lecture 5 (4)

Cell division

The process by which cells reproduce, either through binary fission or mitosis.

Binary fission

A type of cell division in prokaryotes, where one cell divides into two identical cells.

Mitotic cell division

A type of cell division in eukaryotes, where one cell divides into two identical cells.

Meiotic cell division

A type of cell division in eukaryotes, where one cell divides into four cells with half the number of chromosomes.

Cell cycle

The life cycle of a cell, consisting of interphase and mitotic phase.

Interphase

The phase of the cell cycle where the cell grows and copies its chromosomes in preparation for cell division.

G1 phase

The first subphase of interphase, where metabolic changes prepare the cell for division.

S phase

The second subphase of interphase, where DNA synthesis replicates the genetic material.

G2 phase

The third subphase of interphase, where metabolic changes assemble the necessary materials for mitosis and cytokinesis.

Mitosis

The process of nuclear division in eukaryotic cells, consisting of prophase, metaphase, anaphase, and telophase.

Prophase

The first stage of mitosis, where chromosomes condense and the nuclear membrane disappears.

Metaphase

The second stage of mitosis, where chromosomes align at the cell equator.

Anaphase

The third stage of mitosis, where sister chromatids separate and move towards opposite poles of the cell.

Telophase

The fourth stage of mitosis, where daughter chromosomes are separated into two groups and nuclear envelopes reappear.

Cytokinesis

The process of cytoplasmic division, resulting in the formation of two daughter cells.

Cell plate

A structure formed during cytokinesis in plant cells, separating the two daughter nuclei.

Gametes

Haploid cells produced by meiosis, which fuse during fertilization to form a diploid zygote.

Meiosis

A type of cell division that reduces the number of chromosome sets from diploid to haploid.

Meiosis I

The first set of cell divisions in meiosis, consisting of prophase I, metaphase I, anaphase I, and telophase I.

Meiosis II

The second set of cell divisions in meiosis, consisting of prophase II, metaphase II, anaphase II, and telophase II.

Crossing over

The exchange of genetic material between non-sister chromatids during meiosis.

Chiasmata

The points of crossing over between homologous chromosomes during meiosis.

Anaphase-I

The first stage of meiosis where every chromosome migrates to one of the two cell poles, and centromeres do not divide.

Telophase-I

The first stage of meiosis where the nuclear envelope is reformed around each chromosome group at the two cell poles, nucleoli reappear, and two haploid daughter nuclei are formed.

Prophase II

The second stage of meiosis where the nucleus contains one chromosome set (haploid set) and chromosomes become shorter and thicker.

Metaphase II

The second stage of meiosis where the nuclear envelope and nucleoli disappear, spindle fibers appear at the two cell poles, and the chromosomes arrange on the equatorial plane of the cell.

Anaphase II

The second stage of meiosis where chromatids of each chromosome migrate to one of the two cell poles.

Telophase II

The second stage of meiosis where chromatids reach the cell poles, the nuclear envelope and nucleoli reappear at each pole.

Meiosis II

The second division of meiosis, consisting of Prophase II, Metaphase II, Anaphase II, Telophase II, and cytokinesis.

Mitosis

A type of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.