Biotechnology is technology based on biology especially when used in agriculture food science and medicine. The United Nations Convention on Biological Diversity has come up with one of many definitions of biotechnology Biotechnology has contributed towards the exploitation of biological organisms or biological processes through modern techniques which could be profitably used in medicine agriculture animal husbandry and environmental cloning.Biotechnology is a popular term for the generic technology of the st century. Although it has been utilized for centuries in traditional production processes modern biotechnology is onlyyears old and in the last decades it has been witnessing tremendous developments. Bioengineering is the science upon which all Biotechnological applications are based. With the development of new approaches and modern techniques traditional biotechnology industries are also acquiring new horizons enabling them to improve the quality of their products and increase the productivity of their systems.Beforethe term biotechnology was primarily used in the food processing and agriculture industries. Since the s it began to be used by the Western scientific establishment to refer to laboratorybased techniques being developed in biological research such as recombinant DNA or tissue culturebased processes. In fact the term should be used in a much broader sense to describe the whole range of methods both ancient and modern used to manipulate organic materials to reach the demands of food production. So the term could be defined as The application of indigenous andor scientific knowledge to the management of parts of microorganisms or of cells and tissues of higher organisms so that these supply goods and services of use to the food industry and its consumers.
The most practical use of biotechnology
The most practical use of biotechnology which is still present today is the cultivation of plants to
produce food suitable to humans. Agriculture has been theorized to have become the dominant way of
producing food since the Neolithic Revolution. The processes and methods of agriculture have been
refined by other mechanical and biological sciences since its inception. Through early biotechnology
farmers were able to select the best suited and highestyield crops to produce enough food to support a
growing population. Other uses of biotechnology were required as crops and fields became increasingly
large and difficult to maintain. Specific organisms and organism byproducts were used to fertilize
restore nitrogen and control pests. Throughout the use of agriculture farmers have inadvertently
altered the genetics of their crops through introducing them to new environments and breeding them
with other plantsone of the first forms of biotechnology. Cultures such as those in Mesopotamia
Egypt and Iran developed the process of brewing beer. It is still done by the same basic method of
using malted grains containing enzymes to convert starch from grains into sugar and then adding
specific yeasts to produce beer. In this process the carbohydrates in the grains were broken down into
alcohols such as ethanol. Later other cultures produced the process of Lactic acid fermentation which
allowed the fermentation and preservation of other forms of food. Fermentation was also used in this
time period to produce leavened bread. Although the process of fermentation was not fully understood
until Louis Pasteur’s work init is still the first use of biotechnology to convert a food source into
another form.Combinations of plants and other organisms were used as medications in many early civilizations. Since as early asBC people began to use disabled or minute amounts of infectious agents to
immunize themselves against infections. These and similar processes have been refined in modern
medicine and have lead to many developments such as antibiotics vaccines and other methods of
Applications Biotechnology has applications in four major industrial areas including health care crop production
and agriculture non food uses of crops e.g. biodegradable plastics vegetable oil biofuels and
environmental uses. For example one application of biotechnology is the directed use of organisms for
the manufacture of organic products examples include beer and milk products. Another example is
using naturally present bacteria by the mining industry in bioleaching. Biotechnology is also used to
recycle treat waste clean up sites contaminated by industrial activities bioremediation and also to
produce biological weapons.Red biotechnology is applied to medical processes. Some examples are the
designing of organisms to produce antibiotics and the engineering of genetic cures through genomic
manipulation.White biotechnologyalso known as industrial biotechnology is biotechnology applied
to industrial processes. An example is the designing of an organism to produce a useful chemical.
Another example is the using of enzymes as industrial catalysts to either produce valuable chemicals or
destroy hazardouspolluting chemicals examples using oxidoreductases are given in Feng Xu
“Applications of oxidoreductases: Recent progress” Ind. Biotechnol. . White
biotechnology tends to consume less in resources than traditional processes used to produce industrial
goods.Green biotechnology is biotechnology applied to agricultural processes. An example is the
designing of transgenic plants to grow under specific environmental conditions or in the presence or
absence of certain agricultural chemicals. One hope is that green biotechnology might produce more
environmentally friendly solutions than traditional industrial agriculture. An example of this is the
engineering of a plant to express a pesticide thereby eliminating the need for external application of
pesticides. An example of this would be Bt corn. Whether or not green biotechnology products such as
this are ultimately more environmentally friendly is a topic of considerable debate.
Deoxyribonucleic acid
Deoxyribonucleic acid DNA is a nucleic acid that contains the genetic instructions used in the
development and functioning of all known living organisms. The main role of DNA molecules is the
longterm storage of information and DNA is often compared to a set of blueprints since it contains
the instructions needed to construct other components of cells such as proteins and RNA molecules.
The DNA segments that carry this genetic information are called genes but other DNA sequences have
structural purposes or are involved in regulating the use of this genetic information.Chemically DNA
is a long polymer of simple units called nucleotides with a backbone made of sugars and phosphate
groups joined by ester bonds. Attached to each sugar is one of four types of molecules called bases. It
is the sequence of these four bases along the backbone that encodes information. This information is
read using the genetic code which specifies the sequence of the amino acids within proteins. The code
is read by copying stretches of DNA into the related nucleic acid RNA in a process called
transcription. Most of these RNA molecules are used to synthesize proteins but others are used
directly in structures such as ribosomes and spliceosomes.Within cells DNA is organized into
structures called chromosomes. These chromosomes are duplicated before cells divide in a process
called DNA replication. Eukaryotic organisms such as animals plants and fungi store their DNA inside
the cell nucleus while in prokaryotes such as bacteria it is found in the cells cytoplasm. Within the
chromosomes chromatin proteins such as histones compact and organize DNA which helps control its
interactions with other proteins and thereby control which genes are transcribed. Physical and chemical properties
DNA is a long polymer made from repeating units called nucleotides. The DNA chain isto
Ångströms widetonanometres and one nucleotide unit isÅngstroms . nanometres
long. Although each individual repeating unit is very small DNA polymers can be enormous
molecules containing millions of nucleotides. For instance the largest human chromosome
chromosome numberismillion base pairs long.In living organisms DNA does not usually
exist as a single molecule but instead as a tightlyassociated pair of molecules. These two long
strands entwine like vines in the shape of a double helix. The nucleotide repeats contain both the
segment of the backbone of the molecule which holds the chain together and a base which interacts
with the other DNA strand in the helix. In general a base linked to a sugar is called a nucleoside and a
base linked to a sugar and one or more phosphate groups is called a nucleotide. If multiple nucleotides
are linked together as in DNA this polymer is referred to as a polynucleotide.The backbone of the
DNA strand is made from alternating phosphate and sugar residues. The sugar in DNA is
deoxyribose which is a pentose five carbon sugar. The sugars are joined together by phosphate
groups that form phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar
rings. These asymmetric bonds mean a strand of DNA has a direction. In a double helix the direction of
the nucleotides in one strand is opposite to their direction in the other strand. This arrangement of
DNA strands is called antiparallel. The asymmetric ends of DNA strands are referred to as the ′ five
prime and ′ three prime ends. One of the major differences between DNA and RNA is the sugar
with deoxyribose being replaced by the alternative pentose sugar ribose in RNA.The DNA double
helix is stabilized by hydrogen bonds between the bases attached to the two strands. The four bases
found in DNA are adenine abbreviated A cytosine C guanine G and thymine T. These four
bases are shown below and are attached to the sugarphosphate to form the complete nucleotide as
shown for adenosine monophosphate.These bases are classified into two types adenine and guanine
are fused five and sixmembered heterocyclic compounds called purines while cytosine and thymine
are sixmembered rings called pyrimidines. A fifth pyrimidine base called uracil U usually takes
the place of thymine in RNA and differs from thymine by lacking a methyl group on its ring. Uracil is
not usually found in DNA occurring only as a breakdown product of cytosine but a very rare
exception to this rule is a bacterial virus called PBS that contains uracil in its DNA. In contrast
following synthesis of certain RNA molecules a significant number of the uracils are converted to
thymines by the enzymatic addition of the missing methyl group. This occurs mostly on structural and
enzymatic RNAs like transfer RNAs and ribosomal RNA. Major and minor grooves
Animation of the structure of a section of DNA. The bases lie horizontally between the two spiraling
strands. Large versionThe double helix is a righthanded spiral. As the DNA strands wind around each
other they leave gaps between each set of phosphate backbones revealing the sides of the bases inside
see animation. There are two of these grooves twisting around the surface of the double helix: one
groove the major groove isÅ wide and the other the minor groove isÅ wide. The
narrowness of the minor groove means that the edges of the bases are more accessible in the major
groove. As a result proteins like transcription factors that can bind to specific sequences in
doublestranded DNA usually make contacts to the sides of the bases exposed in the major groove.
Each type of base on one strand forms a bond with just one type of base on the other strand. This is
called complementary base pairing. Here purines form hydrogen bonds to pyrimidines with A bonding
only to T and C bonding only to G. This arrangement of two nucleotides binding together across the
double helix is called a base pair. In a double helix the two strands are also held together via forces
generated by the hydrophobic effect and pi stacking which are not influenced by the sequence of the
DNA. As hydrogen bonds are not covalent they can be broken and rejoined relatively easily. The
two strands of DNA in a double helix can therefore be pulled apart like a zipper either by a
mechanical force or high temperature. As a result of this complementarity all the information in
the doublestranded sequence of a DNA helix is duplicated on each strand which is vital in DNA
replication. Indeed this reversible and specific interaction between complementary base pairs is
critical for all the functions of DNA in living organisms.The two types of base pairs form different
numbers of hydrogen bonds AT forming two hydrogen bonds and GC forming three hydrogen bonds
see figures left. The GC base pair is therefore stronger than the AT base pair. As a result it is both
the percentage of GC base pairs and the overall length of a DNA double helix that determine the
strength of the association between the two strands of DNA. Long DNA helices with a high GC
content have strongerinteracting strands while short helices with high AT content have
weakerinteracting strands. Parts of the DNA double helix that need to separate easily such as the
TATAAT Pribnow box in bacterial promoters tend to have sequences with a high AT content making
the strands easier to pull apart. In the laboratory the strength of this interaction can be measured
by finding the temperature required to break the hydrogen bonds their melting temperature also called
Tm value. When all the base pairs in a DNA double helix melt the strands separate and exist in
solution as two entirely independent molecules. These singlestranded DNA molecules have no single
common shape but some conformations are more stable than others.