Meiosis Lecture Notes

These flashcards cover critical concepts of meiosis, including its process, terminology, and distinctions from mitosis.

Meiosis

The process of cell division that produces gametes, reducing the chromosome number by half.

Gametes

Reproductive cells (sperm and egg) that are haploid and contain half the number of chromosomes as the parent cell.

Haploid (n)

A cell that contains one complete set of chromosomes; in humans, this is 23 chromosomes.

Diploid (2n)

A cell that contains two complete sets of chromosomes; in humans, this is 46 chromosomes or 23 pairs.

Ploidy

The number of complete sets of chromosomes in a cell.

Crossing Over

The exchange of genetic material between non-sister chromatids during prophase I of meiosis, increasing genetic variation.

Meiosis I

The first division in meiosis where homologous chromosomes separate to reduce the chromosome number by half.

Meiosis II

The second division in meiosis where sister chromatids separate, similar to mitosis.

Genetic Variation

Differences in genetic makeup among individuals, which can be increased by processes like crossing over during meiosis.

Terminal Event

An event in cell division that signifies the end of the cell cycle for certain cell types, such as germ cells undergoing meiosis.

Cytokinesis

The final step in cell division where the cytoplasm divides, resulting in the formation of two daughter cells.

Sister Chromatids

Two identical copies of a single chromosome that are joined together by a centromere.

Prometaphase I

The stage in meiosis I where the meiotic spindle attaches to kinetochores on chromosomes.

Metaphase I

The stage in meiosis I where bivalents align at the cell's equatorial plane.

Anaphase I

The stage in meiosis I where homologous chromosomes are pulled apart to opposite poles of the cell.

Telophase I

The stage in meiosis I where the nuclear envelope reforms around separated chromosomes.

Mitosis

A type of cell division that results in two genetically identical daughter cells, occurring in somatic cells.

Recombination

The process by which genetic material is reshuffled during meiosis, leading to genetic diversity in offspring.

Interphase

The phase of the cell cycle where the cell prepares for division, including DNA synthesis.