Atom And Molecule


An atom is the smallest unit into which matter can be divided without the release of electrically charged particles.

It also is the smallest unit of matter that has the characteristic properties of a chemical element.

The atom is the basic building block of all matter.

Atoms are very small, they are smaller than anything that we can imagine or compare with.

More than millions of atoms when stacked would make a layer barely as thick as a sheet of paper.

Most of the atom is empty space.

The rest consists of a positively charged nucleus of protons and neutrons surrounded by a cloud of negatively charged electrons.  More…



BIOLOGY: The Living World


Characteristics of Living Organisms : Growth, reproduction, metabolism, cellular organization, consciousness (ability to sense environment), self-replicating and self regulation.
• Reproduction and growth are NOT defining properties.
• Metabolism, cellular organization and consciousness are defining properties.


Term used to refer to the number of varieties of plant and animals on earth.
Nomenclature: standardize the naming of living organism such that a particular organism is known by the name all over the world.
Identification: nomenclature or naming is only possible when the organism is described correctly and we known to what organism the name is attached to.
Need for classification: To organize the vast number of plants and animals into categories that could be named, remembered, studied and understood.


Rules for Nomenclature

1.Latinized names are used, written in italics
2.First word represents the genus, second word is species name.
3.Printed in italics; if handwritten then underline separately.
4.First word starts with capital letter while species name written in small letter.

ICBN: International Code of Botanical Nomenclature (for giving scientific name to plants.)

ICZN: International Code of Zoological Nomenclature (for giving scientific name to animals.)

Taxonomy: Study of principles and procedures of classification.
Binomial Nomenclature: Given by Carolus Linnaeus. Each scientific name has two components – Generic name + Specific epithet.
Systematics: It deals with classification of organisms based on their diversities and relationships among them. Term was proposed by Carolus Linnaeus who wrote ‘Systema Naturae’.

Taxonomic Hierarchy: Arrangement of various steps (categories or taxa Species → Genus → Family → Order → Class → Phylum (for animals) /Division (for plants) Kingdom→


All the members that can interbreed among themselves and can produce fertile offsprings are the members of same species. This is the bio-logical concept of species proposed by Mayer.
Three Domains of Life: Proposed by Carl Woese in 1990 who also proposed the six kingdom classification for living organisms. The three Do-mains are Archaea, Eubacteria and Eukarya.



Storehouse of dried, pressed and preserved plant specimen on sheets.
Botanical Garden: Collection of living plants for reference.
Taxonomical aids: Zoological Park (Places where wild animals are kept in protected environment.)

• Keys (Used for identification of plant and animals on the basis of similarities and dissimilarities.)
• Fauna: (Index to animal species found in a particular area)
• Flora (Index to plant species found in a particular area.)
• Manuals (Provide information for identification of name of species in an area.)
• Monograph (Contain information on one taxon.)



Fibers And Plastics

Fibers and fabrics play a large role in everyday applications. A fiber is a hair-like strand of material. They are the smallest visible unit of a fabric and are denoted by being extremely long in relation to their width (at least 100 times longer than it is wide). Fibers can be spun into yarn and made into fabrics.

Synthetic fibers are a subset of the larger area of textiles. Textiles can be natural or synthetic. Natural fibers include cotton, fur, wool, etc. Regenerated fibers are natural materials that have been processed into a fiber structure. Regenerated fibers such as cellulose and wood pulp are used to make materials such as rayon and acetate. Synthetic fibers are man made from chemicals. They are generally based on polymers and are stronger than natural and regenerated fibers



These are the most widely used semisynthetic fibres. They are derived from cellulose and are available in three different varieties— viscose, cuprammonium (or cupro) and acetate rayons.



The first synthetic fibre obtained was of this class. Polymers obtained by the reaction between certain sets of organic (carbon-containing) compounds form a melt which can be spun into filaments. The special property of these filaments is that they can be stretched several times their original length. Terylene and Dacron belong to this class of synthetic fibres. Terylene is used to make clothes. In general, polyesters are used to make textiles, bottles and insulating tapes.




Polyamides (nylons):

Nylon 6 and nylon 6, 6 are the most important fibres of this class. Nylon 6 is made of an organic compound which contains six carbon atoms. Nylon 6, 6 is made of a more complicated monomer. Nylon was first made in 1935.


It was intended to be a substitute for silk and was used in place of silk in parachutes in 1941, when the USA entered World War II. Nylon is very suitable for women’s wear. Having a high tensile strength, nylon is also used for making ropes.




Acrylic fibres are a substitute for natural wool. These polymers decompose without melting. So, they are dissolved in a suitable solvent and the solution is forced through spinnerets to obtain filaments. The filaments can be cut into staples and the staples spun into yarns.
Acrylic fibres are crimpy (i.e., wavy) and not straight like polyester or nylon fibres. So acrylic yarns appear to be bulky and compete with wool. They are generally used to make knitwear, upholstery and artificial furs.





Materials that can be reshaped (remolded) by applying heat and pressure. Most plastics are made from synthetic resins (polymers) through the industrial process of polymerization. Two main types of plastics are thermoplastics and thermosets.









Microorganisms are microscopic, living, single-celled organisms such as bacteria. Ubiquitous throughout the world, microorganisms play a vital role in supporting and maintaining nature and life. The vast majority are beneficial: They keep nature clean by removing toxins from water and soil, and degrade organic matter from dead plants and animals. In the human body they aid in digestion and help prevent invasion by harmful bacteria. Without bacteria, life would not be possible. More…





Exponents rules


Exponents are shorthand for repeated multiplication of the same thing by itself. For instance, the shorthand for multiplying three copies of the number 5 is shown on the right-hand side of the “equals” sign in (5)(5)(5) = 53. The “exponent”, being 3 in this example, stands for however many times the value is being multiplied. The thing that’s being multiplied, being 5 in this example, is called the “base”.
This process of using exponents is called “raising to a power”, where the exponent is the “power”. The expression “53” is pronounced as “five, raised to the third power” or “five to the third”.




The Cell,(comes from Latin word cella,meaning “small room”) is the smallest unit of life. It is basic structural,functional, and biological unit of all living organisms.
Cell was discovered by Robert Hooke in 1665.
Cells are often called the “building blocks of life”.
All plants and animals are made of cells.
Organisms are classified as Unicellular (consisting of single cell,such as bacteria) and Multicellular (consisting of multiple cells,such as Plants and Animals).
Number of cells are varies from species to species.Human contains more than 10 trillion cells.
Most of cells are visible only under microscope.

Types of cells
There are two types of cells:
Prokaryotic cells: Single celled organisms.
Doesn’t contains Nucleus.
Eukaryotic cells: Single or multi cellular organisms.
Contains Nucleus.

Prokaryotic cells
The first form of life on Earth.
Prokaryotic cell is a unicellular organism lacking membrane bound organelles.
Most of prokaryotic cells are unicellular.They are generally small in size.
There Nucleur region is not well defined as they lack a Nucleus but it is known as Nucleoid.

Eukaryotic cells
Eukaryot are those organisms whose cells have a Nucleus and other organelles enclosed within membrane.
Eukaryotic organisms may be unicellular or multi-cellular and only Eukaryotes form multi-cellular organisms consists of many kinds of tissue made up of different types of cells.
They are generally larger in size.
Plants and animals cells are Eukaryotic cells.
Contains more than one chromosomes.


All cells posses DNA except for red blood cells.




A microprocessor is a computer processor which incorporates the functions of a computer’s central processing unit (CPU) on a single integrated circuit (IC), or at most a few integrated circuits.

The first use of the term “microprocessor” is attributed to Viatron Computer Systems describing the custom integrated circuit used in their System 21 small computer system announced in 1968. The microprocessor, also known as the Central Processing Unit (CPU), is the brain of all computers and many household and electronic devices.

The computer you are using to read this page uses a microprocessor to do its work. The microprocessor is the heart of any normal computer, whether it is a desktop machine, a server or a laptop. The microprocessor you are using might be a Pentium, a K6, a PowerPC, a Sparc or any of the many other brands and types of microprocessors, but they all do approximately the same thing in approximately the same way.


How Microprocessor work

A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things:

A microprocessor can make decisions and jump to a new set of instructions based on those decisions.

2. Using its ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operations like addition, subtraction, multiplication and division. Modern microprocessors contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.

3.A microprocessor can move data from one memory location to another.