A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
This information is not enough to tell which of the traits A or O dominant. In human hereditary characters, A, B, ABO blood group is dominant or O is recessive. But in the above case we cannot detect which blood group is dominant. If father’s blood group is A, genotypes will be homozygous AA or heterozygous AO. And women having the blood group O, then the genotype will be homozygous OO and heterozygous AO.
If A is dominant, the cross of father genotype IAIA with mother have IoIo and the progeny will have 50- 50 percent of the genetic material, where the father blood group is A and mother’s is O.
IA IA
IAIO | IAIO |
IAIO | IAIO |
Io Io
If the blood group O is dominant, when we cross the father genotype IAIO with the mother genotype IoIo, the child will contain blood group O.
IA Io
IAIO | IOIO |
IAIO | IOIO |
Io Io
So, in both cases the child will have O. So, this is not clear which trait is dominant.
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Outline a project which aims to find the dominant coat colour in dogs.
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(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
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(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
Calculate the number of electrons constituting one coulomb of charge.
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(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
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(i) iron with steam
(ii) calcium and potassium with water.
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(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?
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Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.