Mention if the following statement is true or false. If false, rewrite the sentence by changing only the word printed in bold face-
The resting stage in mitosis is called interphase.
Important Points to Remember in Chapter -1 - Cell Cycle, Cell Division and Structure of Chromosomes from Dr. K.K. Aggarwal A New Approach to Biology Solutions
1. Cell theory:
Cell theory states that cells are the basic unit of life and all cells are formed from pre-existing cells.
2. Cell division:
(i) The continuity of life depends on cell division.
(ii) Cell undergo two kinds of division: mitosis and meiosis.
3. Amitosis:
Amitosis is a simple division also called as direct cell division which is most common in lower algae, fungi and some protozoans.
4. Haploid:
Haploid refers to having only one set of chromosome.
5. Diploid:
Diploid cells have two sets of chromosomes.
6. Homologous chromosomes:
Homologous chromosome refers to a pair of chromosomes in a diploid cell that are exactly similar in shape and size.
7. Cell cycle:
(i) The sequence of events including growth and division. that a cell undergoes from the time of its formation upto its division into daughter cells is called cell cycle.
(ii) Cell cycle includes two main stages: interphase and mitotic phase.
(iii) Interphase is divided into G1 phase S face and G2 phase.
8. Mitotic phase or Mitosis:
(i) Mitosis includes karyokinesis and cytokinesis.
(ii) Karyokinesis is divided into four stages: prophase, metaphase, anaphase and telophase.
(iii) Mitosis helps in growth, healing of wounds, replacement of cells, regeneration and asexual reproduction.
9. Meiosis:
(i) Meiosis occurs in reproductive cells to form four haploid cells.
(ii) Meiosis is divided into meiosis I and meiosis II.
(iii) Meiosis I is classified into prophase I, metaphase I, anaphase I and telophase I.
(iv) After telophase I, cytokinesis takes place to form two haploid daughter cells.
(v) Meiosis II is also divided into prophase II, metaphase II, anaphase II and telophase II.
(vi) After meiosis II, cytokinesis occurs and form four haploid cells.
(vii) Meiosis helps to restore the original chromosome number during sexual reproduction.
(viii) Meiosis leads to variations in the offspring.
