3b - Cell Division

Anaphase

（有丝分裂）后期 ((yǒusī fēnliè) hòuqī) The stage of mitosis (and meiosis) where sister chromatids (or homologous chromosomes in meiosis I) separate and move towards opposite poles of the cell, pulled by spindle fibres.

Cell Cycle

细胞周期 (xìbāo zhōuqī) The series of events that take place in a cell leading to its division and duplication (replication). Includes interphase, mitosis, and cytokinesis.

Centromere

着丝点 (zhuósīdiǎn) The specialized region of a chromosome where sister chromatids are joined together and where spindle fibres attach during cell division.

Chromatids

（姐妹）染色单体 ((jiěmèi) rǎnsè dāntǐ) Two identical copies of a replicated chromosome that are joined together at the centromere. They separate during mitosis (or meiosis II) to become individual chromosomes.

Chromosome

染色体 (rǎnsètǐ) A thread-like structure of nucleic acids and protein (mainly DNA) found in the nucleus of most living cells, carrying genetic information in the form of genes.

Clone

克隆 (kèlóng) An organism or cell produced asexually from one ancestor or stock, to which it is genetically identical. Results from processes like mitosis.

Cytokinesis

胞质分裂 (bāozhì fēnliè) The division of the cytoplasm of a parent cell into two daughter cells, occurring after nuclear division (mitosis or meiosis) is complete.

Diploid (2n)

二倍体 (èrbèitǐ) Having two complete sets of chromosomes, one from each parent (e.g., in most somatic cells of humans). Chromosomes exist in homologous pairs.

Gamete

配子 (pèizǐ) A mature haploid male or female germ cell (e.g., sperm or egg) which is able to unite with another of the opposite sex in sexual reproduction to form a zygote. Produced by meiosis.

Haploid (n)

单倍体 (dānbèitǐ) Having a single set of unpaired chromosomes (e.g., in gametes like sperm and egg cells). Contains half the number of chromosomes of a diploid cell.

Homologous Chromosomes

同源染色体 (tóngyuán rǎnsètǐ) A pair of chromosomes (one from each parent) that are similar in shape, size, and gene content (though they may have different alleles). They pair up during meiosis.

Interphase

（细胞分裂）间期 ((xìbāo fēnliè) jiānqī) The stage in the cell cycle before mitosis or meiosis, during which the cell grows, replicates its DNA (chromosomes duplicate), and prepares for division.

Meiosis

减数分裂 (jiǎnshù fēnliè) A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell (haploid), as in the production of gametes and plant spores. Involves two divisions.

Metaphase

（有丝分裂）中期 ((yǒusī fēnliè) zhōngqī) The stage of mitosis (and meiosis) where chromosomes (or homologous pairs in meiosis I) align along the equator (middle) of the cell, attached to spindle fibres.

Mitosis

有丝分裂 (yǒusī fēnliè) A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus (diploid); typical of ordinary tissue growth and asexual reproduction.

Prophase

（有丝分裂）前期 ((yǒusī fēnliè) qiánqī) The first stage of mitosis (and meiosis) where chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibres begin to form.

Spindle Fibres

纺锤丝 (fǎngchuísī) Microtubule structures that form during cell division and are responsible for separating chromosomes/chromatids and moving them to opposite poles of the cell.

Telophase

（有丝分裂）末期 ((yǒusī fēnliè) mòqī) The final stage of mitosis (and meiosis) where chromosomes arrive at opposite poles, decondense (uncoil), and new nuclear envelopes form around the two sets of chromosomes, resulting in two distinct nuclei.

Zygote

受精卵 (shòujīngluǎn) A diploid cell resulting from the fusion of two haploid gametes (fertilization); a fertilized ovum (egg). The first cell of a new individual.