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.