12th Class Biology Principle Of Inheritance And Variation Question Bank

done MCQs - Principles of Inheritance and Variation Total Questions - 84

• question_answer1)
  Genetics is the branch of biology which deals with, inheritance of characters from parents to progeny, called as ...24... and the degree by which progeny differ from their parents, called ...A.. .
  A)
  A-variation, 8-heredity done clear
  B)
  A-resemblance, B-inheritance done clear
  C)
  A-heredity, B-differences done clear
  D)
  A-heredity, B-variation done clear
  View Solution play_arrow

• question_answer2)
  The experimental material in Mendel's experiment was
  A)
  Pisum sativum    done clear
  B)
  Oryza sativa done clear
  C)
  Mirabilis jalapa   done clear
  D)
  Lathyrus odoratus done clear
  View Solution play_arrow

• question_answer3)
  Which one from those given below is the period for Mendel's hybridization experiments?
  A)
  1856-1863                     done clear
  B)
  1840-1850 done clear
  C)
  1857-1869                     done clear
  D)
  1870-1877 done clear
  View Solution play_arrow

• question_answer4)
  The number of contrasting characters studied by Mendel for his experiments was
  A)
  14                     done clear
  B)
  4        done clear
  C)
  2                      done clear
  D)
  7 done clear
  View Solution play_arrow

• question_answer5)
  Among the following characters, which one was not considered by Mendel in his experiments on pea?
  A)
  Stem-Tall or Dwarf done clear
  B)
  Trichomes - Glandular or Non-glandular done clear
  C)
  Seed - Green or Yellow done clear
  D)
  Pod - Inflated or Constricted done clear
  View Solution play_arrow

• question_answer6)

  What contributed to Mendel's success?

  I. Selection of pureline pea varieties.

  II. Knowledge of history.

  III. Selecting one character at a time.

  IV. Statistical analysis and mathematical logic.

  Choose the correct option.

  A)
  I, II, III and IV                done clear
  B)
  II and III done clear
  C)
  I, III and IV done clear
  D)
  II, III and IV done clear
  View Solution play_arrow

• question_answer7)
  Choose the incorrect match.
  A)
  Phenotype - Physical appearance of an organism done clear
  B)
  Genotype-Expressed genes done clear
  C)
  Homozygous - Identical alleles of a gene present at the same locus done clear
  D)
  Heterozygous - Genes of an allelic pair are not same done clear
  View Solution play_arrow

• question_answer8)
  The character which appears in \[{{F}_{1}}-generation\] is called
  A)
  recessive            done clear
  B)
  dominant done clear
  C)
  latent                done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer9)
  3: 1 ratio in \[{{F}_{2}}-generation\] is explained by
  A)
  law of partial dominance done clear
  B)
  law of dominance done clear
  C)
  law of incomplete dominance done clear
  D)
  law of purity of gametes done clear
  View Solution play_arrow

• question_answer10)
  A graphical representation using which probability of all possible genotypes of an offspring in genetic cross can be calculated is called
  A)
  Burnett square                done clear
  B)
  Morgan square done clear
  C)
  Punnett square               done clear
  D)
  Test cross done clear
  View Solution play_arrow

• question_answer11)
  Test cross is used to
  A)
  check heterozygosity in \[{{F}_{1}}-generation\] done clear
  B)
  check heterozygosity in \[{{F}_{2}}-generation\] done clear
  C)
  check independent assortment done clear
  D)
  check segregation done clear
  View Solution play_arrow

• question_answer12)
  A cross between two tall plants resulted in offspring having few dwarf plants what would be the genotypes of both the parents?    
  A)
  TT and Tt         done clear
  B)
  Tt and Tt done clear
  C)
  TT and TT                     done clear
  D)
  Tt and tt done clear
  View Solution play_arrow

• question_answer13)
  Match the following columns.

  	Column I		Column II
  A	Monohybrid cross	1	T and t
  B	Test cross	2	TT
  C	Alleles	3	TT x Tt
  D	Homozygous tall	4	Tt x tt

  Codes
  A)
  A-3       B-1       C-4       D-2 done clear
  B)
  A-4       B-3       C-2       D-1 done clear
  C)
  A-3       B-4       C-1       D-2 done clear
  D)
  A-3       B-1       C-4       D-2 done clear
  View Solution play_arrow

• question_answer14)
  The law of segregation of characters is also called the law of purity of gametes because gametes cannot be contaminated.
  A)
  True                  done clear
  B)
  False done clear
  C)
  Cannot say                    done clear
  D)
  Partially true or false done clear
  View Solution play_arrow

• question_answer15)
  \[{{F}_{1}}-generation\] in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1. It represents a case of
  A)
  codominance done clear
  B)
  dihybrid cross done clear
  C)
  monohybrid cross with complete dominance done clear
  D)
  monohybrid cross with incomplete dominance done clear
  View Solution play_arrow

• question_answer16)
  Incomplete dominance is shown by
  A)
  Primrose           done clear
  B)
  Mirabilis done clear
  C)
  Helianthus                     done clear
  D)
  China rose done clear
  View Solution play_arrow

• question_answer17)
  During the study of incomplete dominance, in a cross between true breeding red flowers (RR) and true breeding white flowers (rr), when \[{{F}_{1}}\] was self-pollinated, the resulted \[{{F}_{2}}\] ratio may be
  A)
  1(RR)red:2(Rr)pink:1(rr)white done clear
  B)
  2(RR)red: 1(Rr)pink: 1(rr)white done clear
  C)
  1(RR)red: 1(Rr)pink: 2(rr)white done clear
  D)
  3(RR)red:1(rr)white done clear
  View Solution play_arrow

• question_answer18)
  In Antirrhinum two plants with pink flowers were hybridised. The \[{{F}_{1}}\] plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridisation? Red flower colour is determined by RR and white by rr genes.
  A)
  rrrr done clear
  B)
  RR     done clear
  C)
  Rr                                 done clear
  D)
  rr done clear
  View Solution play_arrow

• question_answer19)
  Which Mendelian idea is depicted by a cross in which the \[{{F}_{1}}-generation\] resembles both the parents?
  A)
  Incomplete dominance done clear
  B)
  Law of dominance done clear
  C)
  Inheritance of one gene done clear
  D)
  Codominance done clear
  View Solution play_arrow

• question_answer20)

  Which of the following characteristics represents 'Inheritance of blood groups' in humans?

  I. Dominance

  II. Codominance

  III. Multiple allele

  IV. Incomplete dominance

  V. Polygenic inheritance

  A)
  I, IV and V                    done clear
  B)
  I, II and III done clear
  C)
  II, III and V                    done clear
  D)
  I, III and V done clear
  View Solution play_arrow

• question_answer21)
  Starch synthesis gene in pea plant in heterozygous condition produces starch grain of intermediate size. This shows
  A)
  complete dominance done clear
  B)
  incomplete dominance done clear
  C)
  Codominance done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer22)
  When there are more than two alleles controlling the same character. These are called
  A)
  pleiotropy                      done clear
  B)
  polyalleles done clear
  C)
  multiple alleles     done clear
  D)
  All of these done clear
  View Solution play_arrow

• question_answer23)
  The types of gametes formed by the genotype RrYy are
  A)
  RY, Ry, rY, ry                done clear
  B)
  RY, Ry, ry, ry done clear
  C)
  Ry, Ry, ry, ry                 done clear
  D)
  Rr, RR, Yy, YY done clear
  View Solution play_arrow

• question_answer24)
  Independent assortment means
  A)
  separation of characters of one parent done clear
  B)
  non-separation of characters of one parent done clear
  C)
  combination of parental characters done clear
  D)
  separation of parental characters done clear
  View Solution play_arrow

• question_answer25)
  When a pure tall plant (TT) having rounded seeds (RR) is crossed with dwarf plant (tt) having wrinkled? (rr) and, their \[{{F}_{1}}\] progeny are crossed among themselves to produce \[{{F}_{2}}\] -generation, how many phenotypes will be observed?
  A)
  16                     done clear
  B)
  9       done clear
  C)
  4                      done clear
  D)
  12 done clear
  View Solution play_arrow

• question_answer26)
  Chromosomal theory of inheritance was proposed by
  A)
  Sutton and Boveri done clear
  B)
  Bateson and Punnett done clear
  C)
  TH Morgan done clear
  D)
  Watson and Crick done clear
  View Solution play_arrow

• question_answer27)
  The chromosomes as well as genes occur in pair and the two alleles of a gene pair are located on
  A)
  homologous chromosomes done clear
  B)
  non-homologous chromosomes done clear
  C)
  single chromosome done clear
  D)
  All of the above done clear
  View Solution play_arrow

• question_answer28)
  Morgana experimental organism was
  A)
  Drosophila melanogaster done clear
  B)
  Nangifera indica done clear
  C)
  Nirabifisjalapa done clear
  D)
  Drosophila indica done clear
  View Solution play_arrow

• question_answer29)
  The term, ...A... describes the physical association of genes on a chromosome and the term, ...A.. describes the generation of non-parental gene combinations.
  A)
  A-association, B-recombination done clear
  B)
  A-linkage, B-recombination done clear
  C)
  A-recombination, B-linkage done clear
  D)
  A-association, B-dissociation done clear
  View Solution play_arrow

• question_answer30)
  Which of the following will not result in variations among siblings?
  A)
  Independent assortment of genes done clear
  B)
  Crossing over done clear
  C)
  Linkage done clear
  D)
  Mutation done clear
  View Solution play_arrow

• question_answer31)
  Linkage was discovered by
  A)
  Miller                 done clear
  B)
  Morgan done clear
  C)
  deVries              done clear
  D)
  Mendel done clear
  View Solution play_arrow

• question_answer32)
  All genes located on the same chromosome            (NCERT Exemplar)
  A)
  form different groups depending upon their relative distance done clear
  B)
  form one linkage group done clear
  C)
  will not form any linkage group done clear
  D)
  form interactive groups that affect the phenotype done clear
  View Solution play_arrow

• question_answer33)
  Select the correct statement from the ones given below with respect to dihybrid cross.
  A)
  Tightly linked genes on the same chromosome show higher recombinations done clear
  B)
  Genes far apart on the same chromosome show very few recombinations done clear
  C)
  Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones done clear
  D)
  Tightly linked genes on the same chromosome show very few recombinations done clear
  View Solution play_arrow

• question_answer34)
  Which of the following is suitable for experiment on linkage?
  A)
  aaBB x aaBB                  done clear
  B)
  AABB x aabb done clear
  C)
  AaBb x AaBb                 done clear
  D)
  AAbb x AaBB done clear
  View Solution play_arrow

• question_answer35)

  Genes A, B and C are linked. Genes A and B are more close than A and C.

  I. A might be before B and C.

  II. B might be between A and C.

  III. C might be between A and B.

  IV. More crosses cannot occur between A and C than A and B.

  Find out the correct option for the given information.

   
  A)
  I and II         done clear
  B)
  II and III done clear
  C)
  III and IV                       done clear
  D)
  I, II and IV done clear
  View Solution play_arrow

• question_answer36)

  Mendel conducted a number of crosses and studies but could never discover linkage. What could be the reason for this?

  I. Some genes are linked but they are too far apart for crossing over to be distinguished from independent assortment.

  II. Linked genes were never tested for the same time in same cross.

  III. The seven genes were present on the 7 chromosomes.

  IV. The genes underwent mutations during subsequent crossings.

  Choose the correct option.

   
  A)
  I and II          done clear
  B)
  II and III done clear
  C)
  III and IV                       done clear
  D)
  Only lV done clear
  View Solution play_arrow

• question_answer37)
  Distance between the genes and percentage of recombination shows (NCERT Exemplar)
  A)
  a direct relationship done clear
  B)
  an inverse relationship done clear
  C)
  a parallel relationship done clear
  D)
  no relationship done clear
  View Solution play_arrow

• question_answer38)
  In polygenic inheritance,
  A)
  many genes govern a single character done clear
  B)
  heterozygous organisms express only one allele done clear
  C)
  heterozygous organisms express both alleles done clear
  D)
  a single gene influences many characters done clear
  View Solution play_arrow

• question_answer39)
  The polygenic genes show
  A)
  similar genotype              done clear
  B)
  different karyotype done clear
  C)
  different phenotype         done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer40)
  Which one of the following pairs of features is a good example of polygenic inheritance?
  A)
  Human height and skin colour done clear
  B)
  ABO blood group in humans and flower colour of Mirabilis jalapa done clear
  C)
  Hair pigment of mouse and tongue rolling in humans done clear
  D)
  Human eye colour and sickle-cell anaemia done clear
  View Solution play_arrow

• question_answer41)
  In human skin colour inheritance, the genotype with three dominant and three recessive alleles will produce
  A)
  darkest skin colour done clear
  B)
  lightest skin colour done clear
  C)
  intermediate skin colour done clear
  D)
  patches of black and white done clear
  View Solution play_arrow

• question_answer42)
  Occasionally, a single gene may express more than one effect. The phenomenon is called
  A)
  multiple allelism              done clear
  B)
  mosaicism done clear
  C)
  pleiotropy          done clear
  D)
  polygeny done clear
  View Solution play_arrow

• question_answer43)
  A pleiotropic gene
  A)
  controls a trait only in combination with another gene done clear
  B)
  controls multiple traits in an individual done clear
  C)
  is expressed only in primitive plants done clear
  D)
  is a gene evolved during Pliocene done clear
  View Solution play_arrow

• question_answer44)
  The best example for pleiotropy is
  A)
  skin colour         done clear
  B)
  phenylketonuria done clear
  C)
  colourblindness               done clear
  D)
  ABO blood group done clear
  View Solution play_arrow

• question_answer45)
  Match the following columns.

  	Column I		Column II
  A.	Dominance	1.	Many genes govern a single character
  B.	Codominance	2.	In a heterozygous organism, only one allele expresses itself
  C.	Pleiotropy	3.	In a heterozygous organism, both alleles express themselves fully
  D.	Polygenic inheritance	4.	A single gene influences many characters

  Codes
  A)
  A-2       B-1       C-4       D-3 done clear
  B)
  A-2       B-3       C-4       D-1 done clear
  C)
  A-4       B-1       C-2       D-3 done clear
  D)
  A-4       B-3       C-1       D-2 done clear
  View Solution play_arrow

• question_answer46)
  Sex-determination is controlled by ... A... and the remaining chromosomes which are not involved in sex-determination are ...B... .
  A)

  A	B
  allosomes	autosomes

    done clear
  B)

  A	B
  allosomes	sex-chromosomes

    done clear
  C)

  A	B
  sex-chromosomes	allosomes

    done clear
  D)

  A	B
  autosomes	sex-chromosomes

  done clear
  View Solution play_arrow

• question_answer47)
  In XX and XY type of sex- determination,
  A)
  males are heterogametic done clear
  B)
  females are isogametic done clear
  C)
  Both [a] and [b] done clear
  D)
  None of the above options are correct done clear
  View Solution play_arrow

• question_answer48)
  Heterogamety is the term where an individual produces two types of gametes. The most appropriate answer is
  A)
  male Drosophifa fly done clear
  B)
  female Drosophila fly done clear
  C)
  female bird       done clear
  D)
  Both [a] and [c] done clear
  View Solution play_arrow

• question_answer49)
  In XO type of sex-determination,
  A)
  females produce two different types of gametes done clear
  B)
  males produce two different types of gametes done clear
  C)
  females produce gametes with Y- chromosomes done clear
  D)
  males produce single type of gametes done clear
  View Solution play_arrow

• question_answer50)
  The condition in which females lack one sex chromosome whereas males are homogametic, the sex chromosomal representation is
  A)
  ZO-ZZ done clear
  B)
  XY-XX  done clear
  C)
  XX-XO              done clear
  D)
  ZW-ZZ done clear
  View Solution play_arrow

• question_answer51)
  In case of birds, the females are
  A)
  homogametic                 done clear
  B)
  heterogametic done clear
  C)
  Both [a] and [b] done clear
  D)
  None of these done clear
  View Solution play_arrow

• question_answer52)
  Which of the following is incorrect regarding ZW-ZZ type of sex- determination?
  A)
  It occurs in birds and some reptiles done clear
  B)
  Females are homogametic and males are heterogametic done clear
  C)
  1:1 sex ratio is produced in the offspring done clear
  D)
  All of the above done clear
  View Solution play_arrow

• question_answer53)
  In a certain taxon of insects, some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosomes bearing organisms are
  A)
  males and females, respectively done clear
  B)
  females and males, respectively done clear
  C)
  all males done clear
  D)
  all females done clear
  View Solution play_arrow

• question_answer54)
  An unfertilised human egg contains two X-chromosomes.
  A)
  True                              done clear
  B)
  False done clear
  C)
  Cannot say        done clear
  D)
  Partially true or false done clear
  View Solution play_arrow

• question_answer55)
  Match the following columns.

  	Column I (Animals)		Column II (Chromosome complements)
  A	Fruitfly	1	2n=6+XY
  B	Fowl	2	2n=44+XY
  C	Human	3	2n=14+XX

  Codes
  A)
  A-1       B-3       C-2 done clear
  B)
  A-2       B-1       C-3 done clear
  C)
  A-3       B-1       C-2 done clear
  D)
  A-1       B-2       C-3 done clear
  View Solution play_arrow

• question_answer56)
  Identify the incorrect statement for sex-determination in humans.
  A)
  Humans contain 23 pairs of autosomes done clear
  B)
  Females produce only one type of ovum done clear
  C)
  Genetic makeup of sperm determines the sex of the child done clear
  D)
  In males, two types of gametes are produced done clear
  View Solution play_arrow

• question_answer57)
  There are five daughters and no son in a family. It may be due to
  A)
  father produced only X containing sperms done clear
  B)
  father produced no sperms at all done clear
  C)
  Y type sperms are weaker and not effective done clear
  D)
  by chance each time X sperm fertilised the egg done clear
  View Solution play_arrow

• question_answer58)

  Find out A, B and C in the diagram given below.

   
  A)
  A-Male gamete, B-Female, C-Gametes done clear
  B)
  A-Male. B-Female, C-Sperm done clear
  C)
  A-Female, B-Male, C-Gametes done clear
  D)
  A-Gametes, B-Female, C-Male done clear
  View Solution play_arrow

• question_answer59)
  A mother in a family of five daughters is expecting her sixth baby. The chance of this being a son is
  A)
  0%                                done clear
  B)
  25% done clear
  C)
  50%                  done clear
  D)
  100% done clear
  View Solution play_arrow

• question_answer60)
  Haploid-diploid mechanism of sex-determination (haplodiploidy) takes place in
  A)
  humans and cockroaches done clear
  B)
  birds and reptiles done clear
  C)
  butterflies and moths done clear
  D)
  honeybees, ants and wasps done clear
  View Solution play_arrow

• question_answer61)
  Females in haplodiploidy sex- determination are
  A)
  n                                  done clear
  B)
  2n done clear
  C)
  4n                                 done clear
  D)
  3n done clear
  View Solution play_arrow

• question_answer62)
  In haplodiploidy, determination of male sex is
  A)
  haploid          done clear
  B)
  diploid done clear
  C)
  haplodiploid                   done clear
  D)
  diplohaploid done clear
  View Solution play_arrow

• question_answer63)
  Which of the following is/are Mendelian disorder? (NCERT Exemplar)
  A)
  Thalassemia                   done clear
  B)
  Cystic fibrosis done clear
  C)
  Phenylketonuria              done clear
  D)
  All of these done clear
  View Solution play_arrow

• question_answer64)
  Colour blindness in humans
  A)
  results in defect in either red or green cone of eyes done clear
  B)
  is caused due to the mutation in gene found on X-chromosome done clear
  C)
  affects males more frequently than females done clear
  D)
  All of the above done clear
  View Solution play_arrow

• question_answer65)
  A woman has an X-linked condition on one of her X-chromosomes. This chromosome can be inherited by
  A)
  Only grand children done clear
  B)
  Only sons done clear
  C)
  Only daughters done clear
  D)
  Both [b] and [c] done clear
  View Solution play_arrow

• question_answer66)
  A normal- visioned man whose father was colourblind, marries a woman whose father was also colourblind. They have their first child as a daughter. What are the chances that this child would be colourblind?
  A)
  100%                done clear
  B)
  0%     done clear
  C)
  25%                  done clear
  D)
  50% done clear
  View Solution play_arrow

• question_answer67)
  A man whose father was colourblind marries a woman, who had a colourblind mother and normal father. What percentage of male children of this couple will be colourblind?
  A)
  25%                              done clear
  B)
  0%     done clear
  C)
  50%      done clear
  D)
  75% done clear
  View Solution play_arrow

• question_answer68)
  A normal woman whose father was colourblind, marries a normal man. What kinds of children can be expected and in what proportion?
  A)
  All daughters normal, 50% of sons colourblind done clear
  B)
  All daughters normal, all sons colourblind done clear
  C)
  50% daughters colourblind, all sons normal done clear
  D)
  All daughters colourblind, all sons normal done clear
  View Solution play_arrow

• question_answer69)
  Which of the following most appropriately describes haemophilia?
  A)
  X-linked recessive gene disorder done clear
  B)
  Chromosomal disorder done clear
  C)
  Dominant gene disorder done clear
  D)
  Recessive gene disorder done clear
  View Solution play_arrow

• question_answer70)
  In haemophilia, the affected protein is a part of a cascade of protein which is involved in the
  A)
  formation of RBCs done clear
  B)
  formation of WBCs and platelets done clear
  C)
  coagulation of blood done clear
  D)
  anticoagulation done clear
  View Solution play_arrow

• question_answer71)
  Thalassemia in humans
  A)
  is an autosome linked recessive blood disorder done clear
  B)
  can transmit from parents to offspring when both parents are unaffected carriers (heterozygous) done clear
  C)
  caused due to the mutation or deletion of one of the \[\alpha \] or \[\beta \]-globin chain done clear
  D)
  All of the above done clear
  View Solution play_arrow

• question_answer72)
  \[\alpha \]-thalassemia in humans is controlled by
  A)
  HBA1 and HBA2 genes on chromosome 16 done clear
  B)
  HBA1 gene on chromosome 12 done clear
  C)
  HBA2 gene on chromosome 11 done clear
  D)
  HBA1 and HBA2 genes on chromosome 9 done clear
  View Solution play_arrow

• question_answer73)
  \[\beta \]-thalassemia in humans is controlled by
  A)
  HBA2 gene on chromosome 16 done clear
  B)
  HBB gene on chromosome 11 done clear
  C)
  HBA1 gene on chromosome 15 done clear
  D)
  HBA1 and HBA2 gene on chromosome 8 done clear
  View Solution play_arrow

• question_answer74)
  Failure of segregation of chromatid during cell division cycle results in the gain or loss of chromosome which as called
  A)
  aneuploidy         done clear
  B)
  hypopolyploidy done clear
  C)
  hyperpolyploidy done clear
  D)
  polyploidy done clear
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• question_answer75)
  Karyotype of Down's syndrome has how many chromosomes?
  A)
  43                     done clear
  B)
  46      done clear
  C)
  47         done clear
  D)
  45 done clear
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• question_answer76)
  Klinefelter's syndrome results from
  A)
  XX egg and Y from sperm done clear
  B)
  XX egg and XY sperm done clear
  C)
  X egg and XY sperm done clear
  D)
  Both [a] and [c] done clear
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• question_answer77)
  Female suffering from Turner's syndrome possess
  A)
  45+XO done clear
  B)
  rudimentary ovaries done clear
  C)
  lack of secondary sexual characters done clear
  D)
  All of the above done clear
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• question_answer78)
  Choose the correct pair.
  A)
  Gynecomastia - Development of breasts done clear
  B)
  Turner's syndrome - Loss of an X-chromosome in females done clear
  C)
  Syndrome-A group of symptoms done clear
  D)
  All of the above done clear
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• question_answer79)
  A sterile female having reduced mental ability is said to be suffering from
  A)
  Turner's syndrome done clear
  B)
  Klinefelter's syndrome done clear
  C)
  Down's syndrome done clear
  D)
  Edward's syndrome done clear
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• question_answer80)

  I. Short statured body with small round head.

  II. Furrowed tongue and partially opened mouth.

  III. Palm is broad with characteristic palm crease.

  IV. Slow physical, psychomotor and mental development.

  These are the characters of

  A)
  Down's syndrome done clear
  B)
  Turner's syndrome done clear
  C)
  Klinefelter's syndrome done clear
  D)
  Edward syndrome done clear
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• question_answer81)
  In Down's syndrome, karyotyping has shown that the disorder is associated with trisomy of chromosome number-21 usually due to non-disjunction during formation of egg cells.
  A)
  True done clear
  B)
  False done clear
  C)
  Cannot say done clear
  D)
  Partially true or false done clear
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• question_answer82)
  Match the syndrome and chromosomal abnormalities given in columns I and II, respectively.

  	Column I  (Syndromes)		Column II  (Chromosomal abnormalities)
  A	Klinefelter's syndrome	1	45 + XY
  B	Turners syndrome	2	44 + XXY
  C	Superfemale	3	44 + XXX
  D	Down's syndrome	4	44 + XO

  Codes
  A)
  A-2       B-4       C-3       D-1 done clear
  B)
  A-1       B-3       C-2       D-4 done clear
  C)
  A-2       B-1       C-3       D-4 done clear
  D)
  A-4       B-3       C-2       D-1 done clear
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• question_answer83)
  Down's syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder?
  A)
  100%                done clear
  B)
  75%   done clear
  C)
  50%                  done clear
  D)
  25% done clear
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• question_answer84)
  Gamete mother cells of the chromosome 44+XY suffers from non-disjunction at first meiotic division. Identify the set of gametes in which this condition would occur
  A)
  22 + XX, 22+YY and 22, 22 done clear
  B)
  22+XY,22+XY and 22,22 done clear
  C)
  22+X,22+Y and 22+Y,22 done clear
  D)
  22 + X, 22 +X and 22+Y, 22+Y done clear
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