Cell Division: Mitosis and Cytokinesis – Key Vocabulary

Vocabulary flashcards summarizing the essential terms related to animal cell division, mitosis, and cytokinesis as presented in the lecture notes.

Cell Cycle

The ordered series of events (G1, S, G2, and M phases) that a cell goes through from one division to the next.

Interphase

The non-dividing portion of the cell cycle in which the cell grows, performs normal metabolism, and duplicates its DNA and organelles.

G1 Phase

First gap of interphase; cell is metabolically active, grows, and duplicates organelles while centrosome replication begins.

S Phase

Synthesis phase of interphase during which DNA is replicated.

G2 Phase

Second gap of interphase; cell growth continues, proteins are synthesized, and centrosome replication is completed.

M Phase

Mitotic phase consisting of mitosis (nuclear division) and cytokinesis (cytoplasmic division).

Mitosis

Division of the nucleus in somatic cells, producing two genetically identical daughter nuclei; subdivided into prophase, metaphase, anaphase, and telophase.

Prophase

First stage of mitosis; chromatin condenses into visible chromosomes, the nuclear envelope and nucleolus disappear, and mitotic spindle forms from centrioles migrating to poles.

Metaphase

Second stage of mitosis; chromosomes align along the cell’s equator forming the metaphase plate, with spindle fibers attached to centromeres.

Anaphase

Third stage of mitosis; sister chromatids separate and are pulled backward toward opposite poles by spindle fibers.

Telophase

Final stage of mitosis; chromosomes arrive at poles and decondense, nuclear envelope and nucleolus reappear, signaling the end of nuclear division.

Cytokinesis

Division of the cytoplasm, occurring alongside telophase, in which a cleavage furrow partitions the cell into two daughter cells.

Chromatin

Diffuse, threadlike DNA-protein complex present during interphase that condenses into chromosomes at prophase.

Chromosome

Rod-shaped structure of condensed chromatin; in humans each somatic cell has 46 chromosomes.

Sister Chromatids

Two identical DNA strands of a duplicated chromosome joined together at their centromere until separated in anaphase.

Centromere

Constricted region joining sister chromatids and serving as attachment site for spindle fibers.

Mitotic Spindle / Spindle Fiber

Microtubule structure originating from centrioles that attaches to chromosomes and moves them during mitosis.

Centriole

Cylindrical organelle that helps organize spindle formation; duplicates during interphase and migrates to opposite poles in mitosis.

Aster

Star-shaped array of microtubules radiating around each centriole during metaphase.

Metaphase Plate

Imaginary plane at the cell’s equator where chromosomes line up during metaphase.

Cleavage Furrow

Indentation of the plasma membrane that deepens during cytokinesis to separate daughter cells.

Somatic Cell

Any body cell other than a sex cell; undergoes mitosis for growth and repair.

Blastula

Early embryonic stage with rapidly dividing cells, often used on slides to observe mitosis.

Whitefish Embryo

Model organism whose blastula cells are commonly prepared on slides to study stages of animal mitosis.