10.3 and 10.4

Prokaryotic cell division time under optimal conditions

Some prokaryotic cells can divide every 20 minutes.

Eukaryotic cell cycle length

The length of the eukaryotic cell cycle is constant for any given cell type under optimal conditions.

Cell-cycle checkpoints

Control mechanisms that temporarily block key events to ensure all previous events are completed before the next stage initiates.

Cyclin-dependent kinases (Cdks)

Protein kinases involved in regulating the cell cycle; they are active only when bound to cyclins.

Asexual reproduction

A reproductive process where a single parent splits or fragments to produce genetically identical individuals.

Gametes

Sex cells involved in sexual reproduction that unite to form a zygote.

Homologous chromosomes

Chromosome pairs that are similar in size, shape, and genetic traits, although they may carry different alleles.

Diploid chromosome number

The total number of chromosomes in a somatic cell, containing two sets of each chromosome.

Meiosis

A cell division process that reduces the chromosome number by half, producing haploid cells.

Checkpoint gene defect consequences

A defective checkpoint gene can lead to cancer or other serious diseases.

Crossing-over during meiosis

The exchange of genetic material between homologous chromosomes during prophase I.

Independent assortment

During meiosis, the maternal and paternal chromosomes of homologous pairs are distributed randomly to gametes.

Zygote

The single cell formed by the union of two gametes in sexual reproduction.

Polyploidy

A condition in which a cell has three or more sets of chromosomes, common among plants.

Interkinesis

A brief interphase-like stage between meiosis I and meiosis II, with no DNA replication.

Mitosis vs. Meiosis

Mitosis results in two genetically identical diploid cells, while meiosis results in four genetically different haploid cells.