PSEB Notes

This PSEB 10th Class Science Notes Chapter 13 Magnetic Effects of Electric Current will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 13 Magnetic Effects of Electric Current

→ A current-carrying conductor behaves like a magnet. Magnet and electricity are related to each other.

→ Hans Christian Oersted did remarkable work to make us understand electromagnetism.

→ That end of freely suspended magnet which points towards north direction is called North Seeking or the North Pole and the other end which points towards south direction is called South Seeking or the South Pole.

→ Like poles repel each other while unlike poles attract each other.

→ The field or area around a magnet in which its effect or force can be experienced is called the magnetic field of the magnet.

→ The direction of magnetic lines of force inside the magnet is from the south pole to the north pole while outside the magnet it is from the north pole to the south pole. Therefore, magnetic lines are closed curves.

→ Two magnetic lines of force never intersect each other.

→ On passing a current through a metallic conductor, the magnetic field is produced around it.

→ The magnetic field produced all around it is inversely proportional to its distance.

→ The magnetic field at a point inside the magnetic field produced due to the current flowing through a conductor is proportional to the current flowing through the conductor.

→ A coil consisting of a cylindrical-shaped coil having closely packed turns of insulated copper wire is called a solenoid.

→ Inside a solenoid, magnetic lines of force are just like parallel straight lines. The magnetic field is the same at all points inside the solenoid.

→ The force acting in a conductor is in the direction of current and perpendicular to the direction of the magnetic field. This is called Fleming’s left-hand rule.

→ Electric motor, electric generator, loudspeaker, microphone, and electric meter are related with current-carrying conductor and magnetic field.

→ Production of the magnetic fields is necessary for our heart and brain.

→ MRI is important in medical treatment.

→ The electric motor is a device in which electrical energy is transformed into mechanical energy.

→ Electric motors find their use in electric fans, refrigerators, electric mixers, washing machines, computers, MP3 players, etc.

→ In electric motors, a rectangular coil of insulated wire is placed in between two poles.

→ That device that alternately changes the flow of current is called an AC motor.

→ Soft iron core and coil together form an armature. This increases the power of the motor.

→ Faraday discovered how the moving magnet can be used in producing current.

→ A galvanometer is an instrument that is used to detect the presence of current in a circuit.

→ That process by which the change in the magnetic field of a conductor produces a current in another conductor is called electromagnetic induction.

→ When the direction of motion of a coil is perpendicular to the direction of the magnetic field, then the induced electric current in the coil becomes maximum.

→ In electric generators, mechanical energy is used to rotate a conductor placed in a magnetic field as a result of which current is produced.

→ The device used to produce electricity is called an A.C. generator.

→ Electromagnet: A soft iron piece placed inside an insulated conducting coil becomes an electromagnet on passing current.

→ Magnetic Field: The field around a magnet in which its effect can be felt.

→ Solenoid: A coil made by winding a conducting wire having a large number of closed turns.

→ Iron Core: The soft iron rod placed inside the solenoid is called the iron core.

→ Snow Rule: When a wire placed above a magnetic needle carries current from the south direction to the north direction then the north pole (N-pole) of the magnetic needle gets deflected westward.

→ Electromagnetic Induction: Due to change in the magnetic field the current produced in the neighboring coil is called electromagnetic induction.

→ Electric Energy: The capacity for doing work by an electric current is known as electric energy.

→ Electric Power: The rate at which electric energy is consumed in a conductor is called electric power.

→ Electric Generator: The instrument which produces electric current is called an electric generator.

→ Alternating Current (A.C): That current which continuously changes direction alternately is called alternating current.

→ Direct Current (D.C.): That current which has the same direction always is called direct current (D.C.)

→ Short Circuit: When the live wire comes in direct contact with the neutral wire due to damaged wiring or uncovered wire, the resistance of the circuit becomes zero, and the current flowing through the circuit increases suddenly. This is called short-circuiting.

→ Fuse (Safety Fuse): A wire of low melting point connected in an electric circuit is called a fuse.

→ Electric Meter: A device that is connected to an electric circuit to measure electric energy being used is called an electric meter.

→ Electric Shock: When any part of the human body touches any point of the unsheathed (without insulation) circuit having high potential, shock is experienced which is known as electric shock.

→ Overloading: If the current through a circuit is more than the maximum prescribed limit then the wires become hot and may catch fire. It is called overloading.

→ Right Hand Thumb Rule: If we imagine that current is passing through a conductor held in your right hand such that the thumb points in the direction of current then the curling fingers would represent the direction of the magnetic field.

→ Flemming’s Left-Hand Rule: Stretch your left hand in such a way that the first central fingers are mutually perpendicular to each other, then if the first finger points in the direction of the magnetic field, the central finger in the direction of current then the thumb points in the direction of motion of the conductor.

→ Earthing: The joining of metallic frame of the electric appliance of high power with the earth wire of domestic circuit is called earthing.

This PSEB 10th Class Science Notes Chapter 12 Electricity will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 12 Electricity

→ Electric current is the rate of flow of charge Q through the conductor or it is the charge Q flowing per unit time i.e., I = \(\frac{Q}{t}\)

→ Charge always flows from a body at a higher potential to a body at a lower potential.

→ Electrostatic potential determines the direction of flow of charge from one body to the other when they are brought in contact.

→ Electrostatic potential at a point is defined as the amount of work done is bringing a unit positive test charge from infinity to that point.

→ Conductors have a large number of free electrons whereas insulators have very few free electrons. The motion of free electrons constitutes the electric current.

→ An electric circuit is a closed path through which electrons flow readily.

→ As per convention, the direction of current is taken as opposite to the direction of the flow of electrons.

→ Electric Current: The rate of flow of charge through a conductor is called electric current.
I = \(\frac{Q}{t}\)

→ Ohm: The resistance of a conductor is said to be 1 ohm if a potential difference of 1 volt is maintained between its ends and it allows 1 ampere of current to flow through it.

→ Voltmeter: It is a device used to measure the potential differences.

→ Conductor: Those substances which allow the current to flow through them are called conductors or good conductors.

→ Insulators: Those substances which do not allow the current to flow through them are called insulators.

→ Ammeter: It is an instrument used to measure electric current.

→ Rheostat: It is a device that is used to increase or decrease the current flowing through the electric circuit.

→ One Volt: If 1 coulomb of charge is allowed to pass through a conductor and in doing so 1 joule of work is done then the potential difference across its ends is 1 volt.

→ Ohm’s Law: The ratio of potential difference across the ends of a conductor and the current flowing through it is always constant, provided the physical state of the conductor such as temperature and pressure remains unchanged.
i.e. V ∝ I or \(\frac{V}{I}\) = R

→ Electrical Energy: The capacity of doing work by an electric current is called electrical energy.

→ Electric Power: The rate of consumption of electric energy in a conductor is called electric power.

→ Watt: Watt is an S.I. unit of electric energy in which 1 joule of work is done in 1 sec. Kilowatt. It is the power of an agent which can do 1000 joule of work in 1 second.

→ Kilowatt Hour: It is that electric energy which is consumed in an electric circuit in 1 hour.

→ Coulombs’ Law: Electric force between two charged particles is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them.
F = K\(\frac{q_{1} q_{2}}{r^{2}}\)

→ Joule’s Law of Heating Effect. If T is the electric current that flows through a resistor ‘R’ and as a result of which heat produced is ‘H’. Then heat produced is directly proportional to the square of the current and time ‘t’
H = I² Rt

This PSEB 10th Class Science Notes Chapter 11 The Human Eye and The Colourful World will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 11 The Human Eye and The Colourful World

→ The eye is the most useful natural optical instrument.

→ Distance between near and far points is called accommodation.

→ The least distance of distinct vision for a normal eye is 25 cm.

→ The retina is the most sensitive part of the eye.

→ Rods present on the retina are sensitive to the intensity of light and cones are sensitive to colours of light.

→ The most sensitive part of the retina where the image of the object is formed is called the yellow spot.

→ The focal length of the eye lens can be varied with the help of ciliary muscles.

→ The defects of the eye are myopia, hypermetropia, presbyopia, astigmatism, and colour blindness.

→ Colour blindness cannot be cured while myopia can be corrected by using a diverging (say a concave) lens of suitable focal length.

→ Hypermetropia can be corrected by using a converging (say a convex) lens of suitable focal length. For correcting presbyopia, bifocal lenses are required. Astigmatism is corrected by using a cylindrical lens.

→ Eyes can be donated after death. Even a person using spectacles, contact lens or who have been operated on for cataract or suffering from hypertension can also donate eyes.

→ The cornea of dead persons’ eyes is removed within 6 hours of death and transplanted in blind persons’ eyes.

→ Eye Lens: It is a convex lens made of a fibrous jelly-like substance on the retina of which the real and inverted image of the object is formed.

→ Cornea: It is a transparent membranous bulged out coating in the front part of the eyeball through which light enters the eye, is called the cornea.

→ Iris: The structure just behind the cornea which controls the size of the pupil is called the iris.

→ Myopia: It is the defect of the eye in which the near objects are clearly visible while distant objects are not distinctly visible.

→ Hypermetropia: The defect of the eye in which the distant objects are clearly visible whereas the near objects are not.

→ Retina: It is a delicate membrane having a large number of light-sensitive cells that become active on being illuminated produce electric signals carried to the brain.

→ Near Point: The shortest distance at which if an object is placed is seen clearly without any strain, is called the near point of the eye.

→ Far Point: The farthest point at which an object is placed is seen very clearly.

→ Cataract: The formation of a milky translucent layer on the crystalline lens is called a cataract which results in less visibility and ultimately complete loss of eyesight.

→ Least Distance of Distinct Vision: The minimum distance at which if the object placed can be seen very clearly is called the least distance of distinct vision.

→ Colour Blindness: That defect of the eye in which a person can see clearly but can not distinguish colours is called colour blindness.

→ Persistence of Vision: The sensitiveness of the retina which retains the existence of image for \(\frac{1}{216}\)th of a second even after when it is actually removed.

→ Presbyopia: With aging, the power of accommodation of eyes decreases, and the person cannot read. This defect is due to the weakening of the ciliary muscles.

→ Bifocal Lens: Defect of the eye in which a person suffers both from myopia and hypermetropia. Such a person needs a bifocal lens consisting convex lens (lower part) to see near objects and a concave lens (upper part) to see far-off objects.

→ Prism: It is a piece of a transparent refracting medium having two triangular and three rectangular surfaces. These surfaces are inclined to each other.

→ The angle of Prism: The angle between two surfaces of the prism is called the angle of prism.

→ Tyndal Effect: If a strong beam of light is passed through a colloidal solution, the path of the beam becomes visible when seen with a microscope placed at a right angle. This effect is called the Tyndal effect.

This PSEB 10th Class Social Science Notes Geography Chapter 1 India: An Introduction will help you in revision during exams.

India: An Introduction PSEB 10th Class SST Notes

→ Location – A tropical country.

→ Total Geographical Area – 32, 87, 263 km2

→ Latitudinal extent – 8°4′ North to 37°6′ North.

→ Longitudinal extent – 68°7′ East to 97°25′ East.

→ North-South extent – 3214 km.

→ East-West extent – 2933 km.

→ Land Frontiers – 15,200 km.

→ Coastline – 7,516 km.

→ Standard Meridian – 82½° East longitude.

→ Southernmost point – Indira Point.

→ The southernmost tip of the mainland – Kanyakumari

→ Number of States – 28

→ Number of union territories – 8

→ The Largest State – Rajasthan

→ The Smallest State – Goa.

ਭਾਰਤ-ਇਕ ਜਾਣ-ਪਛਾਣ PSEB 10th Class SST Notes

→ ਭਾਰਤ : ਸੰਖੇਪ ਜਾਣਕਾਰੀ-ਭਾਰਤ ਤਿੰਨ ਪਾਸਿਆਂ ਤੋਂ ਹਿੰਦ ਮਹਾਂਸਾਗਰ ਨਾਲ ਘਿਰਿਆ ਹੋਇਆ ਇਕ ਤ੍ਰਿਭੁਜ ਅਕਾਰ ਦਾ ਭੂ-ਖੰਡ ਹੈ । ਉੱਤਰ ਵਿਚ ਇਸ ਨੂੰ ਹਿਮਾਲਿਆ ਦੀਆਂ ਉੱਚੀਆਂ ਪਹਾੜੀਆਂ ਨੇ ਘੇਰਿਆ ਹੋਇਆ ਹੈ । ਆਥਾਹ ਸਮਰੱਥਾਵਾਂ ਵਾਲਾ ਇਹ ਵਿਸ਼ਾਲ ਦੇਸ਼ ਖੇਤਰਫਲ ਦੇ ਪੱਖੋਂ ਸੰਸਾਰ ਦਾ ਸੱਤਵਾਂ ਅਤੇ ਜਨਸੰਖਿਆ ਦੇ ਪੱਖੋਂ ਦੂਸਰਾ ਵੱਡਾ ਦੇਸ਼ ਹੈ ।

→ ਸਥਾਨਕ ਵਿਸਥਾਰ- ਭਾਰਤ ਦਾ ਵਿਸਥਾਰ 8°4′ ਉ. ਤੋਂ ਲੈ ਕੇ 37°17 ਉੱਤਰੀ ਅਕਸ਼ਾਂਸ਼ਾਂ ਵਿਚ ਫੈਲਿਆ ਹੋਇਆ ਹੈ । ਕਰਕ ਰੇਖਾ ਇਸਨੂੰ ਉੱਤਰੀ ਅਤੇ ਦੱਖਣੀ ਦੋ ਭਾਗਾਂ ਵਿਚ ਵੰਡਦੀ ਹੈ । ਇਸਦਾ ਦੇਸ਼ਾਂਤਰੀ ਵਿਸਥਾਰ 68°7′ ਪੂਰਬ ਤੋਂ 97°24` ਪੂਰਬ ਤੱਕ ਹੈ ।

→ ਅਕਾਰ ਅਤੇ ਖੇਤਰਫਲ-ਭਾਰਤ ਦਾ ਅਕਾਰ ਤਿਕੋਨਾ ਹੈ ਜਿਸ ਦਾ ਅਧਾਰ ਉੱਤਰ ਵਿਚ ਅਤੇ ਸਿਖਰ ਦੱਖਣ ਵਿਚ ਕੰਨਿਆਕੁਮਾਰੀ ਦੇ ਉਪਰ ਸਥਿਤ ਹੈ । ਇਸਦਾ ਕੁੱਲ ਖੇਤਰਫਲ ਲਗਭਗ 32 ਲੱਖ 88 ਹਜ਼ਾਰ ਵਰਗ ਕਿਲੋਮੀਟਰ ਹੈ । ਖੇਤਰਫਲ ਦੇ ਅਨੁਸਾਰ ਇਹ ਸੰਸਾਰ ਦਾ ਸੱਤਵਾਂ ਵੱਡਾ ਦੇਸ਼ ਹੈ ।

→ ਗੁਆਂਢੀ ਦੇਸ਼-ਭਾਰਤ ਦੀ ਥਲ ਸੀਮਾ ਸੱਤ ਵੱਡੇ ਦੇਸ਼ਾਂ ਨੂੰ ਛੂੰਹਦੀ ਹੈ । ਉੱਤਰ ਅਤੇ ਉੱਤਰ- ਪੱਛਮ ਵਿਚ ਪਾਕਿਸਤਾਨ, ਅਫ਼ਗਾਨਿਸਤਾਨ, ਚੀਨ ਅਤੇ ਨੇਪਾਲ ਸਾਡੇ ਗੁਆਂਢੀ ਦੇਸ਼ . ਹਨ । ਉੱਤਰ-ਪੂਰਬ ਵਿਚ ਸਾਡੇ ਗੁਆਂਢੀ ਦੇਸ਼ ਭੁਟਾਨ, ਮਯਨਮਾਰ ਅਤੇ ਬੰਗਲਾ ਦੇਸ਼ ਹਨ ।

→ ਪ੍ਰਸ਼ਾਨਿਕ ਵੰਡ-ਪ੍ਰਸ਼ਾਸਨਿਕ ਪੱਖੋਂ ਭਾਰਤ ਵਿਚ 28 ਰਾਜ ਅਤੇ 8 ਕੇਂਦਰੀ ਸ਼ਾਸਿਤ ਦੇਸ਼ ਸ਼ਾਮਲ ਹਨ ।

→ ਅਨੇਕਤਾ ਵਿਚ ਏਕਤਾ-ਭਾਰਤ ਦੇ ਧਰਾਤਲ, ਜਲਵਾਯੂ ਅਤੇ ਜਨ-ਜੀਵਨ ਵਿਚ ਬਹੁਤ ਜ਼ਿਆਦਾ ਅਨੇਕਤਾ ਪਾਈ ਜਾਂਦੀ ਹੈ ਪਰ ਭਾਰਤੀ ਸੰਸਕ੍ਰਿਤੀ ਅਤੇ ਮਾਨਸੂਨ ਰੁੱਤ ਇਸ ਅਨੇਕਤਾ ਨੂੰ ਏਕਤਾ ਦੇ ਸੂਰਤ ਵਿਚ ਬੰਨ੍ਹਦੀ ਹੈ ।

This PSEB 10th Class Science Notes Chapter 10 Light Reflection and Refraction will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 10 Light Reflection and Refraction

→ Light is an external physical agent which produces in us the sensation of sight.

→ When light travelling in one medium falls on the surface of another medium, the following three effects are observed:

• A part of the incident light is turned back (or reflected) into the first medium.
• Another part travels through the second medium along a changed path (i.e the fight is refracted).
• The remaining part is absorbed by the second medium.

→ Objects are always placed in front of the mirror to their left, so u (object distance) is always negative.

→ The focal length of the convex mirror is taken as positive (+) and that of the concave mirror as negative (-).

→ Magnification of a concave mirror forming real image is m = \(\frac{v}{u}\) and that of convex mirror and also a concave mirror forming virtual image is m = \(\frac{-v}{u}\).

→ All distances measured in the direction of the incident light are taken as positive and distances measured in a direction opposite to the incident ray are taken as negative.

→ The phenomenon of bending of a light ray when it travels from one medium to another medium of different optical densities is called the refraction of light.

→ When a ray of light travels from an optically rarer to an optically denser medium, it bends towards normal.

→ When a ray of light travels from an optically denser to an optically rarer medium, it bends away from normal.

→ The higher the refractive index the more is the denser medium.

→ The ratio of the sine of the angle of incidence (Sin i) to the sine of the angle of refraction (Sin r) is constant, called the refractive index of the medium.

→ The Refractive index of a medium is the ratio of the velocity of light in a vacuum to the velocity of light in a medium.

→ The lens is a portion of the transparent and refracting medium.

→ The relation between the object distance (u), the image distance (v) and the focal length (f) of a lens is called lens formula i.e. \(\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\)

→ The power of a lens is the reciprocal of its focal length. Its unit is dioptre.

→ Mirror: Any smooth and polished surface is called a mirror.

→ Reflection of Light: When light falls on a mirror or a polished surface then without any change in the medium it returns into the same medium along a particular direction. This phenomenon of change of path of light is called reflection.

→ Incident Ray: A ray of light coming from a source of light falling on any surface is called an incident ray.

→ Reflected Ray: After reflection, a ray of light coming back from point of incidence into the same medium is called a reflected ray.

→ Incident Point: The point on the reflecting surface where incident ray strikes is called incident point.

→ Normal: The perpendicular drawn at the point of incidence is called normal.

→ The angle of Incidence: The angle between the incident ray and the normal is called the angle of incidence.

→ The angle of Reflection: The angle between the reflected ray and the normal is called the angle of reflection.

→ Ray of Light: The straight path of light is called a ray of light.

→ Spherical Mirror: If the mirror is a part of some hollow sphere whose one surface is polished and the other surface is reflecting then such mirror is called a spherical mirror.

→ Concave Mirror: A spherical mirror whose reflecting surface is towards the centre of a hollow sphere of which the mirror is a part, is called a concave mirror.

→ Convex Mirror: A spherical mirror whose reflecting surface is away from the centre of a sphere of which the mirror is a part, is called a convex mirror.

→ Centre of Curvature: Centre of curvature of a spherical mirror is the centre of a sphere of which the mirror is a part.

→ Pole: The midpoint of a spherical mirror is called the pole of the mirror.

→ Principal Axis: An imaginary line joining the pole and centre of curvature of a spherical mirror is called the principal axis.

→ The radius of Curvature: It is the radius of a sphere of which the spherical mirror is a part.

→ Aperture: That part of the mirror from where actually reflection takes place is called the aperture of the mirror.

→ Principal Focus: It is the point on the principal axis where the rays of light coming parallel to the principal axis after reflection actually meet or appear to diverge is called the principal focus of the mirror.

→ Focal Length: The distance between pole and principal focus of spherical mirror is called the focal length of the mirror. It is usually denoted by f.

→ Magnification: The magnification of a spherical mirror is the ratio of the length (size) of the image to the length (size) of the object. It is denoted by ‘m’.

→ Refraction of Light: The change of path of light when it goes from one medium to another medium is called refraction of light.

→ Transparent Medium: Mediums like air, water, and glass through which light can pass easily are called transparent mediums.

→ Lens: A portion of transparent and refracting medium bounded by two surfaces is called the lens.

→ Power of Lens: The capacity of a lens to converge or diverge light rays is called the power of the lens. It is denoted by ‘P’.

→ Centres of Curvature of Lens: The centres of spheres of which the spherical surfaces of the lens are part, are called centres of curvature of the lens.

→ Principal Axis of Lens: The line passing through the centres of curvature of the lens, is called the principal axis of the lens.

→ Optical Centre: A point of the lens through which rays of light go undefeated, is called an optical centre.

→ Principal Focus of Lens: The point on the principal axis of the lens, where rays coming parallel to the principal axis after refraction either actually converge or appear to diverge, is called the principal focus of the lens.

This PSEB 10th Class Science Notes Chapter 9 Heredity and Evolution will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 9 Heredity and Evolution

→ Heredity: It is the transmission of genetic characters from parents to the offspring i.e., from one generation to the next.

→ Variation: The differences among the individuals of a species and also in the offsprings of the same parents are referred as a variation.

→ Every organism produce offsprings either through asexual or sexual reproduction. The individuals produced through these reproductive processes are similar but subtly different.

→ In asexual reproduction, although all the offsprings resemble each other and also to their single parent, yet very minor differences (variations) arise in them.

→ For example, if we observe a field of sugarcane we find very few variations among the individual plants.

→ The reproductive processes give rise to new individuals that are similar, but subtly different.

→ The number of successful variations is maximized by the process of sexual reproduction.

→ Inheritance from the previous generation provides both a common basic body design and subtle changes in it, for the next generation.

→ The second generation will have differences that they inherit from the first generation, as well as newly created differences.

→ Some amount of variation is produced even during asexual reproduction.

→ The selection of variants by environmental factors forms the basis for evolutionary processes.

→ A child bears all the basic features of a human being.

→ Both the father and the mother contribute practically equal amounts of genetic material to the child.

→ Mendel was the first one to keep count of individuals exhibiting a particular trait in each generation.

→ Mendel used a number of contrasting visible characters of a garden pea. Cellular DNA is the information source for making proteins in the cell.

→ A section of DNA that provides information for one protein is called the gene for that protein.

→ Plant height can also depend on the amount of a particular plant hormone. Genes control characteristics or traits.

→ Each cell will have two copies of each chromosome, one each from the male and female parents.

→ Every germ cell will take one chromosome from each pair and these may be of either maternal or paternal origin.

→ In some animals, the temperature at which fertilized eggs are kept determines whether the animals developing in the eggs will be male or female.

→ In other animals, such as snails, individuals can change sex, indicating that sex is not genetically determined.

→ Human has 23 pairs of chromosomes.

→ Women are XX, while men are XY.

→ The frequency of inherited traits changes over generations.

→ The germ cells of sexually reproducing populations are made in specialized reproductive tissue.

→ Change in non-reproductive tissues cannot be passed on to the DNA of the germ cells..

→ An individual cannot pass on to its progeny the experiences of its lifetime.

→ Charles Darwin formulated in his hypothesis that evolution took place due to natural selection.

→ We often associate Darwin solely with the theory of evolution.

→ J.B.S. Haldane, a British scientist (who became a citizen of India later), suggested in 1929 that life must have developed from the simple inorganic molecules which were present on earth soon after it was formed.

→ Some basic characteristics will be shared by most organisms.

→ The cell is the basic unit of life in all organisms.

→ Bacterial cells do not have nuclei while the cells of most other organisms do.

→ Among multicellular organisms, whether they can undertake photosynthesis or not, is an important level of classification.

→ The skeleton is inside the body or around the body is another fundamental design difference.

→ The more characteristics two species will have in common, the more closely they are related.

→ The more closely they are related, the more recently they will have had a common ancestor.

→ Non-living material must have given rise to life.

→ The characteristics in different organisms would be similar because they are inherited from a common ancestor.

→ Mammals have four limbs, as do birds, reptiles, and amphibians.

→ The wings of birds and bats are more closely related to each other.

→ The preserved traces of living organisms are called fossils.

→ If we dig into the earth and start finding fossils, it is reasonable to suppose that the fossils we find closer to the surface are more recent than the fossils we find in deeper layers.

→ The dating of fossils is done by detecting the ratios of different isotopes of the same element in the fossil material.

→ The complex organs 4vill be created bit-by-bit over generations.

→ Like the wing, the eye seems to be a very popular adaptation.

→ The structure of the eye in different organisms is different. It shows that they have separate evolutionary origins.

→ A flatworm named Planaria has very simple ‘eyes’ that are really just eye spots that detect light.

→ A change that is useful for one property to start with, can become useful later for quite a different function.

→ Feathers, for example, can start out as providing insulation in cold weather but later, they might become useful for flight.

→ The birds are very closely related to reptiles.

→ Humans have started cultivating wild cabbage as a food plant for over more than two thousand years and generated different vegetables from it by selection.

→ Changes in the DNA during cell division would lead to changes in the proteins that are made from new DNA.

→ The organisms which are more distantly related will accumulate a greater number of differences in their DNA.

→ It is not true that human beings have evolved from chimpanzees. The two resultant species have probably evolved in their own separate ways to give rise to the current forms.

→ Evolution is simply the generation of diversity and the shaping of diversity by environmental selection.

→ The tools for tracing evolutionary relationships are excavating, time-dating, and studying fossils, as well as

→ DNA sequences determination has been used for studying human evolution.

→ All humans are a single species. We all come from Africa.

→ The earliest members of the human species, Homo sapiens, can be traced in Africa.

→ The origin of man, like other species on the earth, is an event of biological evolution.

→ Genetics: The branch of biology which deals with the study of heredity and variation is called genetics.

→ Heredity: The transmission of characters from generation to generation is called heredity.

→ Gene: The basic unit of heredity which transmits the traits into the next generation.

→ Sex chromosome: The pair of chromosomes which decide the sex of male and female.

→ Homologous chromosome: The pair of chromosomes each from mother and father together is called a homologous chromosome.

→ Autosomes: The chromosomes other than sex chromosomes are autosomes.

→ Evolution: The slow and continuous process of changing organisms from simple to complex form is called evolution. In simple words descend with modification.

→ Homologous organs: The organs have the same origin and basic structure but are adapted to perform various functions.

→ Analogous organs: The organs have a different origin and basic structures but perform the same function.

→ Transgenic organism: The organism produced by the introduction of foreign DNA or genes.

→ Fossils: The remains of dead animals in earth strata are called fossils.

→ Haploid: The single set of chromosomes obtained from one parent.

→ Nucleotide: A molecule made up of nitrogen base, sugar, and phosphate.

→ Chromatid: When the chromosomes divide into two each part is called a chromatid.

→ Vestigial organs: Organs in our body having no functional importance are called vestigial organs.

→ Genetic drift: The effect on the genetic continuation in a population due to the death of organisms or immigration is called genetic drift.

→ Variations are differences between young one of the same parent: They differ from their parents.

→ Variations arise due to inaccuracies in DNA replication in asexually reproducing organisms.

→ Offsprings: Young ones produced as reproduction are ailed offsprings.

→ Genotype: The internal genetic constitution of an organism is termed genotype. The environment has no effect on it.

→ Phenotype: It refers to externally visible characters of an organism. It is the net result of interactions between genotype and environment. Individuals of the same genotype breed alike are termed phenotype.

→ Recessive traits: An allele (gene) that is not expressed phenotypically when present in heterozygous conditions.

→ Speciation: The origin of species is termed speciation.

→ Acquired characters: The characters acquired during a lifetime are ailed acquired characters.

→ Life: Life is the power that an organism possesses to maintain and reproduce itself.

→ Natural selection: According to Darwin the individual with special traits survive and multiply while others perish is called natural selection.

This PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce? will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ The phenomenon of the formation of new individuals by the existing ones is called reproduction.

→ Reproduction is a means of the perpetuation of the species, and also a method of their multiplication.

→ Reproduction, unlike other life processes, is not essential to maintain the life of an individual organism.

→ Reproduction is the formation of similar organisms with the same body design, due to information of inheritance. (DNA or RNA).

→ Reproduction involves the creation of a DNA copy and additional cellular apparatus by the cell involved in the process.

→ DNA copies formed are not identical and have some variations but if variations are drastic then-new DNA copies cannot work.

→ All organisms reproduce. The reproducing organisms create new individuals that look very much like themselves.

→ The chromosomes in the nucleus of a cell contain information for the inheritance of features from parents to the next generation in the form of DNA (Deoxyribose Nucleic Acid) molecules.

→ The DNA in the cell nucleus is the information source for making proteins. Cells use chemical reactions to build copies of their DNA.

→ No biochemical reaction is absolutely reliable. Therefore, the process of copying the DNA will have some variations each time.

→ Some of the variations might be so drastic that the new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die.

→ The inbuilt tendency for variation during reproduction is the basis for evolution.

→ If a population of reproducing organisms were suited to a particular niche and if the niche were drastically altered, the population could be wiped out.

→ If the water temperature increases by global warming, most of the bacteria living in temperate waters would die.

→ In unicellular organisms, cell division or fission leads to the creation of new individuals.

→ Many bacteria and protozoa simply split into two equal halves during cell division.

→ In Leishmania (which causes kala-azar), binary fission occurs in a definite orientation of the body.

→ The malarial parasite, Plasmodium, divides into many daughter cells simultaneously by multiple fission.

→ Yeast can produce small buds that separate and grow into new individuals.

→ Multicellular organisms have more complex ways of reproduction.

→ Hydra and Planaria can be cut into any number of pieces and each piece grows into a complete organism. This is known as regeneration. It is carried out by specialized cells.

→ Organisms such as Hydra use regenerative cells for reproduction in the process of budding.

→ There are many plants in which parts like the roots, stems, and leaves develop into new plants under appropriate conditions.

→ The methods such as layering or grafting to grow many plants like sugarcane, roses, or grapes are used for agricultural purposes.

→ Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds.

→ Such methods also make possible the propagation of plants such as banana, orange, rose and jasmine that has lost the capacity to produce seeds.

→ In tissue culture, new plants are grown by taking tissue or cells from the growing tip of a plant.

→ This technique is commonly used for ornamental plants.

→ The hyphae of Rhizopus grow on the bread. They have sporangia, which contain cells or spores, which can eventually develop into new Rhizopus individuals.

→ In sexual reproduction, both sexes, males and females, are needed to produce new generations.

→ Combining variations from two or more individuals would create new combinations of variants.

→ As organisms become more complex, the specialization of tissue increases.

→ The motile germ cell is called the male gamete (pollen) and the germ cell containing the stored food is called the female gamete (ovule).

→ The reproductive parts of angiosperms are located in the flowers.

→ The flower may be unisexual (papaya, watermelon) when it contains either stamens or carpels or bisexual (Hibiscus, mustard) when it contains both stamens and carpels.

→ The ovary contains ovules and each ovule has an egg cell.

→ The fusion of the germ cells or fertilization produces the zygote.

→ The transfer of pollen from one flower to another is achieved by agents like wind, water, or animals.

→ After fertilization, the zygote divides several times to form an embryo within the ovule.

→ The seed contains the future plant or embryo which develops into a seedling under appropriate conditions. This process is known as germination.

→ Humans use a sexual mode of reproduction.

→ As adolescence starts, there are some changes taking place that are different among boys and girls. These do not happen all at the same time in one person, nor do they happen at an exact age.

→ The period of adolescence is called puberty.

→ The male reproductive system consists of portions that produce the germ cells and other portions that deliver the germ cells to the site of fertilization.

→ The formation of germ cells or sperms takes place in the testes.

→ In addition to regulating the formation of sperms, testosterone brings about changes in appearance seen in boys at the time of puberty.

→ The female germ cells or eggs are made in the ovaries.

→ The fertilized egg, the zygote, gets implanted in the lining of the uterus and starts dividing.

→ The embryo gets nutrition from the mother’s blood with the help of a special tissue called the placenta.

→ Since the ovary releases one egg every month, the uterus also prepares itself every month to receive a fertilized egg.

→ If the egg is not fertilized, the uterus lining slowly breaks and comes out through the vagina as blood and mucus. This cycle takes place roughly every month and is known as menstruation. It usually lasts for about two to eight days.

→ The process of sexual maturation is gradual.

→ Gonorrhea and syphilis and viral infections such as warts and HIV-AIDS are sexually transmitted diseases.

→ The sexual act always has the potential to lead to pregnancy.

→ Many mechanical, hormonal, and surgical methods are used to avoid pregnancy.

→ Pre-natal sex determination has been prohibited by law.

→ Because of reckless female foeticides, the child sex ratio is declining at an alarming rate.

→ Population explosion is raising problem in our country.

→ Birth control is an attempt to control the number of births in a family so that a couple may not have more children than required.

→ Physical barriers include the use of condoms, diaphragm, and cervical caps.

→ Chemical methods include the use of specific drugs by females i.e. oral pill and vaginal pill.

→ The use of IUCD (Copper-T) is very effective.

→ Surgical methods include vasectomy and tubectomy.

→ The communicable diseases occurring due to sexual contact are called sexually transmitted diseases such as gonorrhea, syphilis, and AIDS.

→ Reproduction: It is the process of producing new organisms by existing organisms of a species.

→ Sexual reproduction: The production of offspring by the fusion of male and female gametes is called sexual reproduction. It is biparental.

→ Asexual reproduction: The production of progeny without the fusion of male and female gametes is called asexual reproduction. It is uniparental.

→ Fission: The division of an organism into two or more individuals is called fission.

→ Budding: The process of development of an outgrowth due to repeated cell division at one specific site which grows into a tiny individual is called budding.

→ Vegetative propagation: The process of development of the new individual from any part of the body is called vegetative propagation.

→ Grafting: The technique of joining the different parts of two different plants to grow into one plant.

→ Unisexual: When the male and female are separate individuals, they are called unisexual.

→ Bisexual/Hermaphrodite: The organisms having male and female in a single individual are called bisexual/hermaphrodite.

→ Scion: A stem piece of good quality plant is grafted to grow into a new plant is called the scion.

→ Layering: The production of a new plant by covering the leaned branches of a plant under the soil.

→ Pollination: The transfer of pollen from another to stigma.

→ Fertilization: The fusion of male and female gametes is called fertilization.

→ Syngamy: The fusion of male gamete with female gamete is called syngamy.

→ Double fertilization: When the fertilization occurs two times (with ovum and polar cell) in angiosperms the process is called double fertilization.

→ DNA Replication: Duplication of DNA molecule by copying from a molecular template of DNA.

→ Regeneration: The formation of the lost part is called regeneration.

→ Gamete: Haploid sex cell is called gamete.

→ Zygote: Diploid fertilized egg is called a zygote. If undergoes cleavage (non-motile division) to form a complete organism.

→ Sperm: Haploid male gamete is called sperm.

→ Ovum: Haploid female gamete is ailed ovum.

→ Ovule: A structure in the ovary of a seed plant that develops into a seed after fertilization.

→ Puberty: The process of becoming sexually mature.

→ Ovulation: The release of the ovum from the ovary.

→ Implantation: The fixation of the embryo in the uterus is called implantation.

→ Placenta: It is the connection between mother and embryo.

→ Parturition: The process of giving birth to foetus is called parturition.

This PSEB 10th Class Science Notes Chapter 7 Control and Coordination will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 7 Control and Coordination

→ Control and coordination are the functions of the nervous system and hormones in our bodies.

→ The responses of the nervous system can be classified as a reflex action, voluntary action, or involuntary action.

→ The nervous system uses electrical impulses to transmit messages.

→ The neuron is the functional unit of the nervous system that responds to stimuli by electrical impulses.

→ The Central Nervous System (CNS) consists of the brain and the spinal cord.

→ The brain is the highest coordinating centre of the body.

→ The nervous system gets information from our sense organs and acts through our muscles.

→ In many animals and some plants, there are some movements not connected with growth.

→ Some movements, in response to the environment, are carefully controlled. Each kind of change in the environment evokes an appropriate movement in response.

→ Living organisms must use systems providing control and coordination.

→ Specialized tissues are used to provide these control and coordination activities.

→ All information from our environment is detected by the specialized tips of some nerve cells.

→ We have generally five sense organs such as the eye, the ear, the nose, the tongue, and the skin.

→ The information is acquired at the end of the dendritic tip of a nerve cell.

→ It sets off a chemical reaction that creates an electrical impulse.

→ The nervous tissue is made up of an organized network of nerve cells or neurons.

→ ‘Reflex’ is a word we use very commonly when we talk about some sudden action in response to something in the environment.

→ Thinking is a complex activity, so it is bound to involve a complicated interaction of many nerve impulses from many neurons.

→ The thinking tissue in our body consists of dense networks of intricately arranged neurons. It sits in the forward end of the skull.

→ Nerves from all over the body meet in a bundle in the spinal cord on their way to the brain.

→ Nerves supply information to various organs of the body.

→ The reflex arcs have evolved in animals because the thinking process of the brain is not fast enough.

→ Brain and reflex arcs receive information from all parts of the body.

→ In fact, many animals have very little or none of the complex neuron networks needed for thinking.

→ The spinal cord is made up of nerves that supply information to think about.

→ The brain and spinal cord constitute the central nervous system.

→ The brain also has to send messages to muscles.

→ The brain allows us to think and take actions based on that thinking.

→ The brain has three major parts or regions, namely the fore-brain, mid-brain, and hind-brain.

→ The fore-brain is the main thinking part of the brain. It has regions that receive sensory impulses of hearing, smell, sight, and so on.

→ Many involuntary actions are controlled by the mid-brain and hind-brain.

→ All the involuntary actions including blood pressure, salivation, and vomiting are controlled by the medulla in the hind-brain.

→ The vertebral column or backbone protects the spinal cord.

→ The plants also use electrical-chemical means to convey the information from cell to cell.

→ Some tendrils are sensitive to touch.

→ Light and gravity change the directions of growing parts of the plant.

→ The directional or tropic movements can be either towards the stimulus or away from it.

→ The stimulated cells release a chemical compound, this compound would diffuse all around the original cell.

→ Hormones are used by multicellular organisms for control and coordination, show a great deal of diversity.

→ Different plant hormones help to coordinate growth, development, and responses to the environment.

→ A hormone called auxin, synthesized at the shoot tip, helps the cells to grow longer.

→ The plant hormones are gibberellins which, like auxins, help in the growth of the stem.

→ Adrenaline is a hormone secreted by the adrenal (kidney) gland in humans. It affects the heart, respiration, digestion, skeleton muscles in humans and other organisms.

→ Iodine is necessary for the thyroid gland to make the thyroxine hormone.

→ Thyroxine regulates carbohydrate, protein, and fat metabolism in the body so as to provide the best balance for growth.

→ In case of iodine is deficient in our diet, there is a possibility that we might suffer from goiter.

→ Growth hormone is one of the hormones secreted by the pituitary. As its name indicates, growth hormone regulates the growth and development of the body.

→ There is the secretion of testosterone in males and estrogen in females.

→ Insulin is a hormone that is produced by the pancreas and helps in regulating blood sugar levels.

→ Neuron: The structural and functional unit of the nervous system is called a neuron.

→ Sensory organ: The organs which sense the changes in the surrounding environment and pass on the information to the central nervous system are called sensory organs.

→ Hormone: The special chemical substances secreted by endocrine glands (ductless glands) and transported by the blood to control the body functions.

→ Phototropism: The movement of plants towards light is called phototropism.

→ Geotropism: The movement of plant roots due to the earth’s gravity is called geotropism.

→ Chemotropism: The movement of plant parts or plants due to the chemical stimulus is called chemotropism.

→ Phytohormones: These are the hormones secreted by plants to perform various functions.

→ Nastic movements: When the stimulus does not produce any movement in plants.

→ Phytochrome: These are special pigments that respond to the photoperiod.

→ Ganglion: The group of cell bodies of nerve cells is called a ganglion.

→ Reflex action: The involuntary actions towards emergency situations.

→ Reflex arc: The path through which the signal travels during reflex action is called the reflex arc.

→ Spinal cord: Nerves from all over the body meet to form a bundle/cord on their way to connect with the hindbrain is called the spinal cord.

→ Central nervous system: The brain and nerve cord together constitute the central nervous system.

→ Motor neurons: The neurons which carry the responses to the concerned organs.

→ Sensory neurons: The neurons which carry the message from sensory organs to the brain.

→ Nerve impulse: The conduction of chemical or electric signals by nerve cells is called nerve impulse.

→ Voluntary action: These are the actions that need thinking. They are performed knowingly, i.e., controlled by conscious thought. Example. Speaking to a friend, writing a letter, etc.

→ Involuntary action: These are not under the control of the will of an individual. They are automatic responses to a stimulus that is not under the voluntary control of the brain. Example. Touching a hot plate unknowingly.

→ Endocrine glands secrete the hormones directly into the blood.

→ Exocrine glands are glands with ducts that pour their secretion at the site of action.

→ Insulin is the hormone produced by β-cells of islets of Langerhans which controls sugar metabolism.

This PSEB 10th Class Science Notes Chapter 6 Life Processes will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 6 Life Processes

→ Visible movement is not the only defining characteristic of life.

→ Plants do not show locomotory movements, but movements occur at the molecular level.

→ Viruses are living only inside living organisms.

→ Every living organism takes food, derives energy, passes out waste material, and responds to changes within the body and environment. All these activities are collectively termed life processes.

→ These life processes are required for the maintenance of life.

→ The body needs energy which is obtained from the food that the organism eats.

→ The source of energy is called food. So there must be a process to transfer a source of energy (food) from outside to inside the body of an organism. This process is commonly called nutrition.

→ Since life on earth depends on carbon-based molecules, most of these food sources are also carbon-based.

→ Oxidizing-reducing reactions are some of the most common chemical means to break-down large molecules.

→ The process of acquiring oxygen from outside the body and using it in the process of breakdown of food sources for cellular needs is called respiration.

→ In the case of a single-celled organism, there are no specific organs for taking in food, exchange of gases, or removal of wastes because the entire surface of the organism is in contact with the environment.

→ In multicellular organisms, various body parts are specialized for the functions they perform.

→ The uptake of food and of oxygen will also be the function of specialized tissues.

→ We need energy every time for our life activities.

→ The general requirement for energy and materials is common in all organisms, but it is fulfilled in different ways.

→ The heterotrophs’ survival depends directly or indirectly on autotrophs. Heterotrophic organisms include animals and fungi.

→ The carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis.

→ Photosynthesis is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy.

→ This material is taken in the form of carbon dioxide and water which is converted into carbohydrates in the presence of sunlight and chlorophyll.

→ Some of the energy derived from the food we eat is stored in our bodies in the form of glycogen.

→ The green dots are cell organelles called chloroplasts which contain chlorophyll.

→ Stomata are tiny pores present on the surface of the leaves.

→ Massive amounts of gaseous exchange take place in the leaves through these pores for the purpose of photosynthesis.

→ Since large amounts of water can also be lost through these stomata, the plant closes these pores when it does not need carbon dioxide for photosynthesis.

→ Plants take up materials like nitrogen, phosphorus, iron, and magnesium from the soil.

→ Nitrogen is an essential element used in the synthesis of proteins and other compounds.

→ The form of nutrition differs depending on the type and availability of food material as well as how it is obtained by the organism.

→ Fungi like bread moulds, yeast, and mushrooms break down the food material outside the body and then absorb it.

→ In single-celled organisms, the food may be taken in by the entire surface.

→ Amoeba takes in food using temporary finger-like extensions of the cell surface which fuse over the food particle forming a food vacuole.

→ In Paramecium, which is also a unicellular organism, the cell has a definite shape, and food is taken in at a specific spot.

→ The alimentary canal is basically a long tube extending from the mouth to the anus.

→ When we eat something we like, our mouth ‘waters’. This is actually a fluid called saliva secreted by the salivary glands.

→ The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give sugar.

→ The stomach is a large organ that expands when food enters it.

→ The gastric glands present in the wall of the stomach release hydrochloric acid, a protein-digesting enzyme called pepsin and mucus.

→ The small intestine is the longest part of the alimentary canal.

→ Meat is easier to digest, hence carnivores like tigers have a shorter small intestine. It is the site of the complete digestion of carbohydrates, proteins, and fats.

→ The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats.

→ The undigested food is sent into the large intestine where a large number of villi absorb water from this material.

→ The food material taken in during the process of nutrition is used in cells to provide energy for various life processes.

→ The respiration takes place in the presence of air (oxygen), it is called aerobic respiration.

→ The release of energy in this aerobic process is much greater than in the anaerobic process.

→ The synthesis of lactic acid in our muscles during strenuous activity causes cramps.

→ The energy released during cellular respiration is immediately used to synthesize a molecule called ATP which is the fuel for all other activities in the cell.

→ ATP is broken down to release a fixed amount of energy which can drive the endothermic reactions taking place in the cell.

→ At night, when there is no photosynthesis occurring, CO₂ elimination is the major exchange activity going on.

→ Aquatic animals that live in water need to use the oxygen dissolved in water.

→ Since the amount of dissolved oxygen is fairly low as compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that of terrestrial organisms.

→ The air passing through the nostrils is filtered by fine hairs that line the nasal passage.

→ Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in balloon-like structures called alveoli.

→ The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by the blood in the alveolar blood vessels to be transported to all the cells in the body.

→ In human beings, the respiratory pigment is hemoglobin which has a very high affinity for oxygen.

→ If the alveolar surface were spread out, it would cover about 80 square meters.

→ The blood is a fluid connective tissue.

→ Blood consists of a fluid medium called plasma.

→ Plasma transports food, carbon dioxide, and nitrogenous wastes in dissolved form.

→ The heart is a muscular organ that is as big as our fist.

→ The heart has two regions; the atrium and ventricle. Ventricle has a thicker muscular wall than the atrium because the ventricle has to pump blood through the whole body.

→ Valves ensure that blood does not flow backward when the atria or ventricles contract.

→ The separation of the right side and the left side of the heart is to prevent oxygenated and deoxygenated blood from mixing. Such separation allows a highly efficient supply of oxygen to the body.

→ Amphibians or many reptiles have three-chambered hearts while Fishes have only two-chambered hearts.

→ Blood goes through the heart twice during each cycle in amphibians and other vertebrates. This is known as double circulation.

→ The force that blood exerts against the wall of a vessel is called blood pressure. This pressure is much greater in arteries than in veins.

→ The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg.

→ Blood pressure is measured with an instrument called a sphygmomanometer.

→ High blood pressure is also called hypertension. It can lead to the rupture of an artery and internal bleeding.

→ Arteries are the vessels that carry blood away from the heart to various organs of the body. Veins collect the blood from different organs and bring it back to the heart.

→ The blood has platelet cells that circulate around the body and they plug the leaks by helping to clot the blood at these points of injury.

→ There is another type of fluid also involved in transportation. This is called lymph or tissue fluid.

→ The xylem tissue (vessels and tracheids) of the roots, stems, and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant.

→ The loss of water in the form of vapours from the aerial parts of the plant is known as transpiration.

→ The transport of soluble products of photosynthesis is called translocation and it occurs in the part of the vascular tissue known as phloem.

→ Unlike transport in the xylem which can be largely explained by simple physical forces, the translocation in the phloem is achieved by utilizing energy.

→ Excretronr-All plants and animals produce harmful substances due to a number of metabolic activities occurring in their body tissues. These harmful substances are to be eliminated from the body, otherwise, they act as toxic substances.

→ In human beings, excretory products in the form of soluble nitrogen compounds are removed by the nephrons in the kidneys.

→ Plants use a variety of techniques to get rid of waste materials that are stored in the cell vacuoles, like removing them in the falling leaves or excreted into the surrounding soil.

→ The excretory system of human beings includes a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.

→ The purpose of making urine is to filter out waste products from the blood.

→ Nitrogenous wastes such as urea or uric acid are removed from blood in the kidneys.

→ Enzymes: The bio-catalysts initiate or enhance the rate of reaction in a living system without undergoing any change in themselves. They are proteinic in nature.

→ Nutrition: It is the process by which living organisms take up nutrients from the environment and use them for the development of cells and tissues and also for energy.

→ Autotrophs: The organisms which make their food from simple substances like CO₂, water, and minerals with their own chlorophyll in the presence of sunlight are called autotrophs.

→ Heterotrophs: The organisms which cannot synthesize their own food. They depend on autotrophs for their food supply directly or indirectly. Saprophytes. The organisms which depend on dead, decaying organic matter for their nutritional requirements are called saprophytes.

→ Parasites: Those organisms which depend upon other living organisms (host) for their food and shelter are called parasites. There are two types of parasites i.e. ectoparasites (outside the body) and endoparasites (inside).

→ Holozoan: Holozoans are heterotrophs that involve the intake of solid pieces of food. Since solid food is taken in, holozoic nutrition is also called ingestive nutrition. It is found in animals and Protozoa.

→ Herbivorous: The organisms which take their food in the form of plants and plant products are called herbivorous.

→ Carnivorous: Those organisms which rely on the flesh of other organisms are called carnivorous.

→ Omnivorous: Those organisms which can feed upon plants, as well as other organisms, are called omnivorous.

→ Ingestion: The process of intake of food in the mouth is called ingestion. Digestion. The process of breakdown of complex food material into -simpler substances is called digestion.

→ Photosynthesis: The autotrophs take in CO₂ and H₂O and convert these into carbohydrates in the presence of chlorophyll and sunlight is called Photosynthesis.

→ Compensation point: In the shadow (morning and evening) when photosynthesis is very low, the CO₂ produced in respiration is equal to the CO₂ consumed in photosynthesis. This situation when the CO₂ absorption from the environment is about nil is called a compensation point.

→ Respiration: It is the process of oxidation of carbohydrates in the cells to release energy that is used by the cells for different purposes.

→ Aerobic respiration: The respiration taking place in the presence of air – (oxygen) is called aerobic respiration.

→ Anaerobic respiration: The respiration taking place in the absence of air is (oxygen) called anaerobic respiration.

→ Respiratory substrate: The substance which is oxidized during respiration is called the respiratory substrate.

→ Glycolysis: It is the metabolic pathway in the cytoplasm that converts glucose into pyruvate.

→ Anabolism: It refers to chemical reactions in which simpler substances are combined to form more complex molecules. Anabolic reactions usually require energy.

→ Catabolism: It refers to chemical reactions that result in the breakdown of more complex organic molecules into simpler substances.

→ Fermentation: Fermentation is a metabolic process that converts sugar/glucose to CO₂ and other simple carbon compounds like alcohol, lactic acid, malic acid, acetic acid, etc.

→ ATP: Adenosine triphosphate is a nucleoside triphosphate used in cells as a coenzyme often called the “molecular unit of currency” of intracellular energy transfer.

→ Stomata: These are tiny pores present on the surface of the leaves. Massive amounts of gaseous exchange take place in the leaves through these pores for the purpose of photosynthesis.

→ Breathing: The process of taking air into and expelling it from the lungs is called breathing.

→ Inspiration: The intake of oxygen from the environment into the lungs is called inspiration.

→ Expiration: The process of throwing out CO₂ from the lungs is called expiration.

→ Transpiration: The loss of water in the form of vapours from the aerial parts of the plant is known as transpiration.

→ Xylem: A continuous system of water-conducting channels reaching all parts of the plant is called the xylem.

→ Phloem: The system transporting products of photosynthesis from the leaves where they are synthesized to other parts of the plant is called phloem.

→ Translocation: The transport of soluble products of photosynthesis is called translocation and it occurs through the phloem.

→ Artery: The blood vessels which carry the oxygenated blood from the heart to various parts of the body are called arteries.

→ Veins: The blood vessels which bring the deoxygenated blood from various parts of the body to the heart are called veins.

→ Capillaries: Very thin blood vessels within the tissues which connect arteries with veins.

→ Lymph: It is a clear-to-white fluid containing white blood cells that attack bacteria in the blood.

→ Hemoglobin: The iron-containing red pigment present in red blood cells to transport oxygen is called hemoglobin.

→ Clotting: The process of blood clot formation in the body is called clotting.

→ Dialysis: It is a process of removing waste and excess water from the blood and is used as an artificial replacement for kidney failure.

→ Osmoregulation: The process of maintaining a balance of water and ions inside the body is called osmoregulation.

→ Excretion: Excretion is the process by which waste products of metabolism are eliminated from the body.

→ Nephron: The basic functional unit of the kidney is called a nephron.

This PSEB 10th Class Science Notes Chapter 5 Periodic Classification of Elements will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 5 Periodic Classification of Elements

→ The arrangement of elements in such a manner that the elements having similar elements are grouped together whereas the elements having different properties are separated is called classification of elements.

→ According to Dobereiner Triads, the elements were arranged in order of increasing atomic masses and grouped into three elements such, that the elements had similar properties such that the atomic mass of the middle element was average of the other two elements.

→ The classification done by Dobereiner on the basis of triads was not applicable to classify all the elements.

→ In 1866, on the basis of the law of octaves, Newland classified elements till calcium whose atomic mass is 40.

→ Russian chemist, Mendeleev discovered periodic law which is famous by the name Mendeleev’s periodic law which states that the physical and chemical properties of the elements are the periodic functions of their atomic masses.

→ Mendeleev’s periodic table was arranged into periods and groups.

→ Horizontal rows are called periods and vertical columns are called groups.

→ In the main periodic table, Mendeleev left the places for those elements which were not discovered till then.

→ According to Modern Periodic Law, the physical and chemical properties of elements are the periodic functions of their atomic number.

→ In modern periodic tables, elements are arranged in 18 vertical columns known as groups and 7 horizontal rows known as periods.

→ Elements of group zero/18 are known as noble gases.

→ The repetition of the similar properties of elements placed in a group and separated by definite gaps of atomic number is called periodicity.

→ There are also some defects in the long form of the periodic table.

→ Scandium, gallium, germanium, etc., were discovered after Mendeleev’s periodic table. In 1913, Henry Moseley said that in comparison to the atomic mass of elements, atomic number is a more fundamental property.

→ By arranging the elements in ascending order of atomic number, their properties can be estimated more precisely.

→ By atomic size, we can find the atomic radius.

→ The atomic radius of Hydrogen is 37 pm (Picometer, 1 pm = HP12 m).

→ Atomic radius decreases on moving left to right along a period.

→ By metalloids properties of metal and non-metals are differentiated. Metalloids are-Boron, Silicon, Germanium,

→ Arsenic, Antimony, Tellurium, and Polonium. Oxides of metals are basic and oxides of non-metals are acidic.

→ The minimum energy required to remove an electron from the valence shell of an isolated gaseous atom is known as ionization energy.

→ The energy released when an electron enters the outermost shell of a neutral gaseous atom is known as electron affinity.

→ As we move down in a group, metallic properties increases.

→ On moving down in a group from top to bottom ionization energy decreases.

→ Periodic Table: This is a table in which we classify the elements in a specific order.

→ Newlands’ Law of Octaves: It states that when the elements are arranged in the ascending order of their increasing atomic weights, every eighth element has properties similar to the first element like the notes of an octave of music.

→ Dobereiner’s triads: It is a group of three elements having similar chemical properties in which the atomic weight of the middle element is the average of the other two elements.

→ Periodic classification is the systematic study of the properties of the elements.

→ Periodic Table: It is a table or chart in which the various elements are arranged in such a manner that elements having similar properties fall in the same vertical column whereas dissimilar elements are separated.

→ Mendeleev’s Periodic Table: The table of elements made by Mendeleev is known as Mendeleev’s Periodic Table, which is based on atomic mass.

→ Modern Periodic Table: The table which was made after the modification of Mendeleev’s Periodic Table, is known as Modern Periodic Table or extended form of the periodic table. It is based on atomic number.

→ Mendeleev’s Periodic Law: Physical and chemical properties of elements are the periodic functions of their atomic masses.

→ Periods: Horizontal rows in a periodic table are known as periods.

→ Groups: Vertical columns of the periodic table are known as groups.

→ Modern Periodic Law: The physical and chemical properties of elements are the periodic function of their atomic number.

→ Periodicity: Repetition of characteristics of elements in a group is known as periodicity.

→ Atomic Radius: The distance from the nucleus of an atom to its outer shell is known as atomic radius.

→ Valence Electrons: The number of electrons in the valence shell of an atom is known as valence electrons.

→ Ionization Potential: The ionization potential of an element is the minimum energy required to separate an electron from the outermost shell of a gaseous atom of that element.

→ Electron Affinity: The energy released when an electron enters the outermost shell of a neutral gaseous atom is known as electron affinity.

→ Valency is the combining capacity of the element and is equal to either the number of valence electrons or eight minus the number of valence electrons.

→ Lanthanides: Fourteen elements starting from lanthanum having atomic numbers 58 to 71 are called lanthanides.

→ Actinides: Fourteen elements starting from actinium having atomic numbers 90 to 103 are called actinides.

→ Metalloids: Elements that behave both as metals and non-metals are called metalloids.

→ Periodic Properties: These are the properties of an element that are related to the electronic configuration of its atom and change periodically down a group and along a period.

→ Atomic Size: In a period, with the increase of atomic number, there is a decrease in atomic radius. By going from left to right, the atomic number increases, and the size of the atom decreases. This is called atomic size.

→ Representative Elements: The elements of sub-group A are known as representative elements.

→ Need for classification: Elements are grouped based upon similarities in their properties in order to simply and systematically study of the properties of the elements.

Modern Periodic Table: