Cell Division: Mitosis & Meiosis

Vocabulary flashcards summarizing key terms and concepts for mitosis, meiosis, chromosome structure, cell-cycle phases, and genetic variation.

Mitosis

Type of cell division in somatic cells that produces two genetically identical diploid daughter cells (2n).

Meiosis

Two-step division in germ cells that yields four genetically unique haploid gametes (n).

Somatic Cells

All body cells except eggs and sperm; divide by mitosis.

Gametes

Sex cells—ova and sperm—produced by meiosis and carrying a haploid set of chromosomes.

Diploid (2n)

Cell or organism with two copies of each chromosome—46 total in humans.

Haploid (n)

Cell with one copy of each chromosome—23 total in human gametes.

Chromosome

DNA-protein structure that carries genetic information; visible as condensed X-shapes during division.

Karyotype

Ordered visual map of an individual’s chromosome pairs arranged by size and shape.

Interphase

Non-dividing portion of the cell cycle (G1, S, G2) in which the cell grows and replicates DNA.

G1 Phase

First gap phase of interphase; cell grows and duplicates organelles.

S Phase

Synthesis phase of interphase where DNA replication occurs.

G2 Phase

Second gap phase; cell prepares enzymes and components for mitosis.

Prophase

First mitotic stage: chromatin condenses, nuclear envelope begins to break down, spindle forms.

Metaphase

Stage where chromosomes line up at the cell’s equatorial plane attached to spindle fibers.

Anaphase

Stage when sister chromatids separate and are pulled to opposite poles.

Telophase

Final nuclear stage: chromosomes de-condense, nuclear membranes re-form around two nuclei.

Cytokinesis

Physical division of the cytoplasm, producing two separate daughter cells.

Chromatin

Loosely coiled DNA-protein complex present in the nucleus during interphase.

Sister Chromatids

Identical copies of a chromosome joined at a centromere, separated during anaphase.

Homologous Chromosomes

Pair of chromosomes—one maternal, one paternal—that carry the same gene loci; separate in meiosis I.

Crossing Over (Synapsis)

Exchange of genetic material between homologous chromosomes during prophase I; generates diversity.

Mitotic Spindle

Microtubule structure that organizes and separates chromosomes during mitosis and meiosis.

Reductional Division

First meiotic division (meiosis I) that halves the chromosome number from diploid to haploid.

Genetic Diversity

Variation in genetic makeup of organisms, enhanced by crossing over and independent assortment in meiosis.

Meiosis I

First meiotic division separating homologous chromosomes, producing two haploid cells with duplicated chromatids.

Meiosis II

Second meiotic division resembling mitosis; sister chromatids separate, yielding four haploid gametes.