Major themes that unify biology include structure and functioning of cells. It is amazing to know that just 4 (carbon, oxygen, hydrogen and nitrogen) elements constitute 96% of living matter with water as solvent of life.

Major themes that unify biology include structure and functioning of cells which are basic building blocks of all organisms, inheritance of biological information in the form of DNA, unity and diversity of life through evolution, and flow of matter and energy through cycles of life.

It is interesting to understand the hierarchical organization of structures extending from molecules to bio-sphere and how incremental changes add to the changes in properties.

It is amazing to know that just 4 elements constitute 96% of living matter with water as solvent of life. In fact, the above are just a tip of the iceberg. Inside the web pages you will find a whole host of topics ranging from plant form and function to animal form and function, from human physiology to health, from evolutionary biology to ecology, and from biochemistry to molecular genetics. The concepts and principles are well laid with practical examples and visualized with clear graphics for your clarity.

Get ready to travel into the inner world and change the way you look at life and world around.

Cell membranes serve as barriers and gatekeepers The plasma membrane is the boundary that separates the inside of the cell from the outside environment.

Cell membrane controls what can enter and leave as most of the molecular interaction in the cell occur in a water solution and require a fairly narrow range of temperature and acidity.

Protein molecules perform most of the basic functions like DNA replication, repair of cell structures, helping other molecules get in and out of the cell and regulation of molecular interactions. Proteins are a sequence of amino acids (there are about twenty different types of amino acids) and the function of each protein depends on the specific sequence of amino acids it contains and its shape.

Proteins also do various other functions like carrying oxygen, effect contraction and provide material to body structures. They also serve as hormones, antibodies and enzymes.

The single fertilized cell divides and multiplies to form millions of cells. The variation and formation of special cells such as gland cells and nerve cells happens by activating and deactivating different parts of the DNA depending on the differences in the immediate environment of their predecessors. Cell processes are controlled by interaction between different kinds of molecules within the cell and also by molecules from outside the cell like hormones and neurotransmitters. Exposure to chemicals or radiation may affect the functioning of cells.

Human Genome Project- Incredible achievement Human genome project (HGP) – Genome sequencing of Homo sapiens, completed in April 2003. The HGP gave us the ability to, for the first time, to read nature's complete genetic blueprint for building a human being.

One of the great achievements of modern science has been the sequencing of the human genome, which was largely completed by 2003.

Recombinant DNA is a DNA in which nucleotide sequences from different sources - often different species - are combined in vitro into the same DNA molecule. The methods for making recombinant DNA are central to genetic engineering (the direct manipulation of genes for practical purposes).

Scientists can make recombinant DNA and then introduce it into cultured cells that replicate the DNA and express its genes, yielding a desired protein. For example, Golden rice, a genetically modified crop to which has been added a battery of genes that overcome deficiencies in vitamin A and iron, was planted for the first time in Asian fields.

Neurobiologists for the first time caught a glimpse of the molecular basis of learning. DNA technology has launched a revolution in the area of biotechnology, the manipulation of organisms or their components to make useful products.

Animals consume the food synthesized by plants. Plants provide food and shelter for animals, and as they photosynthesize, regulate the levels of oxygen and carbon dioxide in the atmosphere.

Animals inhabit almost every part of the biosphere with their amazing diversity of habitat, form, and function. An exhaustive knowledge of the structure of an animal imparts a lot of information about the various functions it is capable of performing.

Discerning knowledge of animal structure and physiology is obtained by observing the activities of the organ systems, organs, tissues, and cells of animals. Usually animals are extensively used for experiments in scientific laboratories to determine how altered conditions affect its physiological conditions and the results are compared with the human physiological conditions. In addition, the activities of healthy organs are often compared with those of diseased ones.

Much knowledge of human physiology has been obtained by studying animals, as animals form the models for studying human beings. Thus, most aspects of human physiology are closely analogous to corresponding aspects of animal physiology, and animal experimentation has provided much of the foundation of physiological knowledge.

In animal biotechnology, advanced techniques are being used to improve genetics and for pharmaceutical or industrial applications of animals. Molecular biology techniques can help drive breeding programs by directing selection of superior animals. Animal cloning has been the subject of scientific experiments for many years, but didn't prove to be true until the birth of the first cloned mammal in 1997 - a sheep named Dolly. Since Dolly, several scientists have cloned other animals, including cows and mice.

Thus, using recombinant DNA technology, it can be possible to alter the genetic makeup of an organism (including animals) for selected purposes, producing therapeutic proteins in cows and goats, producing transgenic animals and improving the animal variety.

Humans are unique among the earth’s life forms The pattern of human postnatal brain growth differs from that of other apes, and allows for extended periods of social learning and language acquisition in juvenile humans.

Humans are unique among the earth’s life forms in their ability to think, imagine, create, evaluate, learn and apply what they learnt to improve their quality of life by adapting well to the environment they live in. So it is interesting to know about ourselves, our body and our relationship with everything around us.

The human body is a complex system which integrates different organ systems which perform specialized functions. At one end of the spectrum, it includes the study of individual molecules—for example, how a particular protein’s shape and electrical properties allow it to function as a channel for ions to move into or out of a cell.

At the other end, it is concerned with complex processes that depend on the integrated functions of many organs in the body—for example, how the heart, kidneys and several glands all work together to cause the excretion of more sodium in the urine when a person has eaten salty food.