THE CELL

Cells are the Starting Point

All living organisms on Earth are divided into cells. The main 

concept ofcell theory is that cells are the basic structural unit 

for all organisms. Cells are small compartments that hold the

 biological equipment necessary to keep an organism alive and 

successful. Living things may be single-celled or they may be

 very complex such as a human being.

There are smaller pieces that make up cells such as macromolecules andorganelles. A protein is an example of

 a macromolecule while amitochondrion is an example of an 

organelle. Cells can also connect to form larger structures. 

They might group together to form the tissues of the stomach 

and eventually the entire digestive system. However, in the 

same way that atoms are the basic unit when you study matter,

 cells are the basic unit for biology and organisms.

In larger organisms, the main purpose of a cell is to organize. 

Cells hold a variety of pieces and each cell type has a different

 purpose. By dividing responsibilities among different groups of

 cells, it is easier for an organism to survive and grow.

If you were only made of one cell, you would be very limited.

 You don't find single cells that are as large as a cow. Cells have

 problems functioning when they get too big. Also, if you were

 only one cell you couldn't have anervous system, no muscles

 for movement, and using the internet would be out of the 

question. The trillions of cells in your body make your way of 

life possible.

One Name, Many Types

There are many types of cells. In biology class, you will usually

 work withplant-like cells and animal-like cells. We say 

"animal-like" because an animal type of cell could be anything 

from a tiny microorganism to a nerve cell in your brain. Biology 

classes often take out a microscope and look at single-celled 

microbes from pond water. You might see hydra, 

amoebas, or euglena. 

Plant cells are easier to identify because they have a protective 

structure called a cell wall made of cellulose. Plants have the 

wall; animals do not. Plants also have organelles such as the 

green chloroplast or large, water-filled vacuoles. Chloroplasts 

are the key structure in the process ofphotosynthesis.

Cells are unique to each type of organism. If you look at very 

simple organisms, you will discover cells that have no defined 

nucleus (prokaryotes) and other cells that have hundreds of 

nuclei (multinucleated).

Humans have hundreds of different cell types. You have red 

blood cells that are used to carry oxygen (O2) through the body 

and other cells specific to your heart muscle. Even though cells 

can be very different, they are basically compartments 

surrounded by some type of membrane. 

• Overview
• Cell Membrane
• Memb. Proteins
• Cell Walls
• Connections
• Cytoplasm
• Nucleus
• Chromosomes
• Centrioles
• Ribosomes
• Mitochondria
• Chloroplasts
• Endo. Reticulum
• Golgi Complex
• Vacuoles
• Microfilaments
• Microtubules
• Lysosomes
• Peroxisomes
  

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Inside the Cell (Canadian Museum of Nature Video)

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RATIONALISATION

                               RATIONALISATION                    

In elementary algebra, root rationalisation is a process by which radicals in the denominator of an algebraic fraction are eliminated.

If the denominator is a monomial in some radical, say  with k < n, rationalisation consists of multiplying the numerator and the denominator by  and replacing  by x (if k ≥ n, the same replacement allows us to reduce k until it becomes lower than n.

If the denominator is linear in some square root, say  rationalisation consists of multiplying the numerator and the denominator by  and expanding the product in the denominator.

This technique may be extended to any algebraic denominator, by multiplying the numerator and the denominator by all algebraic conjugates of the denominator, and expanding the new denominator into the norm of the old denominator. However, except in special cases, the resulting fractions may have huge numerators and denominators, and, therefore, the technique is generally used only in the above elementary cases.

Rationalisation of a monomial square root and cube root

For the fundamental technique, the numerator and denominator must be multiplied by the same factor.

Example 1:

To rationalise this kind of monomial, bring in the factor :

The square root disappears from the denominator, because it is squared:

This gives the result, after simplification:

Example 2:

To rationalise this radical, bring in the factor :

The cube root disappears from the denominator, because it is cubed:

This gives the result, after simplification:

Dealing with more square roots

For a denominator that is:

Rationalisation can be achieved by multiplying by the Conjugate:

and applying the difference of two squares identity, which here will yield −1. To get this result, the entire fraction should be multiplied by

This technique works much more generally. It can easily be adapted to remove one square root at a time, i.e. to rationalise

by multiplication by

Example:

The fraction must be multiplied by a quotient containing .

Now, we can proceed to remove the square roots in the denominator:

Example 2:

This process also works with complex numbers with 

The fraction must be multiplied by a quotient containing .

•  This video talks about how to rationalise denominator of an expression by multiplying it with another irrational number.

Generalizations

Rationalisation can be extended to all algebraic numbers and algebraic functions (as an application of norm forms). For example, to rationalise a cube root, two linear factors involving cube roots of unity should be used, or equivalently a quadratic factor.

Motion in One Dimension

In this chapter we discuss motion in one dimension. We introduce definitions for displacement, velocity and acceleration, and derive equations of motion for bodies moving in one dimension with constant acceleration. We apply these equations to the situation of a body moving under the influence of gravity alone.

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• Displacement
• Average Velocity
• Instantaneous Velocity
• Acceleration
• One Dimensional Motion with Constant Acceleration
  • Derivation of Kinematic Equations of Motion
  • Freely Falling Bodies
• Problems

GREATEST DISCOVERIES OF THE WORLD

GREATEST Science Discoveries!

Try to imagine life without antibiotics. We wouldn’t live nearly as long as we do without them. Here’s a look at some discoveries that have changed the world. It’s impossible to rank their importance, so they’re listed in the order they were discovered.

The Copernicum System

In 1543, while on his deathbed, Polish astronomer Nicholas Copernicus published his theory that the Sun is a motionless body at the center of the solar system, with the planets revolving around it. Before the Copernicum system was introduced, astronomers believed the Earth was at the center of the universe.

Gravity

Isaac Newton, an English mathematician and physicist, is considered the greatest scientist of all time. Among his many discoveries, the most important is probably his law of universal gravitation. In 1664, Newton figured out that gravity is the force that draws objects toward each other. It explained why things fall down and why the planets orbit around the Sun.

Electricity

If electricity makes life easier for us, you can thank Michael Faraday. He made two big discoveries that changed our lives. In 1821, he discovered that when a wire carrying an electric current is placed next to a single magnetic pole, the wire will rotate. This led to the development of the electric motor. Ten years later, he became the first person to produce an electric current by moving a wire through a magnetic field. Faraday's experiment created the first generator, the forerunner of the huge generators that produce our electricity.

Evolution

When Charles Darwin, the British naturalist, came up with the theory of evolution in 1859, he changed our idea of how life on earth developed. Darwin argued that all organisms evolve, or change, very slowly over time. These changes are adaptations that allow a species to survive in its environment. These adaptations happen by chance. If a species doesn't adapt, it may become extinct. He called this process natural selection, but it is often called the survival of the fittest.

Louis Pasteur

Before French chemist Louis Pasteur began experimenting with bacteria in the 1860s, people did not know what caused disease. He not only discovered that disease came from microorganisms, but he also realized that bacteria could be killed by heat and disinfectant. This idea caused doctors to wash their hands and sterilize their instruments, which has saved millions of lives.

Theory of Relativity

Albert Einstein’s theory of special relativity, which he published in 1905, explains the relationships between speed, time and distance. The complicated theory states that the speed of light always remains the same—186,000 miles/second (300,000 km/second) regardless of how fast someone or something is moving toward or away from it. This theory became the foundation for much of modern science.

The Big Bang Theory

Nobody knows exactly how the universe came into existence, but many scientists believe that it happened about 13.7 billion years ago with a massive explosion, called the Big Bang. In 1927, Georges Lemaître proposed the Big Bang theory of the universe. The theory says that all the matter in the universe was originally compressed into a tiny dot. In a fraction of a second, the dot expanded, and all the matter instantly filled what is now our universe. The event marked the beginning of time. Scientific observations seem to confirm the theory.

Penicillin

Antibiotics are powerful drugs that kill dangerous bacteria in our bodies that make us sick. In 1928, Alexander Fleming discovered the first antibiotic, penicillin, which he grew in his lab using mold and fungi. Without antibiotics, infections like strep throat could be deadly.

DNA

On February 28, 1953, James Watson of the United States and Francis Crick of England made one of the greatest scientific discoveries in history. The two scientists found the double-helix structure of DNA. It’s made up of two strands that twist around each other and have an almost endless variety of chemical patterns that create instructions for the human body to follow. Our genes are made of DNA and determine how things like what color hair and eyes we’ll have. In 1962, they were awarded the Nobel Prize for this work. The discovery has helped doctors understand diseases and may someday prevent some illnesses like heart disease and cancer.

Periodic Table

The Periodic Table is based on the 1869 Periodic Law proposed by Russian chemist Dmitry Mendeleev. He had noticed that, when arranged by atomic weight, the chemical elements lined up to form groups with similar properties. He was able to use this to predict the existence of undiscovered elements and note errors in atomic weights. In 1913, Henry Moseley of England confirmed that the table could be made more accurate by arranging the elements by atomic number, which is the number of protons in an atom of the element.

X-Rays

Wilhelm Roentgen, a German physicist, discovered X-rays in 1895. X-rays go right through some substances, like flesh and wood, but are stopped by others, such as bones and lead. This allows them to be used to see broken bones or explosives inside suitcases, which makes them useful for doctors and security officers. For this discovery, Roentgen was awarded the first-ever Nobel Prize in Physics in 1901.

Quantum Theory

Danish physicist Niels Bohr is considered one of the most important figures in modern physics. He won a 1922 Nobel Prize in Physics for his research on the structure of an atom and for his work in the development of the quantum theory. Although he help develop the atomic bomb, he frequently promoted the use of atomic power for peaceful purposes.

Atomic Bomb

The legacy of the atomic bomb is mixed: it successfully put an end to World War II, but ushered in the nuclear arms race. Some of the greatest scientists of the time gathered in the early 1940s to figure out how to refine uranium and build an atomic bomb. Their work was called the Manhattan Project. In 1945, the U.S. dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. Tens of thousands of civilians were instantly killed, and Japan surrendered. These remain the only two nuclear bombs ever used in battle. Several of the scientists who worked on the Manhattan Project later urged the government to use nuclear power for peaceful purposes only. Nevertheless, many countries continue to stockpile nuclear weapons. Some people say the massive devastation that could result from nuclear weapons actually prevents countries from using them.

HIV/AIDS

In 1983 and 1984, Luc Montagnier of France and Robert Gallo of the United States discovered the HIV virus and determined that it was the cause of AIDS. Scientists have since developed tests to determine if a person has HIV. People who test positive are urged to take precautions to prevent the spread of the disease. Drugs are available to keep HIV and AIDS under control. The hope is that further research will lead to the development of a cure.

GREATEST SCIENTISTS WHO CHANGED THE WORLD

GREATEST  SCIENTISTS  WHO  CHANGED  THE  WORLD?

Right from the beginning of human settlement, a lot of people came up with ideas, philosophies, beliefs, experiments, research, redesigning of thoughts, and surveys to bring myths to reality. People contributed for science to study different aspects of nature to prosper mankind. These genius minds put a keen interest on every phenomenon right from when they were kids. The zeal, passion, dedication, hard work and the effort they put in their work helped them discover something new about the world we live in.

The world today dwells in the abode of scientific advancement in different sectors of medical science, engineering and technology because of these scientists. The present picture of the world that we see would not have transformed without the contribution of these great personalities. Great philosophers and masterminds that existed in the ancient Greek era to the present day scientists, we’ve seen inexplicable abilities that helped us define our existence and human life.

Their names are engraved in the sands of time for their work in the welfare of mankind with different inventions that has made our modern lives easy. The following list commemorates 10 of the greatest scientists we’ve ever seen who changed the world.

10. Aristotle (384-322 BC)

Student of Plato and a tutor to Alexander the Great, Aristotle was a genius Greek philosopher and scientist of the ancient age. Born on 384 BC Aristotle was a biologist, a zoologist, ethicist, a political scientist and the master of rhetoric and logic. He also gave theories in physics and meta physics.

Aristotle gained knowledge in different fields with his expansive mind and prodigious writings. However, only a fraction of his writings are preserved at present. Aristotle made collections to the plant and animal specimens and classified them according to their characteristics which made an standard for future work. He further gave theories on the philosophy of science.

Aristotle also elaborated and estimated the size of earth which Plato assumed to be globe. Aristotle explained the chain of life through his study in flora and fauna where it turned from simple to more complex.

9. Archimedes (287-212 BC)

Regarded as the greatest mathematician ever, Archimedes developed profound and influential knowledge on mathematical physics and engineering that are widely used in machines as well as in constructions. Born on 287 BC, Archimedes is one of the finest scientist who broke through in both theories and practice.

He introduced infinitesimals and laid the foundation for calculus. He gave descriptions on the first finite geometric progression, computed areas and volumes of sphere and parabolic segments.

He also discovered the laws of lever, density, fluid equilibrium, buoyancy in different fields statics and hydrostatics. He is regarded as the prophet to the formal science that was started in Ancient Greece.

“Give me a place to stand and I can move the whole world”, he said and we can still fill the impact of his generosity even today. All other scientists after him stand on his shoulders. Even though most of his work were burned in the museum of Alexandria, the remnants gave enough ideas for modern day science and technology.

 8. Galileo Galilei (1564-1642 AD)

Born in Pisa, Italy in 1564, Galileo is called as the father of modern science because of his discoveries in astronomy and physics.

He was sent to study medicine by his father, but he chose his career in science and mathematics and made the first telescope to observe stars and planets.

He also discovered the law of pendulum as he watched a chandelier swing in the cathedral of Pisa. He also discovered that the surface of moon was not smooth but contained burrows and holes to what he called crater.

Galileo discovered 4 revolving moons around Jupiter which are named after him. He proved what Copernicus said about sun being the center of the solar system. Galileo became blind in his old days and died in the year 1642.

 7. Michael Faraday (1791-1867 AD)

Born on 1791, British citizen Michael Faraday was a son of a blacksmith who had to leave school in the fourth grade.It started working as a bookbinder and taught himself to read and writer. He developed a fascination with science and particularly in electricity after he studied lot of serious academic works during his days.

Faraday is specially known for his discoveries of electromagnetic inductions and rotations, field theory, dia-magnetization and the magneto-optical effect. This humble genius invented the electric motor and Faraday’s ring.

Faraday’s inquisitive and curious nature made him take chemistry lectures and taught at the Royal Institution as a lecturer later when Humphry Davy retired.

Faraday also published research papers optical deceptions, condensation of gases and isolation of benzene from gas oils. He also wrote books on ”Experimental Researches in Electricity” and the “Chemical history of the Candle”. Faraday died on 1867.

 6. Thomas Alva Edison (1847-1931 AD)

“The Wizard of the Menlo Park” nicknamed Thomas Alva Edison was born in 1847. Excelled as both scientist and inventor, Edison patented a whopping total of 1,093 inventions in his life time. Most of the inventions that came from Edison are batteries, phonographs, cement, mining, telegraphs, lights and powers.

He also improved the telephone made by Graham Bell and invented the kinetoscope that was used for viewing moving films. He was seen working almost more than 20 hours a day.

Edison masterminded the digital voting system with his electro-graphic vote recorder for the legislative of the parliament. He also proposed ideas on preserving fruits by keeping it in vacuum. Edison pioneered the idea for storage batteries that was later used by Henry ford in his automobile.

“Genius is one percent inspiration and 99 percent perspiration” is one of the most famous quote by this genius. He died in the year 1931.

 5. Marie Curie Sklodowska (1867-1934 AD)

 Marie Curie holds record for the first female to be awarded with a Nobel Prize. Inventor and scientist Curie was born as the youngest of five children in the year 1867 in Warsaw, Poland.

Marie Curie has always remained a source of inspiration and motivation for different female scientists because of her determination to work. She invented the first mobile X-ray machine which helped to check the injured soldiers in the battlefield.

Radium is another great invention from her. Curie experimented different elements to check their radio activity and found thorium. She also invented the pitch-blend which was the source of radiation in a mixture more powerful than uranium or thorium. She is also called ”the mother of atom bomb” with her invention of the radio active materials.

However, with all her brilliance, hard work and patience in careful experiments she performed, her own invention killed her because of radiation poisoning in 1934.

 4. Louis Pasteur (1822-1895 AD)

Louis Pasteur made astounding contributions in the field of science, technology and medicine. This genius was born on 1822 and spent his life working in chemistry and microbiology.

Pasteur was the first ever scientist to study about fermentation in food elements that was caused by microbes. He also explained about biogenesis and proposed a theory named as the “Germ Theory”. He also created a process of toning and treating milk free from the damage causing microbes to what he called ”Pasteurization”.

Pasteur is also regarded as the first man on earth to ever discover cure for puerperal fever and make the vaccines for rabies and anthrax. He also explained the asymmetry in various crystals on a molecular basis.

His breadth of accomplishment and approaches in different fields of discoveries and inventions makes him a giant genius. He died in 1895.

3. Sir Isaac Newton (1643-1727 AD)

Born on 1643 in Woolsthrope, England, Sir Issac Newton is best known for his law on gravitation. He was a poor student at school or at running the family estate. However, he loved making mechanical toys and models of windmills.

Newton explained the theory of gravity and gravitation by inventing calculus as no other principles could explain it. The new revolution in mathematics, calculus was derived from his binomial theorem to infinite series which accurately could measure the area inside the curve or rate of change of it.

He also explained the theory on tides which occurred due to the gravitation pull from the sun, moon and earth.

He also invented the reflecting telescope. Newtons laws can be found in different areas of mechanics, optics and chemistry. He was knighted with the title Sir by Queen Anne in 1705. Newton died at the age of 84, in 1727.

2. Albert Einstein (1879-1955 AD)

Born on 1879 in Ulm, Einstein is considered as one of the greatest revolutionary scientist the world has ever known.

The “Man of Century” has some spectacular works in physics which even makes him the father of modern physics for his contribution in developing the general theory of relativity. The world’s most famous equation E=mc2 on which the bomb is based comes from his theory.

One of the greatest scientist of the 20th century, Einstein’s Special theory of relativity revolutionized physics which even challenged the scientists at CERN. Albert Einstein’s genius mind for the scientific advancement cause immeasurable change to the world. Together with his intellect, he was also a celebrity with his flirtatious behavior that could impress any women.

This rare genius was awarded Nobel Prize in 1921 ”For his work on theortical physics, and for his discovery of the photoelectric effect”. Greatest physicist ever voted Einstein died on 1955 in Princeton.

1. Nikola Tesla (1856-1943 AD)

 This Serbian born scientist atop the list because of his immense knowledge in different fields of science and technology.

Without a question, this 1856 born guy was a cool geek. He could speak 8 languages, recite a whole book completely just with one reading, make a device just by seeing it once and not writing down anything. A funny fact about him was that he was a celibate his whole life.

Tesla had developed almost everything by himself and did not expose any of it which later was invented by other scientists in his time. Tesla had generated ac current before Edison knew about charges. Markoni who got Nobel prize for inventing radio used all the ideas of Tesla. X-rays by Roentgen, RADAR by Watson-watt were all devised by Nikola Tesla.

 

There was almost nothing that Tesla did not do. First hydro electricity plant in Niagara falls, experiments with cryogenic engineering, transistors, radio wave recorder from outer space were all built by Tesla. Remote control, neon lightening, modern electric motor, earthquake machine are finest inventions from Tesla. He was a true genius.

However, most of his ideas and inventions were either copied, stolen or taken by somebody else. Tesla made a way to charge a house with electric lightening for electricity purpose but did not share it thinking somebody else will take it.

This incredible mind created revolution with his inventions. He was a future-thinker and his minds would run on any wavelengths. However, he died tragically in a hotel room and was found dead only after two days of his death in 1943.