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Cell Division. Cell divides into two daughter cells. Revised 10-09-2006. Cell Cycle. G 1 phase Cellular Growth Development S phase DNA Replication Protein synthesis G 2 phase Synthesis of organelles Materials for cell division M Phase Mitosis. Length of the Cell Cycle.

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Cell division
CellDivision

Cell divides into two daughter cells

Revised 10-09-2006


Cell cycle
Cell Cycle

  • G1 phase

    • Cellular Growth

    • Development

  • S phase

    • DNA Replication

    • Protein synthesis

  • G2 phase

    • Synthesis of organelles

    • Materials for cell division

  • M Phase

    • Mitosis


Length of the cell cycle
Length of the Cell Cycle

  • Intestine

    • 24-48 hours

  • Frog embryo

    • 1 hour


Control of the cell cycle
Control of the Cell Cycle

  • Cyclins

  • Cyclin Dependent Kinases


Cell cycle regulation
Cell Cycle Regulation

The cyclins are named “cyclins”

because their appearance during the cell cycle is cyclical



G1 phase cellular growth and development
G1 phaseCellular Growth and Development

Cyclin D

CDK4

CDK6

Cyclin E

CDK 2

  • Checkpoint 1

  • Cell size?

  • DNA?




S phase dna replication and protein synthesis
S phase DNA Replication and Protein synthesis

Cyclin A

CDK 2


Cyclin a
Cyclin A

  • Residues 173-432

  • 2 similar domains

  • Cyclin fold

    • 5 α-helices


Cdk 2
CDK 2

  • Domain 1

    • 85 residues

    • 1 α-helix

    • 5 stranded β-sheet

  • Domain 2

    • 213 residues

    • α-helices



Cyclin a cdk 2 complex1
Cyclin A/CDK 2 Complex

Inactive

Active


G2

  • Checkpoint 2

  • All DNA Duplicated?

  • Cell size?

  • All DNA Intact?

    • Repair DNA

  • Cyclin B


Cell cycle regulation1
Cell Cycle Regulation

M-phase promoting Factor MPF

  • Checkpoint 3

  • Chromosomes attached to spindle fibers?


Mitosis
Mitosis

  • Process by which the nucleus of the cell is divided into two nuclei, each with the same number and kinds of chromosomes as the parent cell.

  • Cytokinesis is the process by which the cytoplasm is divided.

.



Prophase
Prophase

Longest (50 - 60%)

  • Appearance of chromosomes

  • Nucleolus disappears

  • Nuclear membrane breaks down

  • Centrioles separate and migrate to opposite poles of cell


Metaphase
Metaphase

Shortest

  • Chromosomes line up across center of cell

  • Spindle fibers form from centrioles to centromere


Anaphase
Anaphase

  • Sister Chromatids split at Centromere

  • Individual Chromosomes move toward poles


Telophase
Telophase

Final Phase

  • Spindle fibers breakdown

  • Chromosomes uncoil into Chromatin

  • Nuclear envelope reforms

  • Nucleolus becomes visible


Mitosis in whitefish and onion
Mitosis in Whitefish and Onion

PROPHASE

METAPHASE

ANAPHASE

TELOPHASE


Cytokinesis
Cytokinesis

The process by which the cytoplasm divides, forming two new cells.


Cytokinesis1
Cytokinesis

The process by which the cytoplasm divides, forming two new cells.

  • Animals

    • Cell membrane

    • pinches inward

  • Plants

    • Cell plate


Result of cell division
Result of Cell Division

Two cells that are identical to each other.


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