Biology For Class X - Chapter No. 6 - Inheritance - Review Exercise From Text Book

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CHAPTER 6: INHERITANCE
Review Exercise From Text Book

By Mrs. Ayesha Arif
Vice Principal
(Jauhar Progressive School)

A. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:
i) Branch of biology deals with the study of heredity and variation is called:
(a)Inheritance
(b) Heredity
(c) Genetics ✓
(d) Evolution

ii) The way by which gene transmits characters from parents to offspring is:
(a) Genetics
(b) Inheritance ✓
(c) Heredity
(d) Allele

iii) Two similar chromosomes in a cell which are similar in shape, size and position of centromere called:
(a) Chromatids
(b) Arms
(c) Homologous ✓
(d) Homology

iv) The chemical material of a chromosome is called:
(a) Chromatin ✓
(b) Chromeres
(c) Chromonema
(d) Chromatid

v) The outer part of DNA helix made up of sugar and phosphate is called:
(a) Nucleoprotein
(b) Rungs
(c) upright ✓
(d) Phosphoester

vi) The small segment of DNA which has information to code one protein is called:
(a) Nucleotide
(b) Polynucleotide
(c) Gene ✓
(d) Exon

vii) The exact duplication of DNA is called:
(a) Duplication
(b) Replication ✓
(c) Transcription
(d) Translation

viii) If both the parents donate same factors of a character is called:
(a) Homologous
(b) Heterologous
(c) Homozygous ✓
(d) Heterozygous

ix) The Genetic constitution of a trait is called:
(a) Genotype ✓
(b) Phenotype
(c) Genome
(d) Phenyl

B. SHORT QUESTIONS
1. What is gene and how it works?
Ans: GENES:
Gene is the smallest segment of DNA which has genetic information in the form of code to synthesize a protein. Life of every organism, every character of his structure, function and behaviour, all the level of biological organization is programmed and controlled by a set of instructions. These instructions are in the form of coded biological information called 'Genes'. Thus:
Genes are the basic unit and structure of Biological information. They are unit of inheritance which is copied and inherited from generation to generation.

LOCATION:
Each gene is located at specific position on the chromosomes .This position of gene on chromosome is called Gene Locus (loci).

FUNCTION:

• Gene is the localised part of DNA which has a coded information to synthesize a protein which works as enzyme.
• Each gene has specific function e.g. a gene determines the height of plant; another gene determines the colour of their petals etc.
• The coded information may change due to any reason which is called genetic variation caused by mutation. This genetic variation among off spring lead to tremendous variety in their traits.
• The variation in the genes of a trait give rise two or more than two alternative forms of a gene. These alternative form of gene are called alleles or allomorph.
• All the inherited characters are determined by genes which are transmitted from generation to generation.

2. Define following terms:
(a) Homologous Chromosome
(b) Heterologous Chromosome
(c) Dominant allele
(d) Allele
(e) Recessive allele
(f) Homozygous
(g) Heterozygous
(h) Parental generation
(i) Filial one Generation
(j) Second Filial Generation
(k) Phenotype
(l) Genotype
(m) Heredity
(n) Genetics
(o) Inheritance
(p) Variations
Ans: (a) Homologous Chromosome:
The two chromosomes which are similar in their shape, size and position of centromeres and are present in same cell are called homologous pair of Chromosomes. These homologous sets of chromosomes provide the physical traits basis of heredity of an organism.

(b) Heterologous Chromosome:
A heterologous chromosome is a chromosome that contains different set of genes for a given trait. 

(c) Dominant allele:
The factor (gene) which express and masks the expression of other factor in heterozygous condition is said to be Dominant factor (allele).
For example:
(i) Mendel represent it with capital letter like T for tall, which is a dominant character.
(ii) The allele for brown eyes is dominant. Therefore in pair one copy of brown eye is needed to have brown colour eye.


(d) Allele:
"The alternative form of gene developed as a result of variation is called allele or allomorph."
Alleles are described as either dominant or recessive depending on their associated traits. Some gene may have as many as 300 alleles. A diploid cell thus have any two of these alleles while a haploid have one allele.

(e) Recessive allele:
The factor which is unable to express or masked in heterozygous condition is said to be recessive allele.
For example:
(i) It represents by small letter of same alphabet like t for small (dwarf).
(ii) Allele for blue eye is recessive. Therefore in a pair both (two) copies of blue eye is needed to have blue eye colour.

(f) Homozygous:
An individual having same factors (allele) of a trait called homozygous. For example, TT (factor for tallness).

(g) Heterozygous:
An individual having different factors of a trait called heterozygous. For example, Tt (factors of tallness and dwarfness both).

(h) Parental generation:
The original true breeding organisms were called parental generation or P1 by Mendel.

(i) Filial one Generation:
The offspring of true breeding organism were called First Filial Generation or F1.

(j) Second Filial Generation:
The offspring of filial one generation produced by crossing self-fertilization were called Second Filial generation or F2.

(k) Phenotype:
It is the physical appearance of the trait on the basis of inherited genes like tall, dwarf, round seed, wrinkled seed etc.

(l) Genotype:
The genetic makeup or genetic constitution of a trait like TT, Tt, tt etc.

(m) Heredity:
The characteristics of the offspring’s to resemble their parents is called heredity.
In other words:
"Heredity is the way by which genes transmit characters from parents to offspring".

(n) Genetics:
The branch of biology which deals with the study of heredity and Variations is called genetics.

(o) Inheritance:
The process by which characters are transmitted from parents to off springs is called inheritance.

(p) Variations:
The differences in characters such as height, colour etc among individual of same species are called variations. Variation may be caused either by the effect of environment or by the changes in the genetic material.

3. Which of the phenomena of inheritance is there where both factor express in heterozygous condition.
Ans: INCOMPLETE DOMINANCE OR PARTIAL DOMINANCE:
The term ”incomplete dominance” was proposed by Carl Correns in 1899.
The phenomenon of inheritance where both alleles of a trait express in heterozygous condition and their expression get blended to produce new phenotype is called incomplete dominance or partial Dominance.

4. List out the factors which are involved in theory of natural selection.
Ans: THEORY OF NATURAL SELECTION:
Charles Darwin a naturalist Englishman proposed the Theory of Natural selection as a mechanism for evolution in the year 1859, through his “Origin Of Species”.

FACTORS WHICH ARE INVOLVED IN NATURAL SELECTION:
The main factors which are involved in this theory are as follows:

1. Over Production:
2. Struggle for Existence:
3. Heritable Variation:
4. Natural selection:

5. Relate artificial selection with natural selection.
Ans: RELATION OR DIFFERENCE BETWEEN NATURAL AND ARTIFICIAL SELECTION:

NATURAL SELECTION	ARTIFICIAL SELECTION
Natural selection is a process of adaptation by an organism to the changing environment by bringing selective changes to its genotype or genetic composition.	Artificial selection, also called selective breeding, is the process where humans identify desirable traits in animals and plants and use these traits to develop desirable phenotypic traits by breeding.
Natural selection is a natural process.	Artificial selection is an artificial or human-made process.
Natural selection takes place in natural populations within natural conditions.	Artificial selection takes place in domesticated populations put together by humans.
The chances of survival of a fit organism increase as a result of natural selection.	The chance of survival of an organism might be at risk if not performed correctly.
Natural selection is a slow process that completes after many generations.	Artificial selection is a faster process that completes within days or weeks with more apparent effects.
Natural selection is not as controlled as artificial selection as natural processes control it.	Artificial selection can be more controlled as humans control it.
Natural selection might occur on all organisms living on the earth.	Artificial selection can be selective and can be performed on selected groups of animals and plants.
Natural selection is based on the adaptive characteristics of animals.	Artificial selection is based on the desirable characters selected by humans.
Only beneficial or favorable traits are inherited over the successive generations by natural selection.	Artificial selection only allows the selected traits to be passed through successive generations.
Natural selection affects the entire population of a species.	Artificial selection only affects the selected individuals.
Natural selection results in a large amount of biological diversity.	Artificial selection only brings desirable changes and desirable traits and brings a decrease in genetic diversity.
Natural selection facilitates speciation and evolution over many generations.	Artificial selection doesn’t facilitate evolution.
Natural selection exerts on a wide-scale on the natural environment.	Artificial selection exerts only on selected individuals that are economically important.
Hybrid vigor is seen in offspring after natural selection.	Hybrid vigor is lost during artificial selection due to the preservation of desired traits.
Natural selection is a natural process, so no human effort is required.	The artificial selection might be labor-intensive and expensive.
After natural selection, the proportion of heterozygous genotype becomes high.	After artificial selection, the proportion of homozygous genotype becomes high.
Some examples of natural selection include the selection of long-necked giraffes and the changes in the size and shape of beaks of birds according to their feeding habits.	Some examples of artificial selection include dog breeding to produce new breeds of dogs and cross-breeding in cash crops like wheat and rice.

OR

Natural Selection:
Natural selection is a natural process of adaptation by an organism to the changing environment by bringing selective changes to its genotype or genetic composition. It is a slow process that completes after many generations. After natural selection, the proportion of heterozygous genotypes becomes high.

Artificial Selection:
Artificial selection, also called selective breeding, is the process where humans identify desirable traits in animals and plants and use these traits to develop desirable phenotypic traits by breeding. It is a faster process that completes within days or weeks with more apparent effects. After artificial selection, the proportion of homozygous genotype becomes high.

More Short Question & Answers

6. How coiling of long DNA is coiled in very small chromosome and nucleus of cell?
Ans: The DNA of a chromosome exists as one very long double stranded, a duplex, which extends unbroken through the entire length of the chromosome. This long DNA (more than 7 feet or 2 meter) is coiled to fit into a much smaller spaces.
If we gently disrupt a eukaryotic nucleus and examine the DNA with an electron microscope, we find that coiling of long DNA is coiled in very small chromosome and nucleus of cell. It is because the histone is positively charged while DNA is negatively charged. This beads of histone and DNA is called nucleosome. When the string of nucleosomes wraps up into high order coil called super coil. This super coiled chromomers form chromosome.

Source: Special Thanks To Sir Syed Arif Ali


C. EXTENSIVE RESPONSE QUESTIONS
i) Describe the Waston and Crick model of DNA?
Ans: Watson and Crick Model Of DNA:
The model of DNA was suggested by James Watson and Francis Crick, in 1953. This model is based on X-Rays, Photographs and chemical analysis of DNA. According to this model:

• Double Helix:
  (i) DNA is a double helical structure.
• Backbone of DNA:
  (ii) Each helix is a polynucleotide chain which are twisted around each other.
  (iii) The outer part is called Upright, which are made up of deoxyribose sugar and phosphate. The inner part called Rungs, made up of paired nitrogenous bases.
• Pairing of Bases:
  (iv) Both helix are complementary to each other which are held together by hydrogen bonds.
  (v) The complementary helix have complementary base pairs i.e Adenine pairs with Thymine and Cytosine always pairs with Guanine.

STRUCTURE OF DNA

ii) How gene expresses describe in detail? OR What do you understand by Central dogma of Protein synthesis?
Ans: CENTRAL DOGMA:
"A set of beliefs where a gene expresses by synthesizing a protein is termed as central dogma."
This protein is work as enzyme, which carry down a chemical reaction to produce a metabolic product. This metabolic product either develops a character or lead to develop a character.

RNAs:
DNA is located in the nucleus of eukaryotic cell while the protein synthesis and metabolic reactions occur in cytoplasm under the instructions of DNA (genes). Therefore DNA requires some other molecules to carry its genetic information from nucleus to cytoplasm. These molecules are different types of RNAs (Ribo Nucleic Acid).

GENE EXPRESSION:
All functions in the body of an organism are controlled by genes. A function expressed or performed by a gene is called gene expression.

Process of Gene Expression:
Genetic information flows from DNA to mRNA and then to ribosomes in cytoplasm. This is a two step process of gene expression for protein (enzyme) synthesis.

1. Transcription
2. Translation

1. Transcription:
The step of protein synthesis where information which contained in a specific segment of DNA (gene) is copied in complimentary from (genetic codes) i.e. RNA. This RNA carries information of DNA sequences to ribosome from nucleus to cytoplasm are called messenger RNA or mRNA. The process of copying DNA information to mRNA is called Transcription.

2. Translation:
In the second step two other types of RNA called tRNA(transfer RNA) and ribosomal RNA(rRNA) translate the information of mRNA into the specific sequence of amino acids which help to synthesize the proteins. This process is called Translation.

iii) State and explain the law of Segregation of Mendel's. OR State and explain the law of Purity of gametes of Mendel's.
Ans: LAW OF SEGREGATION (MENDEL’s FIRST LAW) OR LAW OF PURITY OF GAMETES:
Statement:

"In an organism, the factors (genes) exist in pairs but during gametes formation these factors segregate cleanly from each other, so each gamete has only one factor of a trait."

Experiment:

• Mendel when crossed pure tall and dwarf plants, he got all tall plants in F1 generation but unlike the P1 tall, these plants of F1 generation were heterozygous (Tt).
• Mendel did not stop his experiment here. He planted all the seeds of F1 generation and allowed them to self pollinate.
• He observed that in the generation (F2), both Parental type i.e. tall and dwarf stem varieties were produced. When he counted these, he found that in F2 generation, the two types of individuals were present in the ratio of 3:1, tall and dwarf respectively.

Results:
Mendel perceived from these results that

• When the plants of F1 generation form their gametes, the factors (allele) separate or segregate again in such a way that only one of the two alleles enters each gamete.
• On the basis of these observation, results and conclusions from experiment he presented the law called the "Law of segregation or law of purity of gametes".

iv) Explain the inheritance of dihybrid cross by law. OR State and explain the law of Independent assortment.
Ans: LAW OF INDEPENDENT ASSORTMENT:
Statement:

"The genes of assorted traits are independent in their inheritance."
OR
"Members of one pair of genes separate from each other during gametes formation."

Dihybrid - Cross And Dihybrid Ratio:
Mendel crossed between two individuals (pea plant) differing in two traits. He called it Dihybrid - Cross and the ratio obtained in F2 generation is called Dihybrid-ratio.

Inheritance of two traits:
The results achieved as a consequence of dihybrid-cross is known as Inheritance of two traits.

Experiment:

• In his experiments Mendel crossed between two individual (pea plants) differing in two or more character traits as well.
• Mendel crossed yellow cotyledon and rounded seed containing plant with green cotyledon and wrinkled seed containing plant.
• The F1 generation had all plants with yellow cotyledon and round seeds.
• This proved Mendel previous finding that allele for round seed was dominant over wrinkled while yellow cotyledon over green.
• Mendel self fertilized the F1 generation and expecting any of the two following possibilities:
  i) If the genes for round seed and yellow colour are inseparable (dependent on each other), as well as those for wrinkled shape and green colour, then in F2 generation ³/₄ of the seeds will be round and yellow and ¹/₄ will be wrinkled seed and green.
  
  ii) If the genes for seed shape and cotyledon colour are separable (independent) and distributed to the gametes independent to each other, then in F2 generation some plants will produce round seeds with green cotyledon and some will have wrinkled seeds with yellow cotyledon along with parental combination.

Result:
Mendel actually obtained four different kind of phenotypes in F2 generation. Out of a total 556 seeds, he obtained four different phenotypes i.e.
Phenotype:

• Round and Yellow seeds = 315
• Wrinkled and Yellow seeds = 101
• Round and Green seeds = 108
• Wrinkled and Green seeds = 32

Genotype:

• Genotypes for round and yellow seeds RRYY, RRYy, RrYY, RrYy.
• Genotypes for round and green seeds RRyy, Rryy.
• Genotypes for wrinkled and yellow seeds rrYY, rrYy.
• Genotypes for wrinkled and green seeds rryy.

Dihybrid-cross ratio:
These numbers are in a ratio of about 9:3:3:1 for the four phenotype.

Conclusion:
It showed that the genes for seed colour and shape are independent in their inheritance. They do not necessarily stay together in the combination in which they occurred in parents.

v) Explain the Darwin theory of natural selection.
Ans: THEORY OF NATURAL SELECTION:
Charles Darwin (1809 - 1882) was an Englishman. He studied different plants and animals, collected new specimens and categorized them. In the year, 1859, he published a book “Origin Of Species” where he proposed the "Theory of Natural Selection", in which he presented the mechanism of origin of species.

FACTORS INVOLVED IN NATURAL SELECTION OR MAIN POINTS OF DARWIN'S THEORY:
The main points of the Darwin's theory are as follows:
1. Over Production:
Living organisms reproduce rapidly so that the number of their offspring could increase rapidly.

2. Struggle for Existence:
Due to the limited available resources of food, shelter, etc. the offspring of species compete not only with each other but also with the members of different species to share these resources. In this struggle a large number of individuals of each species are eliminated. As a result the population remains stable.

3. Heritable Variation:
Individual of a species differ from each other in their ability to obtain resources, withstand environmental extremes etc. These differences in character are called minor variations.
Darwin concluded that survival in struggle for existence is not random but depends upon in part on the heredity constitution of the surviving individuals. Those individuals whose inherited characters fit them best to their environment would survive and produce more offspring than less fit individuals who will vanish.

4. Natural selection:
Nature selects the fittest individuals to survive and reproduce. Therefore only the favourable variations are preserved through their inheritance to new young ones.

Conclusion:
Over millions of year of variations, natural selection and inheritance might have led to the accumulation within the species a number of characters with survival values. As a result, a species may slowly change to a better new species. 
Number of evidence are reported in support of evolution from comparative anatomy, homologous organs, analogous organs, vestigial organs and fossils.

Biology For Class X - Chapter No. 6 - Inheritance - Multiple Choice Questions And Fill In The Blanks By Sir Saeed Sarang

GO TO INDEX
CHAPTER 6: INHERITANCE
Multiple Choice Questions And Fill In The Blanks

Special Thanks To Sir Saeed Sarang (Sindh Text Book Board)
Contact # 03023006727
Youtube Channel # Shafquat Ali YouTube

TEXT BOOK EXERCISE

A. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:
i) Branch of biology deals with the study of heredity and variation is called:
(a)Inheritance
(b) Heredity
(c) Genetics ✓
(d) Evolution

ii) The way by which gene transmits characters from parents to offspring is:
(a) Genetics
(b) Inheritance ✓
(c) Heredity
(d) Allele

iii) Two similar chromosomes in a cell which are similar in shape, size and position of centromere called:
(a) Chromatids
(b) Arms
(c) Homologous ✓
(d) Homology

iv) The chemical material of a chromosome is called:
(a) Chromatin ✓
(b) Chromeres
(c) Chromonema
(d) Chromatid

v) The outer part of DNA helix made up of sugar and phosphate is called:
(a) Nucleoprotein
(b) Rungs
(c) upright ✓
(d) Phosphoester

vi) The small segment of DNA which has information to code one protein is called:
(a) Nucleotide
(b) Polynucleotide
(c) Gene ✓
(d) Exon

vii) The exact duplication of DNA is called:
(a) Duplication
(b) Replication ✓
(c) Transcription
(d) Translation

viii) If both the parents donate same factors of a character is called:
(a) Homologous
(b) Heterologous
(c) Homozygous ✓
(d) Heterozygous

ix) The Genetic constitution of a trait is called:
(a) Genotype ✓
(b) Phenotype
(c) Genome
(d) Phenyl

10. The characteristics of the offspring's to resemble their parents called:
(a) inheritance
(b) heredity ✓
(c) genetics
(d) evolution

11. Living things when reproducing sexually, their offspring neither resembles exactly with one another nor with their parents. Such differences are called:
(a) heredity
(b) evolution
(c) inheritance
(d) variations ✓

12. Structure, character, function and behaviour of every organism is programmed and controlled by a set of instructions which are in the form of coded biological information called:
(a) sex cells
(b) gametes
(c) genes ✓
(d) sperm

13. Each kind of organism has specific number of:
(a) chromosomes ✓
(b) genes
(c) gametes
(d) DNA

14. All human contains two sets of:
(a) 21 chromosomes
(b) 23 chromosomes ✓
(c) 26 chromosomes
(d) 27 chromosomes

15. Chromatin is a nucleo-protein (Deoxyribo Nucleoprotein) which is composed of DNA and:
(a) Phosphoric acid
(b) Deoxyribo Nucleotides
(c) Deoxyribo sugar
(d) Histone ✓

16. DNA (Deoxyribo Nucleic Acid) is made up of billions of units called:
(a) Phosphoric acid
(b) Deoxyribo Nucleotides ✓
(c) Deoxyribose sugar
(d) Histone

17. Which is the correct statement?
(a) histone and DNA both are positively charged
(b) histone and DNA both are negatively charged
(c) histone is positively charged while DNA is negatively charged ✓
(d) histone is negatively charged while DNA is positively charged

18. These beads of histone and DNA is called:
(a) nucleosome ✓
(b) chromatids
(c) Genome
(d) Rungs

19. The inner part of DNA is made up of paired nitrogenous bases which are called:
(a) nucleosome
(b) chromatids
(c) Genome
(d) Rungs ✓

20. Both helixes are complementary to each other which are held together by:
(a) ionic bonds
(b) covalent bonds
(c) hydrogen bonds ✓
(d) co-ordinate covalent bonds

21. It is the basic unit of biological information.
(a) Nucleotide
(b) DNA
(c) Gene ✓
(d) Exon

22. Tick the correct statement:
(a) Each chromosome is located at a specific position on the gene, called Gent locus (loci).
(b) Each gene is located at a specific position on a chromosome, called Gent locus (loci). ✓
(c) DNA (Deoxyribo Nucleic Acid) is made up of billions of units called Gent locus (loci).
(d) The string of nucleosomes wraps up into High order coil is called Gent locus (loci).

23. The genetic variation gives rise to two or more than two alternative forms of a gene, called:
(a) allele
(b) allomorph
(c) Both 'a' & 'b' ✓
(d) None of these

24. The process of copying DNA information to mRNA is called:
(a) transcription ✓
(b) replication
(c) translation
(d) duplication

25. He is known as Father of Genetics.
(a) Charles Darwin
(b) Watson
(c) Crick
(d) Gregor John Mendel ✓

26. If both parents donate different factors [allele] of a trait, the organism is:
OR An individual having different factors of a trait called:
(a) Homologous
(b) Heterologous
(c) Homozygous
(d) Heterozygous ✓

27. The factor (gene) which expresses and masks the expression of other factors in the heterozygous condition is said to be:
(a) recessive
(b) dominant ✓
(c) phenotype
(d) genotype

28. It is the physical appearance of the trait on the basis of inherited genes:
(a) Recessive
(b) Dominant
(c) Phenotype ✓
(d) Genotype

29. ”Members of one pair of genes separate from each other during gametes formation" is the statement of:
(a) Mendel's law of independent assortment ✓
(c) Mendel's law of segregation
(b) Mendel's law of purity of gametes
(d) Mendel's law of complete dominance

30. Due to the presence or absence of two specific antigens on the surface of RBC, there are:
(a) two phenotypes
(b) three phenotypes
(c) four phenotypes ✓
(d) five phenotypes

31. This blood group is called a universal donor.
(a) A
(b) B
(c) AB
(d) O ✓

32. Alleles of a trait express in heterozygous condition and their expression blended to produce new phenotype called:
(a) incomplete dominance
(b) partial dominance
(c) Both 'a' & 'b' ✓
(d) None of these

33. The differences in characters such as height, colour etc. among individuals of same species are called:
(a) inheritance
(b) heredity
(c) variations ✓
(d) evolution

34. The variation caused due to changes In genetic material called:
(a) environmental variation
(b) genetic heritable variation ✓
(c) continuous variation
(d) discontinuous variation

35. This type of variation is considered as raw material for evolution.
(a) environmental variation
(b) genetic heritable variation ✓
(c) continuous variation
(d) discontinuous variation

36. Blood groups, six fingers in a hand or a foot, tongue rolling etc. in man are common examples of:
(a) environmental variation
(b) genetic heritable variation
(c) continuous variation
(d) discontinuous variation ✓

37. The phenomenon of producing sudden changes is called:
(a) mutation ✓
(b) evolution
(c) heredity
(d) inheritance

38. He published a book “Origin Of Species" in 1859 where he proposed the theory of Natural Selection:
(a) Watson
(b) Crick
(c) John Mendel
(d) Charles Darwin ✓

39. The differences of sexually reproduced off springs from Parents are called:
(a) Genetics
(b) Inheritance
(c) Heredity
(d) variations ✓

40. The process by which characters are transmitted from parents to offspring is:
(a) Genetics
(b) Inheritance ✓
(c) Heredity
(d) Allele

41. The phenomenon of inheritance where both alleles are dominant and expressed equally is called:
(a) co-dominance ✓
(b) multiple alleles
(c) Transcription
(d) Translation

42. If both Parents donate different factors (allele), the organism is:
(a) Hybrid ✓
(b) homozygous
(c) genotype
(d) phenotype

43. Development of muscles in athletes, loss of some body parts due to accident or disease etc. are example of this type of Variation.
(a) Environmental ✓
(b) Heritable
(c) Continuous
(d) Discontinuous

44. Height, skin colour, intelligence, eye colour etc. are example of this type of Variation.
(a) Environmental
(b) Heritable
(c) Continuous ✓
(d) Discontinuous

45. Blood groups, six fingers in hands or foot, tongue rolling etc. are example of this type of Variation.
(a) Environmental
(b) Heritable
(c) Continuous
(d) Discontinuous ✓

46. This is the process where descends become better than ancestors.
(a) Fertilization
(b) Evolution ✓
(c) Crossing over
(d) Mutation

47. Law of inheritance, law of dominance, law of segregation or purity of gametes and law of independent assortment was presented by _____.
(a) Watson and Crick
(b) Gregor John Mendel ✓
(c) Charles Darwin
(d) Carl Correns

48. The phenomenon of incomplete dominance or partial dominance is purposed by _____.
(a) Waston and Crick
(b) Gregor John Mendel
(c) Charles Darwin
(d) Carl Correns ✓


FILL IN THE BLANKS
1. Living things when reproduce sexually their offspring differ somewhat from their parents, such differences are called variations.
2. Heredity is the way by which genes transmit characters from parents to offspring.
3. Haploid set (n=23) is paternal in origin, which is contributed by sperm while the other haploid set (n=23) is maternal which comes from egg.
4. The genes are located at chromosomes and inherited through chromosomes during sexual reproduction.
5. Two chromosomes which are similar in their shape, size and position of centromeres present in a cell make one homologous pair of chromosome.
6. Deoxyribo nucleoprotein is composed of DNA (Deoxyribo Nucleic Acid) and special protein i.e Histone (H₃P0₄).
7. Eukaryotic chromosome are composed of 40% of chromatin, a complex of DNA and  60 % of protein.
8. DNA is a double helical structure.
9. Each helix is a polynucleotide chain which are twisted around each other.
10. Both helix are complementary to each other which are held together by hydrogen bonds.
11. The process of duplication of DNA is called replication of DNA.
12. A gene expresses by synthesizing a protein which works as an enzyme.
13. Gene is the basic unit of biological information.
14. The position of gene on chromosome is called Gene locus (loci).
15. The coded information may change due to any reason which is called genetic variation caused by mutation.
16. The alternative form of a gene is called alleles or allomorph.
17. Gene is a unit of inheritance which is copied and inherited to next generation.
18. Genetic information flows in a cell from DNA to mRNA than to ribosome in cytoplasm, which is two step process for protein (enzyme) synthesis.
19. DNA (gene) is copied in complimentary form.
20. The process of copying DNA Information to mRNA is called Transcription.
21. In Translation, tRNA and rRNA translate the information of mRNA into the specific sequence of amino acids.
22. Gregor John Mendel studied seven traits (characters) in pea plants one by one.
23. Pure-breed means that if an organism is self fertilized, the offspring always look exactly like parents.
24. If both the parents donate same factor of the trait, the organism is pure or Homozygous.
25.If both parents donate different factors (allele) of a trait, the organism is hybrid or Heterozygous. 26.The factor (gene) which express and masks the expression of other factor in heterozygous condition is said to be Dominant factor.
27. The factor which is unable to express or masked in heterozygous condition is said to be recessive.
28. Phenotype is the physical appearance of the trait on the basis of inherited genes like tall.
29. Genotype genetic makeup or genetic constitution of a trait like TT, Tt.
30. Some trait has more than two and more alternative forms. These traits are called multiple allelic trait or multiple alleles.
31. The phenomenon of inheritance where both alleles of a trait expressed in heterozygous condition and their expression get blended to produce new phenotype called incomplete Dominance or Partial Dominance.
32. Variation may be caused either by the effect of environment or by the changes in the genetic material.
33. Each nucleotide is made up of deoxy ribose sugar (C₅H₁₀O₄), and (H₃PO₄) and Nitrogenous bases.
34. The histone is positively charged while the DNA is negatively charged.
35. The beads of histone and DNA is called nucleosome.
36. When the string of nucleosomes wraps up into high order coil called super coil.
37. Super coils chromomers form chromosomes.
38. The model of DNA was suggested by Watson and Crick in 1953.
39. The term dogma means a set of beliefs where a gene expresses by synthesizing a protein.
40. RNA stands for Ribo Nucleic Acid.
41. mRNA stands for messenger Ribo Nucleic Acid.
42. tRNA stands for transfer Ribo Nucleic Acid.
43. rRNA stands for ribosomal Ribo Nucleic Acid.
44. RNA which carry information of DNA sequences to ribisomes from nucleus to cytoplasm called messenger Ribo Nucleic Acid (mRNA).
45. Biological name of garden pea is Pisum sativum.
46. If an organism is self fertilized, the off springs always look exactly like parents. such varieties are called true breeders.
47. Law of segregation is also called law of purity of gametes.
48. Blood group in human is an example of multiple allele.
49. In R^h blood type, R stands for Rhesus.
50. The chemical cells or organs of an organism can work as antigen to other organism.
51. When antigens enter in the body of other organism, they produce defense protein against this antigen to protect itself. These proteins are called antibodies.
52. The blood serum containing antibodies called antiserum.
53. During transfusion of blood, the clumped cells are produced which lead to serious problem. These clumped cells are called agglutination.
54. Sudden change in genetic material (genome) of an organism is called mutation.
55. Dominant factor represent with capital letter like T for tall.
56. Recessive factor represents by small letter of same alphabet like t for small (dwarf).
57. The original true breeding organisms were called parental generation or P1 by Mendel.
58. The off spring of true breeding organism were called First Filial Generation or Fl.
59. The offspring of filial one generation produced by crossing self fertilization were called Second Filial generation or F2.

Dynamics - Physics For Class IX (Science Group) - Self Assessment and Test book Exercise

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Physics For Class IX (Science Group)
UNIT 3: DYNAMICS
Self Assessment and Test book Exercise

SELF ASSESSMENT QUESTIONS

Q.1: Why momentum is considered equal to zero when a body comes to rest?
Ans: We know that momentum is P = mv.
If a body comes to rest, it means its velocity, v = 0, therefore its momentum becomes:

P = mv

P = m(0)

P = 0

So, when a body comes to rest its momentum is considered equal to zero.

Q.2: Why do you pull your hands while catching a fast moving ball?
Ans: A fast-moving ball tends to keep moving due to inertia. According to Newton's second law, the force with which a ball is moving is equal to its mass multiplied by its acceleration. When we catch a ball, the momentum of the ball is transferred from ball to hand. If we keep our hands stationary, the force with which momentum is transferred might hurt our hands. But as soon as we pull our hands back, it increases the time during which the high velocity of the moving ball decrease to zero and net momentum is decreased, thus reducing the force with which the ball makes an impact with our hands.

Q.3: What is reason that you experience a jerk whenever the school bus stops all of sudden?
Ans: When the school bus stops suddenly, we tend to fall forward because due to our inertia we tend to remain in a state of motion even though the bus has come to rest.

Q.4: Why it is dangerous to jump from a moving bus?
Ans: A man jumping out from a moving bus holds the inertia of motion. As the man lands on the ground, his feet come to rest instantly while the upper part of the body continues to move due to inertia of motion. Therefore, the person may fall forward. So, it is very dangerous to jump out of a moving bus.

Q.5: What is the role of force according to Newton's second law of motion?
Ans: According to Newton's second law of motion,
"A force is a vector that causes an object with mass to accelerate. Newton's second law states that the acceleration of an object depends upon two variables:

• The net force acting on the object and
• The mass of the object"

The acceleration of the body is directly proportional to the net force acting on the body and inversely proportional to the mass of the body. This means that as the force acting upon an object is increased, the acceleration of the object is increased. Likewise, as the mass of an object is increased, the acceleration of the object is decreased.

Q.6(a): What happens according to Newton's third law, while you pull a catapult?
Ans: Newton's Third-law of motion states that:

"For every action force, there is a reaction force that is equal in strength and opposite in direction."

Newton's Third-law is without a doubt the law that is seen most in the launch of the catapult. It is displayed countless moments in the experiment. This law applies a pushing force as well as pulling force too.

• "Pulling back the lever is the action, and flinging forward the marshmallow is the reaction."
• Similarly as the rubber bands of catapult are pulling on the hook forcefully, the hooks are pulling on the rubber bands with just as much force in the opposite direction.
• Also, when the key of the catapult is being pulled out of the key post, the key is pulling the string with the same amount of force that the string is pulling the key. These forces are just going in the opposite direction.

Q.6(b): What happens according to Newton's first law, while you pull a catapult?
Ans: According to Newton's first law of motion:

"An object at rest stays at rest until a force is applied, and an object in motion stays in motion, at the same speed, until a force acts upon it".

An object at rest stays at rest- this means that the projectile will always sit in the cap if we don't apply a force to it. Until a force is applied- the force we applied was the arm of the catapult. When we pull back the arm it stores up a lot of energy, but when we let go of the arm it changed the form of energy and applied a force to the projectile. This change in the energy created a force that launched the projectile forward.

Q.7: Why mass does not differ, while weight differs from place to place?
Ans: Weight of a body is the gravitational force on it and mass is the amount of matter in the body. Thus, weight is dependent on gravitational acceleration, g but mass does not depend on the value of g. Hence, the weight of a body will change from one place to another place because the value of g is different in different places. For example, the value of g on the moon is ¹ /₆ times the value of g on earth. As mass is independent of g, so it will not change from place to place.

Q.8: Why do we feel pushed outward while a car turns on a curved road?
Ans: The force that pulls out from the center on a body in circular motion is called centrifugal force and it increases with acceleration. Centrifugal force results in a strong outward pull on our vehicle. That's why we feel pushed outward while a car turns on a curved road. So we need to slow down a car before entering a curve.

Q.9: Which force prevents a passenger from falling down a roller coaster while it turns the riders into upside-down position?
Ans: This force is inertia which prevents us from falling down or out in a a roller coaster because inertia is a resistance against a change in direction. It keeps us pressed against the bottom of the car with a force stronger than gravity.

Q.10: Why it is easier to walk wearing flat slippers than the high heel sandals?
Ans: Wearing flat slippers will likely be far more comfortable than high heel sandals. This is because the whole of the foot and arch are fully protected without putting too much pressure on sensitive areas such as the toes and heel. Flat slippers have a greater area in contact with the soft sand as compared to high heel sandals. Due to this, there is less pressure on the surface area and less reaction force and it is easy to walk on it.

Q.11: Why leather sheet is used in brake drums of motor bike?
Ans: A drum brake is a brake that uses friction caused by a set of shoes or pads that press outward against a rotating cylinder-shaped part called a brake drum. The leather sheet is used in brake drums because it provides high friction to stop the motorbike.

TEXT BOOK EXERCISE

Section (B) Structured Questions

Momentum

Q.1(a): Define momentum with SI unit?
Ans: MOMENTUM:
The momentum depends upon the quantity of mass and velocity of the object. Greater the mass greater will be momentum. Similarly faster the speed greater will be momentum.
Definition:

"Momentum is defined as the quantity of motion contained in a body."

In terms of an equation,

The momentum of an object is equal to the mass multiplied by the velocity of the object
OR
 Momentum is the product of the mass and the velocity of a moving object.

Momentum = mass x velocity

Symbolically, the momentum is represented by p.
Formula:
Thus, the above equation can be written as:

p = mv

where,

• p is the momentum of a body
•  m is the mass and
• v is the velocity.

Nature:
The momentum is vector quantity. Its direction is same as that of velocity.

SI Unit of Momentum
The SI unit of momentum is kilogram meter per second (kg-ms^-1) or Newton second (Ns).
A mass unit is multiplied by a velocity unit to provide a momentum unit. This is consistent with the equation for momentum. The SI unit of momentum is describe below as:

Momentum = mass x velocity
Momentum = kg-ms^-1
Momentum = kg ms^-2 x s (multiply and divide by second 's')
or Momentum= Ns (Newton second)

OR

Q.2 (a): When a free falling object moves towards earth due to pull of earth on it. Does earth also move towards that object due to reaction? Explain.
Ans: Yes, when a free falling object moves towards earth due to pull of earth on it. Earth also move towards that object due to reaction, but the acceleration produced by the earth towards the object is negligible.
This can be easily explained by the equation of Newton's second law of motion F = ma.
Earth and any free falling object pull each other towards them. The force applied on both of them remaining the same, but the changes in the position of an object are determined by its mass and acceleration.
According to the universal law of gravitation, two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the distance between them. So, theoretically, a free-falling object also pulls the earth in the same way the earth does. But comparing to the mass of the earth, the mass of the free-falling object is negligible. Hence the motion of Earth in not noticed because the acceleration produced in Earth is negligible small, due to large mas of the Earth. So we can say the earth does not move toward the falling object.

Q.3 (a): Why a wire fence is designed in the helmet of batsman?
Ans: When a helmet breaks, it's absorbing that's called "impulse" - a secondary effect of an initial force. Impulse, which gives objects momentum, is what transmits kinetic energy through a system. It takes into account not just force, but also how long that force was applied.
A wire fence is designed in the helmet of batsman aims to reduce the risk of serious jaw and teeth injuries by reducing the impact of a force or collision to the face.

Q.3 (b): How does it (helmet) prevent from injuries?
Ans: When a bike helmet breaks, it's absorbing that's called "impulse" - a secondary effect of an initial force. Impulse, which gives objects momentum, is what transmits kinetic energy through a system. It takes into account not just force, but also how long that force was applied. A helmet aims to reduce the risk of serious head and brain injuries by reducing the impact of a force or collision on the head. A helmet works in three ways: It reduces the deceleration of the skull, and hence the brain movement, by managing the impact.

Laws of motion

Q.4 (a): State the Newton's first law of motion. Give some common examples?
Ans: NEWTON’S FIRST LAW OF MOTION:
Newton's Laws of motion were published in Latin language in 1687 by Issac Newton (1642-1727).
The first law of motion was written in latin language as:
Statement In Latin Language:

“Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.”

So we can state Newton’s first law of motion as:
Statement in English Language:

"A body continues its state of rest or of uniform motion in a straight line unless an external force acts on it." The Newton's first law is also called law of inertia."

Examples Of Newton's First Law of Motion:

1. The table placed in classroom, always remains at the same place until some external force apply to move it.
2. A book placed on the table remains at its place unless someone picks it back.
3. Similarly, a satellite in the space continuously moves with constant speed because there is no air or force of friction in the space.
4. A ball rolling on the ground however stops after some time because friction of ground and air resistance exert force on it and change its state of motion or direction of motion.

Q.4 (b): Enlist some common observations that are caused by the property of inertia?
Ans: Example To Show Property Of Inertia

1. If we put our bag on the seat next to us in a bus. Whenever the bus stops suddenly, the bag slides forward off the seat. It happens because the bag was initially moving forward as it was on a moving bus. When the bus stopped, the bag continued moving forward, which was its initial state of motion, and therefore it slide forward off the seat.
   
   
2. When a bus starts moving the passengers feel a backward jerk, because their lower part of body moves along the motion of bus but the upper part of the body tends to stay at its initial position of rest.
   
   
3. When we stop paddling our bicycle it does not stop at once. The bicycle continues moving. However the road's friction and air resistance act against its motion and bring it to rest after some time.

Q.5 (a): Define Newton's second law of motion.
Ans: NEWTON'S SECOND LAW OF MOTION:
Newton's second law of motion describes the relation between force and acceleration. Newton's second law of motion states that:

”when a net force acts on a body it produces acceleration in the direction of force. The acceleration is directly proportional to force and inversely proportional to mass of body”.

Expression Mathematically:

F = ma

where,

• F = net force acts on a body
• a = acceleration in the direction of force
• m = mass of body

Q.6 (a): Show the relationship between applied force and the acceleration produced in the body?
Ans: According to Newton's second law of motion:

Q.8 (a): Enumerate at least three clear differences between mass and weight?
Ans: Difference Between Mass and Weight

Comparison Chart	MASS	WEIGHT
Definition	Mass is the quantity of matter in a body regardless of its volume or of any forces acting on it.	Weight is a measurement of the gravitational force acting on an object.
Effect of gravity	Mass is always constant at any place.	The weight of an object depends on the gravity at that place.
Unit of Measurement	Mass is measured in kilogram (kg).	Weight is measured in Newton (N).
Nature	Mass has no direction so it is scalar quantity.	Weight always directed downward towards the center of the earth so it is vector quantity.
Formula	Its formula is m = F / a.	Its formula is W = mg.
Balance used for measurement	Mass is measured using a pan balance, a triple beam balance, lever balance or electronic balance.	Weight is measured using a spring balance.

(Note: Write down any three differences as mentioned in above question.)

Circular motion

Q.9 (a): Define the forces acting on an object in circular motion?
Ans: FORCES REQUIRE FOR UNIFORM CIRCULAR MOTION:
There are two types of force required for uniform circular motion:

• Centripetal force
• Centrifugal force

Centripetal Force:
"The force required to move a body along a circular path is called Centripetal force."
It is denoted by F.
The centripetal force is always directed towards enter of the circular path. It depends on three factors:

1. The velocity of the object v
2. The object's distance from the center “r” and
3. The mass of the object “m”.

It is given by relation

Where m = mass of body moving in circle.
v = velocity of body.
r = radius of circle
The velocity of the object is constant and perpendicular to a line running from the object to the center of the circle.

Centrifugal Force:
Centrifugal force is the tendency of an object to leave the circular path and fly off in a straight line. Thus it is defined as:
"A force that acts outward on a body which moves along a curved path is called centrifugal force."

OR

"Centrifugal force is tendency of an object to move away from circular path." 

• It is always directed away from center of curvature.
• The magnitude of centrifugal force is equal but opposite in direction to centripetal force.

Q.9 (b): Draw a figure showing the direction of centripetal force, centrifugal force and velocity of an object along a circular path.
Ans: Diagram Showing The Direction OF Centripetal Fore And Centrifugal Force

Q.9 (d): List down some purposeful uses of centrifuge that human are benefiting everyday.
Ans: Application of Centrifuge:
Centrifuge appliances are used to separate heavier particles from lighter particles in liquids e.g.

• Sugar crystals are separated from molasses.
• Blood analysis is carried out through a centrifuge process in laboratory.
• Cream separator is used to separate the cream from skimmed milk.
• An ultra centrifuge is used for separating small particle from large molecules.
• Gas centrifuge is used for separation of isotopes etc.

Some of them are:

1. Road Banking:

• The outer edge or bank of the road is raised to a certain height at the curved part of roads.
• This provides the centripetal force against the tyres of vehicle hence prevents from skidding.

2. Cream Separator:

• The milk plants in country are using high speed spinners to separate cream from milk.
• The skimmed milk is heavier whereas the cream is lighter.
• When the milk is spun at high speed the heavy particles are pushed towards the walls of the spinner.
• These particles push the lighter particles of cream to the center where from it is collected through a tube.

3. Dryer:

• Now a days built-in dryer is available in most of washing machines.
• It spins the wet clothes hence the water droplets are thrown away from the perforated walls of the dryer and clothes get dry instantly.

Friction

Q.10 (a): What is force of friction? Explain with two examples from daily life.
Ans: FORCE OF FRICTION:

"The force that resists relative motion between two surfaces is called force of friction."

Friction is a contact force caused by the roughness or deformation of the materials in contact.
Frictional forces are always parallel to the plane of contact between two surfaces and opposite to the direction of the applied force.
Example:

• The frictional force between a wooden block and cemented floor caused by the roughness of both the surfaces is projected.
• When we through a ball, it comes to rest after covering some distance.
• When we kick a ball and a box with same force, the ball covers more distance than a box.
• Friction helps us walk easily, it prevents from sliding.

Q.11 (a): How anti-lock braking system prevents the risk of sliding?
Ans: Anti-Lock Braking System:
Now vehicles are equipped with Anti-lock Braking System (ABS). ABS is designed to maintain steering stability, improve vehicle control, avoid skidding and decreases stopping distances on dry and slippery surfaces. The ABS maintains the static friction as the wheel starts slipping it releases the brake automatically for a fraction of a second then holds wheel again to create static friction between road and tyres.

Q.11 (b): Enlist any four uses of rolling friction in everyday life?
Ans: Any ball or wheel has rolling friction when rolled on a surface. Some uses of rolling friction include:

1. Truck, car and skateboard tires
2. Rolling of Ball bearings
3. Bike wheels
4. Rolling pin
5. Roller skate wheels

Q.12: Explore the following phenomenon in relation with dynamics.
(a) When an air filled balloon is released.
Ans: When a hot air filled in a balloon, it released. Different forces acting in opposite direction to raised the hot air filled balloon. These forces are:

1. Buoyancy: Buoyancy or lift is created when the temperature in the balloon is increased, causing the density of the air to decrease. The less-dense (lighter) air inside the balloon tends to float on the more dense (heavier) air on the outside of the balloon That is why hot-air balloons are referred to as lighter than air vehicles. If the amount of lift is greater than the force of gravity acting on the mass of the balloon, then the balloon will rise.
2. Pressure: Warmer air inside the balloon will also cause the pressure inside, the balloon to increase. The pressure inside the balloon will be greater than that on the outside of the balloon. For the balloon to maintain its shape, this force has to be greater than the forces acting in the opposite directions (pushing inward on the balloon).
3. Drag And Force Of  Gravity: In hot-air balloons, drag is the fiction that occurs as the balloon rises and moves through the surrounding air. Friction occurs between the moving balloon and the molecules of air. It hits as it rises. Both drag and the force of gravity pulling on the mass of the balloon act in a downward force in opposition to the lift.
   If the lift is greater than the drag and force of gravity, then the balloon rises.
   If the lift is less than the drag and the force of gravity, then the balloon descends.
   If the lifting force is equal to the force of drag and gravity, then the balloon will neither rise nor fall.
4. Wind: However, wind can also act as a force on the balloon. The wind can come from nearly any direction and will tend to move the balloon in the direction it is blowing.

(b) Riding a bicycle needs continuous paddling.
Ans: Riding a bicycle needs continuous pedalling because When the rider stops pedalling the bicycle, the force of friction between the tyres of the bicycle and the road acting in the direction opposite to the direction of motion of the bicycle, opposes the motion of the bicycle and this force is now unbalanced, thus slowing down the bicycle.

(d) The biker ridding in the death well.
Ans: When a bike moves on the walls, there are a number of forces acting. These include:

• The gravitational force, which acts downward from the bike to the walls.
• The frictional force that the walls exert against the tires of the bike, and
• The normal reaction force, a perpendicular push back by the wall surface when it receives a force.
• There is also centripetal force, which is directed towards the center of the circular path that the bike traces.

For a bike moving in a horizontal circle on a vertical wall, the normal reaction (N) is the factor that supplies enough force to sustain motion in a circle. Also, the fact that the bike does not slide down the wall signifies that the forces of friction and gravitation balance each other out.
In short, the two forces, the gravitational force and the force of friction act in opposite directions and compensate each other, while the normal reaction from the wall keeps the bike moving. However, it's not that simple. The frictional force exerted on the tires of the bike depends on the speed of the bike as it moves along the circle. This means that there has to be a minimum velocity of the bike that produces the maximum frictional force, effectively balancing out the gravitational force. This is crucial because if the gravitational force is greater, then the bike will slide down and the rider will fall off. The friction becomes stronger as the speed increases, but with increasing speed, it becomes more and more difficult for the rider to steer the vehicle safely.
The frictional force is acting on the tires, but the gravitational force is acting through the center of mass of the system consisting of both the bike and the rider. Since the three forces are balanced but do not lie in the same line, the bike will tend to rotate, producing a turning effect that will eventually lead to it fall off. This anomaly has to be compensated for to keep these brave riders safe!
In order to counter this dangerous turning effect, the rider has to lean at an angle away from the vertical. This will make the normal reaction from the wall produce a tendency to rotate (a torque) in the opposite direction. If the rider bends at the correct angle, the torques will be perfectly balanced out; therefore, there will be no rotating or turning effect on the bike and the impressive display can continue. However, if the rider leans at an angle other than the correct one, then the unbalanced torques will cause the bike to rotate and fall. Therefore, the rider will have to push harder in the opposite direction to supply extra torque and maintain his balance.

(e) You always feel a pullback whenever you pull on your school bag or some heavier object.
Ans: By putting a heavyweight on our shoulders in the wrong way, the weight's force can pull us backwards. So people who carry heavy backpacks sometimes lean forward.


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Computer Science (New) - For Class IX - UNIT. UNIT. 4. Data Communication And Computer Network - Text Book Exercise And Activity

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Chapter No.4. Data Communication And Computer Network
Text Book Exercise And Activity

Text Book Exercise

B. Respond the following:

1. List the properties of a good communication system. Explain any one.?
Ans: Properties of a Good Communication System:
The effectiveness of a data communications system depends on the fundamental characteristics which include:

1. Delivery
2. Accuracy and
3. Timeliness

S.No.	Characteristic	Description
1.	Delivery	Making sure that the data is delivered is the first fundamental characteristic of any communication network. The system must be able to deliver data in correct order to the correct destination.
2.	Accuracy	The system must deliver the data accurately. Data that has been altered during transmission and left uncorrected is not useful.
3.	Timeliness	The data must be delivered in a timely manner. Late delivered data is useless.

(Note: Describe anyone (Delivery or Accuracy or Timeliness, as mention in question)

2. Explain different components of a communication system using single example?
Ans: COMPONENTS OF A COMMUNICATION SYSTEM:
A Communication system has following five components:

(i) Message:
It is the information or data to be communicated.
Example: Common forms of information include text, numbers, pictures, audio and video.

(ii) Sender:
It is the device that generates and sends a message.
Example: It can be a computer, telephone handset, etc.

(iii) Receiver:
Any particular digital electronic device which has capability to receive data in form of message. The location of receiving computer is generally different from the sending computer.
Example: Like sender, it can also be a computer, telephone handset, etc.

(iv) Medium:
It is the channel or path through which the message is carried from sender to the receiver.
Example: Some examples include twisted-pair cable, coaxial cable, radio waves, etc.

(v) Protocol:
Protocols are the rules and procedures on which computers exchange data on network.
Sender and receiver follow same protocols to communicate with each other.
In other words, a protocol is an agreement between two parties or venders, using communication devices.
Example: FTP, TCP/IP, HTTP etc.

EXAMPLE OF COMMUNICATION SYSTEM:
When a person talk with another person directly, then the speaker is the sender who conveying the message as information in the form of sound waves through a communication channel, the intervening air and listener are the receiver.
If the distance between the speaker and the listener is large sound waves cannot reach from the speaker to the listener directly and communication is not possible. To make communication possible, different communication channel or method is used like microphone and speakers via telephone or internet services etc.

3. Write the function of following network devices.
Amplifiers, Routers, Switch, Hub
Ans: AMPLIFIERS:
Amplifiers are used to overcome attenuation and make signal stronger again. It is measured in decibels.

ROUTERS:

• A Router is a device that connects two or more networks.
• Routers are a combination of hardware and software.
• The main function of a router is to determine the optimal data path and transfer the information through that path, also known as network traffic controller.

SWITCH:

• A switch or network switch is a networking device that connects computers and other devices like printers, scanners and cameras on a network.
• Data cables from all computers and other devices of network are plugged into the switch to enable communication between them.

HUB:

• In a star topology, all the computers are connected to a central device called hub or switch.
• To communicate with any computer, the sender must send information to the hub. Then the hub transmits that information to the destination.

Q.No.4: List the causes of signal impairments. Explain any one.
Ans: TRANSMISSION IMPAIRMENTS OR FLAWS AND FAULTS IN TRANSMISSION SIGNALS:
Sometimes, signals traveling through transmission media lose their quality. This means that received signal is not same as the signal that was sent. This phenomenon is called transmission impairments. Transmission impairments are those defects that occur when data is transmitted.

CAUSES OF SIGNAL IMPAIRMENTS OR TYPES OF FLAWS AND FAULTS IN TRANSMISSION SIGNALS:
There are three causes of impairment i.e.:

1. Attenuation
2. Distortion and
3. Noise

(i) Attenuation:
Attenuation means loss of energy. A signal loses its energy due to the resistance of medium while it is transmitted. Its strength decreases with increase in distance. Amplifiers are used to overcome attenuation and make signal stronger again. It is measured in decibels.

(ii) Distortion:
Distortion means change in the shape of the signal. A composite signal has several frequencies. When it travels through a medium different component of signal may reach at different time at destination because each component has different speed in that medium. This is called distortion. They have different phases at sender and receiver ends.

(iii) Noise:
Unwanted signal that mixes up with the original signal during the transmission of data is called noise. It can be induced noise, crosstalk noise, thermal noise and impulse noise which may damage the signal.

(Note: Explain any one cause as mention in question)

5. What is the difference between radio wave and microwave?
Ans: Difference Between Radio Wave And Microwave:

S.NO.	Basis	Radio Wave	Micro wave
1.	Direction	These are omni directional in nature.	These are unidirectional in nature.
2.	Penetration	At low frequency, they can penetrate through solid objects and walls but at high frequency they bounce off the obstacle.	At low frequency, they can penetrate through solid objects and walls but at high they cannot penetrate.
3.	Frequency range	3 KHz to 1 GHz	1 GHz to 300 GHz
4.	Security	These offer poor security.	These offer medium security.
5.	Attenuation	High	Variable
6.	Government License	Some frequencies in the radio waves require government license to use these.	Some frequencies in the microwaves require government license to use these.
7.	Usage cost	Setup and usage cost is moderate.	Setup and usage cost is high.
8.	Communication	These are used in long distance communication.	These are used in long distance communication.

6. Why OSI model is broken up in layers?
Ans: The OSI model is conceptual. It is broken up into layers so a person can visualize network communication from the application to the medium. It works going up the stack at the destination as well. Rather than just "all the magic happens", it is broken down so we can visualize the steps a computer takes when it encapsulates data.
Breaking things down into layers also allows for better troubleshooting. If there is no data being received on our NIC, then we can assume it is a layer 1 or 2 problem.
If we are getting routing errors, then we most likely have a layer 3 problem. It allows an administrator to better pinpoint an issue.

7. Explain the purpose of Standard Organization.
Ans: PURPOSE OF STANDARD ORGANIZATIONS:

• Standard Organization develops, coordinates, revises, amends and reissues technical standards.
• These standards are intended to address the requirements of a group of concerned devices.
• There are several organizations working on standardization of computing equipment to enable the interoperability among different devices manufactured by different companies in different regions.
• Example: ISO, IEEE, IETF, ITU and ANSI are the examples of standard organizations.

8. List one merit and one demerit of each topology.
Ans: (i) BUS TOPOLOGY:
Advantage Or Merit of Bus Topology:

• Simplicity
• Cable required is least compared to other network topology.
• Used in small networks.
• It is cost effective i.e. low cost.
• It is easy to understand.
• Easy expansion of the network i.e. easy to expand joining two cables together.

Disadvantage Or Demerit of Bus Topology:

• A breakdown in the bus cable brings the entire network down.
• If network traffic is heavy or nodes are more the performance of the network decreases.
• Cable has a limited length.
• It is slower than the ring topology.

(ii) RING TOPOLOGY:
Advantage Or Merit of Ring Topology:

• Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.
• Cheap to install and expand.

Disadvantage Or Demerit of Ring Topology:

• The failure of a link or a computer can make the entire network nonfunctional.
• Troubleshooting is difficult in ring topology.
• Adding or deleting the computers disturbs the network activity.

(iii) STAR TOPOLOGY:
Advantage Or Merit of Star Topology:

• The advantages of star topology are easy to set up and easy expansion of the network.
• Another feature of Star Topology is that if one link to the hub breaks, only the station using that link is affected not the whole network.
• Fast performance with few nodes and low network traffic.
• Hub can be upgraded easily.
• Easy to troubleshoot.

Disadvantages Or Demerits of Star Topology:

• Cost of installation is high.
• Expensive to use.
• If the hub fails then the whole network is stopped because all the nodes depend on the hub.
• Performance is based on the hub that is it depends on its capacity.

(Note: Write down only one merit and one demerit for each topology as asked in question)

9. Give one example of LAN, WAN and MAN.
Ans: Example Of Local Area Network (LAN):

• Networking between two computers.
• Networking in the home, school, library, laboratory, college / university campus or office.
• Wi-Fi which is also known as wireless LAN.

Example Of Metropolitan Area Network (MAN): 

• Cable TV network
• Telephone networks providing high speed DSL lines.
• IEEE 802. 16 or WiMAX, that provides high-speed broadband access with Internet connectivity to customer premises.

Example Of Wide Area Network (WAN):

• Internet is the example of WAN.

(Note: Give any one example of each as mention in question.)

10. How can we measure bit rate and baud rate? Give an example of each.
Ans: Both bit rate and baud rate are generally used in data communication.
Bit rate is the transmission of number of bits per unit of time (second). Bit rate can be ranging from bps (bits per second) for smaller values to kbps (kilo bits per second) and mbps (megabits per second).
For Example:
DSL connection may be able to download data at 10 kbps, means 10,000 bits are transferred within one second.

Baud rate is defined as the number of signal units transmitted per unit of time (second).
For Example:
If a signal changes 1200 times in one second, it would be measured at 1200 baud.

Formula:
We can measure bit rate and baud rate by the following formula, which relate both:

Bit rate = baud rate x the number of bits per signal unit

OR

Baud rate = bit rate / the number of bits per signal unit

Example:

• When Bit rate and Baud rate are Same:
  Assume 9600 bits are transferred per second and 1 bit used to represent signal level i.e either logic 0 or logic 1 then bit rate is 9600 because number of bits transferred per second are 9600 and baud rate is 9600 because number of changes happening per seconds are also the same.
  
  
• When Bit rate and Baud rate are not same:
  If 9600 bits are transferred per second and 2 bits used to represent the signal level then bit rate is 9600 because the number of bits transferred per second are 9600 but baud rate is 4800 because two bits representing signal level.
  
  

C. Match the columns:

S.NO.	A	S.NO.	B	C
(i)	Parts of an IPV4 address	(a)	WAN	(i)-(b)
(ii)	Physical address	(b)	Network and Host	(ii)-(e)
(iii)	Change in shape of signals	(c)	Transport layer	(iii)-(f)
(iv)	A networking connecting two continents	(d)	Data link layer	(iv)-(a)
(v)	TCP and UDP are used at	(e)	Cannot be changed	(v)-(c)
(vi)	In OSI model the layer responsible to decide the format of data	(f)	Distortion	(vi)-(d)

Activity

More Short Questions Answers

1. List out the names of standards organizations?
Ans: ISO, IEEE, IETF, ITU, ANSI are the examples of standard organizations.

UNIT 03. INPUT/OUTPUT HANDLING in C++ - Chapter From Text Book - Computer Science For Class X

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Computer Science For Class X
Unit 03: Input/Output Handling In C++
Chapter From Text Book