C s a s : I X I P i c n iples of I e n ri a t c n e & a V riation p ssi n Codom n i n a e

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1 Class : XII Principles of Inheritance & Variation 1. A geneticist interested in studying variations & patterns of inheritance in living beings experiments with shorter life cycle. Provide a reason. prefers to choose organisms for 2. In order to obtain the F -generation, Mendel pollinated a pure-breeding tall plant with a pure-breeding dwarf plant. But for 1 getting the F - generation, he simply self-pollinated the tall F plants. Why? Law of independent assortment was based on which observation of Mendel? 4. A cross was carried out between two pea plants showing contrasting traits of height of the plants. The result of the cross showed 50% parental characters. i. Work out the cross with the help of a Punnett square. i i. Name the type of the cross carried out. 5. How does the strength & weakness of linkage depends on linked genes? 6. Do you think Mendel s laws of inheritance would have been different, if the characters that he had chosen were located on the same chromosome. 7. In snapdragon, a cross between true-breeding red flowered (RR) plants & true-breeding white flowered (rr) plants showed a progeny of plants with all pink flowers. i. The appearance of pink flowers is not known as blending. Why? i i. What is the phenomenon known as? 8. Linkage & crossing over of genes are alternatives of each other. Justify with the help of an example. 9. Explain two situations, when independent assortment of genes occur, resulting in 50% recombinants. 10. Explain the following i. What is the most common example of pleiotropy in humans i i. How are the pleiotropic genes useful? 11. Mendel published his work on inheritance of characters in 1865, but it remained unrecognised till Give three reason for the delay in accepting his work. 12. i. You are given tall pea plants with yellow seeds, whose genotypes are unknown. How would you find the genotype of these plants? Explain with the help of cross. i i. Identify A, B & C in the table given below: Pattern of Inheritance C odominance 'B' Incomplete dominance Monohybrid F1 Phenotypic Expression A' Progeny resembled only one of the parents C' 13. Mendelian recombinants are formed due to which phenomenon? 14. Multiple allelism can be investigated only in populations. Justify.

2 i i. Is the trait sex-linked or autosomal? i ii. Give the genotype of the parents in generation I & of their third & fourth child in generation II. 18. Describe the different types of sex-determination in insects. 19. In a court of law, two couples X & Y, claim a child Z of blood group ) as theirs. Couple X has man with blood group ) & woman with blood group AB. Couple Y has man with blood groupa & woman with blood group B. So, a geneticists helps in solving the problem but the judge ordered for use of more recent & advance techniques & then the child was handed o ver ultimately to couple Y. i. Is it a correct judgement regarding the true/biological parents of the child? Justify with your knowledge of genetics. i i. Name the other technique that the judge has ordered for solving this problem. 20. It has been observed that in certain plants a single gene pair is found to be responsible for determination of sex. D iscuss it by taking some example. Is it possible to convert a monoecious maize plant to a dioecious maize plant? Explain. 21. Differentiate between multiple allelism & pleiotropy, with the help of an example each. 22. Identify (i), (ii), (iii), (iv) & (vi) in the table given below. Syndrome Cause D own's Trisomy of 21 ( iii) XXY Characteristic of Affected Individual Male/ Female Both ( i) (a) (b) (ii) Overall masculine T urner's 45 with XO ( v) (a) (b) (vi) 23. Why are human females rarely haemophilic? Explain How do haemophilic patients suffer? 24. Workout a typical Mendelian dihybrid cross & state the law that he derived from it. 25. i. Haemophilia is a sex-linked recessive diseases. Study the pedigree analysis given below showing the inheritance of the disease in a family & answer the questions that follow (iv) ( a) Give the evidence from the above analysis, which suggests that the disease is (1) sex-linked & (2) caused by a recessive allele. ( b) Write the possible genotypes of the individuals 2 & 5 ii. Why is thalassemia categorised as a Mendelian disorder? State the condition when an individual will suffer from the disease.

Class : XII Unit I 1. Cucurbits & papaya plants bear staminate & pistillate flowers. Mention the categories they are put under separately on the basis of the type of flowers they bear. 2.

3 Class : XII Unit I 1. Cucurbits & papaya plants bear staminate & pistillate flowers. Mention the categories they are put under separately on the basis of the type of flowers they bear. 2. Name the biological process that enables continuity of species. 3. Why are mosses & liverworts unable to complete their sexual mode of reproduction in dry conditions. Give reasons. 4. i. State the difference between meiocyte & gamete with respect to chromosome number i i. Why is a whiptail lizard referred to as parthenogenetic? 5. The cell division involved in gamete formation is not of the same type in different organisms. Justify. 6. How do flowers of V allisneria get pollinated? 7. Why is banana considered a good example of parthenocarpy? 8. In angiosperms, zygote is diploid while primary endosperm cell is triploid. Explain. 9. Mention any one application of a pollen bank. 10. Name the product of fertilisation that forms the kernel of coconut. How does the kernel differe from coconut water? 11. State what is apomixis. Comment on its significance. How can it be commercially used? 12. Differentiate between geitonogamy & xenogamy plants. Which one between the two will lead to inbreeding depression & why? 13. i. Describe is sequence the process of microsporogenesis in angiosperms. i i. Draw a labelled diagram of a 2-celled final structure formed. 14. Why are angiosperm anthers called dithecous? Describe the structure of its microsporangium. 15. i. Why does endosperm development proceed embryo development in angiosperm seeds? State the role of endosperm in mature albuminous seeds. ii. Describe with help of three labelled diagrams the different embryonic stages that include mature embryo of dicot plants. 16. Why is fertilisation in an angiosperm referred to as double fertilisation? Mention the ploidy of the cells involved. 17. Give reasons, why? i. Most zygotes in angiosperm divide only after certain amount of endosperm is formed. i i. Groundnut seeds are exalbuminous & castor seeds are albuminous. i ii. Microplyle remains a small pore in the seed coat of a seed. i v. Integuments of an ovule hardens & the water content is highly reduced as the seed matures. v. Apples & cashewnuts are not called true fruits. 18. What is colstrum? Why are breast-fed babies likely to be healthy? 19. Draw a diagram of the structure of a human ovum surrounded by corona radiata. Label the following parts. ( a) Ovum ( b) Plasma membrane ( c) Zona pellucida 20. Draw a labelled diagram of the reproductive system in human female. 21. Explain the development of secondary oocyte (ovum) in a human female form the embryonic stage upto its ovulation. Name the hormones involved in the process. 22. i. Draw s sectional view of seminiferous tubule of human. Lable Sertoli cell, spermatogonia & Leydig cell on it &

4 i. What do contraceptive pills contain, & how do they act a contraceptives? i i. What schedule should be followed for taking these pills? 29. i. Name any two copper releasing IUDs. i i. Explain how do they act as effective contraceptives in human females. 30. A couple where both husband & wife are producting functional gametes, but the wife is still unable to conceive, is seeking medical aid. Describe any one method that you can suggest to this couple to beocme happy parents.

5 Class : XII Principle of Inheritance 1. Agene pair hides the effect of another. The phenomenon is (a) Epistasis (b) Mutation (c) Dominance (d) None of the above & Variation 2. A gene which aftects the character or another gene not located on the similar locus of the homologous chromosome is (a) Duplicate gene (b) Complementary gene (c) Epistatic gene (d) Supplementary gene 3. Supplementary gene interaction in F results in a phenotypic ratio 2 ( a) 12 : 3 :1 (b) 9 : 3 : 4 ( c) 9:7 (d) 12:1: 3 4. Epistatic effect in which the dihybrid crossaabb AaBb resulting in the ratio 12 : 3 : 1 is due to (a) Interaction between two alleles of the same locus (b) Interaction between two alleles of different loci (c) Dominance of one allele on another allele of the same locus (d) Dominance of one another allele on another allele of both loci 5. Which one of the following is more likely to be heterozygous? (a) Cross-pollinated crops (b)autopolyploids (c) Self pollinated crops (d) Pure lines 6. GenesAand B are necessary for normal hearing. What is the possible genotype of a normal child of deaf mother/ father? ( a) Aabb (b) aabb ( c) aabb (d) AaBb 7. F 2 generation of a cross between two white flowered strains of sweet pea yields 9 purple flowered plarts : 7 white flowered plants. This is an example of (a) Gene inhibition (b) Epistatis (c) Complementary genes (d) Supplimentary genes

6 (c) Human height (d)all of these 11. Nonallelic genes, having similar phenotypic effect, interact to produce a different trait and ratio of 9 : 7 in F generatio n 2 are (a) Supplementary genes (b) Epistatic genes (c) Hypostatic genes (d) Complementary genes 12. The ratio 9 : 7 is due to (a) Lethal genes (b) Supplementary genes (c) Complementary genes (d) Epistatic genes 13. In a mating between two mulattors, each heterozygous at all three gene loci for the skin colour, what is the chance their child will have verylight skin? (a)1/64 (b)1/4 (c) 5/8 (d) 9/ The gene which suppresses other genes and masks the expression of other is ( a) Epistatic (b) Codominan t ( c) Recessive (d) Complementar y 15. In a dihybrid cross, F ratio of 15 : 1 is due to 2 (a) Supplementary genes (b) Duplicate genes (c) Recessive.epistasis (d) Dominant epistasis 16. If Mendel had studied the 7 traits usinga plant with 12 chromosomes, instead of 14, in what way, would the interpretatio n have been different? (a) He.would have mapped the chromosome (b) He would not have discovered the law of independent assortment (c) He would have discovered blending or incomplete dominance (d) He would have discovered sex linkage 17. If an individual of genotypeaabbccdd is testcrossed, how many different phenotypes can appear in the progeny? ( a) 4 (b) 8 ( c) 12 (d) Variations occur mostly due to ( a) Linkage (b) Crossing over ( c) Segregation (d) Nutritio n

7 ( a) Two (b) Four ( c) Six (d) Eight 22. If individuals of genotypeaabbcc are intercrossed, how many, different, genotypes can occur in their progeny? ( a) 16 (b) 8 ( c) 6 (d) Skin colour of human beings is determined by cumulative genes. This hypothesis was proposed by ( a) Davenport (b) Correns ( c) Bateson (d) Sutton 24. Mendelian reccombinations are due to (a) Mutation (b) Pleiotropy (c) Independent assortment (d) Crossing over 25. The roan coat colour in shorthorn cattle is the result of (a) Codominance (b) Incomplete dominance ( c) Collaborative genes ; (d) Epistasis 26. A tobacco plant heterozygous for albinism (a recessive character) is self-pollinated and 1200 seeds are subsequentl y germinated. How many seedlings would have parental genotype? ( a)all (b) 300 ( c) 600 (d) None of these 27. Complimentary genes are (a) One pair of genes producing different traits (b) One pair of genes showing two traits (c) One pair of genes interacting to produce one effect (d) Single gene controlling several traits 28. If individuals of genotypeaabbcc are inter crossed, how many different genotypes can occur in their progeny? ( a) 6 (b) 8 ( c) 16 (d) A back cross of the hybrid with the recessive parent is called ( a) Test cross (b) Reverse cross ( c) Crossing over (d) None 30. An organism which receives indentical alleles of a particular gene from both parents is

8 i l 33. A c h d w genotype ( a) I A I A ( b) I B I B ( c) I A I B ( d) I A I 34. Blood grouping in human beings is controlled by (a) 3 alleles in which none is dominant (b) 4 alleles in whichais dominant (c) 3 alleles in whichaand B are codominant and 1 is recessive (d) 3 alleles in which B is dominant 35. Polygenic inheritance shows (a) Different phenotypes (b) Different genotypes (c) Both of these (d) None of these 36. A, B, O blood group system is due to (a) Epistasis (b) Multiple factor inheritance (c) Incomplete dominance (d) Multiple allelism A I B is born of a woman with genotype I B I B. The father could not be a man of 37. When red-flowered snapdragons are crossed with white-flowered snapdragons, their offspring have pink flowers. This type of genotypic expression is called (a) Dominant-recessive (b) Co-dominance (c) Co-recessive (d) Incomplete dominance 38. A polygenic inheritance in human beings is (a) Colour blindness (b) Phenylketonuria (c) Skin colour (d) Sickle cell anaemia 39. Which of the following characters is controlled by quantitative inheritance? (a) Skin colour (b) A, B and O blood groups (c) Colour blindness (d) Haemophilia 40. Multiple alleles control inheritance of (a) Blood groups

9 ( a) 3:1 (b) 1: 1 ( c) 1:2:1 (d) 9:3: A man with blood group B marries a woman with blood groupaand their first child is having group B. What is the genotype of the child? ( a) I A I B ( b) I B I B ( c) I B i ( d) I A i 44. In human beings, height shows a lot of variations. It is an example of (a) Pseudoalleles (b) Multiple alleles (c) Pleiotropic inheritance (d) Polygenic inheritance 45. In human beings, multiple genes are involved in the inheritance of ( a) Sickle cell anaemia (b) Colour blindnes s ( c) Skin colour (d) Phenylketonuria 46. In his experiments with pea plants, Mendel performed test crosses between (a) Dominant parent with recessive parent ( b) F hybrid and F hybrid 1 1 ( c) F hybrid and dominant parent 1 ( d) F hybrid and recessive paren t When a plant of F generation is crossed with homozygous dominant parents, it is known a s 1 ( a) Simple cross (b) Special cross ( c) Back cross (d) Test cross 48. Pure line breed refers to (a) Heterozygosity and linkage (b) Homozygosity and independent assort-ment (c) Heterozygosity only (d) Homozygosity only 49. Chromosome complement with 2n-1 is called as ( a) Nullisomy (b) Monosomy ( c) Trisomy (d) Tetrasom y 50. The largest number of chromosomes are found in ( a) L emna ( b) Adiantum ( c) O phioglossum ( d) Neurospora (c) Recessive character (d) Dominant character (d) None of the above

Observing Patterns in Inherited Traits. Chapter 11

Observing Patterns in Inherited Traits Chapter 11 Impacts, Issues: The Color of Skin Like most human traits, skin color has a genetic basis; more than 100 gene products affect the synthesis and deposition