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.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
Outline a project which aims to find the dominant coat colour in dogs.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
How is the sex of the child determined in human beings?
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
Calculate the number of electrons constituting one coulomb of charge.
What is an homologous series? Explain with an example.
Why is variation beneficial to the species but not necessarily for the individual?
Give an example of a metal which
(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.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
Plaster of Paris should be stored in a moisture-proof container. Explain why?
Give an example of a double displacement reaction other than the one given in activity 1.10.
How would you name the following compounds?
(i) CH3 -- CH2 -- Br
(ii)
(iii)
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
Find out about the traditional systems of water harvesting/management in your region.
Outline a project which aims to find the dominant coat colour in dogs.
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be –
(a) 1:2 (b) 2:1 (c) 1:4 (d) 4:1
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.