CELL DIVISION

Text: Mastering Basic Concepts (3rd), Bk1, pp.92-98

Types of cell division

1. Mitotic cell division 2. Meiotic cell division

– (will be discussed in Ch.22: Genetics)

Mitotic cell division

Mitotic cell division consists of two parts: 1. Mitosis

– the division of the nucleus 2. Cytoplasm division

– the division of the cytoplasm

Mitosis

The nucleus divides into two identical daughter nuclei (sing. nucleus)

Therefore each daughter nucleus can carry the same function as it parent nucleus

MitosisWhat can we find inside the nucleus?

Each nucleus carries many thread-like structures called chromosomes

Chromosomes carry the genetic materials called DNA (deoxyribonucleic acid)

MitosisStructures of chromosome

MitosisStages of mitosis

1. Cell growth– to make an copy of each chromosome

2. The duplicated set is separated 3. Each daughter nuclei receive one set of

chromosomes

Cytoplasmic division starts

Cytoplasmic division

Cytoplasmic division follows mitosis the cytoplasm is divided into two halves mitotic cell division finishes after the compl

etion of cytoplasmic division

Cytoplasmic divisionanimal cell

Two identical daughter cells

Cytoplasmic divisionplant cell

MitosisWhere mitosis occurs?

Mitosis takes place in most types of cells, excepts cells in the testes and ovaries.

In plants, mitosis occurs at the root tips and shoot tips

MitosisImportance of mitotic cell division

1. Growth 2. Repairing the damage tissues 3. Replacement of worn-out cells