Cell Division Cell divides into two daughter cells Revised

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 Intestine hours Frog embryo 1 hour

Control of the Cell Cycle Cyclins Cyclin Dependent Kinases

Cell Cycle Regulation The cyclins are named “cyclins” because their appearance during the cell cycle is cyclical

Cyclins/Kinases Complexes

G1 phase Cellular Growth and Development Cyclin D CDK4 CDK6 Cyclin E CDK 2 Checkpoint 1 Cell size? DNA?

8.07 Steps of Mitosis Slide number: 20 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. G 1, early interphase of daughter cells. Cells resume normal functions or enter another division cycle.

Cyclin D

cyclin D-dependent kinase Cdk6

S phase DNA Replication and Protein synthesis Cyclin A CDK 2

Cyclin A Residues similar domains Cyclin fold –5 α-helices

CDK 2 Domain 1 –85 residues –1 α-helix –5 stranded β- sheet Domain 2 –213 residues –α-helices

Cyclin A/CDK 2 Complex

InactiveActive

G2 Cyclin B Checkpoint 2 All DNA Duplicated? Cell size? All DNA Intact? Repair DNA

8.07 Steps of Mitosis Slide number: 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. G 2, Late interphase Cell checks for complete DNA replication.

8.07 Steps of Mitosis Slide number: 12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. G 2, Late interphase Cell checks for complete DNA replication. Nucleolus Nuclear envelope Chromatid Centrioles

Cell Cycle Regulation M-phase promoting Factor MPF Checkpoint 3 Chromosomes attached to spindle fibers?

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.

Chromosomes

Prophase Longest ( %) Appearance of chromosomes Nucleolus disappears Nuclear membrane breaks down Centrioles separate and migrate to opposite poles of cell

8.07 Steps of Mitosis Slide number: 13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prophase Chromosomes condense, become visible. Spindle apparatus forms.

8.07 Steps of Mitosis Slide number: 14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prophase Chromosomes condense, become visible. Spindle apparatus forms. Condensed replicated chromosome Spindle fibers

Metaphase Shortest Chromosomes line up across center of cell Spindle fibers form from centrioles to centromere

8.07 Steps of Mitosis Slide number: 15 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prometaphase Nuclear envelope fragments. Spindle fibers attach to kinetochores.

8.07 Steps of Mitosis Slide number: 16 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Metaphase Chromosomes align along equator of cell.

Anaphase Sister Chromatids split at Centromere Individual Chromosomes move toward poles

8.07 Steps of Mitosis Slide number: 17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anaphase Sister chromatids separate to opposite poles of cell.

Telophase Final Phase Spindle fibers breakdown Chromosomes uncoil into Chromatin Nuclear envelope reforms Nucleolus becomes visible

8.07 Steps of Mitosis Slide number: 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Telophase Nuclear membranes assemble around two daughter nuclei. Chromosomes decondense. Spindle disappears.

Mitosis in Whitefish and Onion PROPHASE METAPHASE ANAPHASE TELOPHASE

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

Cytokinesis Animals Cell membrane pinches inward Plants Cell plate The process by which the cytoplasm divides, forming two new cells.

8.07 Steps of Mitosis Slide number: 19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cytokinesis Division of the cytoplasm into two cells.

Result of Cell Division Two cells that are identical to each other.

Mitosis Links The Cell Cycle and Mitosis Tutorial Mitosis Labeled Diagram Whitefish Mitosis Molecular Expressions Photo Gallery: Mitosis