(a) Crystallization or evaporation
(b) Sublimation
(c) Centrifugation or sedimentation
(d) Chromatography
(e) Centrifugation
(f) Separating funnel
(g) Filtration
(h) Magnetic separation
(i) Winnowing
(j) Centrifugation

Differences between plant cell and animal cell are given below:
Plant Cell
1. The outermost covering of the plant cell is the cell wall which is formed of cellulose. It is present around plasma membrane.
2. Plastids (e.g., chloroplast) are present.
3. Large vacuole is present.
4. Centrioles are absent but polar caps help in the formation of spindle apparatus during cell division.
Animal Cell
1. The outermost covering is the plasma membrane.
2. Plastids are absent
3. Vacuoles are either absent or are small in size.
4. Centrioles are present within centrosome which help in the formation of spindle apparatus during cell division.

Mitochondria are rod-shaped cell organelle found in the cytoplasm. Each mitochondrion (singular of mitochondria)is a double membrane bounded structure. The outer membrane of mitochondrion is smooth and porous. But the inner membrane of the mitochondrion is folded inwardly, into the matrix of mitochondrion forming finger-like projections. The inward finger-like prajections of inner membrane are called cristae. Cristae increase the surface area of the inner membrane considerably for ATP generating chemical reactions. Mitochondria also contain extra-nuclear DNA and ribosomes.

Functions of Lysosomes:
(i) Extracellular digestion. Sometimes lysosome enzymes are released outside the cell to break down extracellular materials.
(ii) Digestion of foreign material. Lysosomes also destroy any foreign material which enters inside the cell such as bacteria.
(iii) Cellular digestion. In damaged cells, ageing cells or dead cells lysosomes get ruptured, and enzymes are released. These enzymes digest their own cell.
Lysosomes contain about 60 hydrolytic enzymes. Allthe enzymes do not occur in the same lysosome but there are different sets of enzymes in different types of lysosomes. When the cell gets damaged, lysosomes burst and their enzymes digest their own cell. So, lysosomes are called 'suicidal bags'.
Foreign materials entering the cell, such as bacteria or food, as well as old organelles end up in the lysosomes, which brealk them up into small pieces.

Golgi apparatus is also known as Golgi body or Golgi complex. It consists of a set of smooth, flattened membranous sac like structures called Cisternae. These are placed one above the other (stacked) in parallel rows. These membranes often have connections with the membranes of ER.
On the outer edge of cisternae (stacks of membrane), tubules and vesicles (small sacs) are present.In plant cells, the Golgiapparatus consists of many distinet units called dietyosomes.

Endoplasmic Reticulum. It is a large network of membrane bound tubes and sheets, enclosing a fluid-filled lumen. Its main functions are:
(i) Synthesis of proteins (RER).
(ii) Synthesis of lipids and other metabolic products and their secretions (SER).
(iii) Helps in formation of cell plate and nuclear membrane during cell division.
(iv)ER also produces substances for new cellular parts (especially cell membrane).
(v) ER provides internal support (Mechanical support) to the colloidal cytoplasmic matrix of the cell.
(vi) It provides a large surface inside the cell for various physiological activities.
(vii) ER keeps the various cell organelles in their position.
(viii)ER acts as a means of quick intracellular transport.
(ix) Smooth Endoplasmic reticulum (without ribosomes) is the site for membrane assembly.

Prokaryotic Cell
1. Cell size is generally small (1-10 um).
2. Nucle ar region called nucleoid is not surrounded by a nuclear membrane.
3. Only a single chromatin (DNA) is present.
4. Nucleolus is absent.
5. Membrane bound cell organelles are absent.
6. Celldivision by fission or budding (no mitosis).
Eukaryotic Cell 
1. Cell is generally large (5-100 um).
2. Chromatin material is surrounded by a nuclear membrane.
3. Different organisms have variable number of chromosomes present in the nucleus.
4. Nucleolus is present
5. Cell organelles bounded by membrane are present
6. Cell division mitotic or meiotic.

It performs the following functions in the plant cell:
(i) It gives a definite shape to the cell.
(ii) It provides rigidity and strength to the cell.
(iii) It protects the protoplasm and inner cell organelles against mechanical injury.
(iv) It allows cells of plants, fungi and bacteria to withstand very dilute external media or solutions without bursting.
(v) )It helps in transport of the materials in and out of the cell depending on the permeability of the cell.
(vi) Cell wall maintains the shape of the cell when cytoplasm shrinkes away from cell wall during plasmolysis.
(vii) It prevents desiccation of cells.
(viii) It reduces loss of water through transpiration.
(ix) It counteracts osmotic pressure.

Hypotonic solution
1. External solution having higher concentration of water than the cell cytoplasm is known as hypotonic solution.
2. Cell gains water and swells up in this solution.
Isotonic solution
1. External solution having exactly the Same concentration of water as that of cell cytoplasm is called isotonic solution.
2. Cell size does not alter
Hypertonic solution
1. External solution having lower concentration of water than the cell cytoplasm is called hypertonic solution.
2. Cell shrinks in this solution by losing water from cytoplasm.

Osmosis
Osmosis is the passage of water from a region of high water concentration through a semi
permeable membrane to a region of low water concentration.
Diffusion
The process of spontaneous movement of a substance from a region of its high concentration to the region where its concentration is low is called diffusion.

The following three things could happen:
(i) If the solution surrounding the cell is very dilute than cytoplasm, the water will move into the cell, i.e., the cell will gain water by endosmosis.
(ii) If the solution has exactly similar water concentration as that of cytoplasm of cell, will be no net movement of water across the cell membrane, i.e., no gain or loss of water for the cell.
(iii) If the medium (solution) has a lower concentration of water than the cell, i.e., the solution is concentrated, the cell will lose water by exosmosis.

Given below is a comparison of two types of changes:

(i) Composition and properties of fruit initially are entirely different than those after ripening of fruit. It cannot be reversed. Hence, it is a chemical change.
(ii) Crystallization of a substance is a physical change because there is no change in composition and chemical properties of the substance. The crystallized substance can again be made into solution.
(iii) Curd and milk have entirely different properties and curd cannot be changed to
milk. Hence it is a chemical change.
(iv) Separation of gases from air is a physical change because separated gases can again be mixed.

(a) (i) Rigidity. It is a property of matter which signifies least compressibility or change in volume or shape.
(ii) Diffusion. It is a property of matter by which one substance gets mixed with one other. This arises due to the movement of particles of matter.
(iii) Compressibility. It is a property of matter which gives effect of pressure on the matter.
(b) (i) Rigidity. g < l < s
(ii) Diffusion. s < l < g
(iii) Compressibility. s < l < g
(c) Spreading of smell of perfume throughout the room when opened in a corner of the room.

Comparison of properties of true solution, colloidal solution and suspensionTest of a colloidal solution or a suspension. (i) A colloidal solution is turbid and particles settle down on adding a salt. In a suspension, particles settle down on keeping under the influence of gravity.
(ii)If the particles in a heterogeneous and opaque solution can be seen with naked eyes and get settled on keeping, then it is a suspension.

A colloidal solution is said to be intermediate state of the solution and the suspension. It is neither a true solution nor a suspension. In colloidal solution, the particle size is between 1 nm to 100nm. For example, a solution of soap in water, milk, blood, writing inks are some of the colloidal solutions. Though these particles are 10 to 1000 times the size of a single small molecule, these are not visible to naked eyes. But these are large enough to scatter the light that passes through the dispersion medium. The medium of colloidal solution is known as dispersion phase (dispersion medium) and the particles dissolved are called dispersed phase. In milk, water is dispersion phase and fats, proteins etc. are dispersed phase. In fog, water droplets form the dispersed phase and air is dispersing medium.

A suspension is a heterogeneous mixture of a solid in a liquid. A suspension is formed when a liquid contains Small solid particles which are not soluble in it but are visible to maked eyes. If such a mixture is left undisturbed, the solid particles slowly settle down to the bottom under the effect of gravity. If the particle size of the solid is greater than 101 metres (100 nm) and it is insoluble in the given liquid, then the solid particles remain suspended in the liquid. This is called a suspension. For example, mud water, sand water, coarse lime stone particles in water.

A - Liquefaction
B - Vaporisation
C - Condensation
D - Sublimation

(a) Naphthalene has the property of sublimation. So even at room temperature it evaporates to vapours.
(b) The molecules of a gas are continuously moving at random either striking among themselves or with the walls of the container. The pressure on the walls of container is the force per unit area with which the moving gas particles strike per unit area of the containing vessel.

Generally matter changes its state on heating from solid to liquid and from liquid to gas. However, there are some substances that change directly from solid state to gaseous state and vice versa. This change of state from solid to gas without changing into liquid state or vice versa is called sublimation. For example, camphor and ammonium chloride on heating change directly into vapours.

Various points of distinction between a chemical compound and a mixture are summarised below:

On heating a solid substance and then cooling the vapours finally formed we can show that the three states of matter are interchangeable. For example, take ice-crystals in a beaker and heat. Ice changes into water. On further heating water changes into steam. On cooling, water vapour again changes into water and water to ice.

(i) Liquid diffusing into solid. If we put a drop of ink on the centre of a clean blotting paper, we find the liquid spreads out by diffusing into the blotting paper which is a solid.
(ii) Solid diffusing into liquid. When we put a crystal of potassium permanganate in water, slowly the colour of potassium permanganate spreads throughout water.
(iii) Diffusion of solid into a solid. Diffusion of solids into solids is very very slow. So diffusion of a solid into other solids is rare and very small. When we write on a blackboard with a chalk, we can easily clean it. But if it is uncleaned for a few days, it becomes difficult to clean the blackboard. This is because there is a slight diffusion of chalk particles i.e., solid into the solid blackboard.

Particles of matter are always in a state of motion. They move to interact with other particles and distribute themselves equally in all available space. This intermixing of particles of two substances on their own is called diffusion. Particles of a gas diffuse taster than particles of a liquid.
Example: Light an agarbatti in one corner of the room, and stand in the other corner. Very soon, you will feel smell of agarbatti. The particles of perfume in the agarbatti stick mix with particles of air and spread out eventually and reach to us even at a distance. This is due to diffusion of agarbatti particles into particles of air.

(i) Compound microscope.
(ii) 1. Eye piece 2. Fine adjustment screw 3. Coarse adjustment screw.
(iii) Under 10X objective (low power objective).

(a) Saturated solution. A solution in which no more of the solid (solute) can be dissolved at a given temperature is called a saturated solution. Suppose 40 g of a solute is the maximum amount that can be dissolved in 100 g water at 298 K. Then (100 + 40) g. of solution so obtained is the saturated solution at 298 K.
(b) Pure substance. The substances, which always have the same colour, taste or texture at a given temperature and pressure are pure substances. A pure substance has a characteristic melting point or boiling point at a given pressure. For example, pure water is always colourless, odourless and tasteless and boils at 373 K at normal atmospheric pressure.
(c) Colloid. The particles of a colloid are uniformly spread throughout the solution. A colloid has the following characteristics:
(i) It is a heterogeneous mixture.
(ii) The size of particles of a colloid lies between 1- 100nm and are not visible to naked eye.
(iii)The particles of a colloid can scatter a beam of light.
(iv) The particles of a colloid cannot be separated from the mixture by filtration.
(v)The particles of a colloid do not settle when left undisturbed.
Examples are smoke, milk, fog, cloud.
(d) Suspension. A suspension has the following characteristics:
(i) It is a heterogeneous mixture.
(ii) The particles of a suspension are greater than 100 nm and are visible to naked eve.
(iii)The particles of a suspension can scatter a beam of light.
(iv) The particles of a suspension settle down when left undisturbed for some time.
(u) The particles of a suspension can be separated from its mixture by filtration.
Examples - Fine clay particles in water.

If the size of the particles of the solute (also called dispersed 1nm and 100 nm and the particles remain suspended in the dispersing medium, then these are called colloids. Their solutions are known as colloidal solutions. The colloids exhibit the following characteristic properties:
(i) Brownian motion. Colloidal particles move at random in zig-zag paths like gas particles. This is called Brownian motion. This type of motion is caused due to the collisions between the particles of the dispersion medium and the dispersed phase.
(ii)Tyndall effect. When strong beam of light is passed through a true solution taken in a beaker placed in a dark room, the path of light through the solution is dark. But if the light is passed through a colloidal solution under conditions as above, the path of light through the colloidal solution becomes visible. This is called Tyndall effect. The colloidal particles become illuminated because they scatter the light falling on them in all directions.(iii) Electrophoresis. When an electric current is passed through a colloidal solution, the particles move either towards the positive or negative electrode. This phenomenon is known as electrophoresis. By the direction of the movement of colloidal particles, we can know the nature of the charge on them.

1. Cell membrane.
2. (i) Prokaryotes lack membrane-bound cell organelles.
(ii) Nuclear region is poorly defined in prokaryotes. Examples are Bacteria and Cyanobacteria.
3. (i) Eukaryotes have nuclear membrane around chromatin material so nucleus is well defined.
(ii) Cell organelles are enclosed in membrane in eukaryotes. Examples are Man, Tulsi, Banyan tree etc.
4. Differences between prokaryotes and eukaryotes:
Prokaryotic Cell
1. Cell size is generally small (1-10 um).
2. Nuclear region called nucleoid is not surrounded by a nuclear membrane.
3. Only a single chromatin (DNA) is present.
4. Nucleolus is absent.
5. Membrane bound cellorganelles are absent.
6. Celldivision by fission or budding (no mitosis)
Eukaryotie Cell
1. Cell is generally large (5-100 um).
2. Chromatin material is surrounded by a nuclear membrane.
3. Different organisms have variable number of chromosomes present in the nucleus.
4. Nucleolus is present.
5. Cell organelles bounded by membrane are present.
6. Cell division mitotic or meiotic.

1.Bark of a tree. It is dead tissue. Bark is composed of cork, cork cambium and cork cortex. Both cork and bark differ in their structure and function. Cork acts as protective layer while bark helps in storage and transport.
2.Robert Hooke, in 1665. He observed cells through a self designed microscope. It was chance observation.
3. Cell
4. Cork is formed during secondary growtlh from cork cambium. It protects the internal parts of the plant.