NCERT Solution of Class 10 Science Ch-7 How do Organisms Reproduce?
Page No. 114
Question 1:
What is the importance of DNA copying in reproduction?
Answer
DNA – Deoxyribonucleic acid is the genetic material that is present in the cells of all organisms. DNA carries genetic information from one generation to the other and this helps in producing organisms of its own types. DNA copying is a must for inheriting the traits from parents. Any variations in DNA copying will give rise to origin of new species.
Question 2:
Why is variation beneficial to the species but not necessarily for the individual?
Answer
Variations are beneficial to the species than individual because sometimes for a species, the environmental conditions change so drastically that their survival becomes difficult.
For example, if the temperature of water increases suddenly, then most of the bacteria living in that water would die. Only few variants that are resistant to heat would be able to survive. Thus, these variants help in the survival of the species. However, all variations are not necessarily beneficial for the individual organisms.
NCERT Solution of Class 10 Science Ch-7 How do Organisms Reproduce?
Page No. 119
Question 1:
How does binary fission differ from multiple fission?
Answer
(1) Binary fission occurs when a single cell splits into two equal halves. Amoeba and bacteria are two instances of binary fission.
(2) Multiple fission occurs when a single cell divides into several daughter cells simultaneously. Sporozoans and algae are two instances of multiple fission.
Question 2:
How will an organism be benefited if it reproduces through spores?
Answer
An organism is benefited by reproducing through the spores because spores are surrounded by a thick layer which protects them in adverse conditions. When the favourable conditions occur, these spores start to grow again. In this way they are successfully live in unfavourable conditions.
Question 3:
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Answer
In complex multicellular organisms, specialised cells make up tissues, tissue make up organs, organs make up organ systems and finally organ systems make up organisms. Since complex multicellular organisms have a very high degree of organisation in their body, they cannot be reproduced from their cut body parts by the process of regeneration.
Question 4:
Why is vegetative propagation practised for growing some types of plants?
Answer
Following are the advantages of practising vegetative propagation for growing some types of plants:
1.Crops like orange, banana, pineapple do not have viable seeds, so vegetative propagation can be used.
2.It is a rapid, cheap and easier method to grow crops.
3.It can be used in places where seed germination fails.
4.A good quality of variety can be preserved.
Question 5:
Why is DNA copying an essential part of the process of reproduction?
Answer
As DNA transmits genetic information from parents to children, copying DNA is a crucial step in the reproduction process. Two copies of DNA are created when certain chemical processes take place. DNA copying occurs in addition to the extra cellular structure, and cell division into two cells occurs next.
NCERT Solution of Class 10 Science Ch-7 How do Organisms Reproduce?
