M Phase Events in the Eukaryotic Cell Cycle

Eu cell cycle

Eukaryotic cell cycle divides every 24 hours.

Interphase

Cell cycle phase including G1, S, G2, M.

G1 phase

First gap phase, lasts 11 hours in humans.

S phase

Synthesis phase for DNA replication, lasts 8 hours.

G2 phase

Preparation phase for mitosis, lasts 4 hours.

M phase

Mitosis and cytokinesis, lasts 1 hour.

Mitosis

Process of dividing chromosomes during M phase.

Cytokinesis

Separation of cytoplasm after mitosis.

Mitotic spindle

Structure formed for chromosome movement.

Prophase

Nuclear envelope breaks down; DNA condenses.

Prometaphase

Chromosomes align at the metaphase plate.

Metaphase

Sister chromatids are separated at the equator.

Anaphase

Sister chromatids move to opposite cell poles.

Telophase

DNA relaxes; nuclear envelope reforms.

Early prophase

Initial stage of prophase with DNA condensing.

Late prophase

Nuclear envelope disassembled; spindle poles repositioned.

Nuclear lamina

Intermediate filament supporting nuclear structure.

Kinetochores

Protein complexes at centromeres of chromatids.

Microtubule types

Includes kinetochore, polar, and astral microtubules.

Anaphase A

Movement of sister chromatids via kinetochore microtubules.

Anaphase B

Spindles push apart, further separating chromatids.

Contractile ring

Actin and myosin filaments form cleavage furrow.