Cell Division: Mitosis and Meiosis

Flashcards covering definitions and concepts related to the cell cycle, interphase, stages of mitosis, and stages of meiosis.

Cell Cycle

The sequence of stages through which a cell passes from one cell division to the next.

Mitosis

A type of cell division in which the daughter cell receives the same number of chromosomes as the parent cell.

Cytokinesis

The division of the cytoplasm equally between the daughter cells.

Interphase

The time interval between nuclear divisions when a cell increases in mass, doubles its cytoplasmic components, and duplicates its chromosomes.

Gap 1 (G1)

A stage of interphase characterized by a period of rapid cell growth where chromosomes remain unduplicated.

Synthesis (S)

The stage of interphase where cells prepare for division by duplicating their chromosomes.

Gap 2 (G2)

The stage of interphase where the cell grows and completes preparations for nuclear division.

Chromatin

The combination of DNA and proteins that makes up chromosomes.

Centromere

The structure that holds sister chromatids together.

Sister Chromatid

A chromosome and its duplicate attached to one another by a centromere until separated by mitosis.

Prophase

The first phase of mitosis where chromosomes shorten, thicken, and become visible, and centrioles move to opposite poles.

Centriole

A small body found in the cytoplasm of animal cells that provides attachment for spindle fibres during cell division.

Spindle Fibre

A protein structure that guides chromosomes during cell division.

Metaphase

The second phase of mitosis in which chromosomes composed of sister chromatids move towards the equatorial plate.

Equatorial Plate

The centre area of the cell where chromosomes line up during metaphase.

Anaphase

The third phase of mitosis where centromeres divide and sister chromatids move to opposite poles of the cell.

Telophase

The final phase of mitosis where chromosomes reach opposite poles, lengthen, spindle fibres dissolve, and a nuclear membrane forms around each mass of chromatids.

Meiosis

The type of cell division involved in the formation of sex cells (gametes) where the chromosome number of the daughter cell is half of the parent cell.

Haploid (n)

The number of chromosomes in a gamete ($n = 23$ in humans).

Diploid (2n)

The number of chromosomes in body cells having twice the haploid number ($2n = 46$ in humans).

Homologous Chromosome

Paired chromosomes that are similar in shape, size, gene arrangement, and gene formation.

Tetrad

A structure formed when homologous chromosomes come together, composed of a pair of sister chromatids.

Synapsis

The pairing of homologous chromosomes during meiosis.

Crossing Over

The exchange of genetic material between two homologous chromosomes.

Anaphase I

The stage of Meiosis I where homologous chromosomes move towards opposite poles (segregation), resulting in reduction division.

Prophase II

The phase that signals the beginning of the second meiotic division as the nuclear membrane dissolves and spindle fibres begin to form.

Metaphase II

The stage of Meiosis II signaled by the arrangement of chromosomes along the equatorial plate with chromatids pinned together at the centromere.

Anaphase II

The stage of Meiosis II where attachments between chromatids break and they move to opposite poles.

Telophase II

The stage where the second nuclear division and second division of the cytoplasm are completed, producing four haploid daughter cells.