Saturday, October 29, 2011

10th CBSE Question Banks - Ch. How do Organisms Reproduce ?

Chapter - 8 How Do Organisms Reproduce Points to remember:-

Q 1. What is the importance of DNA copying in reproduction?

Ans. DNA contains information for inheritance of features from parents to next generation. DNA 
present in the cell nucleus is the information source for making proteins. If the information is different,  different proteins will be made. Different proteins will eventually lead to altered body designs.

Q 2. Why is variation beneficial to the species but not necessarily for the individual?

Ans. Variations are useful for the survival of species in changed environmental situations. For 
example, if a population of reproducing organisms were suited to a particular niche (well-defined 
place of abode) and if the niche is drastically altered the population could be wiped out. However, if 
some variations were to be present in a few individuals in these populations, there would be some 
chance for them to survive. Thus if there were a population of bacteria living in temperate waters, and  if water temperature were to be increased by global warming , most of these bacteria would die,
but few variants resistant to heat would survive and grow further. Variation is thus useful for the 
survival of species over time

Q 3. How will an organism be benefited I sit reproduces through spores?

Ans. The spores are covered by thick walls that protect them until they come in to contact with 
suitable moist surface and can begin to grow.

Q 4. Can you think of reasons why more complex organisms cannot give rise to new individuals 
through regeneration?

Ans. The reason is that complex organisms are not merely random collection of cells. Specialised 
cells are organised in them as tissues and tissues are organised as organs. These organs have to be 
placed at definite positions in the body. In such a carefully organised situation, cell-by-cell division 
would be impractical. Complex multicellular, therefore, need to use more complex ways of 
reproduction.

Q 5. Why is vegetative propagation practiced for growing some types of plants?

Ans. (i) Plants raised by vegetative propagation can bear flower and fruits earlier than those 
produced from seeds.
(ii) Such methods also make possible the propagation of plants such as banana, orange, rose and 
jasmine that have lost the capacity to produce seeds.
(iii) All plants produced by this method are genetically similar enough to the parent plant to have its 
all characteristics

Q6. As a Goddess, she may be Lakshmi, Kali, Saraswati and Durga but s human she is an unwanted girl. In our highly prejudiced society girls are considered as a financial burden resulting in female foeticides. As a student, what three initiatives would you take in the common concern of "Save girl
child, save the mother Earth".[VALUE BASED]

Ans:  
- By inspiring people to give birth to a girl child.
- By motivating them to understand the fact that girls are not a burden but a boon as Kalpana
Chawala, Kiran Bedi and Indira Gadhi and many others proved to be.
- By making them aware of declining sex ratio and its impacts.

Q.7. Ritu's parent received a proposal for Ritu's marriage from a boy living abroad. Before everything was finalized, Reena, Ritu's friend asked Ritu's parents to ask the boy to get report of his blood test.
(a) Do you think it was right on the part of Ritu's parents to do so ?
(b) What moral value did Reena showed ?   [VALUE BASED]

Ans: 
(a) Yes, it is necessary to go through the blood reports of to be groom as it indicates about his being physically fit and free of STD.
(b) By doing so, Reena not only helped her friend but also made her parents aware of possibility of the groom being infected with STDs as he lived in an open society.

Download full Solved paper   HOW DO ORGANISMS REPRODUCE ?

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