Distinguish between pollination and fertilisation. Mention the site and product of fertilisation in a flower.
Draw a neat, labelled diagram of a pistil showing pollen tube growth and its entry into the ovule.
Pollination | Fertilization |
---|---|
Transfer of pollen grain from the anther (male part of the flower) of stamer to the stigma (female part of the flower) of carpel is known as pollination. | Fusion of male gamete and a female gamete and they together forms a dipliod cell, i.e. zygote is known as fertilisation. |
Agents that carry the pollination process like wind pollination, water pollination, insect pollination, pollination by birds and bats. | It is achieved by growth of pollen tubes so that male gamete reaches the female germ cells in the plants is known as siphonogamy and in animals it is achieved as the fallopian tubes. |
Leads to fertilization. | Lead to production of seeds in plants and production of zygote in animals. |
Ovary is the site of fertilization.
Diagram of a pistil showing pollen tube growth and its entry into the ovule:
Why is variation beneficial to the species but not necessarily for the individual?
Draw a labelled diagram of the longitudinal section of a flower.
What are the functions performed by the testis in human beings?
Why does menstruation occur?
How will an organism be benefited if it reproduces through spores?
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
What are the advantages of sexual reproduction over asexual reproduction?
How does the embryo get nourishment inside the mother’s body?
How does reproduction help in providing stability to populations of species?
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?
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?
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?
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Plaster of Paris should be stored in a moisture-proof container. Explain why?
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
How is the equal genetic contribution of male and female parents ensured in the progeny?
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Why is the use of iodised salt advisable?
Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is
(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.
Oil and fat containing food items are flushed with nitrogen. Why?
What is the need for a system of control and coordination in an organism?