Chromosomes Questions and Answers

Multiple choice Questions of Botany Topic Chromosomes Questions and Answers MCQs ( Chromosomes Questions and Answers Quiz ) for NEET, GATE, AIAPGET, NEET MDS, NEET PG, DNB PDCET, AIIMS SS, PGIMER (Other), AIIMS PG and many more competitive examinations.

Chromosomes and DNA MCQs | Chromosomes & their Behaviour

1. Sutton and Boveri used… movement to explain Mendel’s laws.

(a) gene

(b) chromosome

(c) chromatid

(d) spindle

Ans. b

2. According to chromosomal theory of linkage of Morgan and Castle

(a) strength of linkage between two successive genes is inversely proportional to distance between two genes

(b) genes lie in a linear order in the chromosomes

(c) linked genes are arranged in cis or trans manner cis AB arrangement a brings coupling (parental b. combinations) whiletrans-arrangement Ab brings a recombinations (repulsions)

(d) All of the above

Ans. d

3. Consider the following statements regarding linkage. I. The linked genes are located on the same chromosome. II. Crossing over between linked genes is rare. III. Linked genes are always inherited together. IV. Linkage affects the percentage of homozygosity following hybridisation. Of these statements are correct.

(a) I and II

(b) I and II

(c) II, II and IV

(d) I, II and IV

Ans. a

4. Variability may originate during meiosis due to

(a) crossing over

(b) chromosomal aberrations

(c) polyploidy

(d) mutations

Ans. a

5. Sutton and Boveri argued that the pairing and separation of a pair of chromosomes would lead

(a) the segregation of a pair of factors they carried

(b) the segregation of the characters

(c) recombination of the factors they carried

(d) Both (b) and (c)

Ans. a

6. The coupling and repulsion theory of Bateson and Punnett later on modified in linkage and crossing over by Morgan. Two completely linked genes shows a dihybrid ratio of

(a) 3:1

(b) 1:1

(c) 1:1:1:1

(d) 9:3:3:1

Ans. b

7. Criss-cross inheritance means

(a) X-chromosome from female will pass to female of next generation

(b) X-chromosome from a male will pass to a female of next generation

(c) X-chromosome from male will pass to a male of next generation

(d) None of the above

Ans. b

8. Crossing over occurs at four stranded stage. This was proved by the observation that

(a) usually two gametes resulting frommeiosis arerecombinants

(b) all the four gametes resulting from meiosis are recombinants

(c) chiasmata are seen only at four stranded stage

(d) chiasmata are seen only at two stranded stage

Ans. a

9. Sex-linked inheritance was discovered in 1910 by

(a) McClung

(b) Mendel

(c) Landsteiner

(d) Morgan


10. The first attempt to show linkage in plants was done in

(a) Zea mays

(b) Oenothera lamarckiana

(c) Pisum sativum

(d) Lathyrus odoratus

Ans. d

11. The genetic maps are used as a starting point in the sequencing of whole genomes as in the case of

(a) human project

(b) human gene sequencing project

(c) human genome sequencing project

(d) All of the above

Ans. c

12. Sutton gave chromosomal theory of inheritance he united the knowledge of chromosomal segregation with

(a) recombination

(b) crossing over

(c) Both (a) and (b)

(d) Mendelian principles

Ans. d

13. The crossing over between homologous chromosomes never exceeds beyond

(a) 50%

(b) 75%

(c) 100%

(d) None of these

Ans. a

14. Linkage and cytological maps for the same chromosome

(a) are both based on mutant phenotypes and recombination data

(b) may have different sequences of genes

(c) have both the same sequences of genes and intergenic distances

(d) have the same sequences of genes but different intergenic distances

Ans. d

15. A linkage group is explained as

(a) different groups of genes located on the same chromosomes

(b) that all the linked genes of a chromosome pair

(c) that all the linked genes of a chromosome

(d) None of the above

Ans. b

16. According to the chromosomal theory of inheritance

(a) chromosomes are decondensed in telophase

(b) genetic codes are found on chromosomes

(c) chromosomes carry alleles that are segregated as chromosomes and are pulled apart during the cell division

(d) genes are imitable

Ans. a

17. A pair of genes are linked if their frequency recombination in a test cross is

(a) 75%

(b) 50%

(c) 100%

(d) lower than 50%

Ans. a

18. Linkage in Drosophila was first discovered by

(a) Bateson and Punnett

(b) Bridges

(c) Morgan

(d) Strutevant

Ans. c

19. Sutton and Boveri noted that the behaviour of chromosomes was parallel to the behaviour of

(a) genes

(b) chromatids

(c) nucleus

(d) nucleolus

Ans. a

20. Number of linkage in a polynucleotide would be

(a) same as number of nucleotides

(b) twice as number of nucleotides

(c) one less than the number of nucleotides

(d) one

Ans. d

21. Complete linkage is observed in 

(a) frog

(b) birds

(c) lizards

(d) Drosophila

Ans. d

Multiple Choice Questions on Chromosomal Aberrations

22. The distance between the genes A, B, C and D in mapping units are A-D=3.5, B-C= 1, A-B=6, C-D=1.5, A-C=5. Findout the sequence of arrangement of these genes.

(a) ACDB

(b) ABCD

(c) ADCB

(d) ADBC

Ans. c

23. Chromosomal theory of inheritance was proposed by

(a) Gregor Johann Mendel

(b) Hugo de Vries

(c) Bridges

(d) Sutton and Boveri

Ans. d

24. When a cluster of genes show linkage behaviour they

(a) do not show independent assortment

(b) induce cell division

(c) do not show a chromosome map

(d) show recombination during meiosis

Ans. a

25. Variability may originate during meiosis due to

(a) crossing over

(b) chromosomal aberrations

(c) polyploidy

(d) mutations

Ans. a

26. The chromosomal theory of heredity means that

(a) chromosomes are composed of genes

(b) chromosomes are made up of DNA and protein

(c) genes are located on the chromosome

(d) All of the above

Ans. c

27. Crossing over brings about

(a) recombination of genes

(b) no significant change

(c) study offspring

(d) cytoplasmic reorganisation

Ans. a

28. Experimental verification of the chromosomal theory of inheritance was given by

(a) Gregor Johann Mendel

(b) Hugo de Vries

(c) Langdon Down

(d) Thomas Hunt Morgan

Ans. d

29. Unit of distance between genes in a chromosome is known as

(a) CDNA

(b) Morgan

(c) centiMorgan

(d) Spacer

Ans. c

30. Crossing over is nil between genes located near

(a) telomere

(b) centromere

(c) Both (a) and (b)

(d) None of these

Ans. c

31. Two linked genes, ie, a and b shows about 20% of recombination, the individuals of a dihybrid cross between ++/+ +x ab/ab shall show gametes

(a) ++80: ab: 20

(b) ++50 : ab: 50

(c) ++40 : ab40: +a10: +b: 10

(d) ++30 : ab30: + a20: +b: 20

Ans. c

32. Two dominant non-allelic genes are 50 map units apart. The linkage is

(a) Cis type

(b) trans type

(c) complete

(d) absent/incomplete

Ans. d

33. Which one of the following is considered to be the suitable experiment on linkage?

(a) aaBB x aaBB

(b) AABB x aabb

(c) AaBb x AaBb

(d) AAbb x AaBB

Ans. b

34. Crossing over in diploid organism is responsible for

(a) segregation of alleles

(b) recombination of linked alleles

(c) dominance of genes

(d) linkage between genes

Ans. b

35. If there are three genes a, b, c. And the percentage of crossing over between a and b is 20%, b and c is 28% while. a and c is 8%. Predict the sequence of genes on chromosomes from the following

(a) b, a, c

(b) a, b, c

(c) a, c, b

(d) None of these

Ans. a

36. Mendel fails to observe linkage due to

(a) mutation

(b) crossing over

(c) synapsis

(d) independent assortment

Ans. d

37. Crossing over is more frequent in

(a) males

(b) females

(c) Both (a) and (b)

(d) None of these

Ans. b

MCQ on DNA Sequencing | DNA Sequencing MCQ

38. Complete linkage has been reported in

(a) human female

(b) male Drosophila

(c) female Drosophila

(d) maize

Ans. b

39. How many linkage groups of chromosomes will be present in case of maize, if all its genes are mapped?

(a) 5

(b) 10

(c) 50

(d) 100

Ans. b

40. In which plant phenomenon of linkage was observed first?

(a) Lathyrus odoratus

(b) Pisum sativum

(c) Datura

(d) Mirabilis jalapa

Ans. a

41. Crossing over in diploid organism is responsible for

(a) dominance of genes

(b) segregation of alleles

(c) recombination of linked genes

(d) linkage between genes

Ans. c

42. Who coined the term ‘linkage’?

(a) Correns

(b) Mendel

(c) Morgan

(d) de Vries

Ans. c

43. Linkage prevents

(a) homozygous condition

(b) heterozygous condition

(c) segregation of alleles

(d) hybrid formation

Ans. c

44. Crossing over chromosomes contain the homologous occurs when

(a) one chromatid

(b) two chromatid

(c) four chromatid

(d) eight chromatid

Ans. c

45. Genetic map is one that

(a) shows the stages during cell division

(b) establishes various stages in gene evolution

(c) shows the distribution of various species in a region

(d) establishes sites of the genes on a chromosome

Ans. d

46. In a dihybrid cross, two recessive genes shows 10% recombinants. The distance between two genes is

(a) 10 map unit

(b) 20 map unit

(c) 5 map unit

(d) 100 map unit

Ans. a

47. How many linkage groups will be present in the case ol human beings

(a) 23

(b) 46

(c) 44

(d) 22

Ans. a

48. 1 map unit or centiMorgan (cM) is equal to

(a) 1% recombination

(b) 10% recombination

(c) 100% recombination

(d) 0.1% recombination

Ans. a

49. Linked genes are

(a) located on different chromosomes of same size and shape

(b) located on the same chromosome

(c) rarely inherited together

(d) None of the above

Ans. b

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