Meiosis

Asexual Reproduction

Involves only one parent and produces (nearly) identical offspring.

Pros of Asexual Reproduction

Rapid and efficient.

Sexual Reproduction

Usually involves two parents and produces unique offspring, promoting genetic diversity.

Homologous Chromosomes (homologs)

Pairs of chromosomes that are the same size and carry the same genes, consisting of one maternal and one parental chromosome.

Sex Chromosomes

Chromosomes that determine the sex of an individual; humans have one pair (X,Y).

Autosomes

All of the other chromosomes excluding sex chromosomes; humans have 22 pairs.

Diploid Cells (2n)

Cells that contain both homologs from each chromosome pair, typically somatic body cells.

Haploid Cells (n)

Cells that only contain one homolog from each pair, typically gametes (sex cells).

Fertilization

The process that begins sexual life cycles, where haploid sperm and haploid egg combine to form a diploid zygote.

Zygote

The first diploid cell of an embryo, formed by the fusion of sperm and egg.

Meiosis

A type of cell division unique to sexual reproduction that reduces the number of chromosomes in each cell.

Crossing Over

The exchange of DNA between non-sister chromatids of homologous chromosomes during Prophase I.

Metaphase I

Stage of meiosis where homologous pairs align in the middle of the cell.

Anaphase I

Stage of meiosis where homologous pairs are separated.

Interkenesis

A suspended rest period between meiosis I and II, where no additional DNA replication occurs.

Telophase II and Cytokinesis

Final stage of meiosis where cytoplasm divides to produce four genetically unique haploid daughter cells.

G1 of Interphase (prereplication)

The stage with 4 unreplicated chromosomes, resulting in 2 copies of each gene.

Genetic Diversity

The variability in genetic makeup that arises from processes such as crossing over, independent assortment, and random fertilization.

Independent Assortment

The random lining up and separating of chromosomes during meiosis, leading to various combinations in sex cells.

Random Fertilization

The concept that any sperm can fertilize any egg, leading to countless possible combinations for the zygote.