CLASS 9 - Cell - Fundamental Unit of Life - Question Bank CBSE

Cell - Fundamental Unit of Life

Question 1

Differentiate between organ and organelles.

Solution:
Organ is any distinct part of an organism that is specialized to perform one or a number of functions. Eg: ear, eyes, leaves, roots. Organelles are parts of a cell having definite structure and function. Eg: nucleus, mitochondria.

Question 2

Define chromatin, chromosome and chromatid.

Solution:
The material in the nucleus of a cell that forms the chromosomes during cell division is called chromatin.

Chromosomes appear as definitely shaped structures in the nucleus of a cell and are the carriers of hereditary characters from parents to offspring.

The arms of the chromosomes are known as chromatids.

Question 3 

Why is meiosis termed as reductional division?

Solution:
Meiosis is termed as reductional division as it yields cells that have half the number of chromosomes after completing the process of cell division.

Question 4

What is the significance of crossing over?

Solution:
During meiosis, homologous chromosomes pair up and the chromatids of maternal and paternal chromosomes exchange segments or genes. The resultant chromosome is thus different from the parental chromosomes and has the characters of both the parents. Such crossing over and chromatid exchange leads to variability in the gene combinations in gametes.

Question 5

Define centriole, centromere and chiasma.

Solution:
Centrioles are paired cylindrical structures found in the cytoplasm of a cell near the nuclear membrane and produce spindle fibres.

Centromere is the region in the chromosome where the chromatids are attached.

Chiasma is the point at which the chromatids of maternal and paternal chromosomes exchange segments during meiosis.

Question 6

Differentiate between haploid and diploid cells.

Solution:

The main difference between haploid and diploid cells is the number of chromosome sets found in the nucleus. Ploidy is the area of biology that refers to the number of chromosomes in a cell. Therefore, cells with two sets are diploid, and those with one set are haploid. In diploid organisms, such as humans, the haploid cells are used only for the sex cells for reproduction, while the rest of the cells are diploid. Another difference between haploid and diploid cells is how they reproduce. Haploid cells are reproduced using meiosis, while diploid cells go through mitosis. Most mammals are diploid organisms, and their somatic cells will typically be diploid and their gamete cells will be haploid.

Question 7

What are gametes?

Solution:
Gametes are cells with half the number of chromosomes formed as a result of meiosis.

Question 8

Differentiate between identical and fraternal twins.

Solution:
Identical twins are formed when a one fertilized ovum, separates into two embryos by mitosis. They show no variability in their traits and belong to the same sex. Fraternal twins are the result of simultaneous fertilization of two separate ova by two separate sperms. The two zygotes formed have different sets of chromosomes and are genetically different, but grow together in the same uterus.

Question 9

What are homologous chromosomes?

Solution:
Homologous Chromosomes are those that remains in pairs in a diploid cell, each of which is contributed by the male or the female parent. They are usually similar in shape and size and contain identical sets of loci (position of genes).

Question 10

What is the significance of mitosis?

Solution:
The significance of mitosis is as follows:

1. In unicellular organisms, it is a mode of reproduction.

2. In multicellular organisms, it leads to growth and development.

3. It maintains chromosome number in the body cells of an individual.

4. It repairs the worn out tissues of the body and helps in healing wounds.

Question 11

" All organisms have even number of chromosomes." Why?

Solution:
All organisms have even number of chromosomes because all organisms have chromosomes in homologous pairs where one member of the pair is contributed from each of the parent.

Comment

Question 12

State the relationship between meiosis and fertilization.

Solution:
During meiosis gametes that have the same number of chromosomes are formed. But during fertilization the gametes of male and female unite to form a zygote in which the number of chromosome characteristics of the species is restored.

Question 13

Which type of cell division is responsible for regeneration of tail in a lizard?

Solution:
Mitosis is essential for regeneration of tail in a lizard. The growth and development of every organism depends on mitosis.

Question 14

Distinguish between heterochromatin and euchromatin.

Solution:
The difference between heterochromatin and euchromatin are:
 

Heterochromatin	Euchromatin
Chromatin is rich in RNA.	Forms the bulk of chromosomes.
Responsible for nucleic acid metabolism.	Contains active genes.

Question 15

Why is the cell called the structural and functional

 unit of life?

Solution:
Cells constitute various components of plants and animals. A cell is the smallest unit of life and is capable of all living functions. Cells are the building blocks of life. This is the reason why cells are referred to as the basic structural and functional units of life. All cells vary in their shape, size, and activity they perform. In fact, the shape and size of the cell is related to the specific functions they perform.

Question 16

Why is the plasma membrane called a 

selectively permeable membrane?

Solution:
The cell membrane or the plasma membrane is known as a selectively permeable membrane because it regulates the movement of substances in and out of the cell. This means that the plasma membrane allows the entry of only some substances and prevents the movement of some other materials.

THAT'S ALL GUYS ..!!
THESE ARE IMPORTANT QUESTIONS , MUST STUDY BEFORE EXAMS

AND NOTE THESE MOST OF THE QUESTIONS ARE BEING TAKEN FROM GOOGLE ( I MEAN SITES ) BUT ARE EDITED !!

SO STUDY HARD AND GET GOOD MARKS !!

SUMIT BHADRA 

( ACS )

IMPORTANT TRIGONOMETRIC FORMULAE

GULLIVER'S TRAVELS CLASS 9 SUMMARY

Jonathan Swift
(30 November 1667 – 19 October 1745),

born in Dublin, is one of the most well known satirist, essayist, and political pamphleteer of the eighteenth century England. He studied at Kilkenny College and graduated from the Trinity College, Dublin.He began his career by working as a diplomat and writer to William Temple at Moor Park. From 1696 to 1699, Swift came up with his two major works, A Tale of a Tub and The Battle of the Books. He also wrote several essays, poetry and pamphlets.Published in 1726, Gulliver’s Travels is a satire.

In this book, Swift satirises politics and human nature of the people in the English society in the eighteenth century. His work is a classic and still remains the most widely discussed work of his times.At its first reading, Gulliver’s Travels may seem to be a simple travelogue amalgamated with fantastical events, but itis an acute satire on the lust of power of the English to acquire unknown lands. Set in the 1700s, it attacks the politics, religion, morality and human nature of the English.

It presents a parody of travel tales and satirises human nature and colonialism with its witty use of slapstick and humour.In the novel, Gulliver is a learned surgeon who gives an account of his travelling experiences in the course of his four voyages. In Lilliput, he meets miniature beings who are politically active; in Brobdingnag, he meets the boorish giants in front of whom he himself feels a Lilliputian; then,
he visits Laputians who are too deeply engrossed in science and mathematics; and finally, he meets the Houyhnhnms who seem to be the most virtuous race of rational beings on the earth. Swift uses these imaginary places and their inhabitants to highlight the shortcomings of his own country.

Reading this book is like enjoying a roller coaster ride that not only excites the youngsters with its adventures but also interests the adults with its camouflaged insight into the defects of the eighteenth century England.Lemuel Gulliver, a learned surgeon, decides to go for sea voyages to the remote islands of the world, as he is keen to explore the world.During his first voyage,
Gulliver is shipwrecked because of a storm but manages to swim safely to Lilliput.

While sleeping, Gulliver is held captive by about six inches tall inhabitants of the island. Dueto his large size, Gulliver is initially perceived to be a threat. Later on, he is considered to be a harmless creature but agreat expense on the kingdom.

After getting a brief summary of their historical events, Gulliver decides to assist them in their battle against their rival state, Blefuscu. He stops the battle by bringing the enemy fleets to the kingdom. For this, he is honoured with the title of a ‘Nardac’ by the king. Flimnap and Skyresh Bolgolam,officials of the court, envy his success and conspire against him. They bring out four articles of impeachment against him.

iTheseare extinguishing the fire at the queen’s palace in a disgraceful manner, refusing to obey the king’s order to enslave the Blefuscudians, maintaining good behaviourwith the delegates of the enemy and planning a visit to Blefuscu, their enemy. Therefore, an order is passed to blind him before starving him to death. Fortunately, Gulliver is warned against the charges beforehand and he escapes to Blefuscu. The emperor of Blefuscu welcomes him warmly. In Blefuscu, he finds a broken boat, which he repairs, and sails back to England.Within two months of his return, Gulliver departs for another voyage. During the voyage, their ship gets drifted by a storm. Some of the crew members get down at the shore of a deserted island to find drinking water. Unfortunately, Gulliver is left alone on this island of giants. In Brobdingnag, he is taken to a farmer homeand is left in the care of his nine years old daughter, Glumdalclitch. The farmer earns a good fortune by making him perform at various places. Consequently, Gulliver’s health starts deteriorating and the farmer sells him to the queen. Though the king andthe queen treat him with respect and fondness, Gulliver faces several misfortunes threatening his life. One day, his box apartment, in which he was carried by Glumdalclitch, is picked by an eagle and dropped into the sea. Finally, he is rescued by an English ship.Again, his thirst of seeing the world takes Gulliver on a new voyage.  In this voyage, his sloop is attacked by the pirates. Gulliveris punished by being left in the sea in a small boat with scanty provisions. He reaches a group of islands. On fifth day, he reaches an island where he finds a land mass floating in the air. He is pulled up to the island by chains. He finds the inhabitants busy in their own thoughts and interested in only mathematics and music. Hence, he decides to visit Balnibarbi, where he is hospitably received by Lord Munodi.  Gulliver observes that Lord Munodi’s estate is greener and more systematically built than the other part of the country as it follows the ancient methods of agriculture and construction.Further, he visits the ‘academyof projectors’ in Lagado where the scientists are busy in their researches and the teachers are involved in speculative learning. Then, he visits Glubdubbdrib where he gets a chance to communicate with the world’s great philosophers and tyrants who died several years ago. Finally,he travels to Luggnagg. The king makes arrangements for his departure to Japan from where he boards a ship back to England.In his final voyage, Gulliver takes up the post of the captain of the ship.

As most of his crewmen die because of sea sickness, he hires men from various islands who turnout to be rogues. Consequently, they leave Gulliver on a marooned island. On this island, Gulliver finds a race horses, called Houyhnhnms, governing the island with intelligence. They are being served by a race of wild human-like creatures called Yahoos.

Gulliver realises that the Houyhnhnms are the most virtuous race ontheearth, whereas the humans were full of vices. Therefore, he decides to live in the company of the Houyhnhnms forever. But, Gulliver is forced to leave the Houyhnhnmland. He decides to shun human company and live the rest of his lifeon a secluded island. But, the crew of a Portuguese ship, in command of Pedro de Mendez, discovers him and takes him to Lisbon. Gulliver rejects humans as he feels disgusted by their vices and the offensive odour of their bodies. Yet, the captain treats him hospitably and makes arrangements for his return to England. Gulliver reaches back home safely but maintains distance from his family members and spends most of the time in a stable with a pair of horses whom he treatsas companions and converses well with. Only after about five years, he start comingto terms with the mankind.PART I. A VOYAGE TO LILLIPUT· Gulliver gives a brief account of his early life and his studies.· At London, he works as an apprentice to Mr. Bates. Then, he goes to Leyden to study medicine.· On Mr. Bates’ recommendation, he worksas a surgeon at the Swallow.· After returning, Gulliver marries Mary Burton.· He sets sail on the Antelope from Bristol on May 4, 1699 with Captain William Prichard.·

Gulliver is shipwrecked because of a storm. He manages to swim safely to an unfamiliar island called Lilliput.· While sleeping, he is held captive by about six inch tall inhabitants of Lilliput.· Initially, he is seen as a threat by the Lilliputians. Gradually, they accept him as their ally. He helps them in their fight against Blefuscu and receives the title of ‘Nardac’ (the highest honour) for capturing the enemy fleets.· Flimnap and Skyresh Bolgolam plan a conspiracy against Gulliver. Four articles of impeachment are drawn against him.· Gulliver is secretly informed about his trial and punishments. He escapes to the island of Blefuscu.· Gulliver finds a boat floating in the sea. He repairs it and sets off to England.·

He is taken on board an English ship. He reaches England on April 13, 1702.· Gulliver earns a lot of wealth by selling the Lilliputian miniatures and shifts to a bigger house in Redriff.PART- II. A VOYAGE TO BROBDINGNAG· He sets off for his second voyage on the Adventure on June 20, 1702.· The ship encounters a storm. Some of thecrew men get down a strange island in search of water. But they escape at the sight of a giant, leaving Gulliver alone on the island called Brobdingnag.· Gulliver is seized by a giant and is carriedto his master. The master, a farmer, takes him to his home. Glumdalclitch, the farmer’s nine-year-old daughter, takes careof him.· Gulliver is made to perform in front of hisguests, in the market places and at the distant towns. The farmer earns great fortune. Slowly, Gulliver’s health starts deteriorating.· After a performance at the court, Gulliveris sold to the queen.·

Gulliver gets mistreated at the hands of the jealous dwarf who is punished for his mischief. He is also threatened by a monkey, flies and wasps.· He attempts to win the loyalty of the king and the queen by various means. The king refuses his proposal of revealing the secretof gun powder.· After various discourses with Gulliver about England, the king regards the English as a race of odious people.· Gulliver desires his liberty. An eagle lifts the box in which he lay and drops it in the sea.· Gulliver is rescued by the English crewmen. He reaches England on June 3, 1706.PART III. A VOYAGE TO LAPUTA, BALNIBARBI, LUGGNAGG, GLUBBDUBRIB, AND JAPAN · Gulliver sets sail to East Indies on August 5, 1706.· His sloop is captured by pirates. Gulliver is left alone in the sea in a small boat with scanty provisions. He goes to find refuge in a group of island.· Gulliver finds the island of Laputa, floating in the air and is taken onto it.· He finds the Laputians to be strange beings. They show interest only in the knowledge of mathematics and music.· Soon, Gulliver visits Balnibarbi where he is hospitably received by Lord Munodi.· Gulliver observes that the city, which follows new methods of agriculture and construction and, is in ruins, whereas Munodi’s estate, which still follows the ancient methods, is green and systematically built.· Gulliver leaves Lagado, the metropolis, after making many visits to the Academy ofLagado.·

He visits Glubbdubdrib where he gets a chance to converse with the dead philosophers and tyrants of the world by the magical powers of its governor.· Gulliver arrives at Luggnagg and stays at an apartment in the palace of the king.· Gulliver is told about the immortal beingsstruldbrugs. He learns about the disadvantages of immortality.· Gulliver wishes to leave. The king arranges for his journey to England with a Dutch crew.· He reaches England on April 16, 1710 and goes straight to his house in Redriff.PART IV. A VOYAGE TO THE COUNTRY OF THE HOUYHNHNMS· On September 7, 1710, Gulliver sets sail as the Captain of the Adventurer.· Many of his crew members die due to illness. He hires more crew members who conspire against him. They leave him on a deserted island, the land of the Houyhnhnms.· Gulliver is attacked by a group of abominable wild beast called Yahoos. He issaved by a Houyhnhnm, a horse, who takes him to his house. He stays with the family.· The Houyhnhnms are virtuous beings, with their actions guided by reason. After a careful examination of Gulliver’s behaviour, they consider him a rational being.· Gradually, Gulliver develops a great admiration for the Houyhnhnms and an equal disgust for his country men who are full of vices.· Gulliver has several discourses with his master Houyhnhnm. He decides to stay in the company of the Houyhnhnms forever.· Later, his master is forced to excommunicate Gulliver as he is a Yahoo.· Gulliver leaves the country. He shuns the company of human beings and decides to live in seclusion on an island.· He is found by the crew of Captain Pedro de Mendez’s ship and is taken to Lisbon.· The Captain arranges for his journey to Europe. Gulliver reaches home safely, but discards the company of his family members.· After five years, he is able to reconcile with the natural vices of human beings.

ThNks for ReaDiNG.. BY SUmIT BhADRa

THREE MEN IN A BOAT CLASS 9 SUMMARY

Three Men in a Boat (To Say Nothing of the Dog)

by Jerome K. Jerome was first published in 1889. It is the fictional story of three London friends and a dog taking a leisurelyboat trip up the River Thames, from Kingston-upon-Thames to Oxford. It is narrated by ‘J.’, whose companions are George (awarded no surname), William Samuel Harris and the dog, Montmorency.During a sociable evening in J.’s room, the three men convince themselves that they each have various illnesses. Their collectivediagnosis is overwork, and they prescribe themselves a fortnight’s holiday.

A stay in the country and a sea voyage are both ruled out, and they settle instead on a boating trip, travelling on the Thames by day and camping out in the hired boat at night.They set out the following Saturday. George must work in the City in the morning, and so arranges to join them laterthat day.

The other two, accompanied by the dog and a mountain of luggage, get a cab to Waterloo station, but are unable to find the correct train to Kingston. Eventuallythey bribe the driver of another train to take them there instead, one of the many humorous set-pieces that make the book more than a straightforward travelogue.

George completes the trio at Weybridge, with a dubious-looking parcel tucked underhis arm, which turns out to be a banjo and instruction book.The story is a tapestry of incidents that occur, anecdotes on various topics (including the unreliability of weather forecasts), loosely connected digressions (such as J. 's uncle’s inability to hang pictures), and descriptive pieces on the places that they pass.

It is in these descriptive pieces that the author’s original intention of writing a guidebook is most apparent. What he actually achieved was aclassic of British humorous writing. Although the book was written over a century ago, it has an enduring, timeless quality.