HARD WORK BEATS TALENT WHEN TALENT DOESN'T WORK HARD.

VERY SHORT ANSWER QUESTIONS:-

01.  Which remarkable character of living organisms help in continuity of life and perpetuation?

02.   Which is the fundamental natural process or  Principle of life?

03.   What are the main reasons of variation?

04.   What are the different types of variation?

05.   What is role of variation in evolution?

06.   What is the meaning of word ‘geneses?

07.   What is Mendelism?

08.   Which theory showed influence before Mendel’s work?

09.   Where Mendel was born?

10.  Who was first to say that characters are

      Transmitted from parents to offsprings?

11.  What are factors/determiners?

12.  Where did Mendel joined as Priest?

13.  When did Mendel started his experiments?

14.  When did Mendel publish his work?

15.  What was the title of his research paper?

16.  In which Journal Mendel’s work was published?

17.  Which three scientists rediscovered Mendel’s?

      Work and when?

18.  Name the journal in which De Vries republished Mendel’s work?

19.  Who postulated or framed laws based on

      Mendel’s work?

20.   Name the material selected by Mendel for his

      Experiment?

21.  To which family the plant belongs?

22.   What is diploid chromosome number of pea?

      Plant?

23.   What do you know about life cycle of pea plant?

24.   How many generations can be grown in a year?

      For pea plant?

25.   What type of pollination is naturally shown by pea plant?

26.   What do you understand by the term contrasting characters?

27.   What is advantage of large size of pea flowers?

28.   Which is the most important character of pea plant with reference to experiments on inheritance?

29.   What is the function of factor?

30.   What is trait?

31.  What is gene?

32.   Who coined the term gene?

33.   What are alleles?

34.   Who coined the term allele?

35.   Which character is said to be dominant?

36.   In which two forms a dominant character exists?

37.   Which character is said to be recessive?    

38.   Which condition is necessary for expression of a recessive character?

39.   What is phenotype?

40.   Which is the observable character of an organism?

41.  What is genotype?

42.   What is genome?

43.   What do you understand by the term?

      Homozygous?

44.   What do you understand by the term?

      Heterozygous?

45.   How many types of gametes are produced by a homozygous and heterozygous plants?

46.   What is pure line?

47.   What is hybrid?

48.   What is monohybrid?

49.   What ‘F’ in genetics?

50.   What is the most important character of F1 Generation?

51.  What is F2 generation?

52.   What is Punnet square?

53.   The term ‘Punnet square’ is name after which Scientist?

54.   What is the use of Punnet square?

55.   What are homologous chromosomes?

56.   What are homologues?

57.   Which structures are located over homologous chromosomes?

58.   How many characters Mendel selected at a time?

59.   How many types of crosses were performed by Mendel for his experiments?

60.   Which type of plants were selected as parents by Mendel?

61.  For how many generations Mendel maintained record of his experiments?

62.   What type of record was maintained by Mendel?

63.   How Mendel eliminated chance factor?

64.   What does step- I include?

65.   For how many generations medal carried out setting to maintain homozygosity?

66.   What type of pollination forms the basis of step - II ?

67.   What is emasculation ?

68.   When stamens are removed from a flower ?

69.   Which flower is operated under emasculation ?

70.   What type of corolla is found in pea flower?

71.  What is carina?

72.   Why pea flower shows self-pollination?

73.   What condition is exhibited by stamens in pea flower?

74.   Which type of pollination is carried out in    step-III?

75.   What is monohybrid cross?

76.   How many traits are selected for monohybrid Cross?

77.   What according to Mendel was the reason of Tallness and dwarfness?

78.   What can you predict about results of reciprocal crosses?

79.   What is monohybrid ratio?

80.   What are phenotypic and genotypic ratio in   monohybrid cross?

81.  What do you understand by the term     concomitant?

82.   What is the colour of seed coat in pea plant ?

83.   Which is the discrete particle or unit of     inheritance?

84.   Which organism expresses recessive character?

85.   How many different types of phenotypes are     produced in monophybrid cross ?

86.   How many different types of genotypes are    produced in monohybrid cross ?

87.   What is the ratio of pure tall and dwarf plants is obtained in F2 generation of monohybrid cross ?

88.   What is the percentage true breeding and seggregate plants in F2 generation ?

89.   What are dominant and recessive traits in Guinea pig with respect to skin colour ?

90.   Name two characters in dominant and recessive forms in humans ?        

91.  What is the significance of dominance ?

92.   Name three characters in humans which are  expressed in recessive form ?

93.   How many factors are recieved by the gametes ?

94 . Which law is known as law of purity of gametes ?

95.   How many laws can be explained with   monohybrid cross ?

96.   What is the proof of law of seggregation ?

97.   Which laws of Mendel are not universally   applicable ?

98.   On which cross Mendel’s third law is based ?

99.   What is dihybrid cross ?

100. What is dihybrid ?

101. What are phenotypic and genotypic ratio obtained in F2 generation in dihybrid cross ?

102. Which characters were selected by Mendel for his experiments ?

103. What is the nature of phenotypes obtained in F2 generation in dihybrid cross ?

104. How many parental and non parental   combinations were obtained in dihybrid cross ?

105. How many recombinants were obtained in F2 generation in dihybrid cross ?

106. Which principle was used by Mendel to enunciate phenotypic ratio in dihybrid cross ?

107. How many types of gametes are formed by a

      dihybrid ?

108. How many types of genotypes are produced in F2 generation of a dihybrid cross ?

109. How many double homozygous plants are produced in F2 generation of a dihybrid cross ?

110. How many double heterozygous plants are     produced in F2 generation of dihybrid cross?

111. How many single heterozygous plants are produced in F2 generation of a dihybrid cross ?

112. How many plants with  at least one dominant character are produced in F2 generation in  dihybrid cross ?  

113. How many plants with at least one recessive     character are produced in F2 generation in a    dihybrid cross ?  

114. How many plants with both dominant and both recessive character are produced in F2 generation in a dihybrid cross ?

115. Which character proves third law of heredity ?

116. What is the cause of recombination ?

117. For which traits law of independent assortment is applicable ?

118. What was the most important reason for Mendel’s success ?

Explain monohybrid cross with suitable example.

Ans.: 1] Monohybrid cross: - The cross made between two homozygous plants for a single pair of contrasting character is called as monohybrid cross.

2] Monohybrid ratio: - The phenotypic and genotypic ratios obtained in monohybrid cross are called as monohybrid ratio.

3] The cross can be explained with the help of following example,

A] Tallness is the dominant character and dwarfness is the recessive character in sweet pea plant.

B] A homozygous dominant pea plant (TT) is crossed with a homozygous recessive pea plant (tt).

C] Actual crossing between these two plants can be explained as under,

Character selected: - Height of plant

                  1] Dominant—Tall

                        2] Recessive—Dwarf

Parents: -    Homozygous dominant X Homozygous recessive

Phenotype: -              Pure tall    X      Pure dwarf

Genotype: -                       TT            X      tt    

Gametes: -                 T                t

F1 generation: -                 Tt    (Heterozygous tall (Hybrid)

For F2 Generation:-

Parents: - Heterozygous Tall    X    Heterozygous Tall

Genotypes: -              Tt                 X              Tt

 

Gametes:-       T        t              T           t

Punnet’s square/ checker board:-

                         

Results:- a] Phenotypic ratio: -     Tall : Dwarf

                                      3   :    1

      b] Genotypic ratio:-      

Pure tall : Hybrid tall : Pure dwarf

 1    :          2           :     1

D] Significance: - Monohybrid ratio obtained by Mendel explains the Law of Dominance and Law of Segregation.

 

Dihybrid cross and its explanation:

1) When two allelic pairs are used for crossing, it is called as dihybrid cross.

2) Mendel conducted experiments to study the segregation and transmission of two pairs of contrasting traits at a time.

3) Mendel observed that a cross between round yellow and green wrinkled seeds (P1) produced only round and yellow seeds in F1 generation.

4) But in F2 generation four different types of combinations were produced.

    Round yellow – 9 parental combinations

    Round green – 3 non parental combinations

    Wrinkled yellow – 3 non-parental combinations

    Wrinkled green – 1parental combination.

5) Thus, the offspring of F2 generation were produced in the ratio of 9 : 3 : 3 :1 phenotypically and 1 :2 :1:2:4:2:1:2:1 genotypically.  The ratio is called dihybrid ratio.

6) Mendel’s explanation :

a) Mendel explained the results by assuming that the round and yellow characters are dominant over wrinkled and green so that all F1 offsprings are round and yellow.

b) In F2 generation since all the four characters were assorted out independently he said that a pair of alternating or contrasting characters behave independently of the other pair i.e. seed colour is independent of seed coat.

c) Therefore, at the time of gamete formation genes for round or wrinkled character of seed coat assorted out independently of yellow or green colour of the seed.

d) As a result of this four types of gametes with two old and two new combinations i.e. YR, Yr, yR, yr are produced from F1 hybrid.

e) These four types of gametes on random mating produce four types of offsprings in the ratio 9:3:3:1 in F2 generation (Law of independent assortment).

    Dihybrid test cross ratio is 1:1:1:1