Cell Divison

Cell division

Cell division is the process where a cell divides into two or more daughter cells for growth, repair, or reproduction.

Binary fission (prokaryote)

Binary fission is a type of asexual reproduction where a single organism divides into two identical offspring. It’s common in prokaryotes like bacteria.

1- cell elongate and DNA is replicated

2- chromosomes segregate and cell wall starts to grow in the middle of the cell

3- Completation of the cell wall formation

4- Seperation of the two daughter cells.

Cell cycle in Eukaryote

• last around 20 hours

G0: don’t divide

G1: Productions of protein, production of organelles, increase of the cell size

S: Synthesis of DNA, replication of DNA content.

G2: production of proteins, preparaton for cell division

Mithosis: cell divison

Checkpoints

G1: restriction point, the cell commits to the cell division process

G2: ensure that all chrosomoes have been replicated

G3: ensure DNA integrity or cell size is appropriate.

Mitosis

Mitosis is the process of cell division that results in two genetically identical daughter cells. It is used for growth, repair, and asexual reproduction.

• Prophase: Chromosomes condense, and the nuclear envelope begins to break down.

• Prometaphase: nuclear envelope breaks, spindle attaches to the chromosomes at the centromeres

• Metaphase: Chromosomes line up at the cell’s center.

• Anaphase: Chromosomes are pulled apart to opposite sides of the cell.

• Telophase: New nuclear membranes form around the separated chromosomes.

• Cytokinesis: The cell’s cytoplasm divides, creating two daughter cells.

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Cytokinesis

• Plasma membrane pinches cytoplasm in 2

Difference between mistosis in animals and plants

• Cytokinesis:

  • Animals → Cleavage furrow

  • Plants → Cell plate

• Spindle Formation:

  • Animals → Centrioles present

  • Plants → No centrioles

• Cell Shape:

  • Animals → Rounds up

  • Plants → Stays rigid

• Location:

  • Animals → Throughout body

  • Plants → Meristems only