Question
Explain cell reproduction and tendency for variation inbuilt during cell reproduction.
✓
Answer
- Cell reproduction means cell division.
- A parent cell divides into two daughter cells.
- The creation of a $DNA$ copy is the basic event in the process of reproduction.
- Cells usually use chemicals to build copies of their $DNA$.
- This process results in the production of two similar copies of $DNA$ in a reproducing cell.
- The two copies of the $DNA$ molecule, which are similar with each other, come to two daughter cells.
- Therefore, $DNA$ copying is always accompanied by the creation of another cellular apparatus.
- Finally, the $DNA$ copies are seperated into two similar cells, each with its own cellular apparatus.
- Finally, a cell divides to give rise to two daughter cells.
- So, only creation of a $DNA$ copy is not sufficient for cell division.
- Two daughter cells produced by cell division are similar, however they are not likely to be absolutely identical.
- This is because some variations may arise during the process of copying the $DNA$.
- As a result, the $DNA$ copies generated will be similar, but may not be identical to the original.
- Some of these copies of $DNA$ may possess such drastic variation from the original that their survival becomes difficult. Such a new born cell will simply die.
- On the other hand, some other variations in the $DNA$ copies may be beneficial which can help the cell to survive with slight variation.
- Thus, the surviving cells are different from each other with slight variation in their features.
- This is how tendency for variation is inbuilt during cell reproduction.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Explain disorders caused by hormonal imbalance in human beings.
What is biogas? How is the use of biogas is beneficial?
How does the design of the body solve a problem when immediate response is needed? Where should such connection be made?
State the properties of carbon compounds.
Explain the need to use more complex ways of reproduction for most of multi-cellular organisms.
A milk man adds a very small amount of baking soda to fresh milk.
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?
Give scientific reason : Unlike animals, the plants do not show immediate response.
You are given following seeds :
Maize, Bean, Wheat, Green gram (Mung), Rice, Groundnut.
Classify them into monocot and dicot seeds. Select any one dicot seed and dip in water for about 4 to 5 hours. Press it and observe the part of embryo.
(1) Are the basic structural parts of an embryo equal in all dicot seeds?
(2) What is the function of cotyledons?
(3) Is there any change in size of cotyledon as seed germination progresses?
Maize, Bean, Wheat, Green gram (Mung), Rice, Groundnut.
Classify them into monocot and dicot seeds. Select any one dicot seed and dip in water for about 4 to 5 hours. Press it and observe the part of embryo.
(1) Are the basic structural parts of an embryo equal in all dicot seeds?
(2) What is the function of cotyledons?
(3) Is there any change in size of cotyledon as seed germination progresses?
What are the limitations of extracting energy from $(a)$ the wind? $(b)$ waves? $(c)$ tides?
→