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.
Outline a project which aims to find the dominant coat colour in dogs.
How is the sex of the child determined in human beings?
How do Mendel’s experiments show that traits are inherited independently?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Explain the terms analogous and homologous organs with examples.
How do Mendel’s experiments show that traits may be dominant or recessive?
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How does the creation of variations in a species promote survival?
Why are traits acquired during the life-time of an individual not inherited?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Fe2O3 + 2Al → Al2O3 + 2Fe
The above reaction is an example of a
(a) combination reaction.
(b) double displacement reaction.
(c) decomposition reaction.
(d) displacement reaction.
How does chemical coordination take place in animals?
A solution of a substance 'X' is used for whitewashing.
(i) Name the substance 'X' and write its formula.
(ii) Write the reaction of the substance 'X' named in (i) above with water.
How much energy is given to each coulomb of charge passing through a 6 V battery?
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Balance the following chemical equations.
(a) HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O
(b) NaOH + H2SO4 → Na2SO4 + H2O
(c) NaCl + AgNO3 → AgCl + NaNO3
(d) BaCl2 + H2SO4 → BaSO4 + HCl
The anther contains
(a) sepals.
(b) ovules.
(c) pistil.
(d) pollen grains.
Write the balanced chemical equations for the following reactions.
(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
(b) Zinc + Silver nitrate → Zinc nitrate + Silver
(c) Aluminium + Copper chloride → Aluminium chloride + Copper
(d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride
What can you as an individual do to reduce your consumption of the various natural resources?
How do auxins promote the growth of a tendril around a support?