WHAT THEY SAY ABOUT MOHAMMAD   IF greatness of purpose, smallness of means, and astounding Results are the three criteria of human genius, who could dare to compare any great man in modem history with Muhammad?

The most famous men created arms, laws and empires only. They founded, if anything at all, no more than material powers which often crumbled away before their eyes. This man moved not only armies, legislation, empires, peoples and dynasties, but millions of men in one-third of the then-inhabited world; and more than that he moved the altars, the gods, the religions, the ideas, the beliefs and souls.... His forbearance in victory, his ambition which was entirely devoted to one idea and in no manner striving for an empire, his endless prayers, his mystic conversations with God, his death and his triumph after death- all these attest not to an imposture but to a firm conviction which gave him the power to restore a dogma. This dogma was twofold: the unity of God and the immateriality of God; the former telling what God is, the latter telling what God is not; the one overthrowing false gods with the sword, the other starting an idea with the words.

Philosopher, orator, apostle, legislator, warrior, conqueror of ideas, restorer of rational dogmas, of a cult without images; the founder of twenty terrestrial empires and of one spiritual empire, that is Muhammad.

                     

As regards all standards by which human greatness may be measured, we may well ask, is there any man greater than he?

- LAMARTINE

                          

I

t is not the propagation but the permanency of his religion that deserves our wonder; the same pure and perfect impression  which he engraved at Mecca and Medina is preserved, after the revolutions of twelve centuries by the Indian, the African and the Turkish proselytes of the Koran...The Mahometans have uniformly withstood the temptation of reducing the object of their faith and devotion to a level with the senses and imagination of man.

I believe in One God and Mahomet is the Apostle of God' is the simple and invariable profession of Islam. The intellectual image of the Deity has never been degraded by any visible idol; the honors of the prophet have never transgressed the measure of human virtue; and his living precepts have restrained the gratitude of his disciples within the bounds of reason and religion.

       - Edward Gibbon and Simon Ocklay

H

e was Caesar and Pope in one; but he was Pope without Pope's pretensions, Caesar without the legions of Caesar: without a standing army, without a bodyguard, without a palace, without fixed revenue. If ever any man had the right to say that he ruled by the right divine, it was Mohammad, for he had all the power without its instruments and without its supports.

- Bosworth Smith

M

y choice of Muhammad to lead the list of the world's most influential persons may surprise some readers and may be questioned by others, but he was the only man in history who was supremely successful on both the religious and secular level.

-Michael H. Hart

"I

f any religion had the chance of ruling over England, nay Europe within the next hundred years, it could be Islam."

"I have always held the religion of Muhammad in high estimation because of its wonderful vitality. It is the only religion which appears to me to possess that assimilating capacity to the changing phase of existence which can make itself appeal to every age. I have studied him - the wonderful man and in my opinion far from being an anti-Christ, he must be called the Savior of Humanity."

"I believe that if a man like him were to assume the dictatorship of the modern world he would succeed in solving its problems in a way that would bring it the much needed peace and happiness: I have prophesied about the faith of Muhammad that it would be acceptable to the Europe of tomorrow as it is beginning to be acceptable to the Europe of today."

-Sir George Bernard Shaw

Works Cited

• HISTOIRE DE LA TURQUIE, PANS 1854, VOL. 11, PP. 276-77.z
• History of the Saracen Empire, London 1870, p54.
• Mohammad and Mohammadanism, London 1874, p 92
• The 100: A Ranking of the Most Influential Persons in History, New York: Hart Publishing Company Inc. 1978, p 33.
• 'The Genuine Islam,' Vol. 1, No. 8, 1936.

MUTATIONS
Change in the amount,content or organization of genetic material is called a mutation.  

TYPES OF MUTATIONS:

a)  POINT MUTATIONS (SINGLE BASE SUBSTITUTION): 

It is a type of small scale GENE MUTATION that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA.

They maybe:

• Transitions: replacement of a purine base with another purine or replacement of a pyrimidine with another pyrimidine.
• Transversions: replacement of a purine with a pyrimidine or vice versa.

Functional categorization:
1- Missense mutation: which results in a protein in which one amino acid is substituted for another due to base substitution.

2- Nonsense mutation: in which a stop codon replaces an amino acid codon, leading to premature termination of translation.

3- Frameshift mutation: which causes a change in the reading frame due to indels (insertions or deletions) of a number of nucleotides that is not evenly divisible by three from a DNA sequence, leading to introduction of unrelated amino acids into the protein, generally followed by a stop codon.

b)  CHROMOSOMAL MUTATIONS:
Chromosomal abnormalities involve alterations in large segments of DNA.

• Inversions: occurs when a break is rejoined to the correct chromosome but in an incorrect orientation.
• Interstitial deletions: an intra-chromosomal deletion that removes a segment of DNA from a single chromosome, thereby apposing previously distant genes
• Translocations: interchange of genetic parts from nonhomologous chromosomes.
• Insertions: when a segment from one chromosome is inserted into another chromosome.

Functional Categorization:

• Loss-of-function mutations are the result of gene product having less or no function. 
• Gain-of-function mutations change the gene product such that it gains a new and abnormal function
• Dominant negative mutations have an altered gene product that acts antagonistically to the wild-type allele. 

(IF A GENE REQUIRES ONLY ONE PERFECT ALLELE TO WORK AND THAT GENE IS HETEROZYGOUS OR PART MUTANT BUT THE DEFECTIVE PRODUCT OF ONE ALLELE ANTAGONIZES THE PRODUCT OF THE NORMAL THEN ITS CALLED NEGATIVE........)

• Lethal mutations are mutations that lead to the death of the organisms which carry the mutations.
• A back mutation or reversion is a point mutation that restores the original sequence and hence the original phenotype.

• Recessive mutations lead to a loss of function, which is masked if a normal copy of the gene is present. For the mutant phenotype to occur, both alleles must carry the mutation.
• Dominant mutations lead to a mutant phenotype in the presence of a normal copy of the gene. The phenotypes associated with dominant mutations may represent either a loss or a gain of function.)

The one gene-one enzyme hypothesis
(one gene one polypeptide synthesis is a better name since genes do not always code for enzymes but also structural proteins such as keratin of hair and collagen in our skin)
It is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway.

BEEDLE AND TATUM chose the fungus NEUROSPORA for their experiments.
Neurospora crassa had several advantages:

1.  it required a simple growth medium,
2.  it grew quickly,
3.  because of the production of ascospores during reproduction it was easy to isolate genetic mutants for analysis. 

EXPOSURE AND IDENTIFICATION OF MUTANT STRAINS:
They produced mutations by exposing the fungus to X-rays and then identified strains that had metabolic defects by growing them in minimal medium.

They had created single gene mutations that incapacitated specific enzymes and the mutant strains could be grown by adding the necessary and (formerly non-essential) nutrient to the minimal medium.

ARGININE DEFICIENCY:

In some cases it was the amino acid, Arginine which had to be added in order for the spores to grow.
Arginine is produced by Neurospora in a metabolic pathway controlled by enzymes where the product of one reaction serves as the substrate or precursor for the next.

ACETYLCHOLINE----ORNITHINE----CITRULINE----ARGINOSUCCININE-----ARGININE
                           
The following are the three mutant strains that are blocked at some stage in the above metabolic pathway.

• MUTANT 1:would grow if Ornithine,Citruline or Arginine were added to it showing that the enzyme that produced Ornithine was missing.

• MUTANT 2:would grow if C or A were added showing that the pathway was blocked due to enzyme B that produced Citruline.

• MUTANT 3:would grow if A was added to the minimal medium thus in this case enzyme D was absent and could not contribute to the formation of A.

 CONCLUSION:
They concluded that the irradiation had altered the genes in such a way that one precursor could not convert into another.
Since the addition of one enzyme seemed to be required for the production of Arginine in each mutant Beedle and Tatum argued that the each gene was producing an enzyme.

INTRODUCTION:
It was invented by the German physicist Hans Geiger (co-discoverer of the atom nucleus) and later improved by his student Walther Muller, therefore the name Geiger-Muller counter.

GEIGER MULLER COUNTER:
A Geiger counter is an avalanche detector and is used to measure and detect forms of ionizing radiation (which includes alpha α particles, beta β particles and gamma γ rays)

PRINCIPLE:
It relys on runaway multiplication of electrons.

CONSTRUCTION:
Geiger-Muller tube, is basically a chamber filled with low pressure gas(inert gas or a mix of organic vapor and halogens.)The tube contains two electrodes, the anode and the cathode, which are usually coated with graphite. The anode is represented by a wire in the center of the cylindrical chamber while the cathode forms the lateral area. One end of the cylinder, through which the radiation enters the chamber, is sealed by a mica window.
A potential difference of +1,000 volts relative to the tube is maintained between the electrodes, therefore creating a strong electric field near the wire.

WORKING:

• Ionization in the gas is caused by the entry of photon or a particular radiation coming through the mica window. 
• The positively charged ions are attracted to their appropriate electrode (i.e. cation to cathode, anion to anode) and they gain sufficient energy to eject electrons from the gas atoms as they pass through the gas. This causes more atoms to ionize. 
• Therefore electrons are produced continuously by this process and rapid gas multiplication takes place.
• The effect of "gas multiplication" is that more than one million electrons are collected by the central electrode for every ion produced in the primary absorption process.When this happens an electrical current is established between the two electrodes.

This current can then be easily collected, amplified and measured or counted and played in the form of an acoustic signal made out of clicks each of which should correspond to the detection of a single ion.

Therefore a Geiger counter is able to detect low-energy radiation because even one ionized particle produces a full pulse on the central wire.

REGENERATION:
Regeneration is the process of renewal, restoration, and growth of lost body parts.

ABILITY OF REGENERATION:
Depends on :

• Differentiation and Complexity

The more complex an organism the more will its cells be differentiated and lesser the power of regeneration.

PROCESS:

Some organisms are capable of dedifferentiation, in which specialized cells become more basic.
This process is involved in the regeneration of limbs in animals which are capable of this feat, with the basic cells differentiating again to construct the needed tissues, bones, and other types of cells for the replacement.

A small molecule dubbed reversine, has been discovered that has proven to induce dedifferentiation in myotubes. These dedifferentiated cells could then redifferentiate into osteoblasts and adipocytes.

EXAMPLES:
SPONGES:small parts can regenerate whole colonies.
HYDRA OR STARFISH:chopped parts can form new animal.

ARTHROPODS:can regenerate lost appendages.
SALAMANDERS AND LIZARDS:can regenerate lost tails.

BIRDS AND MAMMALS:new cells can form at points of wounds.

CELL DIFFERENTIATION AND STEM CELLS:

The process during which young, immature (unspecialized) cells take on individual characteristics and reach their mature (specialized) form and function.

EXAMPLES:
Embryonic stem cells Fetal stem cells Cord blood stem cells and some adult stem cells are capable of performing this process.

Totipotent : Toti, meaning total, the zygote and the embryo during early stages of development have the potential to become any type of cell and can produce a whole human being.

Pluripotent: Cells which can differentiate into several different cell types,except placenta, are considered to be pluripotent

EMBRYONIC STEM CELLS:
Cells that form the inner mass of a blastocyst during embryological phase of growth (lasting 8 weeks)are called embryonic stem cells.Like all stem cells they can proliferate and give rise to specialized cells.

CULTURE OF EMBRYONIC STEM CELLS
Credit: The National Academy of Sciences has kindly allowed the images to be reprinted on the weird science blog. Check out the original link called Understanding Stem Cells, courtesy of the National Academies Press in Washington, D.C.

FETAL STEM CELLS:
The cells taken from a fetus (after 8 weeks of development an embryo is termed as such) are called fetal stem cells.

ADULT STEM CELLS:
These are undifferentiated cells found throughout the body that are involved in refurbishing the body with new cells to replace worn out ones.
Examples of stem cells in an adult:
Hematopoietic stem cells
Neural stem cells
intestinal stem cells

CORD BLOOD STEM CELLS:
The cells of the umbilical cord and placenta are unspecialized stem cells and can be cultured.

CAUSE:
Specific groups of genes are expressed in each cell type which leads to production of specific proteins (the other unneeded genes are turned off)
Proteins (coded for by the DNA) are the keys to differentiation in animal cells

The particular combination of genes that are turned on (expressed) or turned off (repressed) dictates cellular morphology (shape) and function. This process of gene expression is regulated by cues from both within and outside cells and lead to differentiation.

CHEMICAL COMPOSITION OF CHROMOSOMES:

The major chemical components of chromosomes are DNA, RNA, histone proteins and non-histone proteins. Calcium is also present in addition to these constituents.

DNA -Deoxyribonucleic Acid:
DNA is the most important of chemical components of chromatin, since it plays the central role of controlling heredity.

Histone proteins:
These are Lysine And Arginine rich, basic and stable proteins in chromosomes.
They are classified into five types called HI, H2A, H2B, H3 and H4. 

Non-histone proteins:
Non-histone proteins provide the scaffolding structure.

DNA PACKAGING:

The diploid human genome contains 6 billion base pairs of DNA per cell.This is enough to make some very lengthy journeys like, to the sun and back.300 times.In order for this massive amount of DNA to exist in a cell ,it has to be made very compact.In short, it needs to be packaged into a very small surface area to volume ratio.
Patterns of packaging are facilitated by associated proteins, which in eukaryotes, could be histones or non-histones.

The unit of compaction is nucleosome consisting of a segment of DNA wound in sequence around four histone protein cores.

• Histone proteins provide the spools about which DNA winds thus compressing 1.8 meters of dna into 90 mm.The negatively charged coil of polynucleotide (due to phosphate) is strongly attracted by the positively charged histone protein which helps in compaction.

• The nucleosomes are linked together by the long strand of DNA called linker DNA. 

• The beads-on-string structure in chromatin is packaged to form chromatin fibres which then fold together into large looped domain.that are further coiled and condensed at metaphase stage of cell division to form chromosomes.

• The packaging at higher level requires non-histone proteins. 

HETEROCHROMATIN AND EUCHROMATIN:

In a typical nucleus, some region of chromatin are loosely packed (and stains light) and are referred to as euchromatin.Euchromatin is said to be transcriptionally active
The chromatin that is more densely packed and stains dark is called as heterochromatin. Heterochromatin is transcriptionally inactive.