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Published on: 29/08/2022
QB365 provides a detailed and simple solution for every Possible Book Back Questions in Class 12 Biology Subject - Botany - Chromosomal Basis of Inheritance, English Medium. It will help Students to get more practice questions, Students can Practice these question papers in addition to score best marks.
Download Tamil Nadu 12th Standard Biology question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Biology Test1.
2.
3.
What is gene mapping? Write its uses
4.
5.
How is Nicotiana exhibit self-incompatibility. Explain its mechanism.
6.
If you cross dominant genotype PV/PV male Drosophila with double recessive female and obtain F1 hybrid. Now you cross F1 male with double recessive female.
i) What type of linkage is seen?
ii) Draw the cross with correct genotype.
iii) What is the possible genotype in F2 generation?
7.
When two different genes came from same parent they tend to remain together.
i) What is the name of this phenomenon?
ii) Draw the cross with suitable example.
iii) Write the observed phenotypic ratio.
8.
1.
2.
3.
The diagrammatic representation of position of genes and related distances between the adjacent genes is called gene mapping.
Uses
(i) Used to determine gene order.
(i) Identify the locus of a gene.
(i) Calculate the distance between genes.
(i) Useful in predicting results of dihybrid and trihybrid crosses.
(i) Allows the geneticists to understand the overall genetic complexity of particular organism.
4.
5.
(i) Multiple alleles are reported in Nicotiana which are responsible for self, incompatibility.
(ii) The gene for self-compatibility can be designated as S, which has allelic series S1, S2, S3, S4 and S5.
(iii) The cross-fertilizing tobacco plants were not homozygous as S1S1 or S2S2.
(iv) But, were heterozygous as S1S2, S3S4, S5S6.
(v) When crosses were made between different S1S2 plants, pollen tube did not develop normally.
(vi) But effective pollen tube developed when crossing was made with other than S1S2.
(vii) When crosses were made between S1S2 (seed parents) S2S3 (pollen parents), two kinds of pollen tubes were distinguished.
(viii) Pollen grains carrying S2 were not effective.
(ix) Pollen grains carrying S3 were capable of fertilization.
(x) In a cross between S1S2 X S3S4, all the pollens were effective.
(xi) So four kinds of progeny resulted. S1S3/S1S4/S2S3/S2S4.
6.
(i) Incomplete linkage
Rano : 1:2:1
7.
(i) Complete Linkage
(ii)
(iii) Observed ratio 1:1
8.
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