" Hereditary and evolution" class 10th

 Topics to be covered

• Introduction
• What is Heredity?
• Inherited traits
• Mendel's experiments
• Laws of Inheritance
• Sex determination
• Evolution
• - Variations & its relation to Evolution
• Acquired vs. Inherited traits
• - Speciation
• -Evolution by stages
• Human evolution

What is Heredity?

• Passing of traits from parents/ancestors to offspring
• Genetics :- The branch of science which deal with the study of heredity

Heredity vs. Inheritance

Heredity

• The process by which characters are transferred from one generation to the next generation is called inheritance / heredity 
• The differences in traits of individuals of a progeny from each other and from their parents are called variations
• The branch of science which deals with inheritance and variation is called genetics

Inherited trait:

A trait that is genetically passed down from one generation to another

Inherited traits: Examples

Hair colour

. Eye colour

. Height

Shape of feet

. Ear lobes

How do the traits get inherited?

1. Mendel's Experiment

• Gregor Johann Mendel (1822-1884) is known as 'Father of Genetics'.
• Mendel performed his experiments with garden pea plant (Pisum sativum)
• He conducted artificial pollination/cross-pollination experiments using several true-breeding varieties having contrasting traits 
• He observed one trait at a time
• He hybridised plants with alternate forms of a single trait (Monohybrid cross). The seeds thus produced were grown to develop into plants of first filial generation (F₁) 
• Mendel then self-pollinated the F, plants to generate plants of second filial generation (F₂)
• Later, Mendel also crossed pea plants that differed in two characters (Dihybrid cross)

2. Mendel's Experimental Plant

Mendel selected garden pea as his experimental material because of the following reasons.

(1) It is an annual plant with a short life-cycle. So, several generations can be studied within a short period.

(2) It has perfect bisexual flowers containing both male and female parts

(3) The flowers are predominantly self-pollmating It is easy to get pure line for several generations.

(4) It is easy to cross-pollmate them because pollens from one plant can be introduced to the stigma of another plant by removing the anthers

(5) Pea plant produces a large number of seeds in one generation

(6) Pea plants could easily be raised, maintained and handled

 (7) A number of easily detectable contrasting characterstraits were available

3. Mendel's Observations

(1) F1 progenies always resembled one of the parents and trait of other parent was not seen

(2) F2 stage expressed both the parental traits in the proportion 3.1.

(3) The contrasting traits did not show any blending at either F1or F2 stage.

 (4) In dihybrid cross, he got identical results as in monohybrid cross

(5) He found that the phenotypes in F2 generation appeared in the ratio 3:1

(6) He found that the genotypic ration in F2 generation appeared in the ratio 1:2:1

4. Mendel's Laws of Inheritance

■ Based on his hybridisation experiments, Mendel proposed the laws of inheritance.

(i) Law of dominance (First law)

■ This law states that when two alternative forms alleles are present in an organism, only one factor expresses itself in F1 progeny and is called dominant while the other that remains masked is called recessive.

(ii) Law of segregation (Second law)

■ This law states that alleles of a pair segregate from each other during gamete formation, such that a gamete receives only one of the two factors. They do not show any blending.

iii) Law of independent assortment

According to this law the two factors of each character separate out independent of the factors of other characters at the time of gamete formation and get randomly rearranged in the offsprings producing both parental and new combinations of characters.

Sex Determination Mechanism :- 

Finalisation of sex at the time of zygote formation is called sex Determination .

XX-XY type :- 

Seen in many insects including humans .

Males have X and Y chromosomes along with autosomes and female have a pair of X chromosomes.

"Magnetic effect of electric current" class 10

 Topics to be covered:- 

• History of magnetism 
• Bar magnet 
• Magnety field
• Operated 's experiment 
• Magnetic field lines
• Magnetic field due to current carrying conductor due to magnetic field
• Electric motor 
• Electromagnetic induction
• Electric generator

Introduction:-

• Nail  attracted towards magnet.
• Refrigerator locked due to magnetic properties
• Metro doors use magnetism
• Electric motors and generators works on magnetism

Story of magnetism:- 

• Shepherd found some rocks that was attracted nail.
• People thought that rocks were magical and so called those rocks magnesia (word from magic)
• Later scientists give it a name magnetism.

Bar magnet:-

• Rectangular object that has a magnetic field .

Properties of bar magnet:-

• Align itself in the north south direction when suspended freely.
• North and South pole cannot be isolated.
• Like led repel and unlike poles attract .

• Not all materials are attracted by magnet.

Magnetic field::

• Region around a magnet where the magnet exerts its influence.

Magnetic field lines:- 

• Magnetic field is a vector quantity [magnitude + direction]
• Visual realization of magnetic field by bar magnet and iron filling experiment.
• Directions:- outside magnet:- North to South and Inside magnet:- South to North

Properties of magnetic field lines :-

• Form continuous closed loops
•  Tangent to magnetic field line at a given point specifies the direction of net magnetic field at that point
• Greater number of magnetic field lines per unit area stronger the magnetic field .
• Two magnetic field lines never intersect each other . If they do so that means it shows two directions at one point which is not possible. 

Operated experiment:- 

• Electricity and magnetism are very closely related .
• Operated observed the inter relation between electricity and magnetism.

Oersted experiment:- 

Observations:- 

• Magnetic compass needle deflected when current passes through a wire.
• A wire carrying electric current behave like a magnet.
• Deflection reverses as the direction of current is reversed.

Conclusion:- 

• A wire carrying electric current behave like a magnet.
• Moving charges produce a magnetic field in the surrounding region.

Magnetic field due to a current carrying 

• Straight conductor 
• Circular loop
• Solenoid

Magnetic field due to a current carrying straight conductor:-

• Magnitude of magnetic field produced at a given point increases as the current through the wire increases. 
• Magnetic field produced by a given current in a conductor decreases as the distance of the point from it increases.

Pattern of field lines:- 

• Concentric circles represent magnetic field around a current carrying straight wire.

Directions of magnetic field:- 

Right hand thumb rule :- If a current carrying straight conductor is held in your right hand such that thumb point towards the direction of current, then the wrapped fingers show direction of magnetic field lines.

Magnetic field due to a current carrying circular loop:-

• Every point on the wire carrying current would give rise to magnetic field appearing as straight lines at the centre of loop 

So

•  magnetic field is directly proportional to current 
• magnetic field is directly proportional to number of turns ,
• magnetic field is inversely proportional to square of distance 

Strength of magnetic field at the centre of coil (loop) depends upon:- 

Radius of coil:-

• Strength of magnetic field is inversely proportional to radius of coil . If radius increases, magnetic strength at the centre decreases.

Number of turns in the coil:- 

• As the number of turns in the coil increases , the magnetic field strength at the centre increases. This is because current in each circular turn is having the same direction thus field due to each turn add up .

The strength of current flowing in the coil:- 

• As the strength increases, the strength of magnetic field increases.

Maxwell Corkscrew Rule/ Right Hand rule:-

•  If we considered ourselves driving a corkscrew in the direction of current, then the direction of corkscrew is the direction of magnetic field.

Magnetic field due to a current carrying solenoid :-

• Solenoid is a coil wound into a tightly packed helix .
• Or 
• A coil of many circular turns of insulated copper wire wrapped in shape of cylinder.
• Field lines of a solenoid are similar to those of bar magnet.
• Field is uniform inside the solenoid.
• Strength of magnetic field is proportional to number of turns and magnitude of current.

Where do we use solenoid:- 

• Transformer creation

Electromagnet:- 

• Strong magnetic field produced inside the solenoid is used to magnetize the magnetic material like steel , soft iron , when placed inside the coil 

Magnetic field :- 

• Introduction of force due to magnetic field:- 
• A current carrying rod experiences a force perpendicular to its length and magnetic field 
• Direction of the force on the conductor depends upon:-
• - Direction of current and 
• - Directions of magnetic field

Fleming Left hand rule:-

Stretch your thumb , forefinger and middle finger of your left hand in such a way that they are mutually perpendicular to each other. If the first finger shows the direction of magnetic field and middle finger show the direction of current then the thumb will show the direction of motion of conductor.

Fleming ' left hand rule demonstration:- 

A relationship between direction of magnetic field, current and the force on the conductor .

Note :- downward :- inward

Upward:- outward

Application:- magnetic field and force exerted by it:- 

• Electric motor ,
• Electric generator
• Loudspeaker,
• Microphone,
• Measuring instruments etc.

Magnetism in medicine

• An electric current always produces a magnetic field. 
• Even weak ion currents that travel along the nerve cells in our body produce magnetic fields. 
• When we touch something, our nerves carry an electric impulse to the muscles we need to use. 
• This impulse produces a temporary magnetic field.
•  These fields are very weak and are about one-billionth of the earth's magnetic field. 
• Two main organs in the human body where the magnetic field produced is significant, are the heart and the brain. 
• The magnetic field inside the body forms the basis of obtaining the images of different body parts.
•  This is done using a technique called Magnetic Resonance Imaging (MRI). 
• Analysis of these images helps in medical diagnosis. 

• Magnetism has, thus got important uses in medicine.

ELECTRIC MOTOR

An electric motor is a rotating device that converts electrical energy to mechanical energy,

 Electric motor is used as an important component in electric fans, refrigerators, mixers, washing machines, computers, MP3 players etc. 

Material requirements:- 

Rectangular coil, magnetic poles , split rings. Axle, brushes and source battery.

Construction:-

An electric motor,  consists of a rectangular coil ABCD of insulated copper wire. 

The coil is placed between the two poles of a magnetic field such that the arm AB and CD are perpendicular to the direction of the magnetic field. 

The ends of the coil are connected to the two halves P and Q of a split ring. 

The inner sides of these halves are insulated and attached to an axle. 

The external conducting edges of P and Q touch two conducting stationary brushes X and Y, respectively, 

Working of electric motor:- 

Current in the coil ABCD enters from the Source battery through conducting brush X and flows back to the battery through brush Y. 

 current in arm AB of the coil flows from A to B. 

In arm CD it flows from C to D, that is, opposite to the direction of current through arm AB.

 On applying Fleming's left hand rule for the direction of force on a current-carrying conductor in a magnetic field .

 We find that the force acting on arm AB pushes it downwards while the force acting on arm CD pushes it upwards. 

Thus the coil and the axle O, mounted free to turn about an axis, rotate anti-clockwise. 

After half rotation. Q makes contact with the brush X and P with brush Y. 

Therefore the current in the coil gets reversed and flows along the path DCBA. 

A device that reverses the direction of flow of current through a circuit is called a commutator. 

In electric motors, the split ring acts as a commutator. 

The reversal of current also reverses the direction of force acting on the two arms AB and CD.

 Thus the arm AB of the coil that was earlier pushed down is now pushed up and the arm CD previously pushed up is now pushed down. 

Therefore the coil and the axle rotate half a turn more in the same direction. 

The reversing of the current is repeated at each half rotation, giving rise to a continuous rotation of the coil and to the axle.

Significance of split rings :- 

• Act as a commutator .
• Commutator is a devise that reverses the direction of flowe of current 
• Reversal of current results in a continuous rotation of coil.

The commercial motors use (i) an electromagnet in place of permanent magnet: (i) large number of turns of the conducting wire in the current carrying coil; and (iii) a soft iron core on which the coil is wound. 

The soft iron core, on which the coil is wound, plus the coils, is called an armature. This enhances the power of the motor. 

Electromagnetic induction:- Process by which changing magnetic field in a conductor induced current in another conductor.

Application:- electric generator, Wireless charger , elevators, metro trains

1. Faraday 's Experiment 1 

Observations:-

• Relative motion between magnet and coil induced electric current in the coil 

2. Faraday 's Experiment 2

Observations:- 

• Relative motion between coil induce electric current.

3. Faraday 's Experiment 3

Observations:-

• Relative motion is not an absolute requirement for inducing current.

Faraday 's  Law of induction:-

First law:- 

• An EMF is induced in circuit whenever the amount of magnetic flux (no. Of magnetic field lines per unit area) linked with a circuit changes.

Second law:- 

• Magnitude of induced EMF in a circuit is equal to time rate of change of magnetic flux through the circuit.

Methods of producing induced EMF:- 

• Varying magnetic field (B)
• Varying area(A)
• Varying relative orientation of coil and magnetic field,

Direction of induced current:-

Fleming 's right hand rule:- 

• Stretch the thumb forefinger and middle finger of right hand so that they are perpendicular to each other . If forefinger indicates the Direction of magnetic field , thumb shows the direction of motion of current then the middle finger will show the Direction of induced current. This is Fleming right hand rule.

* Electric Generator:- 

• Device that convert mechanical energy into electric energy

-Principle Based on Electromagnetic Indrection

•  It says that current is  induced in coil /loop through change in its orientation or a change in its effective area.

Types of Electric Generator :-

• AC Generator
• DC Generator

 AC Generator =

• Alternating current is produced which changes its direction after equal intervals  of time

DC Generator:- 

• Direct current is produced which does not changes its direction with time.

- Construction AC Generator:-

• Rectangular coll induced copper
• Magnetic poles
• split rings.
• Axle
• Brushes
• • Galvanometer

* working of Electric generator :- 

• When the axle attached to two rings is  rolated such that arm AB moves up & CD moves down in the magnetic Field produced by permanent magnet, It rolates the coil clockwise
• By applying Fleming's & right hand, the induced current flows in  direction ABCD
•  Thus in external circult, current flows from B₂ to B₁
• After half a rotation.arm CD starts moving up & AB moving down. 
• As a result induced current in both arms changes, giving rise to net induced current in direction DCBA
• Now in External circuit , current flows from B1 to B2.
• Thus after half a rotation, polarity of current in respective arms changes.
• such a current which changes its direction. after equal intervals of time is called alternating current
• This device is called AC Generator

Note :-If there are larger numbers of turns in  the coil, the current generated in each turn adds up to give large current through coil.

DC Generator - Working

• split ring commutator is used to ensure unidirections flow of current.
•  with this, one brush is at all times contact with arm moving down.
•  This generator is thus called a DC generator

Difference the AC & DC

• DC flows in one direction always

 •Ac flows by reverses its directions periodically

• AC Changes direction after every 1/100 sec. Frequency of AC is 50 Hz

• AC Can transmitted over  long distance without much loss of energy.

Domestic electric current:- 

• In our homes, we receive supply of electric power through a main supply (also called mains), either supported through overhead electric poles or by underground cables.
• For safe conduction , we use 3 coated wire,
•  One with red insulation cover, is called live wire (or positive).
•  Second wire, with black insulation, is called neutral wire (or negative). 
• And third with green coat called earth wire.
• In our country, the potential difference between the two is 220 V.

At the meter-board in the house, these wires pass into an electricity meter through a main fuse. 

Through the main switch they are connected to the live wires in the house. 

These wires supply electricity to separate circuits within the house. 

Often, two separate circuits are used, one of 15 A current rating for appliances with higher power ratings such as geysers, air coolers, etc. 

The other circuit is of 5 A current rating for bulbs, fans, etc. 

Functions of green wire:-

• The earth wire, which has insulation of green colour, is usually connected to a metal plate deep in the earth near the house. 
• This is used as a safety measure, especially for those appliances that have a metallic body, for example, electric press, toaster, table fan. refrigerator, etc.
•  The metallic body is connected to the earth wire, which provides a low-resistance conducting path for the current. 
• Thus, it ensures that any leakage of current to the metallic body of the appliance keeps its potential to that of the earth, and the user may not get a severe electric shock.

Fuse:-

• Electric fuse is an important component of all domestic circuits. 
• It is a safety device which prevents the damage to appliances and the circuit due to overloading.. 
• Overloading can occur when the live wire and the neutral wire come into direct contact. (This occurs when the insulation of wires is damaged or there is a fault in the appliance.)
•  In such a situation, the current in the circuit abruptly increases. 
• This is called short-circuiting.

 The use of an electric fuse prevents the electric circuit and the appliance from a possible damage by stopping the flow of unduly high electric current. 

The Joule heating that takes place in the fuse melts it to break the electric circuit.

 Overloading can also occur due to an accidental hike in the supply voltage.

 Sometimes overloading is caused by connecting too many appliances to a single socket.

Thank you...

- 

"Bioinorganic chemistry " MSc

Bioinorganic Chemistry

• Bioinorganic chemistry is a relatively new and still growing interdisciplinary field of chemistry which largely focuses on the roles of metal ions in living systems.

Metalloporphyrins

• The metaloporphyrins are the complexes in which a metal ion is coordinated to four nitrogen atoms inside the cavity of the porphyrin ring in a square planar geometry. 
• The axial sites are available for other ligands.
•  Some examples of metalloporphyrins are hemoglobin, myoglobin, cytochromes and chlorophylls.

The porphyrin rings are the derivatives of a macrocyclic ligand called porphine.

 The porphine molecule consists of

•  unsubstituted tetra pyrole connected by methylidyne (CH) bridges.
•  These methylidyne carbon positions are labeled the alpha, beta, Gama, delta and 5, 10, 15, 20 positions in porphine and porphyrin rings respectively.
•  The 5, 10, 15, 20-tetraphenyl derivatives (tpd) are readily available because of their ease of synthesis and purification. 
• In porphyrin rings various groups are attached to the perimeter of porphine molecule.
•  The porphyrin ring can accept two hydrogen ions to form the dication (ie,+ 2 diacid) or donate two protons to form dianion.
•  In metalloporphyrin complexes the inner hydrogen atoms are replaced as protons by dipositive metal ions. 
• Therefore, the metal free porphyrin ligand has -2 charges. 
• Since, this macrocyclic ligand has a planar conjugated system of π bonds around its perimeter, it is much more rigid macrocyclic ligand than the crown ethers
•  Therefore, the ligand is more selective for certain metal atoms than the crown ethers.
•  It has a stronger preferences for the d8 Ni2+ ion. 
• The other metal ions may add above or below the square plane.
•  The structures of porphine molecule, metalloporphyrin and Fe-protoporphyrin IX or heme group are shown in Fig. 9.1.
• 
  

Fig. 9.1 Structure of (a) Porphine (b) Metalioporphynin (c) Fe-protoporphyrn DX

The porphyrin rings are rigid because of the delocalization of the π-electrons around the perimeter. 

The size of the cavity in the centre of porphyrin ring is ideal for accommodation of metal ions of the first transition series. 

If the metal ion is too small such as Ni 2+, the ring becomes ruffled to allow closer approach of nitrogen atoms to the metal ion. 

On the other hand, if the metal ion is too large, it can not fit into the cavity and occupies position above the ring which also becomes domed

Role of Iron in Living Systems

Iron is the most important transition metal involved in living systems, being vital for both plants and animals.

 In the living systems, iron has three well characterized systems:

• (1) Proteins that contain one or more porphyrin rings such as hemoglobin, myoglobin and cytochrome P450
• (2) Proteins that contain non-heme iron such as iron-sulphur compounds (ruberdoxin, ferredoxins nitrogenase)
• (3) The non-heme diiron oxo-bridged compounds such as carboxylates (hemerythrin ribonucleotide reductase and methane monooxygenase) 

Some important naturally occuring iron proteins and their functions in living systems are listed in Table 9.1.

Hemoglobin and Myoglobin

Hemoglobin contains two parts:

• heme groups and 
• globin proteins. 

A porphyrin ring containing an Fe atom is called a heme group. 

Cellular respiration is the process of using oxygen to break down glucose to produce CO₂, water and energy for use by the cell.

 It has molar mass of about 64500.

 Hemoglobin is found in red blood cells that are called erythrocytes and is resposible for their characteristic colour.

 Without hemoglobin the blood is either colourless or a different colour

 Hemoglobin picks up the weak ligand dioxygen from the lungs or gills and carries dioxygen in arterial blood to the muscles, where the oxygen is transferred to another heme containing protein, myoglobin which stores it untill oxygen is required to decompose glucose to produce energy, CO, and water 

Hemoglobin then uses certain amino and groups to bind CO, and carry it in venous blood back to the lungs

Each hemoglobin molecule is made up of four subunits, each of which consists of a globin protein in the form of folded helix or spiral. 

The globin proteins are of two types: 

• two are alpha and two are beta .

An alpha globin protein consists of 141 and an beta globin protein consists of 146 amino acids. 

Each protein consists of one polar and one non-polar group.

 In hemoglobin which has no dioxygen attached (and is therefore called as deoxyhemoglobin or reduced hemoglobin), the protein is attached to Fe(II) protoporphyrin IX through imidazole nitrogen of histidine residue in such a way that the polar groups of each protein are on the outside of the structure leaving a hydrophobic interier.

 Therefore, the heme group is held in a water resistant protein pocket.

Perutz has suggested a "trigger" mechanism for the cooperativity of the four heme groups in a process of oxygenation in hemoglobin. According to him there is a comformational change of the beme group upon coordination of an oxygen molecule which triggers interconversion of the T and R conformations. In deoryhemoglobin, iron is coordinated to four nitrogen atoms of the planar protoporphynin IX and the fifth coordination site is occupied by nitrogen atom on imidazole of a proximal histidine of globin protein. The sixth vacant site trans to the imidazole nitrogen is vacat and reserved for dicaygen. In deoxybemoglobin iron present as high spin Fe(II) with one electron ocupying the d orbital that points directly toward the nitrogen atoms of protoporphyrin DC. The presence of this electron increases the size of Fe(II) in these directions by repelling the lone pair of electrons on nitrogen atoms. As a consequence, Fe(ID becomes too large to fit easily within the hole provide by the planar protoporphyrin IX ring. The Fe() ion is, therefore, lies about 40 pm out of the plane in the direction of the histidine group, and the hese group is slightly bent into a domed shape

(Fig.9.2) The imo atom in deoxyhemoglobin has square based pyramidal coordination. The steric interactions between the histidine residue, the associated globin chain and hene group inhibit the free movement of the imm atos into the porphyrin ring Although O, is not a strong ligand, the coordination of the dioxygen molecule trami to the

histidine group as a sixth ligand ahen the strength of the ligand field and causes the pairing of electrons on iron without affecting the oxidation state of iron. Therefore, Fe(l) becomes low spin and diamagnetic. In low spin Fe(II) che six delectrons occupy the d.d. and d ochals. The darbinals is now empty and the previous effects of an electron present in this orbital in repelling the porphyrin nitrogen atoms is diminished. Therefore, the size of low spin Fell) becomes about 17 pm smaller that high spin Feil). Thus, the Fe() slips in the hole of an approximately planar porphyrin ring. As the iron slips into the hole, the midsole side chain of histidine F, al moves toward Fe atom, and the complex has an octahedral geometry Recent X-ray studies show that dioxygen is bound in a bent fashion with an Fe-0-0 angle of approximately 130. There is strong evidence for hydrogen bonding between an imidanile N-H of a distal histidine and the bound dioxygen.

the four subunits of hemoglobin are linked with each other through salt bridges between the for polypeptide chains. These salt bridges are formed mainly due to electrostatic interaction between the-NH; and-C00 groups present on all the four polypeptide chains of hemoglobin. The protein structures in hemoglobin consists of a peptide backbone with various side chains. These tide chains consist of a variety of non-polar (hydrocarboni), cationic (such as-NH;) and anionic (such -C00) groups. These salt bridges between the polypeptide chains in hemoglobin are now believed to introduce strain in the molecule. Therefore, the deoxy form of hemoglobin is called tense

state (or T state). The movement of iron atom and imidazole side chain of histidine F, toward the porphyrin plane results in breaking of some of the salt bridges. The breaking of these salt bridges reduces the strain in hemoglobin molecule. Therefore, the oxyform of hemoglobin is called relaxed state (i.e., R state). The T form of deoxyhemoglobin discourages the addition of first dioxygen molecule.

The bonding of one dioxygen molecule to a subunit of hemoglobin reduces the steric hindrance in the other subunits (due to breaking of salt bridges) and therefore encourages the bonding of dionygen molecules to the iron atom of the second subunit which in turn encourages the third as well as fourth subunits. The binding of dioxygen molecule is the most difficult in first subunit and the easiest in the last subunit due to conformational change in the protein chain (or polypeptide chain). Initial addition of a dioxygen molecule to high spin Fe(II) triggers the oxygenation of deoxyhemoglobin. This is called cooperative effect.

The phenomenon where the addition of dioxygen to one heme subunit encourages addion of the

dotypen molecules to other heme subunits is known as cooperative effect."

The successive equilibrium constants for binding of dioxygen molecules to each of the four iron

woms follow the order:

K₁ < K₂ < K₂ <K4

The fourth equilibrium constant (K) is found to be much larger than the first (K). This indicates that last O, molecule bound much more readily and tightly than the first. In the absence of conformational changes, K, would be much smaller than Ky. As a result, as soon as one or two dioxygen molecules are bound to iron atoms, all the four iron atoms are readily oxygenated. Conversely, as one O, molecule is removed from oxyhemoglobin the reverse conformational changes occur and successively decrease its affinity for oxygen. Therefore, initial removal of O, molecule from deoxyhemoglobin triggers the removal of remaining O, molecules. This phenomenon is also called as cooperative effect.

Fig. 9.3:1-oxo dimer (hematin)

The naked heme, the tron-porphyrin complex without accompanying the polypeptide chains is oxidized to Fe(III) by dioxygen molecule in aqueous solution and is converted immediately into a stableu-oxo dimer (Fig. 9.3) known as hematin. In hematin iron is high spin Fe(III). The hemarin is unable to transport oxygen. The polypeptide chain can be removed by treatment with HCl/acetone. The polypeptide chain in hemoglobin and myoglobin prevents oxidation of Fe(II) because: (1) The hydrocarbon environment round the iron has a low dielectric constant and is

hydrophobic and therefore act as a non-polar and provides non-aqueous environment.

(2) It provides steric hindrance and does not allow the formation of hematin.

The mechanism of the formation of hematin is as follows:

The first step involves the binding of the O, molecule to Fe(II) of the heme group, PFe(II)

PFe +0₂ Pre-O

Second step involves the coordination of bound oxygen to second heme group forming u peroso

complex.

+PFe"

Pre-0-0-Fe p

O Third step involves the cleavage of the peroxo complex into two ferryl complexes in which iron is present in + 4 formal oxidation state.

0. 0-Fe P-2PF-0

In the last step, the ferryl complex combines with an another heme group resulting in the formation of hematin.

Pre-O+PFeFFe-0-Fe P

Myoglobin (Mb)

Myoglobin (or deoxy-myoglobin) is a protein which has only one heme group per molecule and serves as an oxygen storage molecule in the muscles. It has molar mass of about 17000 and binds

Baterpinic Chemistry

9-7

doxygen molecule more strongly than hemoglobin. The yoglobin molecule is sindur to a single vir of hemoglobin Myoglobin is a five coordinate high spin Fell) complex with four of the ordinating positions occupied by N-atoms of the porphyrin ring. The fifth position is occupied by an Naim of an unidazole group of a histidine residue (a globin protein). The protein consists of 153 acids. This protein restricts access to the Fell) by a second heme and reduces the formation of hematin like Fe (III) dimer. The result is that the Fe(1) porphyrin complex survives long enough to nd and release dioxygen molecule. Such five coordinate heme complexes of Feill) are always high pin te with one electron occupying the da, orbital that points directly toward the four the size of Fe(II) in these directions

prpbyzn nitrogen atoms. The presence of this electron increases by repelling the lone pair of electrons of the nitrogen atoms.

The size of Fe(II) is 92 pm in the square pyramidal arrangement which is considered to be peado octahedral environment with the sixth ligand removed. The size of Fe() ia solarge that it in not fit into the hole of the planar porphyrin ring and therefore it lies about 40 pm away from the plane of the ring (Fig. 9.2). Therefore, high spin Fell) porphyrin complexes (in Hb and Mh) involves packering and twisting of porphyrin ring.

When a dioxygen molecule binds to Fe(II) at sixth coordination site trans to imidazole group of hinde residue, the complex converts to low spin Fe(1) octahedral complex and the electronic configuration changes tori (e, the six d-electrons occupy the dg. d, and, orbish leading to and da orbitals empty). The previous effect of two electrons occupying the citals in repelling the N atoms on X, Y and Z axes diminishes. Therefore, the low spin Fellt) son is maller (75 pm) and slips into the hole in the planar pophyrin ring As the Fe(10 kon moves, it pulls

beidzale group of histidine residue. Therefore, all the nitrogen atoms (including that of

painal histidine) approach more closer to the Fe(II) ion.

Physiology of Hemoglobin and Myoglobin Hemoglobin has relatively high affinity for dioxygen at high partial presure of dixygen where

The

vertibiranes diosygen enters the blood in the lungs or gills where the partial pere of dioxygen go has relatively high affauty for dioxygen at lower partial pressure of dissygen. In natively high and hemoglobin is virtually saturated with dioxygen in hurtigs When hemoglobin ramties dinnypen to muscle tissues, it experiences the lower partial pressure of dicaygen and s way for dioxygen has fallen off rapidly and in this situation affany of myoglobin for disaygen is wively high. Therefore, in muscle tissues dioxygen is thermodynamically favourable transferred han hecsoglobin to myoglobin. The reactions occuring in lungs and muscles a

Hb40,

HNO₂)

The cyproation equilibrium for myoglobin is represented as

9-8

Organometallic and Binorganic Chemistry

Mh+ O₂ Mb(0₂)

K

Iff is the fraction of myoglobin bearing oxygen and Po, is the equilibrium partial

dioxygen, then

K

K PO 1+K Pos if

pressure of

to br

or

The equilibrium constant K is called the binding constant of myoglobin for 0₂.

This is the equation for the hyperbolic curve for myoglobin (Fig. 9.4).

100

80

aope w

de

stof

hat tow

avea at

1. Th

harth his

Bohr's

The c

60

Mb

HypH-7.6 Hb pH 6.8

40+

Partial pressure of O, in lungs

Partial pressure of O, in muscle

0

20

40

60

80

100

20

Percentage satuartion with O₂

120

pure d

be Lunge

yhtey

The 1

the w

Partial pressure of O₂ in mm Hg

Fig. 9.4 Oxygen Dissociation Curves for Hemoglobin and Myoglobin. Showing how Hemoglobin is Able to Absorb O, Efficiently in the Lungs yet Transfer it to Myoglobin in Muscle Tissue

The hemoglobin curve does not follow such an equation. Hemoglobin has more complex behaviour ms it has four heme subunits. It follows an emperically modified form with Por replaced by Po

K = [Mb(0₂).]

K M

---

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"Force and Law of Motion"

 Force and law of motion

• Topics to be covered :- 
• Introducing
• What causes motion
• Force
• Balanced and unbalanced forces
• Galileo's idea of force and motion
• Newton's first law of Motion
• Newton's second law of motion
• Mass Vs inertia
• Newton's third law of motion
• Conservation of momentum

Introduction:- What causes motion?

• External force is needed to make a stationary body move 
• External force is needed to stop a moving body

Balanced and unbalanced forces:-

Balanced force:- 

• Equal and opposite forces
• Do not cause any change in motion
• Example:- Tug of war

Unbalanced forces:- 

• Unequal forces 
• Can be in the same or opposite direction
• Causes a change in motion

Law of motion:- 

• Aristotle's law of uniform motion:- An external force is required to keep a body in uniform motion.

Aristotle's fallacy:-

• He didn't discuss about opposite forces like frictional forces

Conclusion:-

• An external force is required to keep a body in motion, only if resistive forces like frictional and viscous force are present.

Galileo's Law :-

• A body moving on a frictionless surface should move with constant velocity.

Conclusion:- 

• Aristotle law was falsified by Galileo.
• A body at rest or in uniform motion experience zero net force.

Newton's first law of motion:- 

• A body at rest tends to remain at rest and a body in uniform motion tends to remain in the state of motion until and unless an external / unbalanced force is applied on it.
• Example:- Ball at rest , Ball in uniform motion

What is inertia?

• Inertia is the resistance of a body. To change its state of motion.
• Or
•  tendency of the body at rest tends to stay at rest  and tendency of the body in motion to keep in motion is called inertia.
• Example:-Jerk experienced when brakes applied suddenly.
• Tendency to bend on one side on a bike during sharp turn.

Newton's second law is about 

• Newton's first law was for scenario where net force is zero
• Newton's second law is for scenario with net force not equal to zero 

What is momentum ?.

• Momentum is product of mass of a body and it's velocity
• It is a vector quantity
• It is denoted by 'p'
• Mathematical expression is p=mv
• SI unit = kgm/s
• Dependency of force on mass 
• Force required to push object with same velocity 
• Greater the mass,more the force required to set the body in motion

Dependency of force on change in velocity

• Greater the velocity of moving object , more the force is required to stop the object
• Dependency of force on change in momentum in a  given time, greater is the force that needed to be applied.

Mathematical formulation of second law of motion:-

• Let an object of mass , m is moving along straight line with initial velocity, u
• It is uniformly accelerated to velocity, v in time t
• So initial momentum p(initial) = mu
• final momentum p(final) = mv
• Change in momentum, 
• dp = p(final) - p(initial) 
• = mv-mu = m(v-u)
• Change in momentum w.r.t time, dp/dt =m(v-u)/t
• Or, the applied force , F = km(v-u)/t = kma
• When k=1 
• F= ma 
• This is second law of motion

Newton's second law of motion:-

• The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts
• F  is directly proportional to (rate of change of momentum) 
• F = k(dp)/dt 
• When k=1 

• F = dp/dt

Alternatively:- 

• The relationship between an object's mass m, it's acceleration a , the applied force F is F=ma the direction of force is the same as the direction of acceleration.
• Another way of derivation :-
• F= dp/ dt

• F = d(mv)/dt
• F = m(dv)/dt
• F = ma 
• Where F= force applied,  m= mass of object , a= acceleration of an object
• Unit of force = Kgm/s^2
• S.I unit of force is newton (N)

Consistency of second law with first law:- 

• According to second law, F= ma
• If F = 0 then a=0 (m cannot be zero)

• Also acceleration is zero if the body is at rest or in uniform motion

According to first law, 

If a= 0 , F=0 

So two laws are consistent with each other.

Impulse:-

• Impulse is defined as a force multiplied by time it acts over. 
• Example :- Tennis racket striking the ball 
• Impulse = change in momentum.
• Because as per definition , I = F×t = dp

Newton's third law of motion:-

• To every action ,there is always an equal and opposite reaction
• Example:- Tonie holding ball
• He exerts force on ball to hold it - action
• The ball exert force back on his hand :- reaction
• Apple falling down the tree.
• Apple is pulled by earth due to gravitational force- action 
• Earth is pulled by Apple also - reaction 
• But mass of earth is very large as compared to Apple . So for e exerted by earth on Apple is also very large .so net force is acting on Apple and apple  down

Action and reaction forces :- 

• Action and reaction forces always act on different bodies 
• Action and reaction forces occurs at the same instant 
• There is no cause effect relation between them 

Conservation of momentum:-

• In an isolated system, the total momentum is conserved (does not mean zero) 

Example1:-

• Bullet from rifle 
• Initial momentum:- zero and kinetic energy = zero
• After fire :- momentum of bullet + momentum of rifle = zero but KE   increase
• So momentum is conserved 
• Momentum before collision = momentum after collision

English grade 6th

  Chapter 1 " Who did Patrick's homework"

1. What did Patrick think his cat was playing with? What was it really? (2)

Ans: Patrick thought that his cat was playing with a little doll. It was, in fact, a very small-sized man, an elf.

2. Why did the little man grant Patrick a wish? (2)

Ans: Patrick had saved the tiny man’s life from the cat by not handing him back to the cat. So he promised to fulfil one wish of Patrick.

3. What was Patrick’s wish? (3)

Ans: Patrick hated doing homework. His greatest wish was that the little man should do all his homework till the end of the session.

4. In what subjects did the little man need help, to do Patrick’s homework? (5, 6)

Ans: The little man needed Patrick’s help in maths, English and history.

5. How did Patrick help him? (7)

Ans: Patrick sat beside the little man and guided him. He brought books from the library and read out to him.

6. Who do you think did Patrick’s homework – the little man, or Patrick himself? Give reasons for your answer. (9, 10)

Ans: It was Patrick himself who actually did all the homework. He had to help the elf again and again with guidance and books.

A House, A Home Summary In English

Poet :- Lorraine M. Halli

A house is made of brick and stone and hard wood. It includes glass windows and very often a yard. There are a few other things also like the tiled floors, plastered walls and many doors.

However, all these things do not really make a home. It is a loving family which makes a real home. In such a family people care for each other and work unselfishly.

Chapter 2 How the Dog Found Himself

Working With the Text  (Page21)

Discuss these questions in pairs before you write the answers.

1. Why did the dog feel the need for a master? (1,2)

Ans: The dog was sick and tired of going about alone in search of food. And he did not feel safe. So he decided to have a master.

2. Who did he first choose as his master? Why did he leave that master? (3)

Ans: The dog first chose a wolf as his master. But he found the wolf afraid of the bear. So he left the company of the wolf.

3. Who did he choose next? (3)

Ans: Next, the dog chose a bear as his master, because he was stronger than the Wolf.

4. Why did he serve the Lion for a long time? (4)

Ans: The dog served the Lion for a long time because he had no complaint against him. Secondly, he felt safe and secure. No other wild animal dared to displease him.

5. Who did he finally choose as his master and why? (9, 10)

Ans: The dog finally chose a man as his master. Even the lion was afraid of man. So the dog was convinced that man was the strongest creature on earth.

B.A summary of the story is given below. Fill in the blanks to complete it taking appropriate phrases from the box. 

This is the story of___________ , who used to be___________ . He decided to find a

master___________ . First he found ______________  , but the wolf was afraid of

_________ . The dog thought that the bear was______________ . After some time the

dog met__________ who seemed the strongest. He stayed with the lion for a long

time. One day he realised that the lion was _________________  . To this day, the dog

remains man’s best friend.

Ans. This is the story of a dog, who used to be his own master. He decided to find a master, stronger than anyone else. First, he found a wolf but the wolf was afraid of the bear. The dog thought that the bear was the strongest of all. After some time the dog met a lion, who seemed the strongest. He stayed with the lion for a long time. One day he realised that the lion was afraid of man. To this day, the dog remains man’s best friend.

Poem 2

The Kite Summary In English

Poet:- Harry Behn

A new kite is wonderful to watch. Diving and dipping in the blue sky it moves its tail with a noise. It soars high with the wind. At this time it sails like a ship with only one sail. It rides on the current of air just as the ship rides on the waves of the ocean. When the wind falls it seems to rest. When the string which holds the kite goes slack, the master of the kite winds back the string. The kite comes back to the earth. It is there again in the sky when a new wind blows filling the wings of the kite with the air again.

However, when the string of the kite is caught in a tree, the kite flaps. It soon turns into a very torn and dirty thing.

Chapter 3 "Taro's Reward"

Date: 1 Sep 2021

Working With the Text    (Page 34)

A   Answer the following questions.

1. Why did Taro run in the direction of the stream? (5)

Ans: Taro ran in the direction of the stream because he was thirsty. Secondly, he had never before heard the sound of falling water in that area:

2. How did Taro’s father show his happiness after drinking sake? (7)

Ans: Sake gave warmth as well as energy to the old man. Taro’s father stopped shivering and started dancing. In this way, he showed his happiness.

3. Why did the waterfall give Taro sakeand others water? (12)

Ans: The waterfall obliged Taro and changed water into sake. The reason was that he was a thoughtful son. He served his old parents sincerely. Sake was the reward for his goodness. Other people were just greedy. So they got only plain water.

4. Why did the villagers want to drown Taro? (10, 11)

Ans: The villagers went to the waterfall to collect sake. But they got only plain cold water. They thought that Taro had tricked them. So they looked for Taro to punish him.

5. Why did the Emperor reward Taro? (13)

Ans: The Emperor of Japan rewarded Taro for being good and kind towards his parents. This was Emperor’s way to encourage all children to respect, obey and serve their parents.

B. Mark the right item.

1. Taro earned very little money because

(i)he didn’t work hard enough.

(ii)the villagers didn’t need wood.

(iii)the price of wood was very low.

2.Taro decided to earn extra money

(i)to live a more comfortable life.

(ii)to buy his old father some sake.

(iii)to repair the cracks in the hut.

3. The neighbour left Taro’s hut in a hurry because

(i)she was delighted with the drink.

(ii)she was astonished to hear Taro’s story.

(iii)she wanted to tell the whole village about the waterfall.

Ans. 1. (iii), 2. (ii), 3. (iii)

The Quarrel Summary In English

Poet ;- Eleanor Farjeon

The poet quarrelled with his brother on some very petty matter. It was so petty that now he does not remember what it was. One thing led to another. Both of them felt that they were right. It had started as something small. It had become big in the end. So they began to hate each other. The afternoon became very tense and unpleasant for both of them.

Then suddenly, the poet’s brother patted him on the back. He said that the two of them could not go along like that for a long time. It would be difficult to pass the night in that manner. He said that it was his mistake, Just then the poet felt that his brother was right. In fact he himself was wrong.

Chap 4 An Indian Woman. In Space : Kalpana Chawla

Answer the following questions.

1. Where was Kalpana Chawla born? Why is she called an Indian-American? (3)

Ans: Kalpana Chawla was born at Kamal, in Haryana. She was born in India, but married an American and became a naturalised citizen. So she is called an Indian- American.

2. When and why did she go to the U.S? Who did she marry? (2, 3)

Ans: Kalpana went to the U.S. for higher studies in aeronautical engineering. There she married the flight instructor Harrison.

3.How did she become an astronaut? What gave her the idea that she could be an astronaut? (3)

Ans: Kalpana had already got a bachelor’s degree in aeronautical engineering before she went to the U.S. She earned her PhD in aerospace engineering. In 1994 she was selected by NASA for training as an astronaut. She was encouraged by the people around her.

4. What abilities must an astronaut have, according to the journalist? (6)

Ans: An astronaut needs to know a lot about biology and aeronautical engineering. He/ she must have a wide knowledge of science subjects.

 5. Describe Kalpana Chawla’s first mission in space. (5)

Ans:  Kalpana’s first mission in the space shuttle, Columbia, was nearly 16 days long. She went around the earth 252 times. Among her colleagues were a Japanese and Ukranian astronauts. They performed so many experiments.

6. What does Kalpana Chawla say about pursuing a dream? Do you agree with her that success is possible? (7)

Ans:  Kalpana Chawla, a girl from a small town, touched the skies. In her message to college students of Chandigarh, from space, she said that it was always possible to realise one’s dream. One could certainly get success provided one had the vision and the courage.

B. Read the newspaper report to find the following facts about the Columbia’s ill- fated voyage.

1. Date and place of lift off:_____________________________________________________

2. Number of astronauts on board:_______________________________________________

3. Number of days it stayed in space:_____________________________________________

4. Number of experiments done by scientists:_______________________________________

5. Date of return journey: ______________________________________________________

6. Height at which it lost contact:_________________________________________________

Ans:

1 .16 January 2003                

2. Seven

3 .About 16 days eighty experiments

4 .1 February 2003 6. 200,000 feet

Beauty Poem Summary

The poet is trying to say in this poem that beauty is in everything. All the small things we do or the environment around us, everything has beauty in it. Everything has its own importance. All things are beautiful in their own unique way. Sunlight has its own beauty. Beauty can be seen in the growing corns, people who are working and dancing for getting good harvest. Beauty is not only seen but can also be heard or felt. For instance, when night falls, wind blows slowly, the sound of rainfall, or when a singer sings. They all give pleasure to the mind and make it feel happy.Beauty is not just outside, it is within. Beautiful is the self. Our good deeds, happy thoughts please everyone are all beautiful.Our dreams are also beautiful as they give us reason to advance and work with zeal. Beauty is in your style of work, the way you take rest and sleep.Beauty is everywhere. It is in attitude, the way we look at things. Actually everything is beautiful in its own unique manner, the need is to feel it.

Chapter 5 A Different Kind of School

 Working With the Text  (Page 62)

A. Put these sentences from the story in the right order and write them out in a paragraph. Don’t refer to the text.

I shall be so glad when today is over.

Having a leg tied up and hopping about on a crutch is almost fun, I guess.

I don’t think I’ll mind being deaf for a day—at least not much.

But being blind is so frightening.

Only you must tell me about things.

Let’s go for a little walk.

The other bad days can’t be half as bad as this.

Ans: Let’s go for a little walk. Only you must tell me about things. I shall be so glad when today is over. The other bad days can’t be half as bad as this. Having a leg tied up and hopping about on a crutch is almost fun, I guess. I don’t think I’ll mind being deaf for a day, at least not much. But being blind is so frightening.

B. Answer the following questions:

1. Why do you think the writer visited Miss Beam’s school? (1)
Ans: The writer had heard much about Miss Beam’s new teaching method. So he visited her school to see the new play-way method personally.

2. What was the ‘game’ that every child in the school had to play? (9)
Ans: Every child in the school had to play the role of being blind, deaf, dumb, injured and lame once in a term. It was a sort of game and training.

3. “Each term every child has one blind day, one lame day …”. Complete the line. Which day was the hardest? Why was it the hardest? (9, 11, 15)
Ans:  “… one injured day and one dumb day.” Being blind was the hardest day. The student felt that he/she was going to be hit by something every moment.

4. What was the purpose of these special days? (5, 9)
Ans: The purpose of these special days was to give the children a personal taste of misfortune. They learnt to help the needy in society. Such training made them good citizens.

Pact with the sun 

Chapter 1

Date: 5 Sep 2021

1. How did the two baby-birds get separated?

Ans: The two baby birds lived in a tall tree with their mother. One day a big storm blew. The tree came down. The mother bird was killed. The strong wind blew the two chicks away to the other side of the forest at a little distance from each other. Thus they got separated from each other.

2.Where did each of them find a home?

Ans: One of the young birds came down near a cave. A gang of robbers lived there. The other bird landed outside the ashram of a rishi at a little distance.

3.What did the first bird say to the stranger?

Ans: The first bird saw the stranger (the King). He called the robbers to hurry up and rob the man of his jewels and his horse. Indirectly he asked the stranger to leave the place at once.

4. What did the second bird say to him?

Ans: The second bird welcomed the king to the ashram. He requested the stranger to drink water, take rest and make himself comfortable. He added that his brother lived in the company of robbers, so he talked like them.

5.’ How did the rishiexplain the different ways in which the two birds behaved?

Ans: The king told the rishi about the different behaviour of the two birds. The rishi explained that the first bird repeated the words of the robbers. The second bird repeated what he had always heard at the ashram. Their different ways were the results of their company.

6. Which one of the following sums up the story best?

(i) A bird in hand is worth two in the bush.

(ii)One is known by the company one keeps.

(iii)A friend in need is a friend indeed.

Ans: (ii) One is known by the company one keeps.

Chapter 2 The Friendly Mongoose

1. Why did the farmer bring a baby mongoose into the house?

Ans: The farmer had a small son. He wanted to have a pet to give company to his child. So he brought home a baby mongoose to play with the child.

2. Why didn’t the farmer’s wife want to leave the baby alone with the mongoose?

Ans:The farmer’s wife did not trust even her pet mongoose. She did n’t want to leave her son alone with an animal.

3. What was the farmer’s comment on his wife’s fears?

Ans: The farmer understood why his wife was afraid of leaving the baby alone with the mongoose. Therefore, he tried to remove her fear. He said that the mongoose was a friendly animal, as sweet and gentle as their own baby.

4. Why did the farmer’s wife strike the mongoose with her basket?

Ans: The farmer’s wife returned home with a heavy basket. She noticed blood on the face and paws of the mongoose. She had no doubt that the mongoose had killed her son. So in anger she hit the animal with the basket. The poor mongoose died on the spot.

5. Did she repent her hasty action? How does she show her repentance?

Ans: The farmer’s wife saw the snake tom into pieces. Her own son was safely asleep. She realised her mistake. She felt very sorry. She touched the mongoose and cried. She saw the painful result of her hasty action.

Chapter 3 The Shepherd’s Treasure

1. The shepherd had n’t been to school because

(i)he was very poor.

(ii)there were very few schools in those days.

(iii)he wasn’t interested in studies.

Choose the right answer.

Ans: (ii) There were very few schools in those days.

2.Who visited the shepherd one day. and why?

Ans:  The shepherd soon became famous for his wisdom and friendly nature. The king of Iran heard about him and visited him. He was riding a mule and dressed like a shepherd.

3.Why did the other governors grow jealous of the shepherd?

Ans: The common shepherd was appointed the governor of a small district. He was loved and honoured by the people. His fame spread far and wide. So the governors of other provinces grew jealous of him.

4.Why was the new governor called to the palace?

Ans: The jealous governors poisoned the king’s ears against the new shepherd-governor. They reported that the new governor was dishonest, and he always carried his ill-gotten treasure in an iron chest. So the king called him to the palace to see that treasure.

5. Why was everyone delighted to see the iron chest on the camel’s back?

Ans: Those who were present in the palace, thought that the iron-box contained valuables. If their report proved true, the king would dismiss the shepherd. So they were delighted. They waited anxiously to see the contents of the box.

6. (i) What did the iron chest contain?

(ii)Why did the shepherd always carry it?

(iii)Is it an example of the shepherd’s humility or wisdom or both?

Ans: (i) The iron chest contained only an old blanket.

(ii)The shepherd always carried his blanket in the box because it was his oldest and time-tested friend. It would protect him in case the king took away his post and power.

(iii)Yes, it is an example of the shepherd’s humility as well as wisdom.

7. How did the king reward the new governor?

Ans:The king was highly pleased with the new governor’s humility and honesty. He rewarded him with a promotion. He made him the governor of a much bigger province the same day.

Chapter 4 The Old-Clock Shop

1. What made Ray think the visitor was not really a shopper?

Ans: Ray was deaf and dumb, but a good judge of men. His old wise eyes told him that the new visitors to his shop at that late hour, was not a shopper or customer. There was no friendliness in his eyes.

2. Why do you think he had come to the shop?

Ans: The visitor had not come to the shop to buy anything. Perhaps his intention was to loot the owner of his cash. He was in dire need of money.

. How did Ray communicate with him?

Ans: Ray could neither speak nor hear. So he communicated with his customer by writing his message on a notepad. The visitor also wrote his reply on paper.

4. What do you think the man said to his friend who waited at the door?

Ans: The older man pointed to his ears and shook his head from side to side. Thus he conveyed to his younger companion that the shop owner could neither hear ‘ nor speak.

5. Raypeople in exchange for their old watches and clocks?

Ans: Ray was not a pawnbroker, a person who lends money on security of some item. He did not lend money on interest. He was, however, kind and helpful. He could n’t say ‘No’ to the needy people.

6. “The watch was nothing special and yet had great powers.” In what sense did it have ‘great powers’?

Ans: The watch was just ordinary. But it had the power to pull a person out of a bad situation. The older man got the money he needed without hurting Ray. The generous shopkeeper also escaped physical injury. In this sense the watch had great powers.

7. Do you think the man would ever come back to pick up the watch?

Ans:No, it is very unlikely that the older man would ever come back to pick up his watch. He had, after all, got a price higher than the watch was worth for.

8. When did “the unfriendly face” of the visitor turn truly friendly?

Ans: The unfriendly face of the visitor turned friendly when he got a fifty dollar note for his ordinary watch. He felt obliged and happy.

.

"Why do we fall ill"

 Topics to be covered in this lesson:-

Introduction 

Health and its failure

• The significance of 'health'
• Personal and community issues both matter for health
• Distinction between "healthy" and "Disease free"

Disease and it's causes 

• what does disease look like?
• Acute and chronic disease
• Chronic diseases and poor health
• Causes of diseases
• Infectious and non- Infectious causes

Infectious diseases

• Infectious agents
• Means of spread
• organ specific and tissue specific manifestation
• Principles of treatment
• Principles of prevention

Introduction:-

Health and its failure:-

What is health?

• A state of being well enough to function well physically , mentally and socially.

Requirements for healthy life cycle:-

• Balance diet
• Clean and hygienic environmental
• Proper exercise
• Proper sleep 
• Social equality and harmony

What is meant by disease?

• Dis--> disturb and Ease --> comfort
• Disease means something is wrong with our body and we feel unwell.

Reasons:- 

• Malfunctioning of body,
• Unbalance diet,
• Dirty and unhygienic conditions,
• Lack of exercise,
• Poor sleep,
• Poverty

Distinction between healthy and disease free:-

Healthy:- 

1.  It is a state of complete physical, mental and social well being
2.  It depends upon the individual as well as physical and social environment.
3. A healthy person will be disease free.
4. Healthy person is energetic and able to perform as per requirement.

Disease free:-

1. It is a state of absence of comfort in any part of body ,
2. It is related to the individual only
3. A disease free person can be healthy or unhealthy,
4. Performance of a disease free person depends upon environment and personal attitude.

Disease:- 

• Dis - Disturbance, Ease - Comfort
• Disease results in a change in either the functioning or appearance of one or more system of the body for the worse.
• Example:- headache,fever etc.

Disease : Sign and symptoms

Symptoms:- 

• symptoms of disease are the things we feel as being 'wrong'
• Symptoms indicate that there might be a disease

Signs:-

•  signs of a disease are the things a. Doctor looks for on the basis of symptoms .
• Signs indicate presence of a particular disease.

Acute Vs Chronic diseases:-

Acute diseases:- 

• Disease which last for very short periods of time.
• Example:- common cold, cough, flu, tonsillitis, appendicitis, headaches.

Chronic diseases:- 

• Diseases which last for a long time
• Example:- Asthma , Diabetes, Glaucoma (eye disease: optic nerve damage) , Allergy

Causes of disease:- 

• There are many levels of cause of a disease

 1. Immediate cause:- 

• The first cause identified when a person is suffering from a disease
• Mostly the immediate causes are the infecting organisms like bacteria, virus , fungi etc.
• Note :- Not all disease 's immediate cause is micro organisms
• Example:- cancer, high blood pressure

2. Contributing cause:- 

• Reason identified after the immediate cause.
• Contributing cause along cannot cause the disease
• Example:-
• Cholera is caused by Bacteria ( immediate cause)
• Here contributing causes are lack of cleanliness, poverty, Genetically weak.
• So contributing cause + Immediate cause together causes the disease.

Infectious Vs Non Infectious diseases:-

Infectious disease:-

• Diseases for which microbes are the immediate cause.
• Infection can spread from one person to another
• Infectious agents:- microbes
• Termed as communicable / contagious diseases.
• Example:- Flu, common cold, cough , measles.

Non Infectious diseases:- 

• Diseases for which microbes are not the cause
• Does not spread from one person to another.
• Internal ,non Infectious causes (like genetic causes) 
• Example:- cancer, diabetes , high blood pressure
• Termed as non- communicable / non contagious diseases

Infectious agents:- 

• Many categories of microbes can act as infectious agents
• Virus , Protozoa, Bacteria, worms, fungi

Diseases caused by different infectious agents:-

Virus :- 

• common cold, influenza, dengue,AIDs (Acquired Immuno-Deficiency Syndrome)

Bacteria:- 

• Typhoid, Cholera, Tuberculosis (TB) ,Anthrax

Fungi :-

•  Skin infections

Protozoa:- 

• Malaria, Kala Azar 

Worms:- 

• stomach ,Interesting infection,  Elephantiasis

How does knowledge of infectious agents helps to decide treatments?

• Different microbes have different like process,so different drugs affect these different life processes.
• Example:- Bacterial infection be Viral infection.

Means of spread of Infectious diseases:-

• Ways by which infection can spread from one person to another.
• Some ways are :- air, water,Direct and indirect contact, sexual contact, vectors

Air:- air borne diseases

• Droplets thrown by an infected person during coughing/ sneezing .
• Example:- common cold , pneumonia, tuberculosis

Water :- Water borne diseases

•  Excreta of infected person gets mixed with drinking water .
• Example:- Cholera, typhoid, hepatitis A 

Direct and Indirect contact:-

Direct contact:- touch , kiss, hand shake

Indirect contact:- Things used by infected person

Example:- Ringworm, Conjunctivitis (eye infection) , head lice, skin infections

Sexual contact:- 

• Sexual act with an infected person. Example:- AIDs , Syphillis
• AIDs spread only by sexual contact, mother to child and blood transfusions and not by air, water and direct and indirect contacts

Vectors:- 

• Insects /animals which act as carrier of infection from infected to healthy person are called vectors.
• Example:- Malaria,Dengue, Chikungunya(mosquitoes) Rabies , a viral infection (dog)

Terminologies related to infection:-

Pathogen:-

• Microbes that cause diseases
• Example:- Bacteria, viruses

Host:- 

• Organism on which microbes attacks/ infects 
• E.g. Human Beings 

Parasite:-

• Organism that live in/on the body of host and derives nutrients from host, not necessarily kill the host 
• E.g.:- Tapeworms, lice

Note:- 

• Pathogen always cause disease to host 
• Parasite may or may not cause disease to host.

Vectors:-  

• Animals which introduce parasites into the host body . Example:- Mosquito.

How do the infectious agents affect our body?

• Target side is decided by the point of entry 
• If it is through mouth it attack on gut line or liver
• If it is bacteria ,then it attack through gut lining and cause Typhoid
• If it is virus, then it attack on Liver and cause Jaundice.

Now if the entry point is nose then it attack on lungs and cause breathing problems such as Asthma.

• Can also spread from one part to different body parts  
• Example:- Mosquito bite --> Malaria --> Brain fiver.

Some agents also target the immune system of the body 

Immune system:-  

• Network of cells that protects the body from foreign particles 
• A group of cells of the affected tissue is employed to kill off the microbes . This process is known as Inflammation.

Consequences of Inflammation:-

•  Pain , Swelling, Fiver
• For example:- In AIDs , virus attack the immune system.

Principles of treatment of an Infectious disease:- 

Two ways to treat :- 

1. Reduce the effect:- 

• Take medicine to reduce pain, fiver. 
• Take rest to conserve energy.

2. Kill the cause:- 

• Take appropriate medicines to kill microbes

Principles of prevention:- 

General ways of prevention:- 

• Prevent exposure to microbes 
• Avoid overcrowded living conditions,
• Clean drinking water.

• Public as well as individual hygiene
• Proper nourishment and food to keep the immune system strong enough

2.specific ways of prevention:- vaccination

Vaccination:-

•  Process in which vaccine is given to improve the immunity of the body against a specific disease

Vaccine :- 

• Biological preparation that resembles a disease causing microbes 
• Made of dead or very weak microbes

Vaccination success:- 

• Smallpox is eradicated 
• Diseases like polio , tetanus, measles have been reduced to a large extent

Effective vaccination :- 

• Effectiveness of vaccines varies with the type of disease.
• For older people , larger doses are needed .
• Vaccination schedule has to be followed.

Prevention is better than cure because:-

• During disease, body functions are damage ,
• Treatment takes time ,
• Diseased person become source for other person.
• So prevention is better than cure.

Thankyou :-)

"Improvement in food resources" Grade 9th

 Topics to be covered :-

Improvement in crop yield

Crop yield improvement

Crop production improvement 

-Nutrient management

• Manure
• Fertilizers

- Irrigation

- Cropping patterns

Crop protection management

Animal husbandry 

• Cattle farming
• Poultry farming
• Egg and Broiler production
• Fish production 
• Bee keeping

Introduction :-

Why do we need to improve crop yields?

Ans :- We need to improve crop yields to meet needs of growing population. But there is less scope of increasing the area of land under cultivation. Therefore , it is necessary to increase our production efficiency. So we need to improve crop yields.

Efforts used in past to improve food productivity are:-

Green Revolution (Bumper production of food grains)

Blue Revolution (Enhance fish production)

White revolution (increased milk production)

Yellow revolution (increased oil production)

Golden revolution (increased pulse production)

However, these revolutions means more use of natural resources that would destroyed natural resource balance completely. 

So there is a need for sustainable practice in agriculture and animal husbandry.

Can improving crop production solve the problem of malnutrition?

Malnutrition:- It means lack of proper nutrition that is mostly seen in children.

Improved crop yield alone cannot solve the persisting problem of malnutrition and Hunger.

Solution of problem:- 

• Good economic conditions to ensure affordability.
• For good economic conditions, one should give better income to those involved in agriculture.

Improvement in crop yield::

Crops :- 

•Pulaes [Gram , pea, black gram, green gram, Lentil] 

• source of protein.

• Cereals [Rice, wheat, Maize, Millets]

• Source of carbohydrates

Oil seeds[Groundnut, Castor, Soyabean, Sesame, Linseed, Sunflower]

• Source of fats

Vegetables:- Source of vitamin and minerals .

Fruits:- Source of vitamin and minerals

A diet which has a combination of carbohydrates, fats, vitamin, minerals is called a good diet.

Crop seasons:- 

• Different crops require different climatic conditions, temperature and photoperiods for their growth and completion of their life cycle
• Photoperiod means duration of sunlight 
• Plants need sunlight for manufacturing of food by the process called photosynthesis.

In India, there are two different season crops:-

1. Kharif season crops:-

• Grow in rainy season (from month of June to October)
• Example :- Paddy, Soyabean, Pigeon pea, maize, cotton, green gram and black gram.

2. Rabi season crops:-

• Grow in winter season (from November to April)
• Example:- wheat, gram, peas mustard, linseed.

There are certain crops which are grown between March and June called "Zaid crops"

Improvement in crop yields:-

The major groups of activities for improving crop yields can  be classified as:-

- Crop variety improvement.

- Crop production improvement

--Crop protection management.

Crop variety improvement:-

1. Improving /finding a variety of crop that gives better yield.

Why is crop variety improvement done?

1. Better yield [increase the productivity of crop per acre]
2. Improved quality 

• Quality consideration of crop products vary from crop to crop
• Example:- greater the protein contained by pulses, better will be the quality

3.3.Enhanc biotic and abiotic resistance

• - crop production can go down due to biotic and abiotic stresses.
• -Biotic causes are diseases, insects and nematodes.
• Abiotic causes are drought, salinity, water logging, heat, cold and frost.
• Varieties resistance to these stresses can improve crop production.

4. Lesser maturity duration:-

• Maturity duration means time interval from sowing to harvesting.
• The shorter the duration of the crop from sowing to harvesting, the more economical is the variety
• Such short duration allow farmers to grow multiple rounds of crops in a year.
• Short duration also reduces the cost of crop production

5. Wider adaptability:-

• One variety which has ability to adopt differned climate, will be grown in different areas so increase the yield.

6. Desirable agronomic characteristics:-

• If we develop those varieties of crops which contain agronomic traits, then it will help in setting higher production.
• Example:- tallness is the desirable character of fodder.
• Dwarfness is desirable character of Cereals, so that less nutrients are consumed by these crops.

How is crop variety improvement done?

By hybridisation

• crossing between genetically dissimilar plants
• - Inter varietal,
• - Inter specific

• - Inter genetic
• Hybridisation introduces desired characteristics resulting in genetically modified crops.

Another way of improving the crop is by introducing a gene that would provide the desired characteristics.

For new varieties of crops to be accepted, it is necessary that 

• - Good quality seeds to be provided to farmers,
• - Crop variety suitable for diverse climatic conditions are good.
• - Crop varieties tolerant to high soil salimity are good.

Crop production management:-

Several practices followed to increase crop production.

Crop production is directly proportional to inputs

• -No cost production 
• - Low cost production
• - High cost production

How is crop production management done?

• Nutrient management,
• Irrigation
• Cropping pattern

Nutrient management:-

• Nutrient is a substance that provides nourishment to the plants.

Plants need 16 nutrients

• - Carbon (by air)
• - Oxygen (by air and water)
• - hydrogen (by water)
• - Nitrogen (by soil)
• - Phosphorus (by soil)
• - Potassium (by soil)
• - calcium (by soil)
• -Magnesium (by soil)
• - Sulphur (by soil)
• - Iron (by soil)
• - Manganese (by soil)
• - Boron (by soil)
• - Copper (by soil)
• - Zinc (by soil)
• - Molybdenum (by soil)
• - Chlorine (by soil) 

Note:- nitrogen, phosphorus, potassium, calcium, Magnesium, sulphur are macronutrients i.e. needed in large amount

Whereas iron, manganese, boron, copper , zinc , molybdenum and chlorine are micronutrients i.e needed in small amount.

Along with these nutrients plants also need sunlight.

Why is nutrient management needed?

Because deficiency of nutrients can results in :-

- reduced growth, 

- Adverse effect on reproduction,

- More prone/ susceptibility to disesdis.

How is nutrient management done?

Enrich the soil with nutrients in the form of manure and fertilizers

Manure:- substance that increases soil fertility

Preparation of manure:- decomposition of animal excreta and plant wastes.

Constituents:- organic matter + nutrients

Functions:- organic matter improves soil structure.

- by increasing waste soil structure

- helps in drainage ( in clayey soil)

- avoid water logging (in clayey soil)

Advantages of its uses:- 

• Non toxic ,
• Recycled biological product,
• Eco friendly

Classification of manure:- two types

Compost and vermi compost:-

• The process in which animal and vegetable waters decomposed in pits is called composting.
• Compost is rich in organic matter and nutrients.
• Compost is also prepared by earthworm. This is called vermicompost.
• Earthworms act as a decomposers and thus increases the rate of Compositing.

Green manure:-

• Some green plants uprooted and stuffed under the soil.
• Prior to the sowing of crop seeds , these plants are grown for a specific period of time.
• Then these crops will be mulched by ploughing them into soil.
• Such green plants thus turn into green manure.
• This manure helps in enriching the soil in nitrogen and phosphorus which are macronutrients.

Fertilizers:- commercially produced plant nutrient that results in higher  yields and healthy plants.

Advantages of fertilizers:- 

• Provide nutrients like nitrogen, phosphorus and potassium to the soil.
• Results in higher yields if given in proper dose 

Disadvantages  of fertilizers:- 

• Cause water pollution, if followed by excessive irrigation .
• Excessive use can soil soil fertility (organic matter and micro organisms are harmed).

Organic farming :-

• Farming with no /minimum use of chemicals 
• Maximum use of manures 
• Healthy cropping pattern.

Irrigation:- Artificial applications of water to soil to ensure growth of agricultural crops 

Why is irrigation needed?

• Agriculture is largely dependent on rains but there is irregular distribute of rainfall in India.
• So , to ensure that crops get proper water at the right stages during their growing season can increase the expected yield  of any crop. That's where irrigation needed.

How is irrigation done?

• Different types of irrigation methods are used depending on the different water resources.

These includes :-

• - wells
• - canals
• - river- lift system
• - tank.

Wells:- ground water extraction is done.

Water is lifted from wells by pumps for irrigation.

Types:- two types 

- tube wells , Dug wells

• In dug wells , water is collected from water bearing strata.
• In tube well , water is collected from deep strata.

Canals:-

• In this system, water is received from rivers by canals.
• The main camal is divided into branch canals
• Branched canals further distributed to irrigate fields.

River lift systems:- 

• In some areas where canal flow is inadequate , the river lift system is used.
• Water drawn directly from rivers from irrigation in nearby areas.

Tanks:-  

• Artificial water reservoir used for irrigation .
• These are small storage reservoirs.

How to ensure water availablity needed for irrigation:- 

Rainwater harvesting 

• - Accumulation of Rainwater for reuse 
• Watershed management 
• Check dams

Advantages:- 

• Checkdams stop the rainwater from flowing away and also reduce soil erosion.

Cropping patterns:-

• Different cropping pattern can be adopted for better results .
• Mixed cropping ,
• Inter cropping ,
• Crop rotation

Mixed cropping:-

• Growing multiple crops on same piece of land .

Example:- wheat + gram 

Wheat + mustard

Groundnut + sunflower

Advantages :-Insurance against failure of one of the crops.

Intercropping :-

• Growing multiple crops on same field in a specific pattern.
• Crops to be chosen so that their nutrient requirements are different.
• In this, a few rows of one crop alternate with a few rows of a second crop.

Example - Soyabeans + maize.

Millet + cowpea 

Advantage:- Maximum utilisation of the nutrients

• Prevents pests and diseases from spreading to all the plants belonging to one crop.

Crop rotation:- 

• Growing different crops on a piece of land in a pre- planned succession.
• Availability of moisture and irrigation facilities decide the choice of the crop to be cultivated after one harvest
• If one rotation is done properly then two three crops can be grown in a year with good harvest.

Crop protection management:-

Why do we need crop protection management?

To protect the crop from weeds, insects and diseases.

Weeds:- unwanted plants in a cultivated field.

• Compete for nutrients space , water and light, therefore adversely affect crop growth.
• Example:- Xanthium , Parthenium.

Insects:- insects can affect the crop health by sticking cell sap, cut root /stem/leaf and bore into stem /fruits

Diseases:- caused by micro organisms

• Transmitted through various means like air , water or soil 

How to ensure crop protection management?

• Chemicals sprayed on plants to getrid of (weeds and insects) pest.
• However, excessive use can spoil the crop health and cause pollution.

Intercropping and crop rotation:-

• Prevents spreading of pests and diseases

Summer ploughing:-

• Fields are ploughed deep to kill weeds and insects.

Storage of grains:- 

• Storage losses in agricultural  produce can be very high

Factors responsible for such losses are 

• Biotic factors:- insects, rodebts, fungi, mites and bacteria
• Abiotic factors:- Inadequate moisture and temperature in the place of storage.

Results:- Loss in weigh, quality, germination ability and discoloration of produce.

• All leads to poor marketability

How to control these factors?

- By proper treatment and systematus management of warehouses.

Preventions and control measures used before grain storage are:-

• Cleaning of produce
• Drying of produce (first in sunlight and them in shade)
• Use of chemical to kill pest

Animal husbandry:- 

• It is the scientific management of animal livestock .
• It includes feeding , breeding and disease control

Animal based farming includes cattle farming, paultry farming, fish farming, bee kekeep.

Cattle farming:-

• Purpose of cattle farming is to get milk and help in agriculture.

Classification :- two types

• Dairy animals (mulch animals), Drought animals.
• Dairy animals are milk producing female animals.
• Drought animals are ones used for farm labour .

Feeding :- the food requirements of dairy animals are of two types:-

(a) maintenance requirement:-needed for healthy survival of the animal

(b) Milk producing lactation period. 

Lactation period:- period during which animal produces milk

Animal feeding includes:-

• Roughage (fibres), concentrates (low fibres and high protein and other nutrients)

Breeding:- 

• Cross breeding of animals to get the desired quality.
• Example:- Foreign breeds e.g. Jersey are selected for long lactation period.

• Local breeds e.g Red Sindhi show resistance to diseases. 

Two can crossbreed to get animals with both desired qualities.

Disease control :- 

Causes of diseases:-

• External parasites (cause skin diseases)
• Internal parasites (cause stomach , intestine and liver diseases)
• Bacterial infection
• Viral infection
• These diseases can cause death or reduce milk production

Disease control measures:- 

• Cleanliness and proper hygiene, 

Vaccination

Cleanliness:- clean , dry, covered and we'll ventilated roofed sheds. 

• Regular cleaning of animals to remove dirt and loose hair.

Bee Keeping:-

• Purpose of bee keeping is to get honey and wax .
• It has low investments  give good income.
• Local varieties of bee used for commercial honey production are Apis indica, Apis veranda 
• Italian bee variety Apis mellifera has been brought in to increase yield of honey .
• This variety is used for high honey production.
• For commercial honey production bee farms or apiaries are established.
• The value or quality of honey depends upon pasturage.
• Pasturage means availability of flowers to the bees for nector and pollen collection 

These flowers will determine the taste of the honey.

Poultry farming :- 

• It is undertaken to raise domesticated fowls for egg production and chicken meat.

It's purpose is to get

• - egg production,
• - chicken meat (broilers)

Breeding :- 

• Cross breeding is done to get desired improved qualities.
• Example:- Aseel X Leghorn

Reasons for cross breeding is to get:-

• Number and quality of chicks ,
• Dwarf of broiler parent for commercial production,
• Summer adaptation capacity / tolerance to high temperature
• Low maintenance requirements,
• Low body weight, hence reduced feed cost.

Broilers:-

• Provided with vitamin rich food
• Ensure better growth
• Avoid mortality
• Sent to markets for meat purposes.

Egg production:-

• Proper hygiene to be maintained in housing and poultry feed.
• Disease and pest control measures to be adapted.

Feeding:- 

• Broilers:- protein rich food, sufficient fat
• Poultry birds :- rich in vitamins A and K

Disease control:-

Causes of diseases:-

• Nutritional deficiencies
• Microbes like bacteria, virus fungi 
• Parasites

Disease control measures:-

• Cleanliness and proper hygiene,
• Use of appropriate disinfectants,
• Vaccination

Fish production:- 

• Fish is a protein rich diet

Two ways to obtain fish:-

Capture fishery:- 

• Fish from natural resources like pond, river sea are caught.

Culture fishery:-

• Commercially raising fish in tank/ enclosures

On the basis of water sources, types of fisheries:- 

Two types:- marine fisheries, inland fisheries

Marine fisheries:- 

• Fishes found in oceans/sea water
• Popular marine fishes are:- 
• - pomphret,
• - Mackerel,
• - Tuna,
• - Bhetki,
• - Prawns,
• - Oysters,
• - Bombay duck

How can we obtain Marine fishes?

Capture fishing:-

• Using fishing nets from fishing boats

Culture fishing:-

• Commercially raising marine fishes in enclosed portion of ocean/tanks/ enclosures.
• Also called mariculture.

Inland fisheries:-

• Fresh water resources like canals ,ponds, reservoire and rivers.
• Brackish water (fresh + sea water) resources like estuaries and lagoons.

Freshwater fishes are:-

Catla, silver carp, Rohu, Grass carp, Mrigal

How do we obtain freshwater fishes?

Capture fishing:- yield is not good

Culture fishing :- 

• Termed as aquaculture.
• Few fish species are used in a single fish pond, selected such that they have different food habits.

Thankyou :-)