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Matter In Our Surroundings - Chapter 1

States of Matter

Matter can be classified as solid, liquid and gas on the basis of interparticle forces and the

arrangement of particles.

These three forms of matter are interconvertible by increasing or decreasing pressure and

temperature. For example, ice can be converted from solid to a liquid by increasing the

temperature.

Property Solid Liquid Gas

Shape and volume Fixed shape and

volume

No fixed shape but

has volume

Neither definite shape

nor volume

Energy Lowest Medium Highest

Compressibility Difficult Nearly difficult Easy

Arrangement of molecules Regular and closely

arranged

Random and little

sparsely arranged

Random and more

sparsely arranged

Fluidity Cannot flow Flows from higher to

lower level Flows in all directions

Movement Negligible Depends on

interparticle attraction

Free, constant and

random

Interparticle space Very less More Large

Interparticle attraction Maximum Medium Minimum

Density Maximum Medium Minimum

Rate of diffusion Negligible

It depends on

interparticle

attraction.

Maximum

Atomic view of the three states of matter


Solid Liquid

Gas

Evaporation

The phenomenon by which molecules in liquid state undergo a spontaneous transition to

the gaseous phase at any temperature below its boiling point is called evaporation.

For example, the gradual drying of damp clothes is caused by the evaporation of water to

water vapour.

Factors affecting evaporation

Temperature: The rate of evaporation increases with an increase in temperature.

Surface area: The rate of evaporation increases with an increase in surface area.

Humidity: The rate of evaporation decreases with an increase in humidity.

Wind speed: The rate of evaporation increases with an increase in wind speed.

Cooling due to evaporation


During evaporation, the particles of a liquid absorb energy from the surroundings to overcome

the interparticle forces of attraction and undergo the phase change. The absorption of heat from

the surrounding makes the surrounding cool.

For example, sweating cools down our body.

Physical Nature of Matter

A physical property is that aspect of the matter that can be observed or measured without

changing its nature or composition.

It is independent of the amount of matter present.

Physical properties include appearance, colour, odour, density, texture, melting point,

boiling point, solubility, etc.

Characteristics of Particles of Matter

Matter

Matter is anything that has mass and occupies space.

Everything that we can touch, see, hear, taste, and also smell is matter.

It is made up of really tiny particles which cannot be seen through the eye.

The particles of which the matter is comprised of influence its state and properties (physical and

chemical).

1. Particles of matter have spaces between them

This characteristic is one of the concepts behind the solubility of a substance in other

substances. For example, on dissolving sugar in water, there is no rise in water level

because the particles of sugar get into the interparticle spaces between the water particles.

2. Particles of matter are always in motion

Particles of the matter show continuous random movements due to the kinetic energy

they possess.

A rise in temperature increases the kinetic energy of the particles, making them move

more vigorously.

3. Particles of matter attract each other In every substance, there is an interparticle force of attraction acting between the particles. To

break a substance we need to overcome this force. The strength of the force differs from one

substance to another.

Diffusion


When the particles of matter intermix on their own with each other, the phenomenon is

called diffusion. For example, spreading of ink in water.

During diffusion, the particles are occupying the interparticle spaces.

The rate of diffusion increases with increase in the temperature, due to increase in kinetic

energy of the particles.

Can Matter Change Its State?

Effect of change of temperature on state of matter

On increasing temperature, the kinetic energy of the particles of the matter increases and they

begin to vibrate with a higher energy. Therefore, the interparticle force of attraction between the

particles reduces and particles get detached from their position and begin to move freely.

As a result, the state of matter begins to change.

Solids undergo a phase change to form liquids.

Similarly, liquids also undergo a phase change to form gases.

Melting point

The melting point of a solid is defined as the temperature at which solid melts to become

liquid at the atmospheric pressure.

At melting point, these two phases, i.e., solid and liquid are in equilibrium, i.e., at this

point both solid state and liquid state exist simultaneously.

Boiling point

The boiling point of a liquid is defined as the temperature at which the vapour pressure of

the liquid is equal to the atmospheric pressure.

Latent heat of fusion

It is the amount of heat energy that is required to change 1 kg of a solid into liquid at

atmospheric pressure at its melting point.

Latent heat of vaporisation

It is the amount of heat energy that is required to change 1 kg of a liquid into gas at

atmospheric pressure at its boiling point.

Sublimation


The transition of a substance directly from its solid phase to gaseous phase without

changing into the liquid phase (or vice versa) is called sublimation.

Sublimation – Solid to Gas Phase Transformation

Effect of change in pressure on state of matter

By applying pressure, the interparticle spaces between particles of matter decreases. Thus, by

applying pressure and reducing temperature we can convert a solid to liquid and a liquid to gas.

Flowchart for inter-conversion of the three states of matter


Is Matter Around Us Pure - Chapter 2

We do know that matter is made up of particles which are arranged in a certain way. Gases

particles are well separated and can freely move about, solids, on the other hand, have particles

that are tightly packed, usually with no scope to move around.

Purity

Pure substances

Pure substances are elements or compounds.

They are made up of only one kind of entity.

They cannot be broken down into simpler entities by chemical or physical methods.

They have a fixed composition.

Example: Diamond, carbon dioxide, etc.

Mixtures

Mixtures are formed by just mixing two or more pure substances (components) such that

each substance retains its own chemical identity.

Types of mixtures

Types:

1. Homogeneous mixture

A mixture which has a uniform composition throughout is called a homogeneous

mixture or solution.

Examples: sugar in water, salt in water.


Heterogeneous mixture

A mixture which contains physically distinct parts and has a non-uniform composition is

called a heterogeneous mixture.

Examples: Mixture of salt and iron filings, sand and sugar.

Physical vs Chemical Changes

Physical and chemical changes

A substance is said to undergo a physical change when only the physical properties such

as the shape, size, colour or state of the substance change. No new substance is formed.

Example: Melting of ice, boiling water.

A substance is said to undergo a chemical change when a new substance with

completely new properties (physical and chemical) is formed.

Example: Burning of wood or paper, souring of milk.

Solutions

Solutions and their properties

A solution is a homogeneous mixture of two or more substances.

Properties:

Its particles are too tiny and have a diameter less than 1 nm.

The particles are not visible to naked eyes.

Particles don’t scatter a beam of light passing through it and hence do not show the

Tyndall effect.

The solute particles never settle down on keeping undisturbed.

The components of a solution cannot be separated using filtration.

Alloys

Alloys are homogeneous mixtures of metals or a mixture of a metal and another element that

cannot be separated into their components by physical methods.

Examples:

Steel, a combination of iron (metal) and carbon (non-metal).

Bronze, a combination of copper (metal) and tin (metal).

Brass, a mixture of copper (metal) and zinc (metal).


Concentration of Solutions

Solubility

Solubility is the property showing the ability of a given substance, which is the solute, to

dissolve in a solvent.

It is measured in terms of the maximum amount of solute dissolved in a solvent at

equilibrium.

The resulting solution is called a saturated solution.

Factors Affecting Solubility:

Temperature – Solubility increases with temperature. The situation is different for gases.

With the increase in temperature, they became less soluble in each other and in water, but

more soluble in organic solvents.

Pressure – For the majority of solid and liquid solutes, pressure does not affect solubility.

The solubility of gas is directly proportional to the pressure of this gas.

Types of solutions based on the concentration of the solution

Three types of solutions exist based on the concentration of the solution:

Dilute

Concentrated

saturated solution.

Ways of representing the concentration of a solution

The concentration of a solution can be represented in many ways

(i) Mass by the mass percentage of a solution = (Mass of solute / Mass of solution) × 100

(ii) Mass by volume percentage of a solution = (Mass of solute/ volume of solution)×100

Suspensions

Suspension and its properties

A suspension is a heterogeneous mixture in which the solute particles do not dissolve but

remain suspended throughout the bulk of the medium.

The solute particles settle down when a suspension is left undisturbed.

They can be separated from the mixture by filtration.

Colloids


Types of mixtures based on particle size

Classified into:

Solution

Suspension.

colloidal solution.

Colloidal Solutions

A colloidal solution is a mixture in which the substances are regularly suspended in a

fluid.

Classified into: Foam, Emulsion, Sol

Tyndall Effect

Tyndall effect is the scattering of light by particles in a colloid or else particles in a very

fine suspension.

e.g.It can be observed when sunlight passes through the canopy of a dense forest.

Dispersed phase

The solute-like component of the dispersed particles in a colloid form the dispersed phase.

Dispersion medium

The component in which the dispersed phase is suspended is known as the dispersing medium.

Aerosol

A colloidal solution with dispersed phase solid/liquid and dispersing medium gas is

called Aerosol. e.g. clouds

Foam

A colloidal solution with dispersed phase gas and dispersing medium solid/liquid is

called Foam. e.g.Shaving cream.

Sols

A colloidal solution with dispersed phase solid and dispersing medium liquid is called Sol. e.g.

Milk of magnesia, mud.

Gels and emulsions


A colloidal solution with dispersed phase liquid and dispersing medium solid is

called Gel.

A colloidal solution with dispersed phase liquid and dispersing medium liquid is

called Emulsion.

Evaporation

The process of conversion of water into water vapour is known as evaporation.

It can be used to separate the volatile component (solvent) from its non-volatile solute.

Introduction to Separation

Separation of components of a mixture

Heterogeneous mixtures can be separated into their constituents by simple physical

methods.

Methods include: handpicking, sieving, filtration.

Handpicking

Sieving

Separation of Two Immiscible Liquids


Separation of a mixture of two immiscible liquids

Separation of a mixture of two immiscible liquids is done by using a separating funnel.

Applications: To separate a mixture of oil and water, in the extraction of iron from its

ore.

Centrifugation

Centrifugation uses centrifugal force for the separation of two liquids in a mixture.

Here, a denser component of the mixture migrates away from the axis and lighter

component migrates towards the axis.

Sublimation

Sublimation is the transition of a substance from solid phase to gaseous phase without

changing into liquid phase.

Example: Naphthalene balls undergo sublimation.

Solid undergoing sublimation

Chromatography

Chromatography is used to separate the different components in a liquid mixture.

It is based on the different properties of compounds in two phases: stationary and mobile

phase.

Distillation

Distillation is a method for separating the component substances from a liquid mixture

by selective evaporation and condensation.


Used in: Production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene etc.

Fractional Distillation

Fractional Distillation is the separation of a mixture into its component parts or

fractions by their melting points.

This is the process of separation of chemical compounds by their boiling point.

The mixture is heated to a temperature at which one or more fractions will vaporize.

Separation of Air into Its Components

Process of obtaining different gases from the air

Air is a homogeneous mixture and can be separated into its components by fractional

distillation.

Fractional

distillation

Crystallization

Crystallisation is a separation technique in which solids are separated from a solution.

In this technique, the solvent molecules start evaporating, leaving behind the solutes

when the solution is heated in an open container.


Separation

of substances by crystallization technique

Water Purification

Applications of crystallisation

Purification of sea water, separation of alum crystals from impure samples etc.

Elements

Elements are species of atoms which have the same number of protons in their atomic

nuclei.

Elements are represented by symbols e.g.Hydrogen (H), Boron (B), Carbon (C), Silicon

(Si) etc.

Metals

Metal is a solid material which is typically hard, shiny, malleable, fusible, and ductile,

with good electrical and thermal conductivity.

Examples: Aluminium, Copper, Iron, Tin, Gold

Metalloids

Metalloids exhibit some properties of metals as well as of non-metals.


Examples: Boron, silicon, germanium, arsenic, antimony, and tellurium

Compounds

Nonmetals

Non-metals are brittle and are not malleable or ductile.

They are poor conductors of heat and electricity.

Examples: Carbon, Boron etc.

Compounds

Compounds are the substances consisting of two or more different types of elements in a

fixed ratio of its atoms.

Difference between mixtures and compounds

Mixtures are constituted by more than one kind of pure form of matter, known as a

substance.

Types: Homogeneous Mixtures, Heterogeneous Mixtures

When two or more elements chemically combine in a fixed ratio by mass, the obtained

product is known as a compound.


Atoms And Molecules - Chapter 3

Atoms and molecules are responsible for forming tiny sand particles, gargantuan black holes and

everything in between. The atom is the most fundamental unit of matter, making up everything

that we see around us. It is extremely small, measuring in at less than 0.1 to 0.5 nanometers.

Laws of Chemical Combination

Chemical Reactions

In a chemical reaction,two or more molecules interact to produce new compounds and are

called reactants whereas the newly formed compounds are called products.

In a chemical reaction, a chemical change must occur which is generally observed with

physical changes like precipitation, heat production, color change etc.

Law of conservation of mass

According to the law of conservation of mass matter can neither be created nor destroyed

in a chemical reaction. It remains conserved.

Mass of reactants will be equal to the mass of products.

Law of constant proportions

A pure chemical compound contains same elements combined together in a fixed

proportion by mass is given by law of definite proportions.

For e.g. If we take water from river or from an ocean, both has oxygen and hydrogen in

the same proportion.

Atoms

An atom is the defining structure of an element, which cannot be broken by any chemical

means.

The atomic symbol has three parts:-

The symbol X: the usual element symbol

The atomic number A: equal to the number of protons

The mass number Z: equal to the total number of protons and neutrons in an element.

Dalton’s Atomic Theory

1. The matter is made up of indivisible particles known as atoms.


2. The properties of all the atoms of a given element are same including mass. This can also

be stated as all the atoms of an element have identical mass and chemical properties;

atoms of different elements have different masses and chemical properties.

3. Atoms of different elements combine in fixed ratios to form compounds.

4. Atoms are neither created nor destroyed. The formation of new products (compounds)

results from the rearrangement of existing atoms (reactants) in a chemical reaction.

5. The relative number and kinds of atoms are constant in a given compound.

Dalton’s Atomic Theory

Atomic Mass

Atomic mass and atomic mass unit

Atomic mass is the total of the masses of the electrons, neutrons, and protons in an atom,

or in a group of atoms, the average mass.

Mass of an atomic particle is called the atomic mass.

This is commonly expressed as per the international agreement in terms of a unified

atomic mass unit (amu).

It can be best defined as 1/12 of the mass of a carbon-12 atom in its ground state.

Molecular mass

Molecular mass of an element is defined as the sum of the masses of the elements present

in the molecule.


Molecular mass is obtained by multiplying the atomic mass of an element with the

number of atoms in the molecule and then adding the masses of all the elements in the

molecule.

Mole Concept

Mole concept & Avogadro Number

In a substance, the amount of entities present for e.g.atoms, molecules, ions, is defined as

a mole. A mole of any substance is 6.022×1023 molecules.

Mole concept is one of the most convenient ways of expressing the amount of reactants

and product in the reaction.

The value of Avogadro’s number is approximately 6.022×1023. The definition of Avogadro’s

number is that it tells us the number of particles in 1 mole (or mol) of a substance. These

particles could be electrons or molecules or atoms.

Mole and Mass

Molar mass

A substance is something which has mass and occupies space. The molar mass/molecular

weight is actually the sum of the total mass in grams of the atoms present to make up a

molecule per mole. The unit of molar mass is grams/mole.

Atomic Valency

Molecules and Atomicity

A molecule is defined as the smallest unit of a compound that contains the chemical

properties of the compound.

The atomicity of an element is the number of atoms in one molecule of the element.

For e.g:- Hydrogen, nitrogen, oxygen, chlorine, iodine, bromine all have two atoms in

each of their molecules. So, the atomicity of hydrogen, nitrogen, oxygen, chlorine,

iodine, bromine is two each.

Structure of atom

Atom is made of three particles; electron, proton and neutron.

The centre of the atom is called the nucleus. The nucleus of an atom contains the whole

mass of an atom.

Electrons in an atom are arranged in shells/orbitals.


Valency

Valence electrons are those electrons which are present in the outermost orbit of the

atom.

The capacity of an atom to lose, gain or share valence electrons in order to complete its

octet determines the valency of the atom.

Writing Chemical Formulae

Compounds

When two or more elements chemically combine in a fixed ratio by mass, the obtained

product is known as a compound.

Compounds are substances consisting of two or more different types of elements in a

fixed ratio of its atoms.

Ions


An ion is defined as an atom or molecule which has gained or lost one or more of its

valence electrons, giving it a net positive or negative charge.

A negatively charged particle is called an anion and a positively charged particle is called

cation.

Ionic compounds: chemical formula

Ionic compounds are chemical compounds in which ions are held together by specialised

bonds called ionic bonds.

An Ionic compound always contains an equal amount of positive and negative charge.

For example: In Calcium chloride, the ionic bond is formed by oppositely charged

calcium and chloride ions.

Calcium atom loses 2 electrons and attains the electronic configuration of the nearest

noble gas (Ar). By doing so, it gains a net charge of +2.

The two Chlorine atoms take one electron each, thus gaining a charge of -1 (each) and

attain the electronic configuration of the nearest noble gas (Ar).


Structure Of The Atom - Chapter 4

Essentially, the structure of an atom comprises of protons, neutrons and electrons. These basic

components provide the mass and charge of the atoms. The nucleus comprises of proton and

neutron, with the electron orbiting around that.

Introduction to Structure of an Atom

Atoms

Atoms are the building blocks of matter. It is the smallest unit of matter that is composed

of three sub-atomic particles: the proton, the neutron, and the electron.

Cathode ray experiment

J. J. Thomson discovered the existence of electrons.

He did this using a cathode ray tube, which is a vacuum-sealed tube with a cathode and

anode on one end that created a beam of electrons travelling towards the other end of the

tube.

The air inside the chamber is subjected to high voltage and electricity flows through the

air from the negative electrode to positive electrode.

The characteristics of cathode rays (electrons) do not depend upon the material of

electrodes and the nature of the gas present in the cathode ray tube.

The experiment showed that the atom was not a simple indivisible particle and contained

at least one subatomic particle – the electron.

Apparatus of the experiment


Electrons

Electrons are the negatively charged sub-atomic particles of an atom.

The mass of an electron is considered to be negligible and its charge is -1.

The symbol for an electron is e–

Electrons are extremely small.

They are found outside the nucleus.

Thomson’s model of an atom

According to Thomson,(i) An atom consists of a positively charged sphere and the

electrons are embedded in it.(ii) The negative and positive charges are equal in

magnitude. So, the atom as a whole is electrically neutral

First model of an atom to be put forward and taken into consideration.

He proposed a model of the atom to be similar to that of a Christmas

pudding/watermelon.

The red edible part of the watermelon is compared with the positive charge in the atom.

The black seeds in the watermelon are compared with the electrons which are embedded

on it.

Radioactivity

Radioactivity

Radioactivity is the term for the process by which an unstable nucleus of an atom loses

energy by giving out particles.

It does so by giving out particles such as alpha and beta particles.

This process is spontaneous.

An atom is unstable if the nucleus has an imbalance, meaning a difference in the protons

and neutrons.


Rutherford Model

Rutherford’s experiment and observations

In this experiment, fast moving alpha (α)-particles were made to fall on a thin gold foil. His

observations were:

A major fraction of the α-particles bombarded towards the gold sheet passed through it

without any deflection, and hence most of the space in an atom is empty.

Some of the α-particles were deflected by the gold sheet by very small angles, and hence

the positive charge in an atom is not uniformly distributed.

The positive charge in an atom is concentrated in a very small volume.

Very few of the α-particles were deflected back, that is only a few α-particles had nearly

180o angle of deflection. So the volume occupied by the positively charged particles

in an atom is very small as compared to the total volume of an atom.

Rutherford’s model of an atom

Rutherford concluded the model of the atom from the α-particle scattering experiment as:

(i) There is a positively charged centre in an atom called the nucleus. Nearly all the mass of an

atom resides in the nucleus.

(ii) The electrons revolve around the nucleus in well-defined orbits.

(iii) The size of the nucleus is very small as compared to the size of the atom.


Rutherford’s Model

Drawbacks of Rutherford’s model

He explained that the electrons in an atom revolve around the nucleus in well defined

orbits. Particles in circular orbit would experience acceleration.

Thus, the revolving electron would lose energy and finally fall into the nucleus.

But this cannot take place as the atom would be unstable and matter would not exist in

the form we know.

Be More Curious!!!

The Millikan’s Oil Drop Experiment was an experiment performed by Robert A.

Millikan and Harvey Fletcher in 1909 to measure the charge of an electron.

In the experiment, Millikan allowed charged tiny oil droplets to pass through a hole into

an electric field.

By varying the strength of electric field, the charge over an oil droplet was

calculated which always came as an integral value of ‘e.’

The conclusion of this is that the charge is said to be quantized, i.e. the charge on any

particle will always be an integral multiple of e which is 1.6*10-19


Neil Bohr Model

Properties of electrons, protons, and neutrons

Bohr’s Model of an atom

Bohr came up with these postulates to overcome the objections raised against Rutherford’s

model:

Electrons revolve around the nucleus in stable orbits without emission of radiant energy.

Each orbit has a definite energy and is called an energy shell or energy level.

An orbit or energy level is designated as K, L, M, N shells. When the electron is in the

lowest energy level, it is said to be in the ground state.

An electron emits or absorbs energy when it jumps from one orbit or energy level to

another.

When it jumps from a higher energy level to lower energy level it emits energy while it

absorbs energy when it jumps from lower energy level to higher energy level.


Bohr’s Model

Orbits

Orbits are energy shells surrounding the nucleus in which electrons revolve.

Electron distribution in different orbits

The distribution was suggested by Bohr and Bury;

The maximum number of electrons present in a shell is given by the formula 2n2, where

‘n’ is the orbit number or energy level index, 1,2,3,….

The maximum number of electrons in different shells are as follows: the first orbit will

have 2*12=2, the second orbit will have 2*2Msup>2=8, the third orbit will have 2*32=18,

fourth orbit 2*42=32 and so on.

The shells are always filled in a step-wise manner from the lower to higher energy levels.

Electrons are not filled in the next shell unless previous shells are filled.

Valency


The electrons present in the outermost shell of an atom are known as the valence

electrons.

The combining capacity of the atoms or their tendency to react and form molecules with

atoms of the same or different elements is known as valency of the atom.

Atoms of elements, having a completely filled outermost shell show little chemical

activity.

Their combining capacity or valency is zero.

For example, we know that the number of electrons in the outermost shell of hydrogen is

1 and in magnesium, it is 2.

Therefore the valency of hydrogen is 1 as it can easily lose 1 electron and become stable.

On the other hand, that of magnesium is 2 as it can lose 2 electrons easily and also

attain stability.

Atomic Number

The number of protons found in the nucleus of an atom is termed as the atomic number. It is

denoted by the letter ‘Z’.

Mass number and representation of an atom

Protons and neutrons are present in the nucleus, so the mass number is the total of these protons

and neutrons.

Isotopes and Isobars

Isotopes are defined as the atoms of the same element, having the same atomic number ( number

of protons ) but different mass numbers ( number of protons+neutrons ).

For example: In the case of Hydrogen we have:


Atoms of different elements with different atomic numbers, which have the same mass number,

are known as isobars.

For example, Calcium and Argon: both have the same mass number – 40

20Ca40 and 18Ar40

Calculation of mass number for isotopic elements

When an element has an isotope, the mass number can be calculated by the different proportions

it exists in.

For example take 98% Carbon-12u and 2% Carbon-13u

This does not mean that any Carbon atoms exists with the mass number of 12.02u. If you take a

certain amount of Carbon, it will contain both isotopes of Carbon and the average mass is 12.02

u.


The Fundamental Unit Of Life - Chapter 5

Life, as we know it, took billions of years to evolve. From the very first precursor of life to the

multitude of multicellular organisms that we see around us today, the most basic unit of all these

is the cell.

Introduction to Fundamental Unit of Life

All About Cells

Cells are the basic structural and functional unit of life. Cell was discovered by Robert Hooke. A

number of cells can work together to form tissues and organs.

Cellular respiration

Cellular respiration is the process by which the food releases energy in the mitochondria. Cells

absorb glucose from the food and burn it to produce energy.

Structural Organization of Cells

Prokaryotic & Eukaryotic cells

Two types of cell; Prokaryotic and Eukaryotic cells. Prokaryotic cells are primitive and lack well

defined nucleus. Eukaryotic cells are more advanced and have well defined nucleus.

Cell structure in Eukaryotic cells

Eukaryotic cells have the most well defined structure. These cells have cell membrane,

membrane bound cell organelles and a well defined nucleus. The nucleus has its own membrane

called nuclear membrane.

Cell membrane

Cell membrane is the outer covering of a cell.

It is made up of phospho-lipid bilayer membrane.

It is selectively permeable in nature.

The structure of cell membrane is best described by the fluid mosaic model.

Diffusion

The movement of molecules from a region of their high concentration to a region of their lower

concentration is known as diffusion.

Osmosis in selectively permeable membrane

Osmosis is the movement of water across a semi-permeable membrane. Osmosis is a selective

process since the membrane does not allow all molecules to pass through it. Water is usually the


only free flowing molecule across this membrane.

Isotonic, hypotonic solutions, hypertonic solutions

Isotonic solutions are those which have the same solute and pH concentration as the

surrounding body fluid or the cytoplasm.

Hypotonic solutions contain lesser amount of solute concentration compared to the

surrounding fluid and can force the cell to rupture due to excess input of water into the

cell.

Hypertonic solutions contain higher concentration of solute compared to the surrounding

fluid and thus push water out of cell, shrinking it.

Cell walls in plants

Plant cells are different from animals cells due to the presence of cell wall. Cell wall is made of

cellulose and gives a rigid structure to the plant cell.

Cell Organelles

Endocytosis

Endocytosis is the invagination of cell membrane, followed by pinching off forming a membrane

bound vesicle. This is commonly seen in Amoeba.

Nucleus in cells

Nucleus is the processing unit of the cell. It is a double membrane bound organelle which

contains the genetic material for inheritance.

Chromosomes

During the growth phase of the cell, the chromatin condenses into much thicker structure called

chromosome.

Chromatin

Chromatin is a thread like structure which serves as the genetic material present inside the

nucleus of the cell. It is made up of DNA and protein molecules. The DNA contains the

hereditary information needed for the structure and function of the organism.

Cytoplasm

Cytoplasm is the fluid found inside the cell. It gives the structure to the cell and houses different

organelles of the cell.

Organelles


Organelles are structures present in the cytoplasm of the cell that help in several functions of the

cell.

Endoplasmic Reticulum

Endoplasmic reticulum is membrane like cell organelle that plays an integral role in the

interpretation of the genetic information present in the nucleus.

Rough ER

Rough ER are the ones that have ribosomes on it. The ribosome is made up of nucleic acids and

proteins. They are the site of protein synthesis. The Rough ER is also involved in the

modification and folding of protein.

Smooth ER

Smooth ER do not have ribosomes and thus are not involved in protein synthesis. They are

however involved in the lipid metabolism and detoxifying poisonous molecules.

Golgi Apparatus

Golgi Apparatus is also called the post office of the cell. They package and transport the proteins

across the cytoplasm.

Lysosomes

They are referred to as suicide bags of the cell as they contain potent enzymes that can digest a

cell. Lysosome also help in defense by attacking a foreign object.

Mitochondria

Mitochondria are also called power plant of the cell. They generate ATP via the electron

transport chain. They also have a DNA called mtDNA, which makes them semi-autonomous

organelle.

Plastids

There are various types of plastids in different cells based on the pigment they contain. The

chloroplast is the plastid where the photosynthesis occurs. Some of the other plastids are

leucoplast and chromoplast.

Vacuoles

Vacuoles are large vesicles that hold water or air in them and give structural rigidity to the cell.

Vacuoles are common in plant cells. In animals the vacuoles are either very small or absent.


Comparison between plant & animal cells

Plants cells are different from animals cells structurally. Plant cells have cell wall and chloroplast

which are missing in animals cells. Plants cells also have large vacuoles which are either very

small or missing in animal cells. The nucleus is present at the center of the cell in animal cells

and at the periphery in plant cells.

matter in our surroundings - chapter 1 9 ch 1 to 5.pdf · mount litera zee school matter in our...

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