1). What is a cell division?
Ans: The biological process in which a pre-existing cell divides into two or four daughter cell division.
2). What is a cell? What is it made of?
Ans: The bodies of living organisms are made up of microscope units is known as cells.
It is made up of protoplasm.
3). Name any two types of cell division.
Ans: They are given below:
i) Mitosis ii) Meiosis
4). What is Mitosis?
Ans: Mitosis is an equational division in which a mother cell divides to from two identical daughter cells.
5). In which cells does mitosis take place.
Ans: It takes place in vegetative or somatic cells.
6). What is interphase?
Ans: The non-dividing stages of the cell between two successive period of mitosis is called interphase.
7). Name any four stages of mitosis.
Ans: They are given below:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
8). What is meiosis? In which cells does meiosis take palce?
Ans: The cell division in which a diploid (2n) Parent. Cell divides into four haploid daughter cells are called meiosis.
It takes place in gemetic or reproductive cells at time of gamete formation.
9). Define karyokinesis and cytokinesis.
Ans: The process of division of the nucleus is called karyokinesis.
The process of division of a cytoplasm in events of cell division is called cytokinesis.
10). What is a diploid cell?
Ans: A Diploid cell is a mother cell which divided into two diploid daughter cell.
11). Why is mitosis called somatic cell division?
Ans: Mitosis called somatic cell division because it take place in vegetative cells or somatic cells.
12). Why is mitosis called equation cell division?
Ans: Mitosis called equation cell division because two daughter cells formed as a result of mitosis are identical to the mother cells in all respects.
13). Why is meiosis called reduction division?
Ans: Meiosis called reduction division because in this chromosomes divide once and nucleus divides twice after which the number of chromosomes in daughter cells reduced to half.
14). Differentiate between:
a) Mitosis and Meiosis
| Mitosis | Meiosis |
| Mitosis occurs in somatic or vegetative cells. | Meiosis occurs in gametic or sexually reproductive cell during gametogenesis. |
| In mitosis two daughter cells are produced from a single parent cell. | In meiosis 4 daughter cell are produced from a single parent cell. |
b) Diploid Cell and Haploid Cell.
| Diploid Cell | Haploid Cell |
| The no. chromosomes in somatic cells of organisms is called diploid cell. | The no. of chromosomes in gametes ( sperm and ovum) is haploid cells |
| It is represented by ‘2n’. | It is represented by ‘n’ |
c) Prophase and Telophase
| Prophase | Telophase |
| It is the first and longest stage of mitosis. | Telophase is the last stage or fourth stage of karyokinesis. |
| It lasts for 100 minute. | It completes in 60 minute. |
| Nucleolus and nuclear membrane disappear. | Two diploid nuclei are formed in the cell. |
d) Karyokinesis and Cytokinesis.
| Karyokinesis | Cytokinesis. |
| It is the division of the nucleus. | It is the division of the cytoplasm. |
| It is the second events of cells divisions. | It is the third events of cell division. |
15). Why is the mitosis important? Give any two reasons.
Ans: They are given below:
i) It is a method of multiplication i.e, asexual reproduction in unicellular organisms.
ii) In the multicellular organisms, mitosis is responsible for the growth and development +
from a zygote
16). Why is meiosis important? Give any two reasons.
Ans: The important is given below:
i) Meiosis is responsible from producing haploid gametes. i.e, Sperm and Ova.
ii) Meiosis cell division helps to maintain genetic stability by keeping the fixed no. of
chromosomes in species.
17). Draw neat and labelled figure:
- Prophase of Mitosis
2. Anaphase of mitosis
3. Meiosis cell division
18). What is the role of mitosis to maintain genetic stability? Explain.
Ans: The role of mitosis to maintain the genetic stability is chromosomes in the original cell are duplicated to ensure that the two new cell have full copies of the necessary genetic information. The process of mitosis generates new cells that are generally identical to each other.
19). Describe the role of mitosis for growth and development of an organisms.
Ans: The process of mitosis generates new cell that are genetically identical to each other. Mitosis helps organisms grow in size and repair damaged tissue.
20). How are gametes formed? Explain.
Ans: Gametes are formed through meiosis ( reduction division) in which a germ cell undergoes two fissions resulting in the production of four gametes during fertilization male and female.
21). Study the given figure and answer the following questions.
Figure: (a)
Figure: (b)
i. Name the type of cell division showing in Fig.(a) and Fig.(b)
Ans: The type of cell division shown in the figure are Fig. (a): Mitosis Fig. (b): Meiosis
ii. What does ‘2n’ mean?
Ans: 2n means diploid cell.
iii. Write down the importance of the cell division Showing fig. b
Ans: They are given below:
1. Meiosis is responsible for producing haploid gamets i.e, Sperm and ova.
2. It helps in sexual reproduction and avoids the multiplication of chromosomes in offspring by reduction division.
22). Which stage of mitotic cell divison is shown in each of the given figure? Also, label the parts A, B, C, D in each figure.
Ans:
23). Which cell division is more important for genetic study, Mitosis or Meiosis? Give Reasons also.
Ans: Meiosis cell division is more important for genetic study. Meiosis ensure genetic variation is organisms that reproduce sexually. Meiosis also produce genetic variation by way of the process of recombination.
24) Mitosis and Meiosis both are important for normal human life. Justify.
Ans: Meiosis and Mitosis both are important for normal human life. Meiosis help in sexual reproduction and avoids the multiplication of chromosomes in offspring by reduction division. Mitosis is responsible for the growth and development from a zygote. It helps in the replacement of damaged or lost body parts.
25). What changes would arise in offspring if there were no reduction division during formation gametes? Explain.
Ans: As we know that any sexual organisms has one pair chromosomes. But when the organisms mate (sexual intercourse) mate then two pair of chromosome collected. If it will not divide then organisms that form will has two pair of sex chromosomes which is not possible. That’s why to maintain the characters of male and female the chromosomes have two divides in sexual organisms.
26). Draw a neat and labeled figure showing.
Ans:
