Page 25 - Biology - XII

Early Prophase I Prophase I Late Prophase I Metaphase I

Metaphase II Anaphase I Anaphase II Late Telophase II
Fig. 5.4: Stages of mitotic cell division in a plant cell (single/individual cell magnifi ed)

Extended Learning
1. The life of an organism starts with a single cell. The cell undergoes repeated cell divisions till the
‘embryo’ is formed which later develops into an adult-like individual.
2. This whole process involves cell division called mitosis. The process of producing two or more daughter
cells is called cell division or cell reproduction.
3. There are two types of cell divisions—mitosis and meiosis.

4. Karyokinesis—division of nucleus—completed in four phases—Prophase, Metaphase, Anaphase, and
Telophase.

5. Cytokinesis—division of cytoplasm, interphase.
6. In mitosis, the chromosome number remains the same as that of its parent cell.

VIVA VOCE

Q1. What is interphase?
Ans. The stage/phase in between two successive cell divisions is called interphase.
Q2. Which stain is used to stain onion root tip cells?
Ans. Acetocarmine

Q3. A cell showed enlarged nucleus occupying most of the cell volume. Name the stage.
Ans. Prophase

Q4. What is mitosis?
Ans. Mitosis is a type of cell division that takes place in organisms.
Q5. Why did you take onion root tip for study of mitosis cell division?
Ans. Because the root tips can be easily grown/obtained and they show better cell division stages.
Q6. What is spindle?
Ans. The astral rays/fi bres that attach to centromeres originate from centrioles at opposite poles. It appears
like spindle.

Q7. Where does mitosis take place?
Ans. Mitosis takes place in the vegetative parts of the plants and somatic parts of the animals.

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