge (q) passed through the electrolyte,
      • m = Z.i.t
      • Where i = electric current.
        • t = time.
        • Z = electrochemical equivalent of the substance deposited at the electrode.
  • Second law:
    • If some amount of electric current is allowed to flow for some time in various electrolytes, then the mass (m) of the substance deposited at the electrodes is directly proportional to their chemical equivalent weight (w), i.e: m directly proportional to w or (m₁ / m₂) = (w₁ / w₂).

Light Year:

• It is to used to measure distances in-universe. 
• It is the distance travelled by a beam of light in a single Earth year.
• It is approximately 6 trillion miles (9.7 trillion kilometres).
• The speed of light is constant throughout the universe i.e: 3 x 10⁸ ms^-1.
• Measuring in light-years also allows astronomers to determine how far back in time they are viewing. 
• It can be divided into smaller units as light-hours, light-minutes or light-seconds.
• According to the IAU, the light-year is the product of the Julian year (365.25 days) & the speed of light.

• There are two other units to determine length, are used in astronomical studies:

The astronomical unit (AU):

• The astronomical unit (AU) is the distance from the Earth to the Sun.
• It is the shortest astronomical unit of distance.
• The distance between the Sun & Earth changes throughout the year.
  • It is due to Earth’s orbit which is an ellipse.
  • It is approximately equal to 93 million miles.
• Short distances between bodies within a solar system which is in fractions of a light-year, is expressed in astronomical units.

The parsec (pc):

• The parsec (pc) is a unit of length used to measure distance in-universe.
• It is the distance from the Sun to an astronomical object with a parallax angle of one arcsecond.
• 1 parsec = 3.3 light years (approx.)
• It is used to measure large distances in-universe.

Refraction of Light:

• It is the phenomenon of deviation of light rays from its path when it travels from one transparent medium to another transparent medium.
• The cause of refraction is the speed of light which is different in a different mediums.
• In refraction, the speed of light & its wavelength change but its frequency remains unchanged.
  • Here, the refractive index is also equal to the velocity of light c of a given wavelength in empty space divided by its velocity v in a substance.
  • Thus, Velocity, Wavelength & Refractive index changes when light travels from one medium to another but Frequency remains unchanged.
• When a light ray travels from a denser medium to a rarer medium, it deviates away from the normal.
• When a light ray travels from a rarer medium to a denser medium, it deviates from the normal.

Laws of refraction:

1. The incident ray, the refracted ray & the normal at the point of incidence all three lie in the same plane.
2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction remains constant for a pair of the medium.
   • sin i / sin r = constant (¹u₂).
     • This is also called Snell's law.

Refractive index:

• ​The ratio of the speed of light in vacuum (c) to the speed of light in any medium (v), is called the refractive index.
• It is given by:  u = c / v.

Relative refractive index:

• ​The refractive index of the second medium with respect to the first medium is given by u = v₁ / v₂.
  • where v₁ = Speed of light in the first medium.
    • v₂ = speed of light in the second medium

Plutonium:

• Symbol: Pu.
• State: Solid.
• Atomic number: 94.
• Atomic mass: 244.
• Electron Configuration: [Rn] 5f⁶ 7s².
• Ionization energy: 6.06eV.
• Element period number: 7.
• Element group: Actinides.
• Melting point: 640^oC.
• Boiling point: 3228^oC.
• Material: Metal.
• It was first produced by Edward M. McMillan, Arthur C. Wohl, Glenn T. Seaborg, Joseph W. Kennedy in 1940.
• It was created by bombarding Uranium 238 with deuterium nuclei in a cyclotron.

Viscosity:

• S I unit: Pascal seconds (Pa·s) or kg·m⁻¹·s⁻¹.
• It is the property of a liquid representing the internal resistance of its different layers to motion.
• The forces between the layers opposing motion are known as Viscous force.
• It is the internal property of liquids & gases which is produced by the cohesive forces of the molecules.
• Generally, viscosity falls rapidly with temperature & it rises with rising pressure except in water.
• The viscosity of the fluid at rest will be 1 Poise.
  • It is independent of the state of the fluid.
• The viscosity of a liquid is measured by a Viscometer or Rheometer.
• According to Newton, the viscous force acting between any two layers of the fluid is proportional to the velocity gradient (dv/dx) in the direction perpendicular to the layers & area (A) of the layer.
  • If the viscous force F is acting between two layers of fluid of area A & have a velocity gradient dv/dx between them, then:
    • F = -n A dv / dx. 
      • ​F / A = - n dv/dx.  i.e: Shear stress is directly proportional to Shear strain.
      • F / A directly proportional dv/dx, where
        (dv/dx) = velocity gradient & n= coefficient of viscosity.

Factors on which viscosity depends:

• Distance between the two adjacent layers.
• Area of contact between the two adjacent layers.
• The velocity difference between the two adjacent layers.

The correct answer is Potassium dichromate-sulfuric acid.

• It a test to check the presence of alcohol in a person's blood & carried out on samples of breath provided by the person.
• It is done with the help of filter paper made of Potassium dichromate-sulfuric acid.

The correct answer is Zymase.

• C₆H₁₂O₆ ----^zymase→ 2C₂H₅OH + 2CO₂ .

The correct answer is CO_2.

• Ca(OH)₂  + CO₂  → CaCO₃ + H₂O.
  • When carbon dioxide (CO₂) is passed through lime water (dilute aqueous solution of Calcium hydroxide) (Ca(OH)₂), a precipitate of calcium carbonate (CaCO₃) of the white colour is formed.

Fuels:

• These substances produce heat & light on combustion.

Petroleum:

• It is a dark coloured oily liquid with an offensive odour.
• It is also called Rock oil, Mineral oil, or Black gold.
• When fractional distillation is carried out, it gives different products at different temperatures.
• It is a naturally occurring oily, flammable liquid.
• It is comprised of hydrocarbons (50–98%).
• Fuels such as natural gas and petrol contain hydrocarbons.
  • These are compounds of hydrogen and carbon only.
• When they burn completely:
  • The carbon oxidises to carbon dioxide.
  • The hydrogen oxidises to water.

Petrol & Diesel:

• It is a flammable liquid primarily used as fuel in vehicles.
• It comprises organic compounds obtained by the fractional distillation of petroleum.
• Incomplete combustion creates carbon monoxide.
  • ​It binds with haemoglobin & reduces the capacity of blood to carry oxygen.
• Both are made from Petroleum/ Crude oil.
• Both are made by Fractional distillation.
• Auto-ignition temperature: Disel = 210°C, Petrol = 246°C.

The correct answer is Decrease 1000 times.

Given, pH = 3.

Therefore, [H+] = 10^–3.

^​Now, pH = 6, so, [H+] = 10^–6.

Hence [H+] reduced by 10^–3 times i.e: 1000 times.

• Naphthalene is a colourless crystalline solid with a strong mothball odour.
• It is also called white tar & tar camphor.
• Melting point: 80.1 C.
• Boiling point: 218.C.
• Molecular Weight: 128.17 g/mol.
• Molecular formula: C10H8.
• Chemical structure: 
  
• It is obtained from either coal tar or petroleum distillation.
• It is a white, volatile, solid polycyclic hydrocarbon.
• It is almost insoluble in water.
  • The solid is denser than water and thus insoluble in water.
• It is highly volatile.
• Uses:
  • It is used in the dyes industry.
  • It is used as a moth repellent.
  • It is used as wood preservatives.
  • It used as fumigant, lubricants, and to make other chemicals.
  • It is used in the manufacture of polyvinyl chloride ( PVC) plastics.
  • It is used in synthetic tanning, preservative, textile chemicals, emulsion breakers.
  • It is used around garden and building peripheries to repel animals such as snakes and rabbits.
• Fuels such as petroleum and coal contain naphthalene. 
• It is the most abundant single constituent of coal tar.
• It is commercially produced by crystallization from the intermediate fraction of condensed coal tar and from the heavier fraction of cracked petroleum.
• Negative effects:
  • Excess exposure to naphthalene can cause the following issues:
    • Hemolytic anaemia.
    • Damage to the liver.
    • Neurological system.
    • Cataracts.
  • It is generally accepted to be a human carcinogen.
  • It may increase the risk of developing laryngeal (larynx) and colorectal (colon) cancer.
  • It is a white solid that evaporates easily because of sublimation.
• Sublimation:
  • It is the process of transition of a substance from the solid-state to the gaseous state without passing through the liquid state.
  • The substance showing this phenomenon is called sublimate.
  • E.g: Camphor, Naphthalene, Dry ice (solid CO₂) etc.
• When naphthalene is heated, it sublimes easily because it is made up of non-polar molecules that are held together only by weak Van der Waal intermolecular forces of attraction.

Structur=al formula: 

As in structure,

• There are 6 C-H & 6 C-C bonds. Therefore, it is 12 sigma bonds.
• There are 3 C=C pi bonds in benzene.
• Therefore, there are 12 sigma & 3 pi bonds in total.
• Hence, Benzene is made of 15 covalent bonds.

Important Points

• Urea is also known as Carbamide.
• It is an organic compound.
• Chemical formula:  CO(NH₂)₂.  
• Molar mass: 60.06 g/mole.
• Two NH2 groups joined by a carbonyl (C=O) functional group.
• It has four elements i.e: carbon, nitrogen, oxygen, and hydrogen.
• Structural Formula:

​

• It is the first organic compound discovered in a laboratory. 
• It is a colourless, odourless solid.
• It is highly soluble in water & non-toxic.
• After dissolving in water, it is neither acidic nor alkaline.
• Urea is prepared by reacting ammonia, sulphur, and carbon monoxide in methanol. 
• Roles of Urea:
  • As fertilizer. 
  • As flour treatment agent.
  • As has the role of human metabolite.
  • It has an important role in the metabolism of nitrogen-containing compounds by animals.
  • It is the chief nitrogen-containing constituent in the urine.
  • The human body uses it in many ways like in nitrogen excretion. 
    • The liver forms it by combining two ammonia molecules (NH₃) with a carbon dioxide (CO₂) molecule in the urea cycle.
  • It is widely used in fertilizers as a source of nitrogen (N).
  • It is used as a raw material for the chemical industry. 
  • It is used in cattle feed as a direct supplier of nitrogen to promote growth.
  • It is also used in skin creams, moisturizers & shampoos.
  • It is used as a raw material in tooth whitening products.

Negative effects:

• It can cause irritation in the skin, eyes & respiratory tract.
• Continuous contact with urea as fertilizer can cause skin disease.
• The higher level of urea in the blood can be damaging.
• It can cause algal blooms to produce toxins.

The correct answer is Lead.

Among metals:

• Copper & Zinc are good conductors.
• Mercury metal is a poor conductor while Lead is the poorest conductor.

Some important Vitamins:

The correct answer is Estrogen.

• Hormones are chemical messengers that the endocrine glands produce & release directly into the bloodstream.
  • Hormones help regulate many bodily processes, such as hunger, sleep, and growth.
• Sex hormones play an essential role in sexual development and reproduction.
  • The main glands that produce sex hormones are the adrenal glands and the gonads.
  • It includes the ovaries in females and testes in males.

Dr Arvid Carlsson (1923-2018) got the Nobel Prize in Physiology or Medicine in 2000 for his research on the brain's chemical signals and the resulting treatment for Parkinson's disease.

• He shared with Paul Greengard and Eric R. Kandel.
• He was a Swedish Neuropharmacologist.
• He was best known for his work with the neurotransmitter 'Dopamine' and its effects on Parkinson's disease.

Parkinson's disease:

• Parkinson’s disease got its name from the English physician James Parkinson.
• He published a comprehensive description titled "An Essay on the Shaking Palsy" related to Parkison's disease in 1817.
• Parkinson’s disease is a progressive disorder that is caused by degeneration of nerve cells in the part of the brain called the Substantia Nigra, which controls movement.
• These nerve cells die or become impaired, losing the ability to produce an important chemical called dopamine.
• Common Symptoms:
  • Tremor or the involuntary and rhythmic movements of the hands, arms, legs and jaw.
  • Muscle rigidity or stiffness of the limbs.
  • The gradual loss of spontaneous movement.
  • Unsteady walk or balance.
  • Depression or dementia.

Noble Prize:

• The Nobel Prizes are given in the memory of Alfred Bernhard Nobel (1833-1896).
• Originally, the Nobel Prize was awarded for works in 5 disciplines that are:
  • Peace, Physics, Chemistry, Medicine & Literature.
• The first prize was given in 1901.
• The Prize for Economics was instituted in 1968 by a Swedish bank. It was awarded first time in 1969.
• The award comprises a Gold Medal, Diploma, extension in Swiss visa & passport & 8 million Swedish Krona.
• The awards can be given to a maximum of three persons in the same field at the same time.
• It is not awarded posthumously.
• Award in 2020 for Medicine: Harvey J. Alter, Michael Houghton & Charles M.Rice.
  • For the discovery of the hepatitis C virus.

Thyroid Gland:

• It is a butterfly-shaped gland.
• It lies in front of the Trachea & below the Larynx.
• It uses iodine to make hormones like Thyroxine, Calcitonin, Tri-odo-thyronine.
• It is a type of Endocrine gland, that secrets hormones directly into the bloodstream.

Thyroxine Hormone:

• This hormone increases metabolism & blood pressure.
• Iodine is essential for the synthesis of thyroxine hormone.
  • It can be obtained from fishes, green leafy vegetable, iodised salt.
• It regulates tissue growth.
• It along with hormones from the Pituitary gland regulates the water level balance in the human body. 

• The tongue is responsible for the sense of taste.
• Special receptors cells present in taste buds are called Chemoreceptors.
  • They are responsible to transmit taste & smell to the brain.
• Taste buds are found in the papillae of the tongue.
  • They are specialized for detecting aqueous chemical stimuli.
• The taste & nature of the food like sour, sweet, bitter, salty etc are realised due to the presence of these taste buds.
• Sweet & salty mainly at the tip of the tongue.
• Sour at the sides of the tongue.
• Bitter at the back of the tongue.
• 
• Taste buds are onion-shaped end organs containing 50– 150 cells commonly.
• Taste bud contains receptor cells and supporting cells that are both derived from epithelial cells.
• These taste receptors are specialized cells surrounded by nerve endings.
• The lifespan of the taste cells within the taste buds is 10-14 days & a variety of different developmental stages are present within a single taste bud.
• The lifespan of the cells is short due to the damaging effects of temperatures, textures, and size of foods.
  • However, the taste bud itself will not die unless significantly damaged.
  • Dying cells are continuously being replaced by new taste cells.
• The taste receptor cells within a bud are arranged such that their tips form a small taste pore, and through this pore microvilli from the taste, cells extend.
• The receptor-stimulus-binding event triggers a neurotransmitter release onto different nerve fibres.
• There starts propagation of sensory information to taste processing areas in the central nervous system & thus, the brain identifies the taste.

Ginger is a stem and not a root because it has nodes and internodes.

• It is a rhizome, an underground modification of the stem.
  • The rhizome is a branched, prostrate, horizontally growing stem having nodes and internodes.
• It has a brownish line that represents nodes and internodes.
• It has scale leaves at nodes, axillary buds & a terminal bud.
  • These leaves lack chlorophyll.
  • The terminal bud gives rise to aerial shoot at the onset of a favorable condition.
• It grows above the ground & runs parallel to the ground.
• It helps the plant to propagate vegetatively.
• The nodes present in ginger give rise to both root & shoot.
• Underground modifications of stems:
  • Underground stems are modified to store food inside them.
  • It becomes thick & tuberous because of the storage of food.
  • Various types of modifications are:
    • Stem tuber: Potato.
    • Bulb: Onion, Garlic, Tulips, Lilies, etc.
    • Corm: Gladius, Sativus, etc.
    • Rhizome: Ginger, Turmeric, Banana, Ferns, etc.

Rhizome:

• The rhizome which grows with lateral buds is called a sympodial rhizome.
  • E.g: Ginger.
• The rhizome which grows through terminal buds is called a monopodial rhizome.
  • E.g: Lotus.

Fructose:

• Its older name is levulose.
• It is a functional isomer of glucose and has a ketone group.
• Fructose is a type of sugar found in many fruits and vegetables.
• It is a monosaccharide, ketose sugar, hexose & reducing sugar.
• It is separated from glucose by crystallisation using alcohol.
• It is a fruit sugar along with glucose & galactose, the three dietary monosaccharides.
• Molecular formula: C₆H₁₂O₆ with one ketonic group & five alcoholic groups.
• Molar mass: 180.15 g.mol^-1.
• Melting point: 103^oC.

Structural formula: 

Features:

• It is sweet in taste.
• During digestion, it gets directly absorbed in the blood.
• It is the sweetest of all naturally occurring carbohydrates.
• It absorbs moisture quickly & thus, becomes sticky.
• It is white, odourless.
• Naturally, they occur in litchi, mango, Guava etc.
• For commercial purposes, it is derived from sugarcane, sugar beets.
• Health effects:
  • Weight gain.
  • Can cause type 2 diabetes.
  • Can cause cardiovascular disorders.
  • Excess consumption leads to liver failure.
• The naturally occurring fructose is (-) isomer with D- configuration.
• The L (+) from either exists in minor amount along with D (-) form or synthesised through various chemical reactions.

Key Points

• Fruits are the ripened ovary of the flower.
  • It can True fruit or False fruit.
• There are three main types of fruits:
  • Simple fruit.
  • Aggregate fruit.
  • Composite fruit.

• Legume is a plant in the family Fabaceae.
• Most of the legumes have symbiotic nitrogen-fixing bacteria in their root nodules.
• These symbiotic bacteria which are known as Rhizobia reside within their root nodules.
• Rhizobia invade the legume root hairs and reside in nodules.
• Effective nodulation and nitrogen fixation depend on favorable interactions between the plant & Rhizobium 
• These bacteria are helpful in fixing nitrogen from atmospheric i.e: molecular nitrogen (N2) into ammonia (NH3).
• The root nodules are sources of nitrogen for legumes, making them rich in plant proteins.
• As all proteins contain nitrogenous amino acids.
  • So, nitrogen is a crucial ingredient in the production of proteins.
• Hence, legumes are one of the best sources of plant protein.
• There are many varieties of legumes.
  • Some of them are Kidney beans. Pinto beans.Soybeans.Chickpeas & lentils.
• Legumes contain fibre, protein, carbohydrate, B vitamins, iron, copper, magnesium etc.
• Health Benefits of Legumes:
  • Legumes are an excellent source of resistant starch which is broken down by bacteria in the large intestine to produce short-chain fatty acids.
  • These fatty acids are used by intestinal cells for energy.
  • They are naturally:
    • Low in fat.
    • Free of saturated fat.
    • Cholesterol free.
    • Low in glycemic index.
• Legumes play an important role in the prevention and management of a variety of health conditions.
• Legumes are used for rotation farming with cereals.
  • They supply nitrogen to the cereal crops.

Important Points

• Cloves (Syzygium aromaticum) are aromatic dried flower buds.
  • It relates to the family Myrtaceae. 
• The clove tree is an evergreen that grows to a height ranging from 8–12 m.
• It has large leaves and flowers.
• The flower buds are at first in a pale colour & then green.
• When they are ready to be plucked, their colours change to bright red.
• Cloves are harvested when 1.5–2 cm long, and consist of a long calyx, terminating in four spreading sepals, and four unopened petals which form a small ball in the centre.
• The buds are hand-picked in late summer and again in winter and are then dried in sun.
• The bud contains approximately 20 per cent essential oil, the principal component of which is the aromatic oil "Eugenol".
• Cloves are strongly pungent because of eugenol.
• Oil from cloves is obtained through distillation.
• This oil is used for various purposes like:
  • To prepare microscopic slides for viewing.
  • As a local anaesthetic for toothaches.
  • Germicides.
  • Perfumes.
  • Mouthwashes.
  • In the synthesis of vanillin &
  • As an intensifier.