Cell Division: Mitosis & Meiosis

Vocabulary flashcards summarizing key terms related to eukaryotic cell division, mitosis, meiosis and associated genetic concepts.

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Eukaryotic Cell Cycle

Sequence of growth and division in a eukaryotic cell, consisting of Interphase and the Mitotic (M) phase.

Interphase

Non-dividing portion of the cell cycle with G1, S and G2 stages; DNA is uncondensed.

G1 Phase

First sub-stage of Interphase where the cell grows and organelles are replicated.

S Phase

Interphase stage in which DNA is replicated and associated proteins are synthesized.

G2 Phase

Final Interphase stage devoted to synthesis of proteins needed for mitosis.

Mitotic Phase (M Phase)

Portion of the cell cycle that includes mitosis (nuclear division) and cytokinesis; DNA is condensed.

Mitosis

Division of somatic cells producing two genetically identical diploid daughter cells.

Prophase

First stage of mitosis; chromosomes condense, spindle fibers form and capture chromosomes.

Metaphase

Mitosis stage where chromosomes align at the cell equator with kinetochores facing opposite poles.

Anaphase

Mitosis stage in which sister chromatids separate and move toward opposite poles.

Telophase

Final mitotic stage; spindle disintegrates, nuclear envelopes reform and chromosomes decondense.

Cytokinesis

Division of cytoplasm following mitosis; involves a cleavage furrow in animals or a cell plate in plants.

Chromatin

Extended, uncondensed form of DNA present when the cell is not dividing; permits replication and transcription.

Chromosome

Condensed DNA molecule visible during cell division; each consists of one DNA molecule.

Sister Chromatids

Identical copies of a chromosome produced during S phase and joined at a centromere.

Centromere

Region connecting sister chromatids and serving as attachment site for spindle fibers via kinetochores.

Spindle Fibers

Specialized microtubules that radiate from centrioles to move chromosomes during mitosis and meiosis.

Centrioles

Paired organelles that organize spindle fiber formation in animal cells.

Kinetochore

Protein structure on chromatids where spindle fibers attach during cell division.

Somatic Cells

Non-reproductive body cells that divide by mitosis and are typically diploid.

Gametes

Sex cells (sperm or ova) produced by meiosis; they are haploid.

Diploid (2n)

Cell condition with two sets of chromosomes, one maternal and one paternal.

Haploid (n)

Cell condition with one set of chromosomes; characteristic of gametes.

Homologous Chromosomes

Chromosome pair in diploid cells that have the same gene sequence but may carry different alleles.

Autosomes

Non-sex chromosomes that occur as homologous pairs.

Karyotype

Photographic inventory of an individual's chromosomes arranged in homologous pairs.

Asexual Reproduction

Generation of genetically identical offspring (clones) from a single parent, usually by mitotic cell division.

Sexual Reproduction

Fusion of two haploid gametes to form a diploid zygote, increasing genetic variation.

Zygote

Diploid cell produced by fertilization, containing 46 chromosomes in humans.

Meiosis

Two-stage nuclear division in germ cells yielding four unique haploid gametes.

Crossing Over

Exchange of DNA between homologous chromosomes during Prophase I of meiosis, creating new allele combinations.

Independent Assortment

Random orientation of homologous chromosome pairs during Metaphase I of meiosis, shuffling genetic combinations.

Spermatogenesis

Meiotic process in males that continuously produces sperm after puberty, about 1,500 per second.

Oogenesis

Meiotic development of ova in females, completed before or shortly after birth and yielding one egg plus polar bodies.

Polar Bodies

Small haploid cells with minimal cytoplasm produced during oogenesis that eventually degenerate.