What is ROM and RAM memory?

What is Computer Memory?

To process information electronically, data are stored in a computer in the form of binary digits, or bits, each having two possible representations (0 or 1).
If a second bit is added to a single bit of information, the number of representations is doubled, resulting in four possible combinations: 00, 01, 10, or 11.
A third bit added to this two-bit representation again doubles the number of combinations, resulting in eight possibilities: 000, 001, 010, 011, 100, 101, 110, or 111.
Each time a bit is added, the number of possible patterns is doubled.
Eight bits is called a byte; a byte has 256 possible combinations of 0s and 1s.
A byte is a useful quantity in which to store information because it provides enough possible patterns to represent the entire alphabet, in lower and upper cases, as well as numeric digits, punctuation marks, and several character-sized graphics symbols, including non-English characters.
A byte also can be interpreted as a pattern that represents a number between 0 and 255. 
A kilobyte—1,024 bytes—can store about 1,000 characters; 
a megabyte can store about 1 million characters; 
a gigabyte can store about 1 billion characters; and 
a terabyte can store about 1 trillion characters. 
Computer programmers usually decide how a given byte should be interpreted—that is, as a single character, a character within a string of text, a single number, or part of a larger number.
Numbers can represent anything from chemical bonds to dollar figures to colors to sounds.

What is ROM and RAM memory?

The physical memory of a computer is either random access memory (RAM), which can be read or changed by the user or computer, or read-only memory (ROM), which can be read by the computer but not altered in any way.

ROM stands for read only memory. 

ROM carries the information the computer needs to carry out its tasks. This information is built into the computer and cannot be altered. It stays there even when the computer is switched off, just as your memory of how to get to the park stays with you until you need it again.

RAM stands for random access memory, or read and write memory. 

This contains the information the computer needs to carry out the particular task you want it to do now. When you switch off the computer, RAM empties itself.
You can save your work on disk or USB stick. Next time you use the computer, you will have to feed in the program again, together with new data and commands.
Programs and data are stored on a disk. The disk drive reads the data and feeds it into the RAM.
People, like computers, have a short-term and a long-term memory.
You won't forget how to get to the park, but you might forget what your friend said an hour ago.

Storing information

ROM and RAM are both made up of memory cells.
Each memory cell stores binary digits.
A chip may be able to store many thousands of bits.
It is easy to see that the size of a computer's RAM is important, because the computer can only do the amount of work that its RAM has room for.
With some computers, it is possible to add extra memory chips to increase the RAM.

Structure of an Atom - What is the Structure of an Atom

Structure of an Atom - What is the Structure of an Atom?

Atoms are composed of smaller particles called protons, neutrons and electrons.
Then Atom consists of a cloud of electrons, surrounding the core - protons and neutrons. 
The electrons and protons have electric charge, which affects the way they interact with each other and with other electrically charged particles.
Electrons have a negative electrical charge, while protons have positive. 
The negative charge is the opposite of the positive charge, and as the opposite poles of a magnet, this opposite electrical charges attract.
However, as the charges (negative and negative or positive and positive) repel.
The attraction between the electrons of an atom and its protons holds the atom together. Normally, an atom is electrically neutral, meaning that the negative charge of the electrons is exactly equal to the positive charge of the protons.
The core contains nearly all of the mass of an atom, but it occupies only a small fraction of the interior space of the atom. The typical diameter of a nucleus is only about 1 × 10-14 m (4 x 10 - 13 in), or about 1/100, 000 of the diameter of the atom.
The electron cloud constitutes the rest of the overall size of the atom.
If an atom is magnified until it is as big as a football stadium, the nucleus would be the size of a grape.
What is the Structure of an Atom

What is an atom - definition of atom?

Atom - small basic building block of matter. 

All materials on Earth are composed of different combinations of atoms.
Atoms are the smallest particles of a chemical element that still have all the unique chemical properties of this element.
A row of 100 million atoms would be about a centimeter long.
Understanding the atoms is the key to understanding the physical world.
More than 100 different elements exist in nature, each with its own unique atomic structure. The atoms of these elements react with each other and make different combinations, forming virtually unlimited number of chemical compounds.
When two or more atoms combine, they form a molecule. 
For example, the two hydrogen atoms (abbreviated to H) combined with an atom of the element oxygen (O),  form a water molecule (H20).
Since all matter, since its creation in the early universe to current biological systems is made up of atoms, understanding their structure and properties play an important role in physics, chemistry and medicine.
In fact, knowledge of atoms is essential to the modern scientific understanding of the complex systems that govern the physical and biological worlds.
Atoms and compounds they form play a role in almost all processes occurring on Earth and in space.
All living organisms rely on a set of chemical compounds and chemicals to digest food, energy transport reactions, and to reproduce.
Stars like the Sun rely on reactions in the atomic nucleus to produce energy. Scientists duplicate these reactions in their laboratories on Earth and study them to learn more about the processes that occur in the universe.
Atom Diagram - What is an atom - definition of atom?
Throughout history, people have sought to explain the world in terms of its most basic parts.
Ancient Greek philosophers conceived the idea of ​​the atom, which they define as the smallest part of a possible substance.
The word atom comes from the Greek word meaning "not divisible."
The ancient Greeks also believed that fundamental particle was indestructible.
Scientists have learned that atoms are not indivisible, but small particles and atoms of different elements contain different numbers of each type of these smaller particles.

What are white blood cells and what is their function in the human body?

White blood cells are almost 900 times less than the red blood cells, there are several types of it, whose primary task is to fight infection.
Small red cells are much more numerous in the blood and give it its color. But white blood cells also play an important role. White blood cells are also called leukocytes.
The most numerous white blood cells are granulocytes.
These cells go in and out in the blood at the point where germs are collected or where is injured tissue. Some of them, which we call Neutrophils, take the bacteria within and destroy them. Leukocytes produce substances that soften and digest dead tissue and produce pus.
Other white blood cells are called lymphocytes.
Their number is often increased when the body for a longer time is exposed to an infection. They are an integral part of the mechanized body, and as we can see, their role is very important.
The third type of white blood cells are Monocytes.
These cells, together with other cells in tissues, have the ability to accept parts of dead matter.  They can also surround some substance such as dust, and prevent it to come into contact with healthy tissue cells.
Although the white blood cells are needed by the body, it is not so good when there are too many.
Basophil White Blood Cells

Eosinophil White Blood Cells

Lymphocytes White Blood Cells

Monocyte White Blood Cells

Neutrophil White Blood Cells

What are red blood cells - what do red blood cells do?

What are red blood cells?

Red blood cells (also called erythrocytes) provide a blood red color. There are so many red blood cells in the blood (about 25 billion) which makes them responsible for the red color of the blood.
These tiny, round and flattened discs, all at the same time circulate through our bodies and are always found in the blood vessels.
It is almost impossible to imagine such a large number, but this may help you to understand it:
Each blood cell is so small that it can be seen only under a microscope.
If we can connect these microscopic cells into a series, than we could encircle the globe four times!
However, during blood tests, only blood cells from one spatial millimeter of blood are counted, not from the whole body.
Although these cells are very small, together they cover a huge area.
For example, if you have woven them into the carpet, its total area would amount to 4,500 square meters. Given that at any moment one-fourth of blood is in the lungs, an area of about 1,100 square meters of red blood cells is constantly exposed to the air.

What do red blood cells do?

When in the bone marrow, a red blood cell grows and becomes mature, it loses its nucleus and contains more hemoglobin.
Hemoglobin is red pigment or color and it contains iron in combination with proteins.
When blood passes through the lungs, oxygen binds to the hemoglobin of red blood cells.
Red blood cells carry oxygen through the arteries and capillaries to all cells of the body.
Carbon dioxide from the cells of the body goes through the veins to the lungs in the same way, usually combined with hemoglobin.

From where originate these blood cells? 

Apparently, the "factory" in which is created such enormous amount of cells “the bone marrow” must have such amazing productivity - especially when we take into account that, sooner or later, each of these cells dissolves and it is replaced by a new one!
Red blood cells live only about four months and then fall apart, mostly in the spleen.
Human bone marrow is adapted to their need for oxygen.
At high altitudes it produces more red blood cells, and at low altitudes less. People who live on mountain tops may have nearly double the number of red blood cells than people who live on the coast!
The number and size of red blood cells, in a human being depends on one's need for oxygen.
Worms do not have blood cells.
Cold-blooded animals - reptiles – are have relatively large and numerous blood cells in their blood.
Small, warm-blooded animals, which live in mountainous areas, have the highest number of red blood cells.

Why Am I Always Tired - Why People Get Tired?

Why am I always tired?

Fatigue can be considered a sort of intoxication. 
When the muscles of our body work, lactic acid is created.
If we remove the acid from the tired muscles, they will be able to work again.

During the day, we are, we are “poisoning” ourselves with lactic acid. 
Also there are other substances which are produced during muscle work, and these substances are called poisons fatigue. They are carried by the blood throughout the body, so we feel tired not just in the muscles, but also in the entire body, especially the brain.
Scientific experiments related to fatigue are showing some interesting results. 
If a dog gets tired to exhaustion and sleep, and then its blood is injected into another dog, that dog will also immediately become tired and fall asleep to.
If, on the contrary, a tired dog receives a blood transfusion from rested, alert dog, this dog will immediately wake up and will not feel tired.
Fatigue is not only a chemical process, but also a biological.
We can’t simply "remove" tiredness, because the cells need rest, to rebuild and be able to work again. Therefore, fatigue is a signal which indicates that the body needs rest to rejuvenate the body's energy.
However, there is something of particular interest in the rest.
Someone who has worked hard for hours at a desk will not want to lie down when he gets tired.

He will want to walk! 
Or when kids get tired from school, they don’t lie down to rest, but they run out to play.
This can be explained as follows:
If only a part of the body is tired, such as the brain, eyes, hands or feet, the best way to refresh that part of the body, is to activate other parts of the body.
Movement enhances breathing, blood circulation and glandular activity, and pollutants leave the tired parts.
But if someone is exhausted, the best rest is a dream.

Human muscles - What is their function?

In some parts of the body there are cells that can shrivel or relax – these are the muscle cells.
There are two types:  
  • smooth and 
  • striated.
Smooth muscles are found in many parts of the body and support the work of almost all organs: they contract and expand the pupil of the eye, regulate breathing and so on. Contraction of smooth muscle is strong, but slow.

Where is necessary to move quickly, are located the striated muscle cells. All the muscles that move our limbs are striated.
The human body has 639 muscles. 
  • Muscles are actually fleshy parts of the body.
  • Meat purchased from a butcher is striated muscle.
  • Muscles are in different sizes and different shapes.
Medium sized muscle is consisted of about ten million of muscle cells, and the whole body from about six billion muscle cells!
Each of the six billion of muscle-like cells, is similar to ten-cylinder engine arranged in a single row. Cylinders are tiny boxes containing liquid. Muscle twitches when the brain sends a message to the muscle boxes. For a fraction of a second fluid in such a tiny box thickens: and then becomes liquid again. This leads to contraction and relaxation of muscles.
The muscles in our body, which we can consciously move are the striated. Smooth muscles (such as those involved in the digestion of food) are independent of our will.
When a muscle is stimulated to act, it reacts quickly: it can shrivel to less than a tenth of a second.
But before it gets to relax, it gets another message, so it writhes and convulses again.
Contractions occurred so rapidly that merge into a single action, as evidenced by the smooth and continuous operation of muscles.

How do muscles work?

Muscles are made of tough, elastic tissue.
 They are built so that they can contract, which means that they become shorter.
When the muscles whose ends are joined to bones contract, they pull at the bones and make them move.
Muscles are made up of long, thin cells that join together to make muscle fibers. When the muscle becomes shorter, all the fibers move closer together, making the muscle bulge.
You can see your muscles bulging and relaxing when you move your arms and legs. If you bend your elbow and clench your fist, the muscles called biceps in your upper arm will bulge.

Muscles can only pull—they can’t push. 

Muscles whose ends are joined to bones work in pairs. One muscle contracts and pulls the bone one way, and the other contracts to pull the bone back again.

Interesting Facts About Muscles

  • Human muscle cells produce enough heat every day to boil almost 2 pints of water for an hour.
  • The tongue is the strongest muscle in the human body. 
  • Muscles make around 40% of human body weight.
  • We utilize more than 200 muscles just to make one step.
  • The foot is responsible for one quarter of all the human body’s muscles
  • Fingers do not have muscles in them, since they are moved by tendons and attached to muscles in the forearm. 
  • When we shiver, our muscles contract involuntarily and this releases energy that keeps the body warm.
  • The heart beats more than 4500 times each hour since the cardiac muscle never gets tired.  While sleeping, playing sport, resting even when going into the toilet, the hearth beats on average 80 beats per minute. 
  • While smiling, we are using about 30 muscles, which control the eyelids, nostrils and brow, working together to show emotions.

Joints of The Human Skeleton Bones - Why Are They Movable?

If the body did not have joints, we would not be able to move. 

Than we could only lie completely motionless, unable to move our head, to walk, to raise our hands or move only one finger!

All this we can do through the joints.

Everywhere where two bones slide over one another, there is a joint. The joint allows the bones to move smoothly with little friction, because the ends of the bones are covered with cartilage, so that the bones do not rub against each other.
In addition, the joint is whitish liquid, thick as a living egg, synovial fluid, and it plays the role of lubricating the machine, which reduces friction.
When the joint is at rest, it generates very little synovial fluid and joint becomes really creaky.

Types of joints

In the human body there are four types of joints:
  • angular, 
  • egg-shaped, 
  • in the form of hinge joints and 
  • rotary joints. 
Shoulder joint, which is spherical, is the most mobile of all the joints in the body. Therefore, we can run hand in all directions.
The hip joint is the largest ball joint, but because it is deeper, it is not so mobile.
The second type is egg-shaped joint.
This joint has an ovoid surface, which retracts into the appropriate socket. One form of this type is the saddle-shaped joint, in which the bones can only move in two directions, as a rider in the saddle. This type of joint we have in the spine, which can only bend in two directions, forward and from one side to the other.

The third type of joint is the joint in the form of hinges. These bones can only move back and forth in a plane, such as a door or a pocket knife.

The fourth type is the rotary joint. It allows bones to rotate. Rotary joint at the base of the skull we have, so we can turn our head and wrist to the elbow, which allows us to turn the key in the lock.

What are slightly mobile joints?

At a typical slightly mobile joint, the bones have a layer of cartilage between them and are held firmly together by strong ligaments. Such joints are found between the pubic bones (symphysis pubis) and the disks between the vertebrae of the spine.

What are immobile joints?

Immobile joints occur where two bones are fused or fixed together before or shortly after birth. Examples are the ilium, pubis, and ischium, which together form the hipbone, and the many flat bones that combine to make up the skull.

Joint disorders

There are many conditions that may involve joints:
  • Degenerative conditions, such as osteoarthritis;
  • Inflammatory conditions, such as rheumatoid arthritis;
  • Conditions involving the membranes surrounding the joints, such as synovitis;
  • Generalized disorders involving the joints, such as gout;
  • Damage to the joint involving dislocation or complicated fracture;
  • Congenital disorders, including congenital dislocation of the hip and clubfoot.






Perthes’ disease polyarthritis


rheumatic fever


shoulder, frozen




spondylitis, ankylosing

Disk, herniated   





spondylosis, cervical





Tissues of the human body?

The cell is the smallest fraction of every living being.
The simplest forms of plants and animals are composed of only one cell.
Within the more complex living beings cells work together, organized into groups, each of which has its own task.

Tissue is a group of cells of the same type that performs specific task.

There is, for example, bone tissue, etc. The tissues are grouped to perform a specific job; such group is called body tissues. For example, the human hand is composed of different tissues: bones, muscles, nerves, etc.
In the human body there are five major types of cells. 
  • Epithelial or cover cells build the skin, glands, and line the blood vessels. 
  • Muscle cells built up three types of muscles. 
  • Nerve cells constitute the brain, spinal cord and nerves. 
  • Blood cells are found in lymph. 
  • The binding cells of the human body form the connective tissue, which is the supporting tissue.

What Is Protoplasm - Protoplasm Definition

What Is Protoplasm - Protoplasm Definition

What Is Protoplasm?

The secret of protoplasm is the secret of life itself.

We still do not know what makes the protoplasm a living substance.

Protoplasm is the living part of every plant and animal.

All organisms, plants and animals, are composed of cells.

In one living organism can be millions of cells, as in human body, or just one – like in protozoa (pre-animals).

But the walls of the cells of all living beings wrap the same living matter – the protoplasm.

In each cell the protoplasm consists mainly of two parts: a stronger central part called the nucleus and the softer, liquid part which is called cytoplasm.

Every living specie has its own kind of protoplasm, and the different types of cells in the body have their own forms of protoplasm.

Although the protoplasm varies, up to 99 percent of its content consists of carbon, hydrogen, oxygen and nitrogen, with traces of many other elements.

When a living beam enters the food it is first digested, ie. converted into liquid form. Then the digested food must be entered in the protoplasm and its stand-components: the process is known as assimilation. We still do not know exactly what is going on all the time during the assimilation.

It is known that the assimilation leads to the replacement of worn-out protoplasm and increase in the amount of protoplasm. During the assimilation, the protoplasm dissolves dead ingredients and incorporates them into living matter and changes them in substances similar to its composition. Protoplasm also accumulates and releases all the energy that plants and animals have.

Protoplasm is sensitive to external influences. Strong light and heat will kill her. Chemicals attract or reject the protoplasm; electric current causes in it different reactions.

If science someday discovers the essence of the processes within the protoplasm, we will then learn about the secrets of life itself.