Biology with Tanveer kurf
5000 Words
Introduction to Biology
INTRODUCTION TO BIOLOGY
BIOLOGY
Biology is the study of living things. It is a branch of science and like other sciences it is a way of understanding nature. The word biology is derived from the Greek words bios meaning life and logos meaning to study so the literal meaning of biology is the study of life.
BIOLOGISTS
The person who study the biology. . Biologists deal with the living part of nature and with the non-living things which affect the living things in any way. They strive to understand explain, integrate and describe the natural world of living things.
Aspects of biology.
Biology is the study of life but there are certain aspects of life that lie beyond the scope of the science of biology like the answers to the questions:
What is the meaning of life?
Why should there be life?
These are the questions not usually taken up by biologists and are left to philosophers and theologians. Biologists mainly deal with the matters relating to how life works.
What is Life?
It is very difficult to define life. However Life, for biologists, is a set of characteristics that distinguish living organisms from nonliving objects (including dead organisms).
Characteristics of Living things. (Living organisms)
Are Highly organized,
Are complex entities.
Are composed of one or more cells
Contain genetic program of their characteristics.
Can acquire and use energy
Can carry out and control numerous chemical reactions.
Can grow in size.
Maintain fairly internal constant environment
Produce offspring similar to themselves;
Respond to changes in their environment.
Any object possessing all these characteristics simultaneously can be declared as a living thing and is an object for biological studies.
Why we classify the biology?
The science of biology is a very wide based study. It includes every aspect of a living thing. Therefore, volumes and volumes of information are available under this major head. It is but natural to divide this science into quite a number of branches for our convenience of comprehending and studying biology.
Some Major Fields of Biology
Embryology
A branch of biology dealing with embryos and their development. It deals with process of development of an individual from the zygote to whole organism.
Physiology
The branch of biology that deals with the normal functions of living organisms and their parts.
Morphology
It is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features.
It may be.
External morphology. This includes aspects of the external appearance (shape,structure,colour,pattern,size ) of an organism.
Internal morphology or anatomy. It deals with internal gross structure of parts of an organism.
Histology
It is microscopic study of tissue of an organism.
Paleontology
It is a branch of biology dealing with study of fossils. It is the way of getting information about history of early life.
Evolution
It is the process by which different kinds of living organisms are thought to have developed from earlier forms during the history of the earth.
Genetics
The branch of biology that deals with heredity information especially the mechanisms of hereditary transmission from parents to offspring.
Zoogeography
The biological study of the geographic distribution of animals, on earth especially the causes and effects of such distribution.
Taxonomy
It is a branch of biology that deals with the description, identification, nomenclature, and classification of organisms
Cytology
The branch of biology concerned with the structure and function of cells.
Molecular Biology
Molecular biology is a branch of biology which deals with the structure of organisms, the cells and their organelles at molecular level.
Environmental Biology
Environmental biology is the study of organisms in relation to their environment. This includes interaction between the organism and their inorganic and organic environment, especially as it relates to human activities.
Microbiology
This is the study of microorganisms which include bacteria, viruses, protozoa and microscopic algae and fungi etc.
Freshwater Biology
This branch of biology deals with the organisms living in freshwater bodies i.e., rivers, Lakes etc. and physical and chemical parameters of these water bodies.
Marine Biology
This is study of life in seas and oceans. This includes the study of the marine life and the physical and chemical characteristics of the sea acting as factors for marine life.
Parasitology
This is the branch of biology which deals with the study of parasites. The structure, mode of transmission, life histories and host - parasite relationships are studied in Parasitology.
Human Biology
It deals with the study of man. This includes form and structure, function, histology, anatomy, morphology, evolution, genetics, cell biology and ecological studies etc. of human beings.
Social Biology
This is the branch of biology which deals with the study of social behavior and communal life of human beings.
Biotechnology
It deals with the use of living organisms, systems or processes in manufacturing and service industries.
BIOELEMENTS
Definition
These elements are commonly used in forming the chemical compounds from which living organisms are made.
Explanation
Hundreds of chemical reactions are involved in maintaining life of even the simplest organism. In view of this, it is something of a surprise to find that of the 92 naturally occurring chemical elements, only 16 are commonly used in forming the chemical compounds from which living organisms are made. These 16 elements and a few others which occur in a particular organism are called bioelements.
Types of Bioelements
Major Bioelements. Only few number of elements are required by living organisms in relatively high concentration. These elements are called as major or primary elements. E.g. In the human body only six bio-elements account for 99% of the total mass. Oxygen 65% , Carbon 18% Hydrogen 10% Nitrogen 3% Calcium 2% Phosphorus 1%
Minor bioelements.
These elements are present in very small amounts. It usually forms 1 % of organism. These are also called as secondary elements.
Examples are potassium (0.35%), Sulphur (0.25%), chlorine (0.15%), sodium (0.15%), magnesium (0.05%), iron (0.004%).
Trace elements.
These are present in very very minute quantity however these are necessary for proper functioning of organisms.
Examples are copper (trace), manganese (trace), and zinc (trace),
iodine (trace).
Facts of Bioelements
The fact that the same 16 chemical elements occur in all organisms, and the fact that their properties differ from those in the non-living world, shows that bioelements have special properties which make them particularly appropriate as basis for life.
LEVEL OF BIOLOGICAL ORGANIZATION
Complexity in organization. Biological organization is not simple. It has high degree of complexity because of which the living organisms are able to carry out a number of processes (some very complicated) which distinguish them from the nonliving things.
Regulatory mechanisms. A living thing has built-in regulatory mechanisms which interact with the environment to sustain its structural and functional integrity.
Protoplasm. A living thing is, therefore, composed of highly structured living substance or protoplasm.
Levels. In order to understand the various phenomena of life, biologists for their convenience, study the biological organization at different levels starting from the very basic level of sub atomic and atomic particles to the organism itself and beyond which the study of community, population and entire world are included.
Atomic & Subatomic Levels
All living and non-living matter is formed of simple units called atoms and sub atomic particles such as protons, electrons & neutrons.
Molecular level
Molecule. In organisms elements usually do not occur in isolated forms. The atoms of different elements combine with each other through ionic or covalent bonding to produce compounds. This stable form is called a molecule.
The different types of bonding arrangement permit biological molecules to be constructed in great variety and complexity.
Common Bioelements. Hydrogen, carbon, oxygen, nitrogen, phosphorous and Sulphur are the most common atoms found in biological molecules.
Types of molecules.
Micro molecules. These may be micro molecules with low molecular weight like CO2, H2O etc. or
Macromolecules with high molecular weights e.g. starch, proteins etc.
Biological world has two types of molecules: organic and inorganic.
Organic molecule. An organic molecule is any molecule containing both carbon and hydrogen. E.g. glucose, ATP, Amino acids etc.
Inorganic molecules do not include carbon and hydrogen together in a molecule. e.g. CO2, H2O
An organism is usually formed by enormous number of micro and macro molecules of hundreds of different types.
Abundant Molecules. Some most important and abundant organic molecules in organisms are glucose, amino acids, fatty acids, glycerol, and nucleotides like ATP, ADP, and AMP etc.
Organelles & cell
Different and enormous number of micro molecules and macromolecules arrange themselves in a particular way to form cells and their organelles.
Organelles. (Organ of cell). It has become clear that functions of cell are accomplished by specialized structures within the cell comparable to the organ of body. These subcellular structures are called as organelles.
Mitochondria, Golgi apparatus, Ribosomes and endoplasmic reticulum etc.
The arrangement of the organelles speaks of the division of labour within the cell.
The prokaryotes have only a limited number and type of organelles in their cytoplasm.
Eukaryotes are rich in number and kinds of membranous organelles.
A cell membrane is however present in all cells whether prokaryotic or Eukaryotic.
Cell. The structural and functional unit of living organism. In case of simple organisms like bacteria and most protists, the entire organisms consist of a single cell. In most fungi, plants and animals, the organism may consist of up to trillions of cells.
Tissue level
Definition. In multicellular animals and plants, groups of similar cells are organized into loose sheets or bundles performing similar functions: these are called tissues.
Each tissue has a particular function in the life of the organism
Examples are
In animal , muscle tissues are specialized for contraction (movement), glandular tissues are specialized for secretion,
In plants, xylem tissues are specialized for conducting water and minerals, phloem tissues are specialized for translocation of sugar, proteins etc.
simple community any change can have drastic and long lasting effects.
Relationships among the community.
As community are collection of many different population so here different organisms’ interactions can take many shapes. It may be
Predation is a biological interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked). Example. lion and zebra, bear and fish, and fox and rabbit
Parasitism, is a relationship in which one species, the parasite, benefits at the expense of the host where the parasite also harms the host. Example are tapeworms,flukes, the Plasmodium species, and fleas
Is a of relationships between two organisms where one organism benefits from the other without affecting it. Example is remoras that gets food from shark.
is the way two organisms of different species exist in a relationship in which each individual benefits from the activity of the other. Example are Lichens
Competition is the relationship between or among living things of an area for limited resources, such as food, space, shelter,
Ecosystem.
Definition.
A community with nonliving surrounding is called as ecosystem.
Examples. a pond, a forest, a grassland.
. a pond, a forest, a grassland.
Biosphere.
The part of earth inhabited by living organism and includes both living and nonliving components.
Living world in space (DISTRIBUTION)
Living world of today is enormous in size. It has been reproducing and evolving since the time of its origin on this planet. Today almost all parts of the world abounds in living organisms. The distribution of organisms in space can be studied through biomes.
Biomes
A biome is a large regional community primarily determined by climate. It has been found that the major type of plant determines the other kind of plants and animals.
How these are named? These biomes have, therefore been named after the type of major plants or major feature of the ecosystem.
Example. Forest Biomes, grassland Biomes marine Biomes, desert Biomes, and tundra Biomes.
Living world in Time (History)
Since the time of origin of life on this planet, various organisms were evolved and dominated this planet during various periods of geological time chart.
Geological Time Chart.
It is a time sequence of the earth's history in which different layers of earth and fossils in these layers are studied to get the information about early life and process of evolution.
This has been found by the evidence obtained from the discovery and study of fossils which allows biologists to place organisms in a time sequence. This time sequence was formed by
Sedimentation method.
As geological time passes and new layers of sediments are laid down, the older organisms should be in deeper layer, provided the sequence of the layers
has not been disturbed.
Radioactive method.
In addition it is possible to date/age rocks by comparing the amounts of certain radioactive isotopes they contain. The older sediment layers have less of these specific radioactive isotopes than the younger layers.
Comparison of layers.
A comparison of the layers gives an indication of the relative age of the fossils found in the rocks. Therefore, the fossils found in the same layer must have been alive during the same geological period.
You can have an idea about the temporal distribution of various forms of life both plants and animals in the various geological periods
and again without ever being falsified is considered well supported and is generally accepted. This may be used as the basis for formulating further hypothesis. So soon there is formation of a series of hypothesis
Theory.
It is a series of hypothesis supported by the results of many tests.
Good Theory. A good theory is predictive and has explanatory power. One of the most important features of a good theory is that it may suggest new and different-hypothesis. A theory of this kind is called productive.
Testing of theory. However even in the case of productive theory the testing goes on. In fact many scientists take it as a challenge and exert even greater efforts to disprove the theory.
LAW.
If a theory survives its skeptical approach and continues to be supported by experimental evidence, it becomes a scientific law.
A scientific law is a uniform or constant fact of nature; it is virtually an irrefutable theory.
Biology is short in laws because of elusive nature of life.
Laws are even more general than theories and afford answers to even more complex questions,
Examples of biological laws are hardy - Weinberg law and Mendel’s laws of inheritance.
Laws are even more general than theories and afford answers to even more complex questions,
Examples of biological laws are hardy - Weinberg law and Mendel’s laws of inheritance.
Different techniques of food preservation have been developed for protecting food from spoilage and for its use and transport over long distance without damaging its quality.
Pasteurization, One of these is Pasteurization, developed by Louis Pasteur. It is being widely used for preservation of milk and milk products. It is the process of heating a liquid or a food to kill pathogenic bacteria to make the food safe to use.
Integrated disease management.
Combating disease utilizing all methods as and when required and ensuring a participation of community in this program is known as integrated disease management.
Requirement. This requires awareness of the community about the severity of the problem, its causes and its remedies.
Significance. This is a very effective program for elimination and control of dangerous diseases from the human society.
Example. Control of dengue in Pakistan
CLONING
It is the process of production of genetically identical copies of organisms/cells by asexual reproduction.
CLONE.
A clone is defined as a cell or individual and all its asexually produced offspring. All members of clone are genetically identical except when mutation occurs.
Natural cloning.
In this cloning an organisms reproduces by its natural methods. Generally no normal animal reproduces naturally by cloning. Several insects and many plants do, in some circumstances whereas few do so regularly.
Artificial cloning.
It is the process of cloning which is done by the humans to get their own benefits. In 1997 scientists in Scotland succeeded in cloning a sheep named ‘Dolly’. Other mammalian species (mice and cows) have since been cloned.
Procedures of Cloning.
Zygote cloning.
In this procedure the nucleus from a fertilized egg is removed
a nucleus from a cell of a fully developed individual is inserted in its place.
The altered zygote is then implanted in a suitable womb where is completes its development.
The new individual formed in this way. It is a genetically identical clone of the individual whose nucleus was used.
Thus cloning could make multiple copies of a desired genotype.
Embryo Cloning.
Another type of cloning is the division of a single egg or early embryo into one or more separate embryos.
This is the same process that normally creates identical twins.
Offspring from this type of cloning are genetically identical but carry chromosomes from each of the two parents.
This type of cloning has already been used to produce genetically identical cattle and other farm animals.
Significance.
Cloning is a technology for achieving eugenic aims.
Man is likely to adopt cloning techniques for commercial production of valuable animals of known pedigree such as horses etc.
Human cloning. At some places scientists are making attempts to clone human embryo which they believe can serve as transplant donor. There is a lot of controversy on this issue as to whether human cloning should be attempted or not.
Protection and Conservation of Environment
Effect of industrialization.
Industrialization has helped mankind to raise the standard of living. It has at the same time destroyed our environment.
Industrial Wastes.
Tons of industrial waste, and effluents in solid, liquid or gas form are being injected into the environment by the industries. These effluents frequently contain sizable amount of certain very toxic even carcinogenic materials.
Heavy metals like lead from automobiles, chromium from tanneries, are playing havoc to human health. Environmental pollution has reached alarming level in some countries.
Need to solve Environmental Pollution.
The problem, therefore, needs to be addressed or else it would soon be out of control in which case the bio components of the world ecosystem would suffer irreparable loss and this environment would no longer support life on this planet.
Role of Biology to solve Environmental Pollution..
Biology has helped mankind in attracting attention to this problem and the biologists are striving to find the solution to set this environment right wherever it has deteriorated.
Biologists have already asked for the treatment of industrial effluents to be made obligatory.
Biologists are trying to develop several ways of bioremediation.
Bioremediation. Removal or degradation of environmental pollutants or toxic materials by living organisms is called as bioremediation. For example algae have been found to reduce pollution of heavy metals by bio absorption. Certain fungi are also used for bioremediation.
Endangered Species Protection.
The species which are eminent danger of extinction are called as endangered species. Such as Panda
Biologists are also working out the list of endangered species of plants and animals which if not protected would soon be extinct. They have, therefore stressed the needs for their protection.
Environmental pollution in Pakistan
The environmental pollution is a national problem in Pakistan.
Our rivers, canals are highly polluted with the mixing of city sewage and industrial wastes. The life in fresh water of Pakistan is towards decline. Fish populations have been most adversely affected.
We need to take protective measures as early as possible.
In cities, particularly the exhaust from automobiles is enormously adding lead into the atmosphere.
There is then a need for lead free petrol to reduce the pollution.
Biological Molecules
IMPORTANCE OF CARBON
Carbon is the basic element of organic compounds. Due to its unique properties, carbon occupies the central position in the skeleton to life. Following are most important characteristics of carbon.
Formation of Covalent Bond
It can react with many other known elements forming covalent bonds.
Covalent Bond. Covalent bonds result when two or more atoms complete their electron shells by sharing electrons. Covalent bond stores large amount of energy.
Single Covalent bond. If one electron pair is shared then single covalent bond is formed. Bond between two hydrogen atoms is single covalent bond.
Double Covalent Bond. If two electron pair are shared then double covalent bond is formed. Bond between two oxygen atoms is double covalent bond.
Triple covalent bond. If three electron pairs are shared then triple covalent bond is formed. Bond between two nitrogen atoms is triple covalent bond.
Tetravalency
Carbon is tetravalent. When a carbon atom combines with four atoms or radicals, the four bonds are arranged symmetrically in a tetrahedron, and result to give a stable configuration.
Significance. The stability associated with the tetravalency of carbon atoms makes it a favorable element for the synthesis of complicated cellular structures.
Catenation (C-C bonding)
Catenation is the linkage of atoms of the same element into longer chains. Carbon atoms can also combine mutually forming stable, branched or unbranched chains or rings. This ability of carbon it responsible for the vast variety of organic compounds. C – C bonds form a skeleton of organic molecules.
temperature by one degree.
Specific Heat capacity of water.
The number of calories required to raise the temperature of 1g of water from 15 C to 16 C.
Value. Its value is 1 Calorie or 4.18 joules.
High heat capacity. Water has high heat capacity and it has great ability of absorbing heat with minimum of change in its own temperature. This is because much of the energy is used to break hydrogen bonds.
Importance. Water thus works as temperature stabilizer for organisms in the environment and hence protects living material against sudden thermal changes.
Heat of vaporization
Heat of vaporization is expressed as calories absorbed per gram vaporized.
Specific Heat of vaporization of water.
Number of calories required as water changes from liquid to gas. The specific heat of vaporization of water is 574 kcal/kg.
Importance.
It plays an important role in the regulation of heat produced by oxidation.
It also provides cooling effect to plants when water is transpired or to animals when water is perspired. Evaporation of only two ml out of one liter of water lowers the temperature of the remaining 998 ml by 1C.
Ionization of water
The water molecules ionize to form H+ and OH- ions:
This reaction is reversible but an equilibrium is maintained. At 25 C the concentration of each of H+ and OH- ions in pure water is about 10 -7 moles/ liter.
The H+ and OH- ions affect, and take part in many of the reactions that occur in cells e.g. buffering of blood.
Protection
Water is effective lubricant that provides protection against damage resulting from friction. For example, tears protect the surface of eye from the rubbing of eyelids.
Water also forms a fluid cushion around organs that helps to protect them from trauma.
nature. Cotton is the pure form of cellulose. It is the main constituent of cell walls of plants.
Hydrolysis
On hydrolysis it also yields glucose molecules and is highly insoluble in water.
Digestion
It is not digested in the human digestive tract. In the herbivores, it is digested because of micro-organisms (bacteria, yeasts, protozoa) in their digestive tract. These micro-organisms secrete an enzyme called cellulase for its digestion.
Iodine test
Cellulose gives no colour with iodine.
hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils.
Fatty acids are one of the most important components of triglycerides.
Fatty acids contain even numbers (2 -30) of carbon atoms in straight chain attached with hydrogen and having an acidic group COOH (carboxylic group).
Types of fatty acids.
Saturated. They may contain no double bond. Example is butyric acid
Unsaturated. They may contain no double bond up to 6 double bonds. Example is oleic acid a monounsaturated fatty acid. .
In animals, the fatty acids are straight chains.
In plants, these may be branched or ringed.
Solubility and melting point.
Solubility of fatty acids in organic solvents and their melting points increase with increasing number of carbon atoms in chain. Palmitic acid (C16) is much more soluble in organic solvent than butyric acid (C4). The melting point of palmitic acid is 63.1°C as against -8°C for butyric acid.
Fats and Oils.
Fats containing unsaturated fatty acids are usually liquid at room temperature and are said to be oils.
Fats containing saturated fatty acids are solids.
Animal fats are solid at room temperature.
Most of the plant fats are liquids.
Specific Gravity.
Fats and oils are lighter than water and have a specific gravity of about 0.8.
Crystallization.
They are not crystalline but some can be crystallized under specific conditions.
Waxes
Definition.
Chemically, waxes are mixtures of long chain alkanes (with odd number of carbons ranging from C25 to C35) and alcohols, ketones and esters of long chain fatty acids.
Functions.
Waxes are widespread as protective coatings on fruits and leaves. Some insects also secret wax. Waxes protect plants from water loss and abrasive damage.
They also provide water barrier for insects, birds and animals such as sheep.
Phospholipids
Phospholipids are derivatives of phosphatidic acid.
Composition.
Phosphatidic acid is composed of glycerol, 2 fatty acids (on C1 and C2), and a phosphoric acid on C3 of glycerol. In phospholipid a nitrogenous base (e.g. choline) is attached to phosphoric acid of phosphatidic acid.
Important nitrogenous bases. Choline, ethanolamine and serine are important components of phospholipids.
Occurrence.
They are widespread in bacteria, animal and plant cells and are frequently associated with membranes.
Example.
Phosphatidylcholine (Lecithin) is one of the common phospholipids.
Terpenoids
Terpenoids are a very large and important group of compounds which are made up of simple repeating units, isoprenoid units. This unit by condensation in different ways gives rise to compounds such as rubber, carotenoids, steroids terpenes etc.
Proteins.
Introduction.
Proteins are the most abundant organic compounds to be found in cells and comprise over 50% of their total dry weight. They are present in all types of cells and in proteins perform many functions.
Functions.
Structural role.
They build many structures of the cell.
Enzymes.
All enzymes are proteins and in this way they control the whole metabolism of the cell.
Hormones.
As hormones, proteins regulate metabolic processes. For example glucagon and insulin regulate the glucose concentration in blood.
Carrier.
Some proteins (e.g. hemoglobin) work as carriers and transport specific substances such as oxygen, Lipids, metal ions, etc.
Antibodies.
Some proteins called antibodies defend the body against pathogens.
Blood clotting.
Blood clotting proteins such as fibrin prevent the loss of blood from body after injury.
Movements.
Movement of organs and organisms, and movement of chromosomes during anaphase of cell division, are caused by proteins.
acids.
Determination. The sequence is determined by the order of nucleotides in the DNA.
Importance. The arrangement of amino acids in a protein molecule is highly specific for its proper functioning. If any amino acid is not in its normal place, the protein fails to carry on its normal function.
The best example is the sickle cell hemoglobin of human beings. In this case only one amino acid in each beta chain out of the 574 amino acids do not occupy the normal place in the proteins i.e. in fact this particular amino acid (glutamic acid) is replaced by some other amino acid (valine), and the haemoglobin fails to carry any or sufficient oxygen, hence leading to death of the patient.
Secondary Structure.
The polypeptide chains in a protein molecule usually do not lie flat. They usually coil into a helix, or into some other regular configuration.
α-Helix.
One of the common secondary structures is the α-helix. It involves a spiral formation of the basic polypeptide chain. The α-helix is a very uniform geometric structure with 3.6 amino acids in each turn of the helix. The helical structure is kept by the formation of hydrogen bonds among amino acid molecules in successive turns of the spiral.
B-pleated
sheet is formed by folding back of the polypstructure.
Tertiary Structure
Usually a polypeptide chain bends and folds upon itself forming a globular shape. This is the proteins’ tertiary conformation and it is maintained by three types of bonds, namely ionic, hydrogen, and disulfide (-S-S-).
Stable Tertiary structure
For example, in aqueous environment the most stable tertiary conformation is that in which hydrophobic amino acids are buried inside while the hydrophilic amino acids are on the surface of the molecule.
Quaternary structure.
In many highly complex proteins, polypeptide tertiary chains are aggregated and held together by hydrophobic interactions, hydrogen and ionic bonds. This specific arrangement is the quaternary structure.
Example
Haemoglobin, the oxygen carrying protein of red blood cells, exhibits such a structure.
Example
Haemoglobin, the oxygen carrying protein of red blood cells, exhibits such a structure
Classification of Protein.
Because of the complexity of structure and diversity in their function. It is very difficult to classify proteins in a single well defined fashion. However, according to their structure, proteins are classified as follows:
Fibrous Proteins
Form. They consist of molecules having one or more polypeptide chains in the form of fibrils.
Structure. Secondary structure is most important in them.
Solubility. They are insoluble in aqueous media.
They are non-crystalline and are elastic in nature.
Function. They perform structural roles in cells and organisms.
Examples are silk fiber (from silk worm, and spider’s web) myosin (in muscle cells), fibrin (of blood clot), and keratin (of nails and hair).
Globular Proteins
Form. These are spherical or ellipsoidal due to multiple folding of polypeptide chains.
Structure. Tertiary structure is most important in them.
Solubility. They are soluble in aqueous media such as salt solution, solution of acids or bases, or aqueous alcohol.
They can be crystallized.
Effect of changes. They disorganize with changes in the physical and physiological environment.
Examples are enzymes, antibodies, hormones and hemoglobin.
Occurrence
Nucleic acids are of two types, deoxyribonucleic acid or DNA and ribonucleic acid or RNA.
DNA
occurs in chromosomes, in the nuclei of the cells and in much lesser amounts.
Tanveer Kurd Mastung Behramshahi
Mastung
Professor Bilal Kurd Behramshahi Mastung
Quetta library.
a
- Writer
