Class 11

While examining the animal and plant cell through a microscope, you might have seen numerous organelles that work together to complete the cell activities. One of the essential cell organelles are ribosomes, which are in charge of protein synthesis. The ribosome is a complex made of protein and RNA and which adds up to numerous million Daltons in size and assumes an important part in the course of decoding the genetic message reserved in the genome into protein.

The essential chemical step of protein synthesis is peptidyl transfer, that the developing or nascent peptide is moved from one tRNA molecule to the amino acid together with another tRNA. Amino acids are included in the developing polypeptide in line with the arrangement of codons of a mRNA. The ribosome, therefore, has necessary sites for one mRNA and no less than two tRNAs.

Made of two subunits, the big and the little subunit which comprises a couple of ribosomal RNA (rRNA) molecules and an irregular number of ribosomal proteins. Numerous protein factors catalyze distinct impression of protein synthesis. The translation of the genetic code is of essential significance for the manufacturing of useful proteins and for the growth of the cell.

Structure

Ribosomes are made of proteins and ribonucleic acid (abbreviated as RNA), in almost equal amounts. It comprises of two sections, known as subunits. The tinier subunit is the place the mRNA binds and it decodes, whereas the bigger subunit is the place the amino acids are included.

Both subunits comprise of both ribonucleic acid and protein components and are linked to each other by interactions between the proteins in one subunit and the rRNAs in the other subunit. The ribonucleic acid is obtained from the nucleolus, at the point where ribosomes are arranged in a cell.

The structures of ribosomes include:

• Situated in two areas of the cytoplasm.
• They are seen scattered in the cytoplasm and a few are connected to the endoplasmic reticulum.
• Whenever joined to the ER they are called the rough endoplasmic reticulum.
• The free and the bound ribosomes are very much alike in structure and are associated with protein synthesis.
• Around 37 to 62% of RNA is comprised of RNA and the rest is proteins.
• Prokaryotes have 70S ribosomes respectively subunits comprising the little subunit of 30S and the bigger subunit of 50S. Eukaryotes have 80S ribosomes respectively comprising of little (40S) and substantial (60S) subunits.
• The ribosomes seen in the chloroplasts of mitochondria of eukaryotes are comprised of big and little subunits composed of proteins inside a 70S particle.
• Share a centre structure which is very much alike to all ribosomes in spite of changes in its size.
• The RNA is arranged in different tertiary structures. The RNA in the bigger ribosomes is into numerous continuous infusions as they create loops out of the centre of the structure without disturbing or altering it.
• The contrast between those of eukaryotic and bacteria are utilized to make antibiotics that can crush bacterial disease without damaging human cells.

Ribosomes Size

Ribosomes comprise of two subunits that are suitably composed and function as one to translate the mRNA into a polypeptide chain amid protein synthesis. Due to the fact that they are made from two subunits of differing size, they are a little longer in the hinge than in diameter. They vary in size between prokaryotic cells and eukaryotic cells.

The prokaryotic is comprised of a 30s (Svedberg) subunit and a 50s (Svedberg) subunit meaning 70s for the entire organelle equal to the molecular weight of 2.7×106 Daltons. Prokaryotic ribosomes are about 20 nm (200 Å) in diameter and are made of 35% ribosomal proteins and 65% rRNA.

Notwithstanding, the eukaryotic are amidst 25 and 30 nm (250–300 Å) in diameter. They comprise of a 40s (Svedberg) subunit and a 60s (Svedberg) subunit which means 80s (Svedberg) for the entire organelle which is equal to the molecular weight of 4×106 Daltons.

Location

Ribosomes are organelles located inside the animal, human cell, and plant cells. They are situated in the cytosol, some bound and free-floating to the membrane of the coarse endoplasmic reticulum.

They are utilized in decoding DNA (deoxyribonucleic acid) to proteins and no rRNA is forever bound to the RER, they release or bind as directed by the kind of protein they proceed to combine. In an animal or human cell, there could be up to 10 million ribosomes and numerous ribosomes can be connected to the equivalent mRNA strand, this structure is known as a POLYSOME.

Function

When it comes to the main functions of ribosomes, they assume the role of bringing together amino acids to form particular proteins, which are important for completing the cell's activities.

Protein is required for numerous cell functions, for example, directing chemical processes or fixing the damage. Ribosomes can yet be discovered floating inside the cytoplasm or joined to the endoplasmic reticulum.

The other functions include:

1. The procedure of creation of proteins, the deoxyribonucleic acid makes mRNA by the step of DNA transcription.
2. The hereditary information from the mRNA is converted into proteins amid DNA translation.
3. The arrangements of protein assembly amid protein synthesis are indicated in the mRNA.
4. The mRNA is arranged in the nucleus and is moved to the cytoplasm for an additional operation of protein synthesis.
5. The proteins which are arranged by the ribosomes currently in the cytoplasm are utilized inside the cytoplasm by itself. The proteins created by the bound ribosomes are moved outside the cell.

Taking into consideration their main function in developing proteins, it is clear that a cell can’t function in the absence of ribosomes.

Those that live inside bacteria, parasites and different creatures, for example, lower and microscopic level creatures are the ones which are called prokaryotic ribosomes. While those that live inside humans and others such as higher level creatures are those ones we call the eukaryotic ribosome. The other major differences include:

1. Prokaryotes have 70S ribosomes, singly made of a 30S and a 50S subunit. While the Eukaryotes have 80S ribosomes, singly made of a 40S and 60S subunit.
2. 70S Ribosomes are relatively smaller than 80S while the 80S Ribosomes are relatively bigger than 70S ribosomes.
3. Prokaryotes have 30S subunit with a 16S RNA subunit and comprise of 1540 nucleotides bound to 21 proteins. The 50S subunit gets produced from a 5S RNA subunit that involves 120 nucleotides, a 23S RNA subunit that contains 2900 nucleotides and 31 proteins.
4. Eukaryotes have 40S subunit with 18S RNA and also 33 proteins and 1900 nucleotides. The big subunit contains 5S RNA and also 120 nucleotides, 4700 nucleotides and also 28S RNA, 5.8S RNA as well as 160 nucleotides subunits and 46 proteins.
5. Eukaryotic cells have mitochondria and chloroplasts as organelles and those organelles additionally have ribosomes 70S. Hence, eukaryotic cells have different kinds of ribosomes (70S and 80S), while prokaryotic cells just have 70S ribosomes.

Yes the traditional handicraft industries were ruined under British rule.There were two reasons

1.Industrial revolution in London.

There was industrial revolution in London.Brishers used to get cheap raw material from India.after that they import there machine made goods to India.That goods were cheap and of good quality .so it's demand raised in India.And demand of handicraft goods declined

2.Britishers did not pay attention to improve the conditions handicraft industries  of india because they want to make India a market for goods made in london

Mixed economy is an economic system in which major economic decisions are taken by the Central Government authority as well as is left to free play of the market. It is the basic framework of planning in India. In this economy the market will provide whatever goods and services, it can produce well and the government will provide essential goods and services which the market fails to provide.
Merits of Mixed Economy—
(i) It gives proper scope for fun play of private initiative and profit motive.
(ii) Planned economy development ensures stability and balanced development.
(iii) Competition between the private sector and public sector industries is generated to maximise productivity.

On October 1, 1949, Chinese Communist leader Mao Zedong declared the creation of the People's Republic of China (PRC). ... The Chinese Communist Party, founded in 1921 in Shanghai, originally existed as a study group working within the confines of the First United Front with the Nationalist Party.

On October 1, 1949, Chinese Communist leader Mao Zedong declared the creation of the People’s Republic of China (PRC). The announcement ended the costly full-scale civil war between the Chinese Communist Party (CCP) and the Nationalist Party, or Kuomintang (KMT), which broke out immediately following World War II and had been preceded by on and off conflict between the two sides since the 1920’s. The creation of the PRC also completed the long process of governmental upheaval in China begun by the Chinese Revolution of 1911. The “fall” of mainland China to communism in 1949 led the United States to suspend diplomatic ties with the PRC for decades.

The Chinese Communist Party, founded in 1921 in Shanghai, originally existed as a study group working within the confines of the First United Front with the Nationalist Party. Chinese Communists joined with the Nationalist Army in the Northern Expedition of 1926–27 to rid the nation of the warlords that prevented the formation of a strong central government. This collaboration lasted until the “White Terror” of 1927, when the Nationalists turned on the Communists, killing them or purging them from the party.

After the Japanese invaded Manchuria in 1931, the Government of the Republic of China (ROC) faced the triple threat of Japanese invasion, Communist uprising, and warlord insurrections. Frustrated by the focus of the Nationalist leader Chiang Kai-shek on internal threats instead of the Japanese assault, a group of generals abducted Chiang in 1937 and forced him to reconsider cooperation with the Communist army. As with the first effort at cooperation between the Nationalist government and the CCP, this Second United Front was short-lived. The Nationalists expended needed resources on containing the Communists, rather than focusing entirely on Japan, while the Communists worked to strengthen their influence in rural society.

During World War II, popular support for the Communists increased. U.S. officials in China reported a dictatorial suppression of dissent in Nationalist-controlled areas. These undemocratic polices combined with wartime corruption made the Republic of China Government vulnerable to the Communist threat. The CCP, for its part, experienced success in its early efforts at land reform and was lauded by peasants for its unflagging efforts to fight against the Japanese invaders.

Japanese surrender set the stage for the resurgence of civil war in China. Though only nominally democratic, the Nationalist Government of Chiang Kai-shek continued to receive U.S. support both as its former war ally and as the sole option for preventing Communist control of China. U.S. forces flew tens of thousands of Nationalist Chinese troops into Japanese-controlled territory and allowed them to accept the Japanese surrender. The Soviet Union, meanwhile, occupied Manchuria and only pulled out when Chinese Communist forces were in place to claim that territory.

In 1945, the leaders of the Nationalist and Communist parties, Chiang Kai-shek and Mao Zedong, met for a series of talks on the formation of a post-war government. Both agreed on the importance of democracy, a unified military, and equality for all Chinese political parties. The truce was tenuous, however, and, in spite of repeated efforts by U.S. General George Marshall to broker an agreement, by 1946 the two sides were fighting an all-out civil war. Years of mistrust between the two sides thwarted efforts to form a coalition government.

As the civil war gained strength from 1947 to 1949, eventual Communist victory seemed more and more likely. Although the Communists did not hold any major cities after World War II, they had strong grassroots support, superior military organization and morale, and large stocks of weapons seized from Japanese supplies in Manchuria. Years of corruption and mismanagement had eroded popular support for the Nationalist Government. Early in 1947, the ROC Government was already looking to the island province of Taiwan, off the coast of Fujian Province, as a potential point of retreat. Although officials in the Truman Administration were not convinced of the strategic importance to the United States of maintaining relations with Nationalist China, no one in the U.S. Government wanted to be charged with facilitating the “loss” of China to communism. Military and financial aid to the floundering Nationalists continued, though not at the level that Chiang Kai-shek would have liked. In October of 1949, after a string of military victories, Mao Zedong proclaimed the establishment of the PRC; Chiang and his forces fled to Taiwan to regroup and plan for their efforts to retake the mainland.

The ability of the PRC and the United States to find common ground in the wake of the establishment of the new Chinese state was hampered by both domestic politics and global tensions. In August of 1949, the Truman administration published the “China White Paper,” which explained past U.S. policy toward China based upon the principle that only Chinese forces could determine the outcome of their civil war. Unfortunately for Truman, this step failed to protect his administration from charges of having “lost” China. The unfinished nature of the revolution, leaving a broken and exiled but still vocal Nationalist Government and Army on Taiwan, only heightened the sense among U.S. anti-communists that the outcome of the struggle could be reversed. The outbreak of the Korean War, which pitted the PRC and the United States on opposite sides of an international conflict, ended any opportunity for accommodation between the PRC and the United States. Truman’s desire to prevent the Korean conflict from spreading south led to the U.S. policy of protecting the Chiang Kai-shek government on Taiwan.

For more than twenty years after the Chinese revolution of 1949, there were few contacts, limited trade and no diplomatic ties between the two countries. Until the 1970s, the United States continued to recognize the Republic of China, located on Taiwan, as China’s true government and supported that government’s holding the Chinese seat in the United Nations.