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Biology online - Study biology topics and its major themes

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It is an exciting time to study biology! It is an exciting time to study biology! Biology has brought an enormous insight into the dynamic interactions of the millions of species existing on our planet.
The wonders of the inner world

Journey into the world of plants, animals and humans

The study of natural phenomenon is exciting. Acquiring proficiency in the language of science is exciting. Well, the study of life in its varied forms, shapes, sizes, and colors is fascinating.

Look around and the diversity offered by life is staggering in scope: microbe to cell, cactus to orchid, butterfly to bald eagle, penguin to a seal and dolphin to human. Understanding the evolution, the structure, and function of varied species and how they live, behave and relate to each other is what biology is about.

Major themes that unify biology 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 of Biology

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.

Humming birds- Magic in the air Humming birds- Magic in the air The humming bird, which is an excellent manager of it's resources uses the chemical energy stored in its food to power flight and other work.
Unity and diversity of life

Welcome to the fascinating study of life in its varied forms and colors. The diversity of life is expressed and seen through beautiful orchids, butterflies, colorful fish and cool penguins.

Biology is the scientific study of life that enables us to understand how the great diversity of life on earth evolved from the first microbe, the structure and function of different species and how they live, behave and relate to each other in their living environment.

Biology is a multi disciplinary science as the organisms and the world they live in are natural systems to which basic concepts of chemistry and physics apply. Living organisms are made of the same elements like any other matter, involve the same kind of energy transformations and move with same kind of forces. However there are special properties that encompass study of life such as regulation, energy processing, reproduction, growth and development.

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 molecules from one generation to the next, unity and diversity of life through evolution, interdependence of organisms with their environment and the flow of matter and energy through cycles of life.

Biological organization Biological organization Hierarchical organization of structures extending from molecules to biosphere
Biological organization

The living world is a hierarchical organization of structures extending from molecules to biosphere. System properties emerge out of interaction between components at the lower level while additional properties emerge at each successive level. The lowest level is the ordering of atoms into molecules and the interactions of molecules in a cell.

The essential elements of life are about twenty five and just four elements namely carbon, oxygen, hydrogen and nitrogen constitute ninety six percent of living matter with water as the solvent of life. Iron, Phosphorous, sulfur, calcium, sodium, potassium, iodine and a few others constitute the remaining four percent.

Biochemistry is the chemistry of life as it deals with study of life molecules that make up cells (proteins, carbohydrates and lipids), those that play key roles in chemical reactions vital to life (e.g., nucleic acids, vitamins, and hormones) and with many other complex and interrelated chemical changes and processes that occur in organisms.

Each of us is a universe of our living cells Each of us is a universe of our living cells A cell, the basic unit of life, is a microscopic structure that forms the basic structural as well as functional unit of living organisms.
Cell - The fundamental unit of life

All life forms are composed of cells. The number may vary from a single cell in Bacteria to trillions of cells in a human body. Many of the basic activities of life such as protein synthesis, extraction of energy from nutrients and replication are carried out in cells. In multi-cellular organisms some cells perform special functions. Gland cells secrete hormones, muscle cells contract and nerve cells conduct electrical signals.

A closer look at the sun flower reveals the highly ordered structure that characterizes life. Sunflowers grow well in full Sun by converting solar energy into chemical energy of food and in the bud stage exhibit heliotropism by tracking the Sun from east to west, while at night they return to an eastward orientation.

This motion is performed by motor cells in the pulvinus, a flexible segment of the stem just below the bud.

Cell membranes serve as barriers and gatekeepers 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 - A selective barrier

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.

Central dogma of molecular biology Central dogma of molecular biology (DNA – mRNA - Protein) The central dogma of molecular biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins.
Inheritance & Molecular Biology

Biology has undergone enormously impressive changes since the developmental contributions of Watson and Crick introduced the era of molecular biology. James D. Watson and Francis Crick were the two co-discoverers of the structure of DNA in 1953.

The more expositive aspects of the field, long associated with the older notion of biology as natural history, have been complemented by investigative insights that afford an understanding of life in terms of the precise characteristics of macromolecules (DNA, RNA and protein).

To a marked extent, control of cell functions, hereditary mechanisms, development of organisms, interactions between organisms and environment (ecology) and even evolution has become better understood by applying the probes of molecular biology.

However, the scope of life and its evolving new diversity needs a perspective of time and an appreciation of meticulous descriptive detail to be truly appreciated. One of the many values of the science of biology is that it opens our eyes to the hidden connections that link human beings to all other living things.

Continuity of life depends on the inheritance of biological information in the form of DNA molecules. The information is coded in thousands of discrete genes which are different segments of a DNA molecule, and DNA molecules as part of chromosomes are embedded in the cells.

In sexual reproduction male and female sex cells fuse during fertilization and thereby carry the genetic information with a combination one half from each parent. The sorting and combination of genes is due to independent assortment of chromosomes and crossing over during meiosis, and random fertilization occurs. In humans, the possible combinations are over seventy trillion.

Human Genome Project 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.
Greatest achievement of Molecular Biology

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.

Light of Evolution! Nothing in Biology makes sense except in the light of Evolution! Evolutionary biology provides the key to understanding the principles governing the origin and extinction of species.
Evolutionary biology

Evolutionary biology deals with the study of organisms' evolution in response to changes in the environment as well as their relationship with other organisms. Life existed on earth for about three billion years and during the first two billion years microorganisms like bacteria existed. Multi celled organisms evolved about a billion years ago with the development of cells with nuclei.

Natural selection caused organisms with inherited advantage for survival and reproduction to grow faster. The process of natural selection in a changing environment over millions of years produced a succession of diverse new species.

Bioinformatics made it possible to trace the evolution of a large number of organisms by measuring changes in their DNA. Evolutionary algorithms made available from Bioinformatics are now used to solve multi-dimensional problems more efficiently and also to optimize the design of systems.

Molecular biology Molecular biology was born in the laboratories of microbiologist, studying microbes. Bacteria and Viruses are the molecular models for studying genomic sequences.
Microbes, Plants & Animals

Microbiology is the study of microorganisms. Molecular biology was born in the laboratories of microbiologists studying viruses and bacteria. Microbes are molecular models for studying genetics and molecular biology. For example, bacteria such as E. coli (Escherichia coli is one of a number of microorganisms which are normal inhabitants of the colons of virtually all warm-blooded mammals) and its viruses are extensively used in molecular studies.

Experiments with viruses and bacteria provided most of the evidence that genes are made of DNA, and they were important in working out the molecular mechanisms of the fundamental processes like DNA replication, transcription and translation. Genomes from organisms like E. coli and baker's yeast were helpful tools in the effort to define the basic biochemical networks within more complex organisms. Small genome sequences, such as those of viruses and bacteria, have shed light on the basic principles of genomics.

Plants Plants: Primary Producers of the Planet Plants synthesize their own food by an important phenomenon known as photosynthesis
Plants - Molecular oxygen providers

The most commonly used distinction among organisms is between plants and animals. Plants get their energy directly from sun light and prepare their food through a process called photosynthesis, while animals consume the food synthesized by plants.

Recent research studies widen the potential of plant biotechnology to enhance production as well as the quality of nutrients from plants. In genetically modified plants, DNA is modified using genetic engineering techniques to introduce a new beneficial trait which does not normally occur in that plant.

Examples include resistance to certain pests, diseases or environmental conditions, or the production of a certain nutrient or pharmaceutical agents. Genetic engineering, using recombinant DNA, alters the genetic makeup of the animal for selected purposes like producing therapeutic proteins.

Animals consume the food synthesized by plants. 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 - Models for studying Humans

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 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.
Human Physiology and Health

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.

Health is Wealth Health is Wealth Learning the basic science of health leads to a healthy lifestyle which will be free from diseases.
Health is Wealth

The digestive system helps in breaking food down to usable nutrients and energy carrying molecules while disposing of waste. Respiratory system obtains oxygen for combustion of food and discharges carbon dioxide. Renal system disposes other dissolved waste products of cell activity.

Circulatory system moves blood along with other essential nutrients to or from cells where they are needed or produced. The coordination of all these systems is carried out by the brain and nervous system. The electrical and chemical signals carried by nerves and hormones provide communication between all the other organ systems and thereby synchronize their functions.

Thus, biology is study of life which is endlessly challenging and uplifting. Biology need not demand relevance towards nature, as it is a natural science. Our very aliveness emphasizes the intimacy of the connection between the discipline of biology and our everyday concerns.

The knowledge of biology that has been gained, provides us with a tool of extraordinary power to improve the human condition and lessen human impact on the world. Biology is the foundation for medical research which improved quality of life with new medical therapies.

Let us explore this exciting study of 'Life' to know more about ourselves and the world around us.

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