How do Mendel’s experiments show that traits are inherited independently?
Mendel gave the law of independent assortment from the dihybrid cross.
Mendel performed an experiment in which he made crosses of pea plant with the round yellow seeds and one with the wrinkled green seeds. And in the F1 progeny, round yellow seeds are dominant over the wrinkled green seeds. And in the F2 generation outcome, he saw all the characters are inherited independently by the use of punnett square that helps to demonstrate the possible combinations of the gametes in F2 progeny. Those independently inherited combinations were round yellow, round green, wrinkled yellow and wrinkled green as shown below :
This punnet square is showing the 16 possible combination of gametes with the phenotypic ratio 9:3:3:1 and 1:2:1:2:4:2:1:2:1 genotypic ratio in F2 generation. Every pair is showing the different characters, showing independent assortment.
Outline a project which aims to find the dominant coat colour in dogs.
How is the sex of the child determined in human beings?
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?
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?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
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?
A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.
How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
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?
Write equations for the reactions of
(i) iron with steam
(ii) calcium and potassium with water.
Why are some substances biodegradable and some non-biodegradable?
Define the following terms.
(i) Mineral (ii) Ore (iii) Gangue
What is a good fuel?
How is the amount of urine produced regulated?
Redraw the circuit of Question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the 12 Ω resistor. What would be the readings in the ammeter and the voltmeter?