Chap. 4; Growth and Division of the Cell

Growth Phase of Cell Cycle

Division Phase of Cell Cycle

Mitosis

Cytokinesis - formation of phragmoplasts

Meiosis occurs in reproduction cells. Gametes form zygote witch then grow into an adult

Prophase- Chromosomes coil, and condense becoming shorter, and thicker.

Anaphase - Chromosomes separate to opposite ends of spindle.

Metaphase - Metaphase plate is formed in center, and Separase releases chromosomes from each other.

Telophase - chromosomes uncoil and spindle depolymerizes and disappears.

Meiosis II

Less Common Types of Division

Cell Division in Algae

Cytokinesis -

Cell Division in Prokaryotes

Division in Chloroplasts and Mitochondria

Karyokinesis occurs without cytokinesis and multinucleate cells are formed.

Interphase

G1 Phase is the longest part of cell cycle, although time spent here varies greatly. The most important process in G1 phase is synthesis of nucleotides.

S Phase - DNA replication.

G2 Phase cells prepare for division. alpha & beta-tubulins synthesize and proteins are produced.

Meiosis I

Prophase I - similar to prophase in mitosis and is divided into 5 stages.

Metaphase I - Metaphase plate is formed.

1) Leptotene - chromosomes condense

2) Zygotene - chromosomes pair up.

3)Pachytene - chromosomes condense, becoming shorter and thicker.

4)Diplotene - Chromosomes move away from each other but are held together by centromere.

5) Diakinesis - seperation continues

Anaphase I - Chromosomes separate from each other and move to opposite sides of spindle.

Telophase I - chromosomes uncoil and spindle depolymerizes and disappears.

Nuclei

Lack mitosis and Meiosis

Several rounds of replication occur.

Cytokinesis occurs by infurrowing

Infurrowing OR pulled apart.

Each daughter cell must receive one mitochondrion and one plastid during cytokinesis.